Improved method to save energy for devices with rotating or reciprocating masses.

(54) Title: IMPROVED METHOD FOR SAVING ENERGY IN DEVICES WITH ROTATING OR OSCILLATING MASSES.

(54) Title: IMPROVED METHOD TO SAVE ENERGY FOR DEVICES WITH ROTATING OR RECIPROCATING MASSES.

(57) Summary

A system and method is described for disconnecting the voltage to an electric rocker motor for predetermined periods of time to save energy. In the method, the response of the motor to closed-loop control can be evaluated over several pump strokes. Pumping stroke periods can be identified when it is feasible to turn off the motor. The consistency of the measurements can be evaluated over several runs. The motor can be switched off for predetermined periods in subsequent pump strokes, when each pump stroke displays behavior similar enough to that anticipated during the closed-loop control process. The system can return to the closed loop control process after a predetermined period of time to adjust any changes in the system.

(57) Abstract

A system and method are disclosed for turning off the voltage to a pump jack electric motor during predetermined periods oí time to save energy. In the method, the motor's response to closed-loop control may be evaluated over several pump strokes. The periods of the pump stroke when it is feasible to turn off the motor may be identified. The consistency of the measurements over several strokes may be evaluated. The motor may be turned off during predetermined periods on subsequent pump strokes when each pump stroke shows sufficiently similar behavior to that predicted during the closedloop control process. The system may return to the closed-loop control process after a predetermined period of time to adjust to any changes in the system.

Institute

Mexican Property

Industrial

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_I KNOW_

Yes l; VUA HAWM! '

PATENT TITLE NO. 338092 't, Ci.

Owner (s): THE POWERWISE GROUP, INC. _: .

Address: 4855 Technology Way, Suite 550, Boca Raton, Florida, 33431, USA

Name: IMPROVED METHOD FOR SAVING ENERGY IN DEVICES WITH ROTATING OR OSCILLATING MASSES.

Classification: lnt.CI.8: F04B49 / 06; H02P27 / 02

Inventor (s); VASAN VENKATARAMAN

REQUEST

Number!

MX / a / 2015/001044

International filing date:

January 2011

Divisional Patent Number: 327259

Pafs:

US

US

PRIORITY

Date:

September 2010 i,. December 14, 20t0

Number:

12/873,510

12/967,128

Validity: Twenty years

Expiration Date: January 6, 2031

The reference patent is granted based on the

Pursuant to Article 23 of the - counted from the date of this right. &lt;

; Law of the intation of the or Sai

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it presents a patent it has an i and «tie subject to the payment of the ice based on the

V, 6th fraction III, and 59 of the Industrial Property Law.

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.veirr.e years imp to keep 'rogables, lenses the

III and 7 “bis 2 of the Federation (DOF) 06/27/1991, amended on 08/02/1994, 10/25/1996, 12/26/1997, ey of '05 / 1999, action V

Who subscribes to this title Industrial Property (Official Diarto S ^ ÍW / »» te-16 / a6 / fíOS5, 01/25/2006. Subsection a), 4th and 12th sections I and III of the Regulations of the Mexican Institute of Industrial Property (DOF 14/12/1999, reformed the

07/01/2002. 07/15/2004. 07/28/2004 and 09/07/2007): articles 1. 3rd. 4th. 5th fraction V Item a). 16 sections I and III and 30 of the Organic Statute of the Mexican Institute of Industrial Property (DOF 12/27/1999, amended on 10/10/2002, 07/29/2004, 08/04/2004 and 09/13/2007); 1, 3 and 5 Clause a) of the Agreement that delegates powers to the Deputy Directors General, Coordinator, Divisional Directors, Holders of the Regional Offices, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the Mexican Institute of Industrial Property. (DOF 12/15/1999, amended on 02/04/2000, 07/29/2004, 08/04/2004 and 09/13/2007).

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Arenal No. 550. Floor 1, i Pueblo Santa María Tepepan.

Xochimic. CP 16020,

Mexico City j; 53 34 07 0ü wwyv.irnpi. .eob.mx

Issue Date: April 1, 2016

DIVISIONAL DIRECTOR OF PATENTS

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NAHANNY CANAL REYES

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MX / 2016/25837

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338o? L

IMPROVED METHOD FOR SAVING ENERGY IN

DEVICES WITH ROTATING MASSES OR OOCILAWTE · »

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V J. x

Cross Reference with SDEL Related Requests?. 'W7iÍDAD - ““ -'-^--““ —— - ————————- | i! R: U3TiU, \ L

This application is a continuation in part of the

North American Application also pending No. 12 / 873,510 filed on September 1, 2010, which claims the benefit of North American Provisional Application No.

61 / 240,399 filed on September 8, 2009, the applications of which are incorporated in their entirety for all purposes for reference.

DEMONSTRATION WITH RESPECT TO RESEARCH OR DEVELOPMENT SPONSORED BY THE FEDERATION

N / A

REFERENCE TO THE APPENDIX MICROFICHE

N / A

Field of the Invention

The present invention relates to electric motors used to operate rocker arms and other devices with rotating or oscillating masses.

Background of the Invention

A rocker arm is a downhole transmission device for a downhole installed with an oscillating piston pump in an oil well. Rocker arm mechanically lifts liquid out of well where there is not enough^ri. JT 1 '

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INDUSTRIAL bottom hole pressure for liquid to flow to the surface by itself. The rocker arm is often powered by an electric motor that receives electrical power from an electric utility grid. A rocker arm converts the motor's rotary mechanism into a vertical oscillating motion to operate the downhole pump. There are many different rocker arm designs including, but not limited to, conventional ones, the Lufkin Mark II, beam balancing, air balancing, tilt hole, and conventional portable. Rocker arms are available from many different suppliers, including Lufkin Industries, Inc. of Lufkin, Texas and Cook Pump Company of Coffeyvllle, Kansas.

The electric rocker motor normally rotates a set of pulleys for a gear system or transmission, which in turn operates a pair of cranks or crank arms. For a typical conventional rocker design, the cranks raise and lower one end of a lever or beam, known as a "rocker," which is pivoted on a sampson pole or A-frame. A curved metal box known as a "horse's head" is at the other end of the rocker, from where the crank arms are connected to the beam. An oscillating counterweight or mass normally attaches to one end of the cranks. A connecting rod arm normally extends between the counterweight and the end of the

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rocking arm opposite the horse's head. A cable that. The horse's head with a vertical polished rod connects to the vertical chain of tubulars or plunger rods running to the downhole pump.

The counterweight helps the engine lift the plunger rod chain or the tubular chain. When the motor raises the counterweight, the horse's head moves downward, pushing down on the piston rods or tubular chain. After the counterweight reaches the top of its rotation, it swings around and helps the motor rotate the rocker arm in the opposite direction using the mass and counterweight momentum (kinetic energy). When the counterweight is freely falling down from its highest position, the horse's head moves upward, lifting the chain of plunger rods. US Patent No.

4,051,736 proposes an improved rocker arm to rock an oil well pump.

Although different downhole pump designs exist, downhole pumps have traditionally comprised a piston or piston that oscillates within a pump barrel located at or near the end of the production line. Two independent valves normally achieve the pumping action. A permanent check valve can be secured in the pump barrel below the piston, and the piston can include a stroke check valve. The

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The piston's up stroke opens the permanent valve, and draws fluid into the pump barrel as the stroke valve remains closed. The downward stroke of the piston opens the flow valve and pushes fluid up from the pump barrel as the permanent barrel remains closed. North American Patents Nos. 3,578,886; 4,173,451; and 6,904,973 propose downhole pumps.

It is well known that electric motors can enter a power generation mode of operation. For an electric motor used with a rocker arm, a power generation mode can occur at any time during counterweight rotation, depending on the condition of the balance between the counterweight and the tubular or rod chain. The balance condition can fluctuate from stroke to stroke, depending on the amount and composition of the fluid being lifted through the rod chain on each stroke. The polished rod and the attached plunger rod or tubular chain can be moved up or down in power generation mode.

