Speed control method and device for a two-pulse motor operating with auxiliary torque

Translation of description of equivalent WO 2005018084 A1

_VLEARN AND DEVICE FOR A fan speed control WITH AUXILIARY WORKING MOMENT Z EIPULSIGEN MOTORS

The invention relates to a method for controlling the speed of an operating with a two-pulse motor invariant assist torque, and it relates to a two-pulse electronically commutated motor which works with an auxiliary torque invariant and having a regulating device for regulating its speed. As a so-called invariant assist torque reluctance is commonly used, but the invention is not limited thereto but such auxiliary torque could be generated mechanically, for example by a cam curve.

Two-pulse electronically commutated motors with auxiliary reluctance moment are inexpensive because they the same size can be produced cheaper in comparison with multi-phase motors, and because this engine design is simple and robust. Such engines are therefore often used to drive fans, eg for cooling in the IT sector.

Due to her assist torque motors have such a rotational direction in which they start easily, because the start-up is supported by the auxiliary torque. This direction of rotation is referred to as a preferred direction. By contrast, even the reverse direction is in the direction opposite to the preferred direction, called the start-up difficult. A four-quadrant operation of such motors also therefore encounters difficulties because there are speed ranges where a scheme for various reasons is not possible, partly because, due to low by the assist torque and its interaction with the electromagnetic torque, in such engine speeds not regulated are. The reason for this is that the size of the assist torque by the speed controller can not be influenced and is virtually a permanent fixture.

Due to this lower speed range, in which a control is not possible, there is the zero speed around a gap in the operating range. This results in particularly difficult when the direction of rotation is to be reversed, as if in a speed of 3000 rev / min Preferred direction is to be switched to 3000 rev / min in the reverse direction.

It is therefore an object of the invention to provide a new method and a new engine of the aforementioned type.

According to the invention this object is solved by the subject matter of claim 1. Because the motor is below a predetermined minimum rotational speed with an independent of the desired rotational speed of flow is driven, the run-up, in a speed window which is defined by the minimum speed, with a the controller is not influenced carried high torque. After leaving this speed window of the engine goes into closed-loop operation over to achieve the desired speed ( "target speed"), and this is done in such a way that the control value is then adjusted depending on the difference between the desired speed and the actual speed so held a speed control, preferably by a PI controller.

In a very advantageous embodiment of the invention the control value (and thus of the motor current supplied) continuously calculated as a function of the difference between the desired speed and the actual speed, but used for the control operation only at or after reaching the minimum speed. This is, after leaving the mentioned speed window immediately already calculated set value for the speed control is available.

Another solution of the problem is the subject of claim 10. Such a motor has a speed window, through which it travels during startup without speed control, and after leaving this window uses the speed control. As a result at the same time that, within the window, a speed control is not possible, and therefore a desired speed that is within this window is interpreted as a speed zero, so as a rotational speed which can not be represented.

Further details and advantageous developments of the invention will become apparent from the hereinafter described and illustrated in the drawing, in no way to be understood as limiting the invention embodiments, and from the remaining dependent claims. It shows:

FIG. 1 is an overview diagram of a preferred embodiment of a Bridge circuit for a two-pulse ECM low power,

FIG. 2 is a diagram with the terminal markings of a microcontroller used in the embodiment 76,

Figure 3 is a circuit diagram of an auxiliary circuit which is connected to the input of the microcontroller RAO. 76; RAO this input is the input of an A / D converter,

Fig. 4 is a diagram of the configuration of the input RB1, alternatively, the input RB7 of the microcontroller 76,

Fig. 5 is a diagram showing how a frequency signal derived from the output signals of a Hall generator 6 and the input of the microcontroller 76 RBO supplied leads is where this signal is converted to Hall interrupts,

Fig. 6 is a general diagram of the hardware used; here, the same reference numerals are used as in the preceding figures 1 to 5,

Fig. 7 is a schematic diagram of a 1 quadrant controller (1 -Q-controller)

8 is a schematic diagram of a 2-Q controller,

FIG. 9 is a schematic diagram of a 4-Q controller,

Fig. 10 shows the curve of internal signals at a transition from +3000 to -3000 U / min,

Fig. 11 is a state diagram showing the change of the states at different operating conditions,

FIG. 12 is a schematic representation of the starting process in the reverse direction,

FIG. 13 is a schematic representation of a typical profile of a reluctance torque, Fig. 14 is a flow diagram of a routine for the comparison between the actual rotational direction and a rotation direction set by the user,

Fig. 15 is a flow diagram of a routine for determining the motor status,

Fig. 16 & 17 is a flowchart for the discrimination between different operating states of an engine,

Fig. 18 is a schematic representation of the sizes, and its use used in the commutation of the motor, and

FIG. 19 is a flowchart RGL, which calculation processes in the speed control of a motor shows.

In the following description the same reference numerals are used for identical or similar parts or functions used and these are usually described only once. When describing speeds and its amendments we follow the language, that is, when the rotor rotates faster, regardless of direction, we speak of an increase in speed. The following abbreviations are used: Y YES

N NO n actual speed, actual speed; is measured as the time t_HALL nsetp desired speed, target speed; is defined as a time t_s

BW block length of a current flowing in the motor 30 current pulse. See Fig. 18. This block length represents the so-called "control value" of the speed controller and is calculated with the flowchart of FIG. 19. In the case of BW = Max BW is set to a value which, for example, is slightly smaller than t_HALL. DIR direction command of rotation (determined from outside)

DIRist current value of the rotation direction

DIRsoii desired value of the rotational direction inv. 180 ° switching of the commutation to the opposite of the instantaneous commutation. In FIG. 18 comes within the range designated by 360 ° el., First, a current pulse 444 (current i ') and then a current pulse 446 (current i). After switching by "inv. 180 °" comes First, a pulse 446 and after that a pulse 444, so that the motor is driven in the reverse direction. By switching again with "inv. 180 °" the state of FIG. 18 is restored. See. To this, the equations (5), (6), (11), (12) and the notes to Fig. 19.

In the embodiment mean:

DIR = 0 command: Desired run in the preferred direction

DIR = 1 command: Desired run counter to the preferential direction, ie in the reverse direction Rt directionality. The value of Rt is not saved until certain conditions are met and therefore may differ from DIR. Rt = 0 preferential direction

Rt = 1 reverse direction.

Rs flag indicating whether the engine is running or uncontrolled.

