Automatic electric battery charging apparatus
20 claims: 6 independent, 14 dependent
- 1Conclusies 1. Automatische, elektrische batterijlaadinrichting, voorzien van middelen voor het waarnemen van de laadstroom en het instellen van deze stroom op een gegeven waarde, gekenmerkt door middelen die reageren op de batterijspanning 30 voor het progressief reduceren van de genoemde waarde volgens een funktie van de batterij spanning, zodat de stroom geleidelijk wordt gereduceerd als de spanning geleidelijk stijgt, althans gedurende het deel van het laadproces, waarin gasontwikkeling optreedt en 770 2 00 1 de batterijspanning bij constante stroom betrekkelijk snel gaat stijgen.
- 2Automatisch werkende, elektrische batterijlaadinriohting, gekenmerkt door een spanningscomparator voor het vergelijken van een referentiespanning met een stuurspanning 5 die varieert met de batterijspanning;middelen voor het herhaaldelijk stapsgewijze laten toenemen van de referentiespanning ten opzichte van de batterij spanning als de stuurspanning de referentiespanning overschrijdt en middelen voor het stapsgewijze doen afnemen van de laadstroom als de referentiespanning met een stap 10 wordt verhoogd.
- 3Inrichting volgene conclusie 2,met het kenmerk, dat het stuursignaal constant wordt gehouden met betrekking tot het batterijsignaal.
- 4Inrichting volgens conclusie 2 of 3,met het 15 kenmerk , dat de spanningsetappen nagenoeg gelijk aan elkaar zijn.
- 5Inrichting volgens één van de conclusies 2 t/m 4, m e t het kenmerk, dat de aanvangsreferentiespanning zodanig wordt gekozen, dat het signaal van de batterijspanning deze pas 20 bereikt na verloop van het grootste deel van de duur van het laadproces.
- 6Inrichting volgens één van de conclusies 2 t/m 5» m e t het kenmerk, dat de middelen voor het opwekken van een referentiespanning bestaan uit een spanningscomparator, die 25 een signaal dat evenredig is met de batterij spanning vergelijkt met de referentiespanning, een klok die door de comparator wordtgestuurd teneinde een puls uit te zenden als het signaal van de batterij spanning de referentiespanning overschrijdt, en een digitaal-analoog-omzetter die een analoog referentiesignaal 30 levert dat overeenkomt met het aantal door de klok uitgezonden pulsen.
- 7Inrichting volgens conclusie 6,met het kenmerk, dat de digitaal-analoog-omzetter een binair weerstandsnetwerk bezit, aangesloten op een binaire referentieteller voor 35 het stapsgewijze wijzigen van de uitgangsspanning (of -stroom) van het netwerk. 770 2 00 1
- 8Inrichting volgens één van de voorgaande oonolusies, gekenmerkt door een invertor die een stijgend referentiesignaal dat met de batterijspanning overeenkomt, omzet in een dalend referentiesignaal waardoor de laadstroom wordt gestuurd.
- 9Inrichting volgens conclusie 8, gekenmerkt door een stroomsignaal-spanningscomparator voor het vergelijken van een signaal dat overeenkomt met de feitelijke laadstroom, met het dalende referentiesignaal en voor het laten afnemen van de laadstroom als de eerste de laatste overtreft en omgekeerd.
- 10Inrichting volgens één van de conclusies 2 t/m 9> m e * het kenmerk, dat bij het laden van loodaccumulatoren de referentiespanning toeneemt met stappen van niet meer dan 0,020 volt per cel.
- 11Inrichting volgens één van de conclusies 2 t/m 10, gekenmerkt door middelen voor het inleiden van het beëindigen van een fase van het laadproces als het tijdinterval tussen de stappen een bepaalde waarde overschrijdt.
- 12Inrichting volgens conclusie 11,met het ken merk, dat de beëindiging van de fase van het laadproces worde voltooid door uitschakeling van het laadproces. 15· Inrichting volgens conclusie 12,met het kenmerk, dat de duur van het eindinterval van het laadproces nie meer dan een half uur bedraagt.