A well owner must pay his electric energy bill based on the amount of energy the rocker motor consumes. The amount of energy consumed is measured through an energy meter. In the past, the amount of energy consumed was measured through a

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INDUSTRIAL analog electricity. Many “ΜΜπ · * · * ΜΜ * · η ··« ··· ηΜ * Μβ * ζ&gt; &amp;: ό digital electricity meters are now used. The energy meter, either analog or digital in design, can be configured, at the discretion of the utility company, to allow or avoid customer credits for the generated energy that is supplied back to the energy grid. A rocker system is an inefficient generator, since the amount of energy consumed required to produce any generation significantly exceeds the energy generated. Therefore, regardless of whether the utility company credits the power generated, it is always beneficial for the customer to avoid power generation.

During generation periods, a motor will attempt to achieve a voltage that exceeds the utility line voltage, thereby causing current to flow in the opposite direction. The load provided by the utility grille serves as a brake, limiting engine acceleration that might otherwise occur. This braking action of the motor prevents the weight of the rocker from falling due to the development of additional kinetic energy that could have helped the pumping action. This converted kinetic energy may have served as an alternative to electrical energy from the utility grid.

In the past, engineers have tried unsuccessfully to save significant amounts of energy by shutting down the electric rocker motor for part of the rocker cycle,

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JLVJ

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INDUSTRIAL which may have a generation period included. This has been attempted with various mechanical switches and relays. However, the parameters of downhole pumps and wells may vary over time, so these mechanical solutions have not been put into operation.

The fluid flow in the reservoir can vary as the reservoir is filled, and then the "pump is turned off." In some cases, the volume of fluid pumped can change from one stroke to the next. Changing the volumes, densities, viscosities, weights, and other properties of the materials and / or fluids pumped, such as gas, oil, water, and paste, can greatly alter the combined weight of the rod chain and the fluid column. , thus affecting the balance of the system and engine demand. In some tanks, tubular chains can be thousands of feet in length. The influx of different fluids in the tank over time will significantly impact the operation of the engine.

With the introduction of the microprocessor, it becomes possible to disconnect the electric motor, observing the current and voltage. However, the problem was knowing when to reconnect the electric motor. Various time delays set by open circuit were attempted in the past, although these attempts failed as the parameters of the bottom pumps

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well and wells vary over time. Failure to restart the engine at the proper time can lead to decreased energy savings and / or other undesirable effects.

When an AC induction motor is lightly charged, lowering the supplied voltage will cause the motor to operate more efficiently, thus saving energy. This is particularly evident in the case of single phase motors, and to a lesser degree, three phase motors. A large three-phase motor is normally naturally efficient at any load greater than about one third of the rated motor load.

The variation in the phase angle between the voltage applied to a motor and the current it draws contains an inverse relationship to the extraction of energy by the motor. A higher phase angle indicates a lightly loaded motor, and a low phase angle indicates a heavy loaded motor.

Most rocker arms use three-phase motors, as small as 5 horsepower (HP), although typically greater than 20 HP. These motors can be subjected to a periodically varying load, with periods normally fluctuating from 5 seconds to 12 seconds. During a typical pumping stroke, the motor experiences a heavy load once or twice, and a light load once or twice. Depending on the geometry and balance of the rocker,

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falling weights (either the counterweights or the rod chain) can force the motor beyond its synchronous speed, thereby causing it to behave like a generator. During that time, the phase angle exceeds 90 degrees.

US Patent No. 6,489,742, proposes a motor controller that includes power transport to an Induction motor with a digital signal processor that calculates and optimizes the current supply of an existing motor load, from a power supply and voltage main via a control element. North American Publication No. 2010/01 17588, proposes a motor controller and a method to save energy in an AC induction motor in each load, where the motor is calibrated at two or more load points to establish a control line, which is subsequently program in non-volatile memory of the motor controller.

North American Publication No. 2009/0046490 proposes an IGBT / FET-based energy saving device, system, and method, where a predetermined amount of voltage is saved below a nominal line voltage and / or below a voltage of a nominal apparatus. North American Publication No. US 2009/0051344 proposes a TRIAC / SCR-based energy saving device, system, and method, where a predetermined amount of voltage is saved

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voltage below a nominal line voltage and / or below a nominal device voltage. North American Publication No. 2009/0200981, proposes a system and method to provide a constant load in AC power applications, where at least one ignition point of at least one half modulation sine wave is determined, at least one disconnection point of at least half a cycle of the modulating sine wave, and at least one slice located between at least one connection point and at least one disconnection point is removed. North American Publication No. 2010/0033155 proposes a power supply for IGBT / FET transmitters that provide isolated power, separate from each IGBT / FET transmitter.

Proportional Integral Derivative Control (PID) is a widely used technique applied to control algorithms and feedback mechanisms. A PID controller, which is generally referenced, calculates a value based on an “error. Typically, "error" is calculated as the difference between the measured process variable and a desired setpoint or target value. The PID controller tries to minimize the error by adjusting the process control variables. In essence, the PID controller is a digital filter that has proportional, integral, and derivative parameters. The proportional value determines the reaction of the current error, the integral value determines the reaction based on the sum of

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Recent errors, and the derivative value determines the based on the range in which the error has been changed.

North American Patents Nos. 3,578,886; 4,051,736; 4, 173,451; 6,489,742; and 6,904,973; and the

North American Publications Nos. US 2009/0046490; 2009/0051344; 2009/0200981; 2010/0033155; and 2010/0117588 described above, are incorporated in their entirety in the present invention by reference for all purposes.

There is a need to efficiently manage the power usage of an electric rocker motor, particularly during the power generation mode. It may be desirable to substantially eliminate, if possible, the power generation mode.

Brief Description of the Invention

An electric rocker motor can be supplied with unmodified total line voltage, and a motor controller can monitor the phase angle. When the phase angle is observed to exceed a predetermined threshold value phase angle, the motor can be considered as extremely lightly loaded, and at the point of entry into the power generation mode. This is considered a potential disconnect time. Upon crossing the threshold value phase angle, a closed loop motor controller system can be activated to control the voltage supply to the rocker electric motor. By controlling supply

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of voltage to the motor, the observed phase angle can be kept at a value no greater than a target phase angle.

By allowing some current flow, primarily of a reactive nature, the closed loop controller system remains enabled, and an observable feedback parameter can be used as an indication of the motor load condition, at which it can React the motor controller, allowing power to be supplied when an increase in load requires an increase in supply voltage. The indication of the increased engine load condition can be detected from a decrease below a predetermined threshold value in the firing angle used to control the switching devices of the engine controller. This is considered a potential connection time. The above process can be repeated over several pumping cycles to ensure consistency. If a closed correlation is observed, then the system can enter an open-connect-disconnect state.

In the on-off state, the phase angle can be monitored during each pump stroke to ensure that it crosses the cutoff threshold value set at the anticipated time during closed loop control. If the phase angle does not meet the expected timing, the system can return to control

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TUTO MEXICANO f * · η —---.- ¿· | RO? RO? UCAD I. '- ζ ¡NDUyfPJAL ^' · closed circuit to repeat the measurements. If the expected synchronization is met, the voltage supplied to the motoK can be completely disconnected in the disconnection time established from the closed circuit control.

Immediately after reconnecting at the set connection time, the observed phase angle can be evaluated and compared to a previously determined ideal phase angle value. If the observed phase angle exceeds the ideal value, it is an indication that the voltage may remain off longer. If the observed phase angle is less than the ideal value, then the voltage must have been disconnected sooner.

Adjustments can be made to the disconnection duration, to optimize behavior on subsequent races. The voltage for the motor can remain full until the next anticipated shutdown time.

The system may be periodically forced back into closed loop control to reevaluate timing. If there is little or no observed change in timing, few or no adjustments can be made, and the system may return to the open-circuit disconnect connection condition. If a substantial change in closed loop control timing is found, then the system can remain in closed loop control until a timing pattern is observed

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Consistent or repetitive, at which point the system can return to the open-circuit disconnect-connect state with new disconnect and connect moments.

The system and method have the advantage of a highly periodic variation in the motor load in a rocker application. The system and method accurately anticipate times during a pump stroke, when power to the motor can be completely disconnected, as well as the appropriate time at which power must be reapplied. Completely disconnecting power from the motor results in superior energy savings.