Rs = 0 Unregulated run in the desired direction of rotation with max. electricity

Rs = 1 run in the desired direction of rotation at a controlled speed

N MIN minimum speed. With increasing speed | n | below | N MIN | the motor coasts with maximum current, and at speeds above with speed control. T_HALL time required by the rotor to run through a predetermined rotation angle, which is defined by two changes of a rotor position signal HALL. In the embodiment t_HALL corresponds to the time for one quarter of a full revolution of the rotor. TJHALL is used as a measure of the current speed n, cf. The equations (9) and (10). t_s target time that the speed controller (Fig. 19) as a desired value for the speed is set, and corresponding to the time for one quarter of a full revolution of the rotor at nset. RGL_DIFF control difference. (Difference between t_HALL and t_s. See S654 in Fig. 19) RGL_P Proporzionalfaktor the speed controller

RGLJ integral factor of the speed controller. See S664 in Fig. 19.

For manipulated variable BW is to be noted that this determines the length of a current pulse (i or i '), which current pulse can be in turn composed by the PWM controller from minor power pulses with the length BW, and some by the processes involved in turning off the current pulse longer than BW. The hardware

Fig. 1 shows symbolically the basic structure of a two-pulse electronically commutated motor 30, which is shown in this preferred embodiment with a full bridge circuit 31 and, therefore, only a single phase winding 32 having two terminals 34, 36 has also a permanent magnet rotor 38, the four-pole rotor is shown. When the rotor 38 rotates, the winding phase 32 is alternately traversed by current pulses i from left to right and from current pulses i 'from right to left. "Two-pulse" means such a motor, because during a rotor rotation of 360 ° el., A pulse i and a pulse i 'flow, that is, two pulses. See FIG. 18. It is also a first winding phase for the pulses i and a second train for the pulses i¹ provide, as is known to the expert. A two-pulse motor can thus be single or double-stranded.

the motor 13 for the interval between two pulses I, I '(or I' and I), in which no current flows, takes his driving an auxiliary torque, which is referred to as reluctance torque MR. See., because it through the interaction of the permanent magnet rotor 38 is formed with provided on the stator iron masses, such as the core (lamination stack) of the stator. Such motors have been manufactured in quantities of hundreds of millions, which is why it does not appear necessary to describe it in its many variants.

The motor 30 is powered from a DC power supply with a positive line 40 (eg, + 24V) and a negative line 42 (GND) with electricity. Further, a voltage source to a regulated supply voltage of +5 V for example is provided whose output is designated 43rd This is described in Fig. 6.

The winding section 32 are associated with four freewheeling diodes 44, 46, 48, 50th The cathodes of the diodes 44, 46 are connected to the positive line 40, the anodes of the diodes 48, 50 to the negative line 42. The anode of diode 44 and the cathode of the diode 48 are connected to the terminal 34th The anode of diode 46 and the cathode of the diode 50 are connected to the terminal 36th

To control the currents I, I 'used in this example, two power operational amplifier (op amp) 52, 54. In this preferred embodiment, they are connected as comparators or as inverting amplifier. The output of op amp 52 is connected to the terminal 34, the output of op amp 54 to the connector 36. Of course, the bridge circuit can also be implemented with other semiconductor elements.

From terminal 43 (+ 5 V) leads a resistance 56 to the positive input 5 of OPV 52, and from there another resistor 60 to the negative line 42nd

Also leading from the terminal 43 (+ 5 V), a resistor 62 to the positive input 64 of op amp 54, and from there another resistor 66 to the negative line 42nd

Preferred values ​​of the components in FIG. 1

Resistors 56, 60, 62, 66 ... 22 kOhm

Operational amplifiers 52, 54 ... L2720, manufactured by SGS

These operational amplifiers preferably include a built-in current limiter to prevent an overload.

Since the odds are the same size, is obtained at the inputs of both OPV Plus 52, 54, a potential of +2.5 V.

The negative input 70 of the op-amp 52 is supplied with a control signal that is either larger or smaller than 2.5 V, and the same applies to the negative input 72 of the op-amp 54th

To control potential is either at the entrance 70 defined by> 2.5 V, so that the point 34 is connected to the negative line 42, and a potential is applied to the input 72 then laid of <2.5 V, so that his output is connected to the positive line 40, here with +24 V. In this case, a current i 'from positive line 40 via the OPV 54, the terminals 36, 34 and the OPV 52 flows to the negative line 42. In the reverse case is the input 70 to a potential <2.5 V and the input 72 on a potential> 2.5 V, so that a current i flows from the connection 34 for connection 36th

To illustrate 1 switches are shown in dashed lines in Fig.. In OPV 52 which are an upper and a lower switch HSL switch LSL. In OPV 54 which are an upper and a lower switch HSR switch LSR. It mean HSL High Side Left

HSR High Side Right Side Left LSL Low

LSR Low Side Right

If HSL and LSR are turned on, a current i flows, and if HSR and LSL are turned on, a current i flows'.

FIG. 2 shows the circuit diagram of a microcontroller 76 of the type PIC16C711 used in the present embodiment. The connections are designated in the usual way with numbers and letters. As shown in FIG. 6, the terminal 70 of op amp 52 is connected via a resistor 78 to the output of RB3 of the microcontroller 76, and the terminal 72 via a resistor 80 to the output of RB2, that is, the full bridge circuit 31 of FIG. 1 is directly controlled by .mu.C 76 and its control program. The latter is described below under "Software". The resistors 78 and 80 can have, for example of 10 ohms.

Fig. 3 shows the generation of the signal for the desired speed (setpoint speed nset). .mu.C 76 has a multi-channel 8-bit A / D conversion, that is, it sets a supplied analog signal into a digital signal having 8 bits in order. From this A / D conversion of one channel is used at the input RAO. Since it is common in the industry, such signals either as a DC voltage with a voltage range of 0 ... 10 V to specify, or as a frequency signal having a duty ratio of 0 to 100%, a circuit according to Fig. 3 is used. This has a connection 84 for the externally supplied signal, either a DC voltage U = or a PWM signal PWM. From terminal 84 86 leads a resistance to a node 88, and from there, a resistor 90 to the negative line 42nd

From junction 88, a resistor 92 for connecting RAO of the microcontroller 76, and of RAO leads to the negative line 42, a capacitor 94. In this manner, the voltage or the PWM signal at the input 84 is converted into a voltage range which are digitized at the entrance RAO can.