The system and method provide a method by which the periodic variation in load on a rocker motor is monitored and characterized, based on the observed phase angle between the applied voltage and the consumed current. Once the load is characterized, a determination is made as to whether there is an opportunity to save energy by disconnecting the motor during parts of each stroke. The system and method anticipate when this opportunity should occur on subsequent pump strokes, and define the criteria that will be met on subsequent pump strokes, as conditions for returning the motor to the off state and returning it to the on state. An algorithm can be implemented that adjusts adaptively to gradual changes in the behavior of the

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rocker, and protections can be implemented to recognize and react to sudden, high-level changes in this behavior.

Brief Description of the Figures

An additional and better understanding of the present invention may be obtained from the following detailed descriptions of the various embodiments described in the drawings in which like parts are provided with like reference numerals, and wherein:

Figure 1 is a block diagram of a digital signal processor (DSP) with hardware inputs and outputs.

Figure 2 is a block diagram of a DSP-based motor controller.

Fig. 3 is a diagram showing a phase rotation detection method.

Figure 4 is a flow chart showing a phase rotation detection method.

Figure 5 is a graph showing the outputs of the energy control device for a positive phase rotation.

Figure 6 is a graph showing the outputs of the energy control device for negative phase rotation.

Figure 7 is a block diagram of a comparator for vtana.

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Figure 8 is a schematic of a window comparator.

Figure 9 is a graph of a current zero-crossing waveform and signals.

Figure 10 is a schematic of a virtual neutral circuit. Figure 11 is a graph showing the outputs of the power control device for single phase applications.

Figure 12 is a three-dimensional graph showing a three-dimensional control line.

Figure 13 is a three-dimensional graph showing a control line projected on a plane.

Figure 14 is a graph showing a two-dimensional plotted control line.

Figure 15 is a graph showing a sweep ignition task / angle cycle in a semi-automatic calibration.

Figure 16 is a graph showing a directed sweep of a task cycle / firing angle.

Figure 17 is a graph showing plotted semi-automatic calibration data.

Figure 18 is a graph showing plotted semi-automatic calibration data.

Figure 19 is a graph showing plotted semi-automatic calibration data.

Figure 20 is a flow graph of a calibration

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<td>The figure</td><td> 21,</td><td>is</td><td>a</td><td>graph</td><td>of</td><td>flow</td><td>of a</td><td>calibration</td>

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RMS motor voltage.

Figure 25 is a graph showing an RMS motor voltage clamp.

Figure 26 is a flow chart of a loss mitigation technique.

Figure 27 is a graph showing a loss mitigation technique.

Figure 28 is an elevation view of an embodiment of a rocker arm placed with a tubular chain in a well.

Figure 29 is a plot of an observed phase angle versus time of a rocker motor in an open circuit mode.

Figure 30 is the diagram of the system block connected to the motor.

Figure 31 is a plot of the observed phase angle versus time of a rocker motor in a closed-loop control mode, with a reduction in motor voltage l xvi. go j

MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

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to achieve a target phase angle within a complete pump cycle.

Figure 32 is a simpl phase phase waveform trace of the voltage entering the line.

Figure 32A is a heavy phase cut phase single phase waveform trace of the voltage supplied to the motor, after application of pulse width modulation (PWM) techniques.

Figure 32B is a lightly cut single phase waveform trace of the voltage supplied to the motor after application of PWM techniques.

Figure 32C is a single phase waveform trace cut variably from the voltage supplied to the motor after the application of PWM techniques.

Figure 32D is the line in Figure 31 illustrating the periods when heavy cutting, light cutting and uncut can occur.

Fig. 33 is a block diagram of a motor controller placed between an existing control panel and an electric rocker motor.

FIG. 34A is a plot of observed phase angle versus time of an example rocker motor in an open circuit mode over several pump cycles, showing exemplary variations in phase angle.

Figure 34B is an observed phase angle trace

<img file="MX338092B_D0025.tif" />

versus time for the rocker motor of Figure 34A, but in a closed-loop control mode for several pump cycles with reductions in motor voltage to achieve a target phase angle.

Figure 34C is a plot of the observed phase angle versus time of the rocker motor of Figure 34B in an open-circuit mode with the motor switched off for predetermined periods.

Figure 35 is a flow chart of a synthesis of a method of disconnecting an electric rocker motor for predetermined periods.

Detailed description of the invention

Referring to Figure 1, a block diagram of a digital signal processor (DSP) and hardware inputs and outputs are shown. DSP 1 can observe the operating characteristics of a motor, and make corrections to the least squares voltage (RMS) for the motor that is running and is under closed-loop control. Hardware inputs 2 capture the phase zero crossing inputs 36, phase line voltage 37, phase motor voltage 38, and current 9 and pass through DSP 1 for processing and later in control devices. power through the output of the power control device 14.

Referring now to Figure 2, a

<img file="MX338092B_D0026.tif" />

block diagram of a DSP-based motor controller system and method 4. First, motor controller 4 reads the voltages 37 of each phase A, B, and C and current 9, to capture the zero crossing inputs 36 At this point the voltage 13 and current 9 can be converted from analog to digital using converters 62. Thereafter, the motor phase angle computations 63 of each phase are calculated to produce an observed phase angle 5. Subsequently, a target phase angle 10 which has been derived from a previously programmed control line 6, is compared with the observed phase angle 5. The difference between the target phase angle 10 and the observed phase angle 5 produces a resulting phase error signal (11, 28) that is processed through a PID controller 12 which has proportional, integral and differential components. The output of the PID controller 12 is the new voltage control (13, 29) for motor 3, which can be obtained through the use of 33 control devices, such as TRIACs, SCRs, IGBTs or MOSFETS, to produce outputs of the RMS 13 motor voltage power control device 14 supplied with the line voltages 50 during each phase, for maximum energy savings.

In this closed loop system, the voltage 13 of each phase of motor 3 and the current are continuously monitored. 4 motor controller will drive phase angle

<img file="MX338092B_D0027.tif" />

observed 5 to the point on the calibrated control line 6 that corresponds to the load that is on the motor. At this point, maximum energy savings will materialize because control line 6 is based on known calibration data from motor 3. Motor controller 4 can control motor 3 just as if a technician manually adjusted the voltage 13. The difference is that DSP 1 can dynamically respond to load changes in real time, and make these adjustments on a cycle-by-cycle basis.

Referring now to Figure 3, in a three phase system, the motor controller 4 is used to automatically determine phase rotation. Zero crossing detectors at line voltages provide an accurate measure of the angle between phase A line zero voltage crossovers 15 and phase B line zero voltage crossovers

16. For a positive phase rotation 18, the angle is nominally 120 °, and for negative phase rotation 19, the angle is nominally 60 °.

Referring to Figure 4, a flow graph for phase rotation detection is shown. After a reset-connect (POR) 20, it is easy for the motor controller 4 to determine a positive phase rotation 18 and negative phase rotation 19. First, the time from the zero voltage crossing of the line is measured. phase A to the zero voltage crossings of the phase B line 39. It is subsequently determined whether the

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INSTITUTO MEXICANO Dt THE INDUSTRIAL PROPERTY time is greater or less than 90 degrees 40. If it is greater degrees, then it is an ACB 42 rotation. If the time is less than 90 degrees, then it is an ABC 41 rotation. You can control three-phase or single-phase motors with the same basic hardware and software architecture. For the three phase case, depending on the phase rotation, the motor controller 4 can drive the outputs of the power control device 14.

Referring now to FIG. 5, which shows the outputs of the power control device for positive drive rotation, the motor controller drives the outputs of the phase A power control device 14 and the outputs of the power control device. Phase B energy 14 together during the connection time of the zero voltage crossings of phase A line 15 as indicated by oval 22a.

Similarly, the motor controller drives the energy control devices, which drive the outputs of the phase B 16 and phase C 14 energy control apparatus together for the phase B connection time as indicated by the oval 22b. Finally, the motor controller 4 drives the output of the phase C 17 and phase A 14 energy control device together during the connection time of the output of the phase C 14 energy control device, as indicated by the oval 22c. It should be noted that the example shown in Figures 5 and 6 illustrates the cycle of

<img file="MX338092B_D0029.tif" />

task / angle d ignition 23 of 90 °.

Referring now to Figure 6, which shows the TRIAC conduction outputs for negative phase rotation, the motor controller 4 drives the outputs of the A-phase energy control device 14 and the outputs of the A-phase energy control device. phase C 14 together during the connection time of the zero voltage crossings of the phase A line 15, as indicated by the oval 22c. Similarly, the motor controller 4 drives the output of the phase B 16 and phase A 14 power control device together, during the connection time of the phase B line zero voltage crossovers, as indicates through oval 22a. Finally, the motor controller drives together the outputs of the phase C 14 power control device and the outputs of the phase B 14 power control device during the connection time of the zero voltage crossovers of the phase C line 17, as indicated by oval 22b.

Referring now to Figure 7, a block diagram of a window comparator is shown. The DSP-based motor controller uses the window comparator 88 to detect zero crossings of both the positive and negative halves of a current waveform. When the RMS motor voltage is reduced through the motor controller, it is difficult to detect zero crossings of the current waveform because the current is zero

<img file="MX338092B_D0030.tif" />

INDUSTRIAL during a significant part of both halves of the cycles.

First, motor current 89 is provided, a positive voltage 90 is provided as a reference for a positive half cycle, and a negative voltage 91 is provided as a reference. Subsequently, the current, positive voltage, and negative voltage are presented to the two comparators 92, and are subsequently passed through an operation output (OR) 93 to create a composite zero-crossing digital signal 94.

As further illustrated in Figure 8, a schematic of a window comparator 88 is shown. The motor current 89 is provided, a positive voltage 90 is provided as a half-cycle positive reference, and it provides a negative voltage 91 as a reference. Subsequently, the current, represented as a positive voltage and a negative voltage, is processed through two comparators 92 and subsequently passed to an OR output 93 to create a composite zero-crossing digital signal 94.

In addition, Figure 9 shows graphs of a current waveform 95, half of a positive voltage cycle 96, half of a negative voltage cycle 97 and an OR function 98.

Referring now to Figure 10, a schematic of a virtual neutral circuit is shown. A virtual neutral circuit can be used as a reference in situations where

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where three phase power is available only in delta mode, and there is no neutral to be used as a reference. The virtual neutral circuit comprises three single ended differential amplifiers 77. Because the phase is high for phase voltages, input resistors 78 are used to form a suitable attenuator 79 along with feedback resistors 80 and ground reference resistors 81. Because there is a danger of phase loss, protection diodes 82 are used to protect single-ended differential amplifiers 77. Single-ended differential amplifiers 77 are coupled to a summation amplifier 83 via DC blocking capacitors 84 and summation resistors 85 along with feedback resistor 80. The output of the summing amplifier 83 is reinforced by the amplifier 27, to thereby provide a low impedance output that is at neutral potential. The additional resistors divide a supply rail to thereby allow the summation amplifier 83 to handle alternating positive and negative signals. An alternate connection is available in the case where a neutral 86 is available along with a jump block for the alternate neutral connection 87.

Referring now to Figure 11 which shows an output from the energy control device 14 of a single phase amplification, output 14 is connected for

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INDUSTRIAL ----— phase A every half cycle based on the output of the power control device 14, derived from the zero voltage crossover input 15. The output of the power control device 14 for zero voltage crossings Phase B line and phase C line zero voltage crossings are disabled on DSP 1 and hardware may not exist. The outputs of the power control device 14 are not paired as they were in the case of three phases.

Referring now to Figure 12, a three-dimensional control line for the motor operating space of a motor linked by an observed phase angle 5 on the y-axis is illustrated. A controlled ignition angle / task cycle 23 is shown showing the decrease in voltage on the x-axis and showing the percent load 24 on a motor on the x-axis.

Each motor operates along a parameter 25 control line within its operating space. For example, when a given engine is 50% charged and the duty cycle / ignition angle 23 is set to 100 ° C, a phase angle 5 of approximately 55 ° is observed.

The parameter control line 25 shown in Figure 12 is defined by five parameter operation points 26 ranging from a loaded compartment 44 in the upper left corner to an unloaded compartment 45 in the lower right corner. Also, the line

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<img file="MX338092B_D0031.tif" />

Parameter control 25 has special meaning because it is the line where a motor is using the least possible energy. If the duty cycle / ignition angle 23 is increased and the voltage of the motor 13 is decreased, then an engine could operate slower and possibly stagnate. Similar results can be seen if the load on the motor is increased 3.

As illustrated in Figure 13, a parameter can be made from parameter control line 25 and projected onto a plane described by phase angle 5 in the vertical direction, and the duty cycle / ignition angle 23 in the horizontal direction.

Furthermore, as shown in Figure 14, the parameter control line 25 can be displayed on a two-dimensional graph. On the x-axis, the increase in duty cycle / ignition angle 23 can be equated with the decrease in motor voltage. This is because small task / ignition angle cycles result in high level voltage, and large task / ignition angle cycles result in low level voltage. The motor controller will drive the observed phase angle 5 to the point on control line 25 that corresponds to the load found on a motor. To accomplish this, a DSP computes the phase angle 5 between the voltage and the current.

Returning again to the block diagram of the figure

<img file="MX338092B_D0032.tif" />

<img file="MX338092B_D0033.tif" />

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2, DSP 1 subsequently computes the next target phase angle 5 based on the current value of RMS voltage 13, or equivalently the value present in the task / firing angle cycle. The difference between the observed phase angle and the target phase angle 10, results in a phase angle error, which is processed by a PID controller 12 or a similar device, to generate a new control target. This control target changes the voltage in such a way that the phase angle error is minimized. Target phase angle 10 is dynamic and changes as a function of task cycle / firing angle.

As indicated above, the motor controller 4 will drive the observed phase angle 5 to the point on the control line 25, corresponding to the load found on the motor 3. This operating point 26 provides the energy savings maximum possible because control line 25 is calibrated directly from motor 3 being controlled.

This calibration method is called semi-automatic calibration. Semi-automatic calibration is based on the DSP 1 sweep of the motor control space. As shown in Figure 15, the sweep of the control space means that the DSP increases the duty cycle / ignition angle 23, and records the current 9 and the duty cycle / ignition angle 23 of each phase at points separated along

<img file="MX338092B_D0034.tif" />

INSTITUTO MEXICANO CE LA RROPISDAP INDUSTRIAL of the route. Therefore, in this way it is possible to observe the start of the loss point 21 of the motor. A well defined lin al portion of the observed calibration data curve obtained from the sweep of control space 7, which is used to determine points on control line 6, has a constant negative slope at lower duty cycle / firing angle 2. 3. Subsequently, as the duty cycle / ignition angle 23 continues to increase, the current 9 begins to fluctuate, and actually begins to increase as the motor 3 begins to slide and starts to stagnate, the so-called "knee" 31.

As shown in Figure 16, subsequent sweeps can be directed at lower ranges of motor voltages for a "close-up" on the knee. The motor controller 4 requires multiple sweeps in order to obtain data that is statistically accurate. There is a trade-off between the number of sweeps and the time required to calibrate control line 25. A measure of calibration quality can be maintained through DSP 1 using well-known statistical processes, and if necessary additional scans can be performed. This is real because DSP 1 has learned the approximate location of knee 31 since the first sweep.

There is little risk of loss during the semi-automatic sweep, due to the controlled environment of the

<img file="MX338092B_D0035.tif" />

MEXICAN INSTITUTE CE INDUSTRIAL PROPERTY configuration. A technician or operator helps ensure that sudden loads are not applied to motor 3 in the test, while a semi-automatic calibration is in progress.

The sweeping process of the control space can be carried out on any fixed load. For example, it can be carried out once with the engine 3 fully charged, and once with the engine 3 unloaded. These two points become the two points that define control line 25. Calibration does not need to be carried out exactly at these two points. If required, DSP 1 will extend control line 25 beyond these two points.

There are many numerical methods that can be applied to find the point of loss 21 on the current motor voltage trace 23. As shown in Figure 17, one method is to use the “least squares” method to calculate the straight line. best fits the tabulated cumulative data for the first five motor voltages 23.

Figure 18 shows the continuation of this method. Using the previous data points, the value of current 9 can be anticipated. Graphically, DSP 1 is reviewed for one or more points that deviate in the positive direction of the anticipated straight line.

As shown in Figure 19, DSP 1 is looking for the beginning of the knee in the curve. The first point

<img file="MX338092B_D0036.tif" />

<img file="MX338092B_D0037.tif" />

that deviates from the early control line, may or may not _ be at the beginning of knee 31. The first point with a positive error may simply be a noisy data point. The only way to verify that the observed calibration data curve obtained from the sweep of control space 7 is changing is to observe the data obtained from additional scans.