Preferred values ​​for FIG. 3

Resistors 86, 90 ... 2.7 kOhm

Resistance 92 ... 680 kilohms

Capacitor 94 ... 68 nF Fig. Figure 4 shows the generation of a signal for the desired direction of rotation, which is the input of the microcontroller 76 RB1 supplied. From an input 98 for an externally supplied logic level (control signal) DIR (either applies DIR = 0 or DIR = 1) takes a resistor 100 to the input RB1, and from there, a capacitor 102 to the negative line 42. Preferred values:

Resistance 100 ... 2.7 kOhm

Capacitor 102nd ... 10 nF

If the desired speed is to be an input 98 'is supplied in the form of a frequency, the circuit of FIG. 4 is also used, but with different values, and therefore the corresponding components are designated with reference numerals in parentheses. The resistor 100 'is here also preferred 2.7 ohms, the capacitor 102' 4.7 nF, and the signal at the output is the input RB7 of the microcontroller supplied 76th

Fig. 5 shows a circuit for detecting a frequency value that is the speed of the rotor 38 is proportional.

For this purpose, in the area of ​​the rotor 38, a Hall generator 106 is provided, as indicated symbolically in FIG. 1. His current inputs are connected via a resistor 108 to the terminal 43 (+ 5 V) and via a resistor 110 to negative line 42nd Its output signals are the negative input 112 and the positive input 114 of 116 OPV supplied its output 118 via a feedback resistor 120 to the negative input 112 and directly to the input of the microcontroller RB0 76th The input RB0 has an interrupt-on Change function, ie when the signal rises rapidly on Hall generator 106 or rapidly falling, in .mu.C 76 a so-called Hall interrupt is generated. This is used to control the commutation of the motor 30 and for detecting its rotational speed. Preferred values ​​in Fig. 5:

Resistors 108, 110 ... 470 Ohm

Resistance 120 kOhm ..J OO

Hall generator 106 ... HW301A FU

OPV 116 ... LM29030 Fig. 6 shows a preferred circuit shown in FIGS. 1 to 5 in the synopsis. The same or similar parts the same reference numerals are used throughout the figures, and these parts are usually described only once.

The positive lead 40 is connected via a diode 128 to a terminal 130, may be connected to a battery 132 of the example. The diode 128 prevents destruction of the circuit, when the battery is 132 connected in reverse polarity. A capacitor 134 (eg, 10 microfarads) is connected between the lines 40 and 42 and serves to absorb energy, which is fed back via the freewheeling diodes 44 to 50 to the line 40th

From the terminal 130 performs a resistor 134 via a node to a zener diode 138 (5.6 V) and from this to the negative line 43, to which also the emitter of an npn transistor 140 is connected, via its base to node 136 and its collector a resistor 142 is connected to the terminal 130th Transistor 140 operates as an emitter follower and supplies at its emitter and thus on the line 43 a regulated voltage of, for example + 5V, which is sieved through a capacitor 144 (10 nF).

The terminal Vss of the microcontroller 76 is connected to the negative line 42, which VDO connection with the conduit 43. At the terminals OSC1 and OSC2 is a quartz oscillator 146 (1 MHz) connected to the a series connection of two capacitors 148, 150 connected in parallel, whose junction point is connected to the line 42nd The unused terminals RA1, RA2, RA3, RA4, MLCR /, RB4, RB5, RB6 each via a resistor R (eg 10 ohms) are connected to the line 43 and are characterized on a defined potential.

The rest of the circuit shown in FIG. 6 has been described already in FIGS. 1 to 5.

Explanation of the four-quadrant operation (4-Q operation)

In Figs. 7 to 9, the four quadrants are designated I through IV.

Fig. 7 shows a diagram for a 1 -Q-operation, including operation of the engine 30 in its preferred direction. On the horizontal axis the speed N is plotted on the vertical axis, the driving or braking torque M.

In an area 150 to the zero point is not a regulated operation is possible with this type of motor, but only in a region 152. In the region 152 of the motor 30 as accelerated to a controlled speed + N. When the rotational speed + N will be exceeded, so that a higher speed value + is achieved N1, the engine 30 is replaced temporarily little or no power, so that its speed along a curve 154 etc. falls again due to friction. An active braking does not take place, but the positive torque M is reduced, possibly to zero.

Fig. 8 shows a 2-quadrant operation, ie a two-quadrant operation, in which the motor 30 can also run backwards. In reverse it is driven with a negative torque, thus achieving the controlled speed -N. Rises by external influences this speed even higher on N 1, the negative torque is its amount gradually reduced (curve 156), if necessary, to 0, so that the speed drops, etc. back to the value -N due to friction.

Fig. 9 shows the representation of a 4-quadrant operation, that is a four-quadrant regulator. It is assumed that is controlled at the drive in the forward direction at a speed + N, corresponding to the point 160th

When the rotational speed N1 is increased to a value + by external influences, corresponding to a point 162 which is above the desired speed, the controller will generate a negative (braking) torque, ie, the engine proceeds to a point 164, and there is the controller generates a braking torque, so that the rotational speed goes to a point 166 which corresponds to the governed speed + N. There is switched back to a positive torque, so that the controller goes back to the point 160, according to the desired speed + N.

The braking torque is generated in this type of motor in a very simple manner by the motor 30 is powered by a 180 ° el. Shifted commutation, ie. With the same commutation as in reverse This is described below in FIG. 19.

When the motor 30 at the speed -N runs backwards, he works at the point 168. If it is there, driven by external influences, its speed can on N 1 rise, so to the point 170. There, the 4-quadrant controller switches to a positive torque to, ie to the point 172, and by the positive torque, the speed drops back to -N, ie to the point 174 where the torque again drive is switched to the reverse direction, so that one is back at the starting point 168, so the desired speed.

In the same manner, a transition from + N (point 160) -N (point 168) is possible. For this purpose, by a command DIR = 1 (at the input 98 of Fig. 6) produces a negative torque at the rotation speed + N, ie the engine goes from the point 160 to the point 166, from there to speed 0, and then - with the same , now driving acting torque that remains on permanently - to speed -nmin at the left end of the window 150. There will be switched to speed control, and the speed is controlled to the value -N, corresponding to point 168. the motor then runs in reverse ichtung with the speed -N.

If you want to get from point 168 to point 160, which therefore the speed by the value zero and the motor reverses its direction of rotation, the course goes from point 168 to point 174 (positive torque is generated), the speed 0, and then - with the same positive torque - the rotational speed + N MIN, and then - with speed control - to the point 160 at the rotational speed + N.