A semi-automatic calibration can be carried out in the field. Referring now to Figure 20, a flow chart is shown showing how semi-automatic calibration is performed. First, motor 3 is placed in a heavy loaded configuration 44. Ideally, this configuration is greater than 50% of the total rated load. Subsequently, a calibration button 32 is pressed on the motor controller 4, to indicate to the DSP 1 that they perform a fully loaded measurement. DSP 1 runs a 46 calibration that takes several seconds to scan the operating space of motor 3 to determine fully loaded points. Motor controller 4 indicates that this step has been completed by connecting an LED.

Subsequently motor 3 is placed in an unloaded configuration 45. Ideally this configuration is less than 25% of the rated load. Subsequently, a calibration button 32 is pressed 47 on the motor controller 4, to instruct the DSP 1 to carry out a discharged measurement. DSP 1 runs

<img file="MX338092B_D0038.tif" />

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INSTiTVTO M .'- X'CANU \ ·: &lt;&lt; Ot THE INDUSTRIAL PROPERTY calibration 46 to determine the unloaded point. The motor controller 4 indicates that the calibration has finished at both ends 47 of the control line 25, by connecting a light emitting diode (LED). Subsequently DSP 1 determines control line 48 using the two measurements and applies this control line when it is driving motor 3.

The values ​​of control line 25 are stored in non-volatile memory 49.

Figure 21 shows a more detailed flow chart of the semi-automatic calibration. First, a first calibration sweep 46 is run with a motor voltage set to a certain degree 51, depending on whether a first sweep or a previous sweep 106 has been run, where the motor controller measures motor 52 until the controller motor detects a knee 53. If a knee 53 is detected, the task / ignition angle cycle is decreased by two degrees 54, and the phase angle and motor voltage are recorded in memory 55. This process is repeated to obtain at least four sweeps 56 to obtain a computerized average value 57 of the phase angle and the duty cycle / firing angle. If during any step along the calibration sweep, the knee is not detected, then the task / firing angle cycle is increased by at least one degree 58, and the next step 59 is measured.

An alternative calibration method is called calibration.

<img file="MX338092B_D0039.tif" />

Handbook. Figure 22 shows a manual calibration flow chart. First, a motor is placed in a dynameter 70. The motor is then connected to a computer for manual control 71, allowing the motor to be run in an open circuit mode, and the duty cycle / ignition angle The AC Induction motor has been manually adjusted to any point of operation. The engine is then placed in a fully discharged configuration 45. Subsequently, the duty cycle / ignition angle is increased and the RMS motor voltage is reduced 72 until the engine is just about to stall. Task cycle / ignition angle and phase angle are recorded, and this becomes a calibrated point that is recorded

73. Subsequently the engine is started with the drive elements fully connected 74. Subsequently the engine is placed in a fully charged configuration 44. Subsequently the duty cycle / ignition angle is increased or decreased until the RMS engine voltage is cut off by motor controller 75, until the motor is just about to stall. The task cycle / ignition angle is recorded and this becomes another calibrated point, which is registered 73. Finally, other calibrated points are used to form a control line 76.

When the RMS line voltage is higher than a programmed fixed voltage, the DSP controller sets the motor voltage

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RMS at the fixed voltage, so that energy savings are possible even at full load. For example, if the main voltage is above the 115V motor nameplate voltage, in the case of a single phase motor, then the motor voltage is set to 115V. This motor voltage setting operation allows the motor controller to save energy even when the motor is fully charged in single phase or three phase applications.

Figure 23 shows a flow graph of the fixed voltage setting. First a phase error is computed 64. A voltage error 65 is then computerized 65. The RMS motor voltage of the AC induction motor is then determined and compared to a fixed voltage threshold value 66. If the RMS motor voltage is greater than the voltage threshold value fixed, then it is determined whether or not the control objective is positive 67. If the control target is positive, then a voltage control circuit is run 68. If the AC induction motor RMS motor voltage is less than a fixed voltage threshold value, then the closed circuit of the control line is run 69, and the whole process is repeated. If it is determined that the control target will not be positive, then a control line circuit is run 69 and the entire process is repeated again.

In some cases, it may not be possible to fully charge motor 3 during the calibration process.

<img file="MX338092B_D0040.tif" />

<img file="MX338092B_D0041.tif" />

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INDUSTRIAL

Possibly 50% is the largest load that can be achieved while the engine is installed in the field. Conversely, it may not be possible to fully charge the motor; this may be that only 40% is the lightest load that can be achieved.

Figure 24 shows an example of both load points being close to the middle of the operating range. At the discharged end 45 on the right hand side of control line 25, DSP 1 will adjust the fixed voltage setting 60 of the voltage to a minimum voltage of 35. When increasing the load on the motor, DSP 1 will completely follow the line of control moving to the left and up of control segment 61. This implementation is a conservative method, and protects engine 3 from running in an uncalibrated space.

As further shown in Figure 25, at the fully loaded end 44 on the left, DSP 1 will synthesize a control segment 61 with a large negative slope. This implementation is a conservative method and conducts the voltage to full-connected.

Referring now to Figure 26, the DSP-based motor controller uses a special technique to protect a motor from stalling. First, the DSP actively monitors a significant increase in current 99, indicating that the motor load η I has increased.

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Subsequently, if 100 a significant increase is observed, then DSP converts the motor voltage to full connected 101. Subsequently, the DSP will attempt to reduce the motor voltage to return to control 102 and the DSP returns to active monitoring for a significant increase in current. 99. This technique is a conservative and safe alternative for the DSP to attempt to track energy requirements that are currently unknown.

As shown in Figure 27, a graph of the loss mitigation technique, the load on the motor is plotted on an x-axis, and time is plotted on a y-axis. The bottom line represents the load on motor 103, and the top line represents the energy applied to the motor by DSP 104. Prior to point 105, the DSP is dynamically controlling the motor on a fixed load. Between point 105 and point 30, the load on the motor suddenly increases, and DSP runs the motor voltage to full-connected. At point 34, the DSP reduces the motor voltage to point 43.

In Fig. 28, a rocker arm 30 'is placed in the adjacent well in land W. The motor or the mobile or main motor 6' drives a gear system or transmission 8 'with the transmission band 18'. The 6 'motor can be connected to an electric utility grid for power supply. One end of the counterweight arm or crank arm 10 'is placed with the gear system 8', and the other end of the arm is placed

<img file="MX338092B_D0042.tif" />

<img file="MX338092B_D0043.tif" />

INSTITUTO MF./.ü of counterweight 10 'with counterweight or rotating mass 12'. There are preferably two counterweight arms 10 ', with the counterweight 12' positioned between them. The 2 'lever or rocker pivots on the sampson pole or A 14' frame. One end of the connecting rod or beam arm 16 'is rotationally adhered to one end of the beam 2', and the other end of the beam arm 16 'is rotationally adhered to the rotating mass 12', and one end of the counterweight arm 10 '. The protrusion or head of the beam 4 ', is placed at the end of the beam 2' adjacent to the well W. As can be understood at this time, the rocker arm 30 'has a conventional design.

One end of the cable 20 'is attached to the head of the beam 4', and the other end of the cable 20 'is attached to the polished rod or rod 22'. Rod 22 'is placed with the tubular chain or plunger rods 26' which extend into reservoir W through the production line to the downhole pump 28 '. The tubular chain may comprise plunger rods, pipes, tubulars, or other components used with a rocker arm or other similar device to aid in the pumping or lifting of fluids from a well. The motor 6 'can drive the rocker arm 30' by rotating one end of the counterweight arm 10 'about a horizontal axis. As the counterweight 12 'moves upward, the beam 2' pivots about a horizontal je on the A-frame 14 ', and moves the head of the beam 4' downward. As the 12 'counterweight moves further

<img file="MX338092B_D0044.tif" />

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INDUSTRIAL from its upper position, falls freely downwards due to gravity and its momentum, and beam 2 'pivots around A-frame 14' and moves head of beam 4 'upward. Pushing and pulling the tubular chain 26 'through the beam head 4' operates the piston in the downhole pump 28 '. Tubular chain 26 'moves and oscillates substantially vertically in well W.

The 6 'motor is normally in a power consumption mode. However, the motor 6 may be in the power generation mode, when the masses fall (either the counterweight 12 'or the rod or tubular chain 26') they are falling freely, thus accelerating the motor 6 'further of its synchronous speed, when the speed is limited by the generated current. Although an exemplary conventional rocker 30 'is shown in FIG. 28, it is contemplated that all rocker designs, including, but not limited to, different conventional designs, the Lufkin Mark II design, the beam balanced design, and the conventional laptop, can be used with the embodiments of the present invention. Although the modes are shown with rocker arms, it is also contemplated that all modes can be used with any device that has a rotating or oscillating mass.

Returning to figure 29, the trace 36 'is shown with the phase angle observed on the vertical axis 32' and the time at

<img file="MX338092B_D0045.tif" />

INSTITUTO MEXICANO DE LA TRO ?: INDUSTRIAL AGE horizontal axis 34 'for an electric motor attached to a rocker arm, such as the 6' motor or rocker arm 30 ', in figure 28, in an open circuit mode. The embodiments of the present invention described below with reference to Figures 30 to 32D, have not been attached to the electric motor; therefore, the motor is in open circuit mode. The second horizontal line 40 'is drawn at an observed phase angle of 90 degrees on the vertical axis 32'. When trace 36 'exceeds an observed phase angle of 90 degrees, which is on the trace of first segment 42' above second horizontal line 40 ', then the motor is in power generation mode. At times when the motor is generating, rather than consuming energy, the current retards the voltage by a phase angle in excess of 90 degrees. The greater the phase angle during generation, the greater the energy generated. The engine is in heavy power consumption mode on the second segment 44 'trace below the first horizontal line 38'. The first horizontal line 38 'is drawn at a phase angle less than 90 degrees on the vertical axis 32'. The objective phase angle is described in more detail below in Figures 30 and

31.

In Figure 30, the closed circuit motor controller 50 'is shown schematically connected to an electric motor 62', such as the motor 6 'in Figure 28, which is

<img file="MX338092B_D0046.tif" />

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IN may connect to a rocker arm, such as rocker arm 30 * of FIG. 28. Other rocker arm designs are also contemplated for use with FIG. 30. Motor controller 50 'may be a PID controller. However, other closed circuit motor controllers are also contemplated. A digital signal processor (DSP) based motor controller is contemplated, such as the DSP based motor controller of Figures 1 and 2, although other types of DSP based motor controllers are also contemplated. The closed circuit motor controller 50 'can be connected to the motor (6', 62 ') in the same way as shown in Figures 1 and 2. A microprocessor based controller is also contemplated. In one embodiment, the closed loop controller system may have a PID controller as a component. In closed loop control system or servo system 48 ', controller 50' can compute 52 'the observed phase angles from the voltage and current supplied to motor 62'.

Conveniently, no sensors need be placed with the motor (6, 62 '), jack rocker 30' or downhole pump 28 '. In addition, the closed loop system 48 'can be tailored to each individual 28' downhole pump, and to change parameters and requirements of pump 28 'and well W over time, including, but not limited to changing volumes, densities, viscosities, weights and others

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<img file="MX338092B_D0047.tif" />

properties of materials and / or fluids pumped, such as gas, oil, water and paste. The voltage and current monitored by system 48 'serves as an Indicator of well condition, allowing the system to adapt to changing well parameters. Monitoring voltage and current on a substantially continuous basis allows a substantially continuous reading of well conditions. The closed loop system 48 'is also adapted when the existing components of the rocker system are replaced with other components having different characteristics, such as for example replacing the tubular chain with a different tubular chain having a different weight, or replacing the counterweight with a different size counterweight, provided the mechanical system is rebalanced after the components are replaced. After rebalancing the mechanical system, the embodiments of the present invention allow the energy savings to be resumed.

An input of the target phase angle 58 'in the controller 50' can be compared to the computerized observed phase angle 52 ', and the error 60' or difference between the two values ​​determined by the controller 50 '. It is contemplated that the objective phase angle 58 'may be substantially 90 degrees, or the objective phase angle 58' may be greater or less than 90 degrees. At the time of

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OF PROPERTY \ 7yssa ^ ii »t ^^ &lt;

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MBMwW-moiμ · ΜΜ · ΜΜ «Μ« ·· Μ · ΤΜ »that produces optimal results for the motor in use. The target phase angle 58 'can be constant for all motor loads, such as 65 degrees, although other constant target phase angles 58' are also contemplated. The objective phase angle 58 'can also be a variable function of the motor load at any time. The target phase angle setting 58 'may be the lowest possible phase angle possible that maintains an observable enough current flow at all times, while still maintaining a sufficient power supply to meet the motor requirements at all times. loads.

The motor controller 50 'can control the supply voltage 54' applied to the motor 62 ', based on the error signal 60'. When the error 60 'is significant because the observed phase angle is too large, such as during the open circuit power generation mode period, the controller 50' can reduce the supply voltage to the motor 62 'by lower value, such as to reduce the observed phase angle 52 'to the target phase angle 58'. When error 60 'is significant because the observed phase angle 52' is too small, such as during heavy power consumption mode, controller 50 'may increase supply voltage 54' to motor 62 'to a larger value to move the observed phase angle 52 'to

<img file="MX338092B_D0048.tif" />

objective phase angle 58 '. In this 48 'closed loop system, the voltage and current are continuously monitored and controlled by the motor controller 50'. It is also contemplated that the supply voltage 54 'can be controlled through the use of power control devices, such as TRIACs, SCRs, IGBTs, or MOSFETs, as shown in Figure 2. Also, controller 50 'uses timers and pulse width modulation (PWM) techniques to control supply voltage, which are described in detail later in Figures 32 to 32D. Other techniques are also contemplated.

Turning now to Figure 30, controller 50 'reads the voltages of each phase and current in motor 62', to capture zero cross points. Figures 5 and 6 of North American Publication No. 2009/0046490, propose an oscillogram and circuit diagram, respectively, of a zero-volt cross point that determines which medium is contemplated. Other types of zero volt crossover point determination means are also contemplated. Voltage and current can be converted from analog to digital using one or more analog to digital converters for monitoring and / or control purposes as shown in Figure 2. Controller 50 'can perform computations 52' of the angle motor phase to produce an observed phase angle. Controller 50 'can compare observed phase angle 52'

<img file="MX338092B_D0049.tif" />

INSTITUTO MEXICANO DE LA P ^ oriF.DAP INDUSTRIAL with the objective phase angle 58 'and control the motor supply voltage 54' in response. The phase angle can be monitored in one or more phases. Controller 50 'can be used to automatically determine phase rotation. In the figure of the North American Publication No. US 2009/0046490, a circuit diagram of a phase support means and a phase rotation determining means is proposed which is contemplated, wherein multiple phase operations are employed.

In addition, it is contemplated that phase-to-phase or phase-to-neutral voltages can be monitored. Figure 10 shows a schematic of a contemplated virtual neutral circuit. Other virtual neutral circuits are also contemplated. A virtual neutral circuit can be used as a reference in situations where three phase power is available only in delta mode, and there is no neutral present to use as a reference. It is also contemplated that a window comparator can be used to detect zero crossings for both the positive and negative halves of a current waveform. Figures 7 and 8 show a window comparator. Other window comparators are also contemplated. Figures 8, 9 and 10 of the

North American Publication No. US 2009/0046490, propose a circuit diagram and oscillogram, respectively, of a half cycle that identifies which medium is contemplated.

<img file="MX338092B_D0050.tif" />

Turning now to Figure 31, trace 64 'is shown with a phase angle observed on vertical axis 32' and time on horizontal axis 34 'for an electric motor attached with a rocker arm, such as motor 6' and the rocker arm 30 'in figure 28, in the closed circuit mode. As in Figure 29, there is a target phase angle of less than 90 degrees on the first horizontal line 38 '. Unlike figure 29, the output of the electric motor represented in figure 31 is from a closed circuit system 48 'placed inside the motor as shown in figure 30. The line of the first segment 70' in figure 31, is when the observed phase angle can exceed the target phase angle in open circuit mode. However, in closed-loop mode on the first segment trace 70 ', error signal 60' creates a control effort through controller 50 'to reduce supply voltage 54' to the motor, to maintain angle phase objective 38 '. When the observed phase angle can exceed 90 degrees in open circuit mode, the large values ​​of the observed phase angle create large values ​​of the error signal 60 'in Figure 30.