The advantage of the 4-quadrant operation is that speed changes take place very quickly, so the drive is very dynamic, and that as well as the drive of a shutter is possible because during the closing of the shutter, where it draws down and thus the motor 30 drives, the latter automatically passes into the braking operation and thereby maintains the set speed. In this type of motor is also switching the torque from positive to negative or vice versa extremely simple and easy.

software

For this purpose, reference is made to Figure 10.. This shows an example of a speed range from -3000 to +3000. In this area there is the window 150, which goes from a lower minimum speed -nmin to an upper minimum speed + N MIN, for example, as shown, from -1000 to +1000.

Is as described above in this window 150, in this type of engine a Speed ​​control is not possible. When the user sets as a speed of +800 r / min, is the reason interpreted by .mu.C 76 as if the speed is set to 0, ie, the engine 30 does not start, or it will be when it is running, shut down.

As long as the current speed n is within the window 150, a flag is set Rs = 0, which "is motor" from the computer is interpreted as though the speed, for example between -999 and +999 r / min can be.

When leaving the window 150, this flag is changed to Rs = 1, so "engine is running", and in this area, where Rs = 1, the speed is controlled by a speed controller.

Further, a direction flag Rt is used. Only if during start-up or a rotation direction change the rotation speed of the window 150 leaves, the direction flag Rt is switched to the value of the currently commanded by the user direction DIR, which receives at input 98 (Fig. 6) is supplied. (DIR, either the value 0 or the value 1).

For example, when working in Fig. 10 of the motor 30 at point A, that is at a speed of 3000, with Rt = 0, and the command DIR = 1, it is given, that is the command that the Reverse motor 30 and to the point B to go, so the speed value -3000, the motor 30 is from the point A with maximum braking current is energized (ie not regulated) and falls rapidly by + N MIN, where R is switched from 1 to 0. The Information Rs = 0 instructs the computer to continue to operate at maximum braking power, so that first the speed 0 is reached, where the braking power - by the changed direction of rotation - automatically for driving current is such that the speed increases in the negative direction. During all this time the "old" rotational direction Rt = 0 remains stored. The speed is 0 through smoothly and continuously.

After reaching the speed -nmin a change of Rs = 0 results saved to Rs = 1, ie from here sets the speed control again, and the new, predefined at the input 98 direction value DIR = 1 is as Rt = 1, so that the motor from - N MIN controlled ramping up to speed -3000. The direction flag Rt is therefore not changed when passing through the speed 0, but only when you exit the window 150 of FIG. 10. In the reverse direction (from B to A) the procedure is the same mirror image exactly, ie the speed 0 is run correctly, because applies in this type of engine:

Brakes in one direction = drive in the opposite direction.

This property is exploited in the present invention in an advantageous manner.

Within the window 150 is not regulated, but the engine 30 is running there unregulated maximum manipulated variable value, so the maximum current, which may have to be limited by a current limit depends on the motor type, the motor current, as in Fig. 1 described. Preferably, the control value BW is already in the area of ​​the window 150 (19 Fig. 18) is calculated continuously for the regulation so that it is immediately available when = 0 switched to Rs 1 = Rs.

In the described 1 and 6 in connection with FIG. Operational amplifiers 52 and 54 of the type L2720 an internal current limitation is provided. Alternatively, particularly at higher powers, an external current limiting are provided.

Fig. 11 shows a state diagram for the various processes that occur in the operation-Q- 4.

The "normal" start in the forward direction

If (the engine stop, 30) by a signal DIR = 0 at the input 98 (FIG. 4 and 6), the rotational direction is right, therefore, preferred direction, specified in the state 181 and the speed setpoint nset at the entrance 86 or 98 'is greater than the minimum speed + N MIN is, the controller enters the state 182, ie, the engine 30 is running at maximum output value BW, so the maximum current, in the preferred direction (DIR = 0). The start in the preferred direction is easily in these motors. In this case, the flag is set to Rs Rs = 0, since the actual speed n is less than N MIN.

has, if the actual speed n exceeds the value + N MIN, the engine 30 goes from state 182 to state 183, ie its operating range is reached, and the speed is n now 19 regulated to the predetermined value nset by the controller of FIG. what 11 is indicated symbolically "BW via RGL" in Fig.. The motor status is switched to Rs Rs = 1, since the actual speed is greater than n NMIN become, and the controller controls the rotational speed by changing the block length BW (Fig. 18, 19) to the desired value. If the motor 30 as run faster, so the output value BW is increased within the permitted limits, ie the motor 30 then operates with a higher output value BW and consequently a higher power.

Start in the reverse direction

This type of motor is actually only for the start in a preferred direction DIR = 0 designed. Therefore, a reliable start in the reverse direction (DIR = 1) "electronic tool" needed. Here, the engine 30 initially takes from the status 181 in the preferred direction, ie against the direction of rotation commanded DIRsoii.

If the rotation direction DIR = 1, ie to the left (backward rotation; rotation in the reverse direction) in the state 181 is specified, and the specified setpoint is nsetp negative than the (negative) minimum speed -nmin, the engine 30 initially accelerated in the preferred direction, ie with DIR = 0, thereby measuring the time t_HALL between two Hall changes, ie between two Hall interrupts until TJHALL has become smaller than a predetermined value TG, and then energized again for a time (TG - EW), so that the motor 30 magnetic energy for the can store lapel Start, then reversed from this state, and speeds up -nmin maximum manipulated variable value BW = MAX in the reverse direction. This is the state value 184. The EW is an empirically determined constant for the relevant motor 30 in its specific application, eg installed in a fan.

After reaching -nmin Rs = 1 is set, and the motor switches to the state 183rd There, the speed of the speed controller (Fig. 19) is regulated to the desired value ( "BW via RGL"), and the set target direction (DIR = 1) is now stored as a flag Rt = 1.

.mu.C 76 has in this example for detecting the speed of a counter which can only count up to 64,000 microseconds, ie to 64 ms. This means that the rotational speed n can be measured only when the time between two Hall interrupts less than TG = become 64 ms. This time corresponds to a rotor rotation of 180 ° el. When the motor 30 is too slow during the measurement, there occurs an overflow, and this measurement can not be used therefore. Therefore, the motor 30 as long as in the preferred direction (DIR = 0) is driven until the time between two Hall interrupt has reached a value of less than TG = 64 ms. When the motor 30 a little DG² has it reaches this speed n already between the two first Hall interrupts, but at a fan with large fan it takes longer for this speed is reached.