During the trace of the first segment 70 ', the motor is effectively switched off using PWM techniques, but without actually cutting power to the motor. There is still current flowing in the motor during this time, which allows the controller 50 'to know when to increase the supply of

<img file="MX338092B_D0051.tif" />

<img file="MX338092B_D0052.tif" />

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INDUSTRIAL motor voltage required during power consumption mode. The actual component of the current can be reduced to virtually zero, leaving a reactive component greater than zero. By allowing some current flow when the voltage is reduced, most of it reactive in nature, an observable feedback parameter is provided which is used in the closed loop control system 48 'as an indication of the load condition at which controller 50 'can react, supplying power when needed in the power consumption phase.

Since the current is reactive in nature, the only remaining energy is of an apparent nature. Current flow allows the controller to continuously observe the phase angle between current and voltage. Maximum motor voltage drop occurs approximately on the first location trace 66 'in Figure 31, when the observed phase angle is in open circuit mode as shown in Figure 29, which otherwise it can be at its maximum value greater than 90 degrees.

When the observed phase angle exceeds the target phase angle in closed loop mode, a supply voltage can be reduced with PWM techniques until the observed phase angle reaches the target phase angle. At the beginning of the trace of the first segment 70 'in Figure 31, the motor controller 50' reduces the observed phase angle

<img file="MX338092B_D0053.tif" />

1Ν37ΓΠ.7Ο MEXICAN IA INDUSTRIAL PROPERTY open circuit mode below target phase angle. Therefore controller 50 'maintains the observed phase angle substantially at the target phase angle. Any further reduction in the phase angle observed below the target phase angle can be interpreted as an increase in load, to which the controller 50 'can respond by increasing the supply voltage 54' until the target phase angle has been reached once again. The maximum increase in supply voltage to the motor occurs at the trace of the second location 68 ', when the observed phase angle falls below the target phase angle. When the counterweight or oscillating mass is driven by the motor, the observed phase angle values ​​will normally be smaller than the target phase angle, which will create an error signal that creates a control stress through the controller 50 'to increase the supply voltage to the motor.

The engine is in heavy power consumption mode on the second segment 44 'trace below the first horizontal line.

Turning now to Figure 32, the trace of the input voltage waveform 200 to the line is illustrated in single phase, although a three phase voltage is also contemplated. In Figure 32A, PWM techniques have been used to cut or remove the trace segments from the voltage waveform.

<img file="MX338092B_D0054.tif" />

204, while simultaneously leaving the segments of the voltage waveform trace 202. Figure 32A illustrates a heavy cut of the supply voltage where the large segments 204 of the voltage waveform are cut. Figure 32B illustrates light cutting of the voltage waveform with PWM techniques, where the segments of the voltage waveform trace 206 that are cut are smaller than the cut segments 204 shown in Figure 32A. In FIG. 32B, the waveform trace segments 208 that are on the left are larger than the waveform trace segments 202 that are on the left in FIG. 32A.

The heavy cut in Figure 32A occurs during the period in which the open circuit power generation mode might be occurring, such as in Figure 31, in the trace of the first location 66 '. In Figure 32D, the heavy cut period 210A is illustrated in the line segment 210. The reduction in voltage shown in Figure 32A reduces the actual current component to virtually zero, while leaving a larger reactive component. to zero. This is the period when the motor effectively shuts down, while leaving enough current to observe the phase angle.

When the motor is in a heavy power consumption mode, as in figure 31 in the second trace

<img file="MX338092B_D0055.tif" />

MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY sgment 44 ', then the waveform segments without voltage are substantially eliminated, and the motor supply voltage is substantially as shown in figure 32. In figure 32D, the period of substantially do not cut 212A, occurs in line segment 212.

In Figure 32D, the DSP controller is in control mode at trace locations 226 and 228. During such periods, the motor is not in power consumption mode.

<td>heavy, and</td><td>not</td><td>this</td><td>in</td><td>the period where I could be</td>

<td>happening</td><td>the</td><td>mode</td><td>of</td><td>circuit power generation</td>

<td>open. In</td><td>the</td><td>mode</td><td>of</td><td>control, light cut may occur</td>

226A as shown in Figure 32B, or a variable cut-off as shown in Figure 32C may occur to control the motor voltage. This can happen when the engine is lightly loaded, saving energy while the engine is still consuming power. The variable cut in Figure 32C uses PWM to cut waveform trace segments (214, 216, 218, 220. 222, 224) of various sizes to control the motor voltage. The size of the segments of the voltage waveform trace (214, 216, 218. 220, 222, 224) cut in Figure 32C may all be different, leaving segments of the voltage waveform trace that they are also all in different sizes.

It should be understood that the motor controller can use any combination or cut swap

<img file="MX338092B_D0056.tif" />

Light, Heavy Cut, Variable Cut, or ... sin. „. f? .O £ te —. to control the observed phase angle of the motor supply voltage at the target phase angle. The digital signal processor (DSP) or motor controller attempts to maintain a substantially constant observed phase angle, and will cut the amount required to do this. The DSP controls the motor voltage based on the observation of the phase angle. The amount of cut-off of the supply voltage may vary.

When the open circuit of the electric motor is in the power generation mode, the load presented by the utility grid effectively acts as a brake on the motor, thereby limiting its speed. This occurs due to the attempted voltage generated to exceed the voltage presented by the utility, whereby the current presented originates from flowing in the opposite direction. When applying the closed loop controller system and method as shown in Figures 30 to 32D, this braking action can be effectively minimized or eliminated, and the motor and system will accelerate normally during this time. This additional kinetic energy stored in the system will be used to carry out part of the pumping action without consuming energy in the motor. Minimizing or substantially preventing power generation eliminates the need to consume energy in other parts of the pumping cycle, thereby saving energy.

<img file="MX338092B_D0057.tif" />

As can be understood, the electrical energy supplied to the motor is disconnected "effectively" during the power generation mode that could occur in the open circuit, while maintaining the voltage and current power signals to determine when to reconnect. the electric motor, or when the observed phase angle is decreased. This system and method will constantly adapt to change parameters in the well, which may not have been done in the past. For one example, the motor and system are adapted to pump two or more fluids at different times having different densities or weights. The voltage and current monitored by the system serve as an indicator of well condition, allowing the system to adapt to changing reservoir parameters. By not entering the power generation mode, the braking action that is created through the open circuit power generation mode can be minimized or eliminated, so that the benefit of acceleration is obtained in the system. By minimizing or eliminating energy that could otherwise be consumed by the system, energy savings can result from both reducing the supply voltage to the motor, and minimizing or eliminating the braking action of the motor when it is in generation mode.

All types and designs of electric motors are contemplated to be used with the different modalities of

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INDUSTRIAL the present invention described above, including but not limited to AC induction motors and AC synchronous motors. All types and designs of rocker arms are contemplated for use with the different embodiments of the present invention described above, including but not limited to all conventional designs, the Lufkin Mark II design, beam balanced design, and conventional portable design. Although the modalities have been shown with rocker arms, it is also contemplated that all of the modalities described above can be used with any device having a rotating or oscillating mass. Although some of the modalities have been shown with a single phase voltage and current, all the modalities of the present invention are contemplated with a single or multiple phase voltage and current.

Returning to Figure 33, an example installation of a motor controller 304 is shown that implements the disconnect method. Motor controller 304 may be a DSP based PID controller as described above and as shown in Figures 1 and 2, although other closed circuit controllers are also contemplated, as described above. The motor controller 304 can be inserted into electrical connection between the existing electrical control panel 302 and the electric motor 306 that drives the rocker arm 308. The electrical power supply

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY can run through utility meter 300 to control meter 302.

Figure 34A shows a typical variation over time of the phase angle measured from an electric motor driving a rocker arm. Trace 314 with a phase angle observed on the vertical axis 310 and time on the horizontal axis (not shown for clarity). Shown for an electric motor driving a rocker arm in an open circuit mode. The first horizontal line 312 is drawn at an observed phase angle of 90 on the vertical axis 310. A first cycle or pump stroke occurs during the first time segment 316, a second cycle or pump stroke occurs during the second time segment 318, and a third cycle or pump stroke occurs during the third time segment 320.

As exemplified in Figure 34A, during a typical pump stroke, the rocker motor experiences a heavy load once or twice, and the motor experiences a light load once or twice. Depending on the geometry and rocking of the rocker arm, the drop weights (either the counterweights or the rod chain) can force the motor beyond its synchronous speed, thereby causing it to behave like a generator. During such periods, the observed phase angle exceeds 90 degrees.

To start implementing the connect-disconnect method, once started, the motor controller can

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MEXICAN INSTITUTE OF PROPERTY

INDUSTRIAL monitor phase angle and operate in one of three states. STATUS 1 OF THE METHOD

In state 1 of the connect-disconnect method, the load profile to which the motor is subjected through the rocker arm is evaluated to determine if there is an opportunity to disconnect the motor, and if so, identify the connection times and proper disconnection during the pumping stroke. The load profile can be characterized by phase angle variations. When the motor is disconnected during power generation times, the motor will accelerate, thereby altering the load profile.

Therefore, it is convenient to characterize this change. This is accomplished by subjecting the engine to the closed loop PID control process (“heavy shear”) as a close approximation of the effect of the on-off process.

Figure 34B shows the effect of the closed circuit PID control process on the motor, and its load profile. During the initial trace segment 322, the motor is supplied with the full, unmodified supply line voltage, as shown in Figure 34A, at which time the phase-angle is monitored. When the phase angle is observed to exceed a predetermined threshold value, such as 70 degrees, as shown at trace location 326, the motor is considered to be lightly loaded and close to entering the power generation condition . This instant is identified

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sr F • vi ri as a potential disconnection time in future pumping runs. Upon crossing this threshold, the closed-loop PID control process is activated, controlling the motor voltage to achieve the target phase angle, as shown on the second horizontal line 313, drawn at a constant target phase angle , such as 60 degrees. Other target phase angles are also contemplated. It is contemplated that the target phase angle may not be constant, although it may vary depending on the load condition of the motor.

During the closed-loop PID control process, enough current flow remains to provide observable feedback for the closed-loop control system. The closed loop PID control process remains enabled until an increase in load requires an increase in voltage supply above a certain threshold value, which is shown at trace location 328. This can be indicated by a decrease, below a predetermined threshold value, such as 90 degrees, in the firing angle used to control switching devices, such as TRIACS, SCRs, IGBTs, or MOSFETS. This instant is identified as a potential connection time in future pumping runs. Upon crossing this threshold value ignition angle, supply line voltage can be restored to the motor

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MEXICAN INSTITUTE OF PROPERTY not modified, until the loading condition '^ f ^ éV once again identified, which is shown by location of trace 330.

To ensure that the above measurements are consistent, the above process can be repeated during several pump strokes, such as four strokes. The period of the altered pump stroke, and the identified disconnection and connection times within the stroke, can be compared between repeated strokes. If a closed or repetitive correlation is observed in all measurements during the various monitored runs, the system can be considered adequate to enter the open circuit disconnection state. A correlation or closed criterion can be considered as a variation of not more than 200 milliseconds (ms) in the periods of pumping strokes. Another correlation or criterion can be a variation of no more than 150 ms in the connection and disconnection moments. Other correlations or criteria are also contemplated. If the correlation requirements are not met, the system can remain in State 1, to continue using the closed-loop PID control process, until the required correlation is observed.

The typical rocker pumping stroke typically has one or two periods during which the motor can be switched off. These two periods can be treated

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as different from each other in their timing and duration. Either one or both of the two periods can meet the criteria for entering the disconnected state. Although there may be more than two periods of light load or generation mode in a single pump stroke, only the two longest periods of these can be considered to provide any significant energy savings. Additional periods normally occur only briefly, when the motor is in a “pump off” condition. A minimum disconnect time condition or requirement can be maintained to support a maximum of two disconnect times that exceed this target. An implementation that supports more disconnection moments is also contemplated. In the event that additional generation conditions are observed, the system can employ the closed loop PID control process during these times.

STATUS 2 OF THE METHOD

Once in the on-off state, the phase angle can be monitored during each pump stroke to ensure that it crosses the set disconnect threshold value at the time anticipated during State 1. If the phase angle fails to meet the expected synchronization (within a reasonable predetermined range, as described above) the profile of ϊΜΡΐ ^ can be considered

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Load has changed since timing was established during closed loop PID status control. The control system can return to State 1 to repeat its measurements.

If the expected timing is met, the voltage applied to the motor can be substantially immediately and completely disconnected, as shown in 34C. It can remain disconnected for the duration of the computation during State 1. Substantially immediately after returning to the Connection State, such as at location I trace 324, the observed phase-angle can be evaluated and compared to a phase angle value previously determined ideal. The ideal phase angle ensures that the motor neither generates power nor consumes excessive power immediately after returning to the connected state. This ideal phase angle value can be 75 degrees, although other values ​​are also contemplated.

If the observed value exceeds this ideal value, it can be considered an indication that the voltage may have been switched off longer. If the observed phase angle value is less than this value, then the voltage may have been turned on sooner. Subsequently, adjustments can be made to the disconnection duration, to optimize behavior on subsequent races. The voltage applied to the motor can remain fully connected, until the next disconnection time

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anticipated. The on-off state, as represented by the observable phase-angle, is shown in Figure 34C. Since there is no current flow when the supply is turned off, there is no observable phase angle during these periods.

STATUS 3 OF THE METHOD

To allow the possibility of gradual shifting over time in the load profile, the control system may be periodically moved back to State 1, to re-evaluate the closed-loop PID control process. This can be done every two minutes. Other time periods are also contemplated. If, after a pump stroke, little or no change is found in the closed loop PID control method, small adjustments can be made to timing requirements, and the control system can return to State 2 for connection strokes. -additional disconnection. If a substantial change in timing is found, the system can remain in the closed loop PID control state until a timing pattern consistent with several consecutive pump strokes can be observed, as described above.

Figure 35 is a summary version of the steps of a method of disconnecting the voltage supply and reconnecting it for predetermined periods. More or less steps are also contemplated. They are also covered

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OF THE PROPERTY

INDUSTRIAL ------ other steps. In the first block 330, the system is started to monitor the phase angle of the rocker motor. In the second block 332, which corresponds to State 1, the response of the motor to the closed circuit PID control is evaluated during several pump strokes. The periods of the pump stroke are identified when it is feasible to turn off the motor. In the third block 334, the consistency of the measurements during various runs is evaluated. In the fourth block 336, which corresponds to State 2, the motor can be switched off for predetermined periods in the subsequent strokes of the pump, if each stroke of the pump shows a behavior sufficiently similar to that anticipated during the circuit PID control process State closed 1. In the fifth block 338, which corresponds to State 3, the system can return to State 1 to the closed loop PID control process, after a predetermined period of time to adjust to any changes in the system.

As can be understood at this time, the on-off method provides a means through which periodic variation in load on a rocker motor is monitored and characterized based on the observed phase angle. Once the load is characterized, the method determines if there is an opportunity to save energy by disconnecting the motor for portions of each stroke. The

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The MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY method anticipates when this opportunity should occur subsequent pumping strokes, and defines criteria that will be met in subsequent pumping strokes as conditions for turning the motor off and on again. The system and method implement algorithms that adjust to adapt to gradual changes in rocker behavior, and implement protections to recognize and react to sudden large changes in this behavior.

The system and method have the advantage of high periodic variation of the load on the motor in a rocker application. The system and method accurately anticipate the times during a pump stroke when power to the motor is completely disconnected, as well as the appropriate time at which power must be reapplied. Total disconnection of power to the motor results in superior energy savings.

The system and method provide a means through which to monitor and characterize the periodic variation in load on a rocker motor based on the observed phase angle between the applied voltage and the consumed current. Once the load is characterized, a determination can be made as to whether there is an opportunity to save energy by turning the motor off during portions of each stroke. The system and method anticipate when this opportunity should occur in

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Subsequent pump strokes, and define the criteria that will be met in subsequent pump strokes as conditions for turning the motor off and on again. The system and method implement algorithms that adjust to adapt to gradual changes in rocker behavior, and implement protections to recognize and react to large, sudden changes in this behavior.

The foregoing description of the present invention is illustrative and explanatory in nature, and various changes may be made in the details of the illustrated system and method of operation without departing from the spirit of the present invention.

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