When the speed n become so high that between two Hall interrupts the

Time TJHALL for 180 ° el. For example, is 63.8 ms, which corresponds to a speed of 235 rev / min, ie 60 / (4 x 0.0638), thus it is drawn from this so determined time t_HALL the empirically determined value EW from , ie performs the operation

(TJHALL - EW) ... (1), and from the next Hall interrupt you measure this time (t_HALL - EW) and turns on its expiry in order to commutation in the opposite direction, ie, until this time, the rotor 38 in the desired direction driven. At this moment the value t_HALL practically corresponds to the value of TG.

This is illustrated in Fig. 12 for a four-pole motor 38. Fig. Figure 12 shows two Hall interrupts 190, 192. Between these a time TJHALL is first measured, which is less than TG = 64 ms. From this time the value EW is subtracted, for example, 5 ms. From the Hall interrupt 192 the calculated time (TJHALL - EW) is now measured, and the time 194 = 0 in energized in the desired target direction, ie with DIR = 1, switched from DIR. This means the drive in the reverse direction.

The motor 38 runs in the process through its stored energy initially to a small angle further in the preferred direction, and EW is empirically determined so that the motor to a rotational position continues where it has stored in its magnetic circuit enough magnetic energy to to support the launch in the reverse direction and allow to. One can say that the rotor 38 at its initial start in the preferred direction, ie the "wrong" direction of rotation, "swing outdated", ie stores magnetic energy for the start in the reverse direction, and by this "momentum" of the motor then runs from this empirically determined to start site in the reverse direction from any problems.

For this purpose, still 13 referenced to the diagram of Fig., Where the variation of the reluctance torque MR is shown schematically. At the point 196 of the rotor 38 has a shape defined by the reluctance torque MR rest position because MR is there = 0, and when, in the preferred direction (DIR = 0) starts the braking reluctance torque 198 so that a start rising, albeit relatively slowly, smoothly is possible. Starts the rotor 38 but in the reverse direction (DIR = 1), as occurs immediately after the start occurring at 196 a steeply rising braking reluctance torque 200, the there can prevent the start. Therefore, the rotor is energized in the direction DIR = 0 rotated to about 38 to a location 202 (Fig. 13) in this case, from which it can easily start in the direction DIR = 1.

Transition from state 183 in the braking state

There are several options: a) The speed n is to be reduced. b) The motor 30 should be stopped. c) The motor is to be reversed.

a) The rotational speed should be reduced.

If only the speed n is reduced without changing the direction of rotation, so the setpoint is nsetp smaller than the value n, and the controller enters the state 185 where added with the corresponding (controlled) power of the engine by 180 ° el. is energized, which is indicated symbolically by "inv 180 °". The sequence of current pulses i, i 'is in this case inverted, so vice versa. The flag Rs retains the value 1.

If the setpoint nset again greater than or equal to the value n, the controller of 185 returns to state 183, ie the el.versetzte 180 ° energization is switched back to a normal energization. The new speed is thus achieved by a "skilful braking" by inverse energization, which enables very fast control processes.

b) The motor 30 should be stopped.

If the setpoint nset smaller than | N MIN | (Including the target value 0), is also braked by the energization is shifted by 180 ° el, and the controller will -. About the state 185 and the path 185 '- in the state 181, so Rs = 0, BW = 0 and halt because below | N MIN | For physical reasons, a speed control is not possible and therefore such a setpoint is interpreted as nsetp desired speed 0th The manipulated value BW is provided thereby to 0, ie, the power to the motor 30 is switched off.

c) The motor is to be reversed.

Target - from the state 183 out - the motor 30 are reversed, as applicable in accordance with

183 '

Desired direction ≠ Istrichtung, and the controller enters the state 186. Here, the engine 30 with maximum output value BW is energized in the direction of braking, ie with "inv. 180 °", below here | N MIN |, and enters the state 188, where Rs is switched to 0 as long as the speed n in the window 150 (Fig. 10), ie between + n MIN and -nmin lies. Status 188 (Rs = 0) therefore does not mean that the engine 30 is actually, only that its actual rotational speed n is below the predetermined values. This shows Fig. 10. Within the entire window 150 is Rs = 0, and that gives .mu.C 76 the information to drive there with maximum output value, ie maximum current, according to the state 186. (The change in R = 0 in state 188 is a state change and is therefore presented separately.)

When reversing the direction of rotation of the motor 30 10 example is shown in Fig. From A to B, ie from state 183 to state 186. Although this case the predetermined target rotational direction DIRsoii has the value 1, the previous value Rt remains = 0 initially for the direction of rotation stored, and because is defined as a new rotation direction DIR = 1 and the new speed outside the window 150 (Fig. 10), is replaced by the .mu.C 76 the information that the engine must be 30 energized with full control value in the reverse direction (state 186 ). In the previous direction of rotation which means a braking operation with a high power, and this type of energization high current is between A and B continued unchanged until the speed - N MIN, ie by leaving the window 150, but being from the speed 0 by the rotor 38 in the winding 32 induced voltage, the amplitude of the current pulses i and i 'is reduced. Here, the speed is 0 through problems continuously.

From -nmin .mu.C 76 goes to state 187 where Rs changes from 0 to 1, ie from where it set the speed control (Fig. 19), and the flag Rt = 1 for the new direction value DIR = 1 (at the entrance 98 Fig. 6) will now be saved (state 187), so that the motor starts up nsetp regulated 30. -nmin to the desired speed, according to the state 183 of FIG. 11.

. In the reverse direction, ie in Figure 10 from B to A, the process is a mirror image from same, ie the speed 0 is run correctly, because in this type of motor applies: brakes in one direction = drive in the opposite direction.

Within the window 150 to the 0 speed around is therefore not regulated, but the engine 30 is running there unregulated maximum manipulated variable value, because in this area a control is not possible, but still the output value BW is preferably continuously calculated for the speed control, so that it is immediately available, if Rs is switched from 0 to 1 and the speed control must also use there.

Fig. Figure 14 shows the flowchart of a routine S204 for comparing the desired direction DIRsoll with the actual direction DIRist as' taking place in Fig. 11 at the location of the 183rd

In step S206, it is checked whether DIRist = is DIRsoll. If so, the program proceeds to S208 (normal operation), ie, in FIG. 11 is the state 183 unchanged.

If in S206 the answer is NO, in S210, the current is set to a maximum value, and in S212 is changed to 180 ° el. Of phase commutation. This corresponds in FIG. 11 the state 186th

Thereafter, the routine goes to step S214 S204 "Return".

Fig. 15 shows a routine S220 labeled "Motor Status". In S222, the instantaneous value of Rs tab Rsalt is stored. It is then checked in S224 whether the absolute value | n | the instantaneous speed is greater than the absolute value | NMIN | the minimum speed, that is, whether the speed n outside the window 150 is located. If YES is set in S226, the flag R to 1, which means that the engine 30 with a | n | > | N MIN | running and there must be a control of the speed. If NO is set in S228 Rs to 0, which means that the speed is within the window 150 (Fig. 10), which is why a speed control is not possible.

It is then checked in step S230 whether Rs continues to have the value in accordance with S222, or has changed. The latter means that the threshold of speed, ie | N MIN |, was exceeded in one direction or another, why then must then be tested, the direction in which this threshold was exceeded. If in S230 the answer is yes, the routine goes to its end, namely to S232 Return. If NO, the value of Rs since step S222 has changed, and in S234, it is checked whether Rsalt = 0 was. If NO, this means that Rsalt had the value 1 and has changed to Rs = 0, meaning that the actual speed has now n has a value within the window 150, and the routine S220 through S232 leaving.

If in S234 the answer is YES, this means that the speed of the motor 30 is increased, the threshold | NMIN | exceeded, and now outside the window 150 (Fig. 10), which is why in S236 the flag Rt now the new desired direction value DIR assumes that was specified by the user at the input 98, and a transition is made in S238 RGL to a speed control, so that the speed controller intervenes and adjusts the speed nset to the value specified by the user. After exiting from this routine S220 through S232.

Figs. 16 and 17 show a discrimination function S250, which serves to control the operations at startup, a speed change or a change of direction of the motor 30.

In step S252, it is checked whether a new value for the target speed is present nset. This value is used as a time t_s specified in the present embodiment, the engine should the need 30 for example for a rotation of 180 ° el.. If YES, the new value for nset (ie t_s) is stored in S254, and in S256, a flag with the label "nset NEWFLG" is set to 1 to indicate that a new value is available.

If in S252 the answer is NO, the program goes to S258, where it is checked whether a new value for the actual rotational speed n is present. (In the embodiment, the time TJHALL used as the value for the actual speed, the rotor 38 is required for a rotation of 180 ° el.). If NO, the program goes to S252 back. If so, the new value of n is stored in S260, and at S262, a flag is set to 1, which has the designation "n NEWFLG", to indicate that a new value of n is present. As described below, when two new values ​​are available, calculation is made with these values, and then both of the flags are set to 0 to indicate that these values ​​are "processed" are at S268.

Subsequent to S256 and S262 it is checked in S264 whether the two flags from S256 and S262 is "1" have. If NO, the program goes back to S252. If YES, calculated in S266 from the two new values ​​for n and nset, ie from TJHALL and t_s, a new control value BW. This value indicates the length of a current block in so-called block control, which will be explained in Fig. 18. (The calculation of BW will be described in Fig. 19). Then in S268, the two flags

"N NEWFLG" and "nset NEWFLG" reset to "0" to indicate that the two current values ​​have been processed to a new control value BW.

In step S272 (Fig. 17), it is checked whether the target speed is nsoll inside or outside of the window 150 (Fig. 10), that is, whether

| Nsoiι | > | N MIN |? ... (2)

If NO ( "N"), is this to be interpreted such that the desired speed is equal to zero, and it is then checked in S274 whether the actual speed n is within the window 150, so if | n | > | N MIN |? ... (3)

If the rotation speed n is outside the window 150 (Answer YES), the routine proceeds to S275, where the motor 30 with the calculated control value BW is braked. If the rotation speed n is within the window 150, so in the example in the range from -1000 to +1000 U / min, is set in S276 Rs = 0 and in S277 BW = 0, ie motor 30 de-energized, and the routine goes to S278 (Return).

If in S272 the response Y (YES), that is the desired speed nset outside the window 150, it is checked in S280, the direction in which the motor is to start 30. The default DIR = 0 at the input 98 indicates that the motor is 30 start in the preferred direction. DIR = 1 means starting counter to the preferred direction.

If in S280 the answer is yes, so start in the preferred direction, the usual commutation is in S282 in the preferred direction "0" at the maximum manipulated value BW, ie maximum current to a quick start, that takes place within the window 150 no speed control.

Then, the routine goes to step S284, where it is checked whether the actual speed n is outside the window 150th If NO, the routine returns to S272. If YES, the routine proceeds to S286, where the flag now Rt gets the current value of DIR, so in this case Rt = 0, since the motor 30 in the preferred direction "0" runs.

Subsequently, in S288 is set Rs = 1, to indicate that the current speed n has a value outside the window has reached 150, and that, therefore, the motor 30 must be operated with speed control now. This flag Rs will be evaluated depending on μC76. See Fig. 15, and switches the speed control n_CTL a, so that in S289 of the engine, ie regulated 30 with the calculated output value BW, accelerated.

If in S280 DIR = 1, this means a start against the preferential direction, as has already been explained in FIG. 12. In this case, the routine proceeds to S290, where the motor 30 is - contrary to the command DIR = 1 - in the preferred direction "0", ie with DIR = 0, with a maximum adjustment value BW is started, as in S282.

is then checked in S292 whether the time TJHALL (Fig. 12), ie the time between two successive Hall interrupts is smaller than a time TG become that is 64 ms in this example, as already explained. (The time TJHALL corresponds to the time for one quarter rotation of the four pole rotor 38. In S292 is thus in this example - indirectly - retrieved, whether the rotor 38 has reached a rotational speed of at least 234 U / min). If the answer is NO, the routine returns to S290, and it will continue with the maximum output value BW, ie maximum current commutated in the preferred direction until the condition is fulfilled by S292.

Most engines situated only a quarter of a turn, a speed of 234 rev / min, because the start is with the maximum current. In some drives it may be that a larger angle of rotation is required to achieve a level of TJHALL, which is less than TG.

If in S292 the answer is yes, so has the value of 234 U / min is reached or exceeded, the speed is in S294 in a TIMER value (TG - EW) loaded, and this TIMER is started. It is then checked in S296 whether TIMER = 0. If NO, that is if the time (TG - EW) has not yet expired, the routine goes to S294 back.

If in S296 the answer is YES, the routine proceeds to S298, where now - is switched commutation to commutation in the reverse direction "1" at the maximum manipulated value BW, so that the speed reached by the - according to the command DIR = 1 at the entrance 98 +234 r / min over the speed 0 to the desired negative speed, eg -1205 U / min, starts up, the speed 0, ie the zone standstill, is running smoothly.

Subsequently, at S298, the program proceeds to S284, where it is checked whether the actual speed n already outside the window 150. If NO, the routine returns to S272, as already described, and if YES, it proceeds to S286, where now Rt = 1 is set, ie the set by the user at input 98 rotation direction DIR = 1 after leaving the window 150 also stored in flag Rt in μC76 so that this value Rt = 1 assumes, and then is set to 1 in S288 Rs to indicate that now the speed control is activated, and at S289, the motor 30 on operation with the routine S266 calculated manipulated value BW switched, ie operation with speed control. In S278 then the routine is exited S250.

FIG. 18 is for explaining operations during the commutation of the motor 30.

Fig. Figure 18a shows a PWM signal, which is continuously generated and, for example, has a frequency of 20 kHz. Its pulse duty factor pwm is programmatically set. It should be noted that the present invention may be practiced without using such a PWM signal. With this duty ratio, the amplitude of the current pulses i, i '(Fig. 1) can be controlled, which are the motor 30, respectively.

Fig. 18b shows signal HALL. This has leading edges 370 at the transition from LOW to HIGH, and has sloping edges 372 at the transition from HIGH to LOW.

The times t1, t2, etc., where these edges occur are measured by a ring counter TIMER1 and saved in a temporary variable t_TEMP. Referring to FIG. 18, to rule the leading edges 370, the switching on of transistors HSL and LSR, ie of current i of FIG. 1. Conversely govern the falling edges 372 the switching on of transistors HSR and LSL, ie of current i 'of FIG. 1.

The duration t_HALL between two flanks is calculated as

TJHALL = t2 - 11 ... (4)

This period of time is a measure of the current speed n of the rotor 38 and corresponds to the time that it requires for a rotation of 180 ° el.. Of course, this time can be measured in many ways. Preference is measured when the speed is high enough, the time for a larger angle of rotation, in particular for one or more full turn (s) of the rotor 38, which corresponds to an angle of rotation of 720 ° el. (Or multiples thereof) in the embodiment , - The measurement over a full turn is particularly accurate, but assumes that a certain minimum speed is reached.

Fig. 18c and Fig. 18d show highly schematically the signals for controlling the H-bridge shown in Fig. 1. Fig. 18c shows signals HSR, LSL for switching on current i '. Fig. 18d shows the signals HSL, LSR for switching on current i.

The beginning of the pulses 444 of FIG. 18c is calculated from the falling edge 372 of an associated signal HALL, which is symbolized by the arrow 445, and the beginning of the pulses 446 of FIG. 18d is calculated from the rising edge 370 of the associated HALL signal as corresponding by arrow 447 symbolisiert.Die edges 370, 372 of signal HALL predetermined, measurable rotational positions of the rotor 38. These are in the calculation of commutation the single rotational positions that are precisely known, and therefore the calculations are based on these "fixed points".

Assuming that the control signals 444, 446 symmetrically with respect to the

Pulses of signal HALL are concerns for the time t3, at which a signal

446 begins, the value of t3 = t1 + t_HALL + (TJHALL - BW) / 2 ... (5)

this means

BW = block length of signals 444, 446. This block length is' the

Speed ​​controller RGL calculated, which will be described below with reference to FIG 19, and it is therefore -. As usual - referred to as the manipulated value.

Analogous to this, for the time t4 at which the control signal 444 is to begin, the value t4 = t2 + t_HALL + (TJHALL - BW) / 2 ... (6)

It should be noted that as the time t3 is calculated not from time t2 (immediately preceding edge 372 of signal HALL), the most densely at t3, but from an earlier time t1, namely from before the previous one edge 370 The reason is that if BW = TJHALL is, the time t2 would coincide with time t3, which is impossible, since between t.2 and t3 calculation steps must be performed.

If a so-called ignition angle, for example by a fixed value VZ used, the above formulas are modified as follows: t3 '= t1 + t_HALL + (OJHALL - BW) / 2) - VZ ... (7)

t4 '= t2 + t_HALL + ((TJHALL - BW) / 2) - VZ ... (8)

In this case, the times are t3 'and t4' to the size VZ further to the left, as shown in Fig. 18d 'indicated what switched on slightly earlier the currents i and i' for t3 means and can bring about an improvement in efficiency. It is also evident that t3 'occurs earlier than t2 in this case, which is possible only because reference time RefTime for calculating t3' is not time t2, that is, the falling edge 372, but the time t1, so the rising Hall edge 370, as symbolized by the arrow 447th VZ is usually a constant, but can also be a speed-dependent function or are constantly being optimized through separate, not shown parts of the program.

Fig. 19 shows the routine RGL S266 for speed control. This is based on a comparison of the Hall time t_HALL with the target time t_s, the latter the desired speed corresponds nset and can be set at the input 84 in the form of a PWM signal or a DC voltage. The controller according to the exemplary embodiment therefore does not work directly with speeds, but with time it takes for the rotor 38 for a given angle of rotation or to need. The reverb time t_HALL corresponds to the time that the rotor 38 required for one rotation of 180 ° el.. If the rotor 38 with four poles and rotates at 3000 rev / min, so shall TJHALL = 60 / (3000 * 4) = 0.005 s = 5 ms ... (9)

Analog is this time at 1000 U / min

TJHALL = 60 / (1000 * 4) = 0.015 s = 15 ms ... (10)

At low speeds, so the actual value t_HALL is very large and is then substantially larger than the target value t_s, is the example of 3000 U / min 5 ms. Out Therefore, the system deviation RGL_DIFF as shown in step S654 preferably the difference (TJHALL - t_s) in order to obtain a positive result of the subtraction.

In S656, it is checked whether the system deviation is greater than an allowable maximum value of positive RGL_DIFF_MAX. If that is the case, at S658, the system deviation is set to this positive maximum value. This is especially when starting up important because there the system deviation would otherwise become very large.

If NO is the answer in S656, the program goes to step S660 and checks there whether the system deviation is less than a permitted negative maximum value -RGLJDIFFJV1AX. If YES, set the control difference to this negative maximum value at S662. (This refers to the case that the engine is faster than the desired speed).

In the steps S658, S660 or S662 follows S664, where the calculation steps of a PL controller to run. For this purpose, the error signal is multiplied by a proportional factor RGL_P, may have a value of 2, for example, and it is the proportional component RGL_PROP.

Similarly, the error signal is multiplied by an integral factor RGLJ, which may be for example 0.0625, and is then added to the old integral component RGLJ NT, so as to obtain a new integral component.

Finally, the length BW of a current block 444 or 446 (FIG. 18) is calculated as the sum of the new proportional component and new integral component.

Proportional factor RGL_P and integral factor RGLJ be determined empirically, depending mainly on the size of the motor 30 and the inertia of the load being driven.

The PI controller S664 can provide a control value BW whose magnitude | BW | is too large. Since this amount can not be greater than the time t_HALL, the 38 required by the rotor to rotate 180 ° el., In the next step S666 checks whether BW is too large, and possibly the block length in step S668 is limited, eg to the instantaneous value TJHALL or a slightly smaller value. If in S666 the answer is no, the routine goes to step S266 S670, where it is checked whether BW is smaller than -TJHALL. If YES, set in S672 BW: = -T_HALL, ie BW is on -T_HALL (or the amount for something smaller value) limited. The in S664 calculated sign (+ or -) will remain here.

The command "inv. 180 °" will always stop the energization of the motor to the instantaneous direction in the opposite direction.

example 1

The engine is running, according to the command DIR = 0, in the preferred direction. The DIR command = 1 is given. The current supply is then "180 ° inv." So switched by that the motor is braked and driven in the reverse direction.

example 2

At the end of Example 1, the motor with DIR = 1 is running in the reverse direction. The engine now gets the instruction DIR = 0. Also, now is a command "inv. 180 °" switched the current supply, in such a way that the motor is braked and is then driven again in the preferred direction.

For the switching of current flow results in the embodiment of FIG. 6 is a very simple way, because there the OPV is 52 controlled by the output of the microcontroller 76 RB3, and the OP 54 is 76 controlled by the output of the microcontroller RB2.

In a reversal of the current flow in .mu.C 76 a switching is made such that the commutation, which were previously supplied to the output RB3, are now applied to the output RB2, and that the commutation, which were previously supplied to the output RB2, now the output RB3 are supplied.

For engines with more complex circuits can also be the signals at the outputs RB2 and RB3 calculated using a slightly different scheme, in accordance with the following formulas

t3 = t2 + TJHALL + (TJHALL - | BW |) / 2 ... (11) t4 = t1 + TJHALL + (TJHALL - | BW |) / 2 ... (12) In "inv. 180 °" by either the formula (7) is then switched to the formula (11), or vice versa, of the formula (11) to the formula (7), and exactly analogous of the formula (8) to the formula (12), or vice versa, of the formula (12) to the formula (8).

The disconnection takes place in all cases (t3 + | BW |) or (t4 + | BW |), so that the current in each case during a time | BW | flows. A preignition VZ can, if desired, be analogous to the equations (7) and (8) are considered.

Following S670, the program goes to S674. Which checks what type of DIR command is present. This command may differ from the current state of the engine naturally. For example, the engine can at the moment the command DIR = 0 have received, so forward motion, but the engine is still running in the reverse direction because the previous command DIR = 1 was.

If DIR = 0, this means that the command to run is in the preferred direction, and the program goes to S676, where the sign of the manipulated value BW is checked, which is accomplished by examination of the most significant bit MSB, which has the value 0, when the manipulated value BW is positive.

If the computed in S664 manipulated value BW is positive, it means that the current is supplied in the right way in order to drive the motor in the preferred direction, and that the speed is not too high, and therefore the output value BW is unchanged supplied to the engine, symbolically indicated in S678. There is symbolically expressed as | BW | ~> MOT.

If it is determined in S676 that the manipulated variable has a negative sign, it means that either the engine speed is too high, but the motor is rotating in the preferred direction, or that the engine is currently being driven in the reverse direction. In both cases, the program goes to S680, where by "inv. 180 °" switches the direction of current flow, the pulse length is determined by the size of the control value BW. This either reduces the speed of the motor (when rotating in the preferred direction) until BW becomes positive again, or the rotational direction is reversed, which then also BW given a positive sign. If in S674 the answer is no, this means the DIR = 1 command, so running in the reverse direction.

In this case, the sign of the calculated manipulated variable BW is checked in S682. If this sign is negative, it means that the command DIR = 1 corresponds to the instantaneous direction of rotation of the engine, ie the engine is running in the reverse direction, and the program goes to S684, where the engine is unchanged energized with the calculated output value BW in the reverse direction ,

Is in S682, the answer is no, this means that the output value BW has a positive sign, ie either that the engine speed is too high, the motor rotates in the reverse direction, or that the motor is energized at the moment in the preferred direction so opposite to the DIR command =. 1

In both cases, the program goes to S686, where the direction of current flow is inverted. Thus, the motor is now energized in a direction opposite to the previous energization direction whereby either its speed falls until until the calculated manipulated variable BW is negative again, or the rotation of the motor is reversed, so that it runs at the desired speed in the reverse direction.

The right half of the flowchart of FIG. 19 (steps S676, 678, 680) thus relates to the case that the engine is the DIR command = 0 has to run in the preferred direction, and means the left half (steps S682, 684, 686), that the engine has the DIR command to run in the reverse direction.

Subsequently, at the steps S678, S680, S684 and S686, the routine proceeds to S688 (RETURN).

By the Fig. 19 routine is thus obtained a control value BW, the amount of which is the smaller, the more the actual speed approaches the desired value nset. The sign of the calculated manipulated variable specifies in this case whether the speed is too high or too low. If the value is exceeded nsetp commutation is switched to commutation counter to the set rotation direction DIR, so that then controlled the motor 30 decelerated nset to the desired speed, whichever the amount to greater than the minimum speed N MIN. Naturally, an extraordinary number of variants and modifications are possible within the scope of the present invention. For example, can be a part of the functions is omitted or replaced by others, or it can be added additional functions, depending on the requirements of customers. Particularly suitable is the invention of the drive fans whose rotation must be switched and where the speed also needs to be respected, for example if the fan speed is increased by gusts of wind. Another application are drives of shutters, blinds and the like. A great advantage of the invention is that both the motor as for the electronics, the cost is lower than with previous actuators with similar functions.