- 1314. Inrichting volgens één van de conclusies 11 t/m 1J, me t het kenmerk, dat de middelen voor het beëindigen van het laadproces (of een fase daarvan) een intervaltijdteller omvatten, die zodanig is uitgevoerd, dat hij wordt teruggesteld als de referentiespanning met een stap toeneemt en die wordt gevoed door een oscillator voor het tellen van de tijd en verder zodanig is uitgevoerd, dat de beëindiging van een fase van het laadproces aanvangt als een bepaalde telstand wordt bereikt.
- 1415. Inrichting volgens conclusie 14» m e t het kenmerk, dat de beëindigingsmiddelen onwerkzaam worden gestuurd totdat de batterij spanning een bepaalde waarde overschrijdt. 770 2 00 1
- 1516. Inrichting volgens conclusie 15, m e t het kenmerk, dat de bepaalde waarde bij een loodaccumulator 2,35 volt per cel bedraagt.
- 1617. Inrichting volgens één van de voorgaande conclusies, met het kenmerk, dat de laadstroom wordt afgeleid van een wisselstroomvoedingseenheid en dat de sterkte van de laadstroom wordt gestuurd door de fasebesturing van de ontsteking van één of meer thyristoren.
- 1718. Inrichting volgens conclusie 17, m e t het kenm e r k , dat de beëindiging van het laadproces plaats vindt door het onderbreken van de ontsteking van de thyristoren.
- 1819. Inrichting volgens één van de voorgaande conclusies, gekenmerkt door middelen die reageren op de laadstroom voor het uitschakelen van de voedingseenheid als de laadstroom daalt tot een bepaalde waarde.
- 1920. Inrichting volgens conclusie 19» m e t het kenmerk, dat het uitschakelen van de voedingseenheid wordt gestuurd door dezelfde thyristoren, die de sterkte van de laadstroom sturen.
- 2021. Automatische, elektrische batterijlaadinrichting, voorzien van middelen voor het sturen van de laadstroom, waarbij de stuurmiddelen in hoofdzaak zijn uitgevoerd als hierboven beschreven aan de hand van de fig. 1 t/m 6. 770 2 0 0 1 ro o o CHT-OHIDE GROUP LIMITED, te Londoii ro o o CHLORIDE GROUP LIMITED, te Londen Y45
Independent claims20
102 paragraphs in 1 section, as filed
Patent Board
<img file="NL7702001A_D0001.tif" />
The Netherlands
Disposal mi 7702001 (19) EN (54) Electric battery charger.
| 51 | Int.CI » .: H02J7 / 04.
(711 Applicant: Chloride Group Limited, London.
(74 | Avg .: 11r. GF van der Beek et al
DUTCH PATENT OFFICE Joh. de Wittlaan 15, The Hague.
| 21 | Application No. 7702001.
(22 | Filed February 24, 1977.
(32) Priority from 9 March 1976.
(33) Priority country: Great Britain (GB).
(31) Number of the priority application: 9393/76. | 23 | -1611 - | 62 | - * | 43) Made available for inspection September 13, 1977.
The printout of the description with claim (s) and any drawing (s) attached to this sheet contains deviations from the documents originally submitted;
the latter can be viewed on request at the Patent Council.
NO 119,065
CHLORIDE GROUP LIMITED to London.
Electric battery charging device
The invention relates to an automatically operating device for charging electric batteries.
It is known that during the last stage of battery charging when gases occur, the charging current must be limited to a value much lower than the current still permissible during the previous stages. The initial current when the voltage of the battery is low can be of the order of two to three times the current permissible in the final stage of the charge. With a simple charging device, which consists of a transformer and a bridge rectifier, as well as an impedance, such as a resistor or a self-induction, which causes the output voltage of the device to drop while the charging current increases, the current draw can be easily achieved, but this still means a long time not that the optimal variations are obtained during loading. It is preferable to keep the charging current almost constant at a maximum value over most of the charging time and only to drop this current very steeply near the end of the charge, as soon as gas development occurs. Obviously, such a property cannot be achieved with a simple loading device with falling current. Moreover, with such a simple charging device with falling current, it is unavoidable that both the charging current and the battery voltage vary with fluctuations of the input voltage.
There are already several godunn sets for lute stabilization and control of the current value godurondo hot loading process. The most famous charging program uses the so-called ΙϋΊ-characteristic, which consists of three stages. The first stage charges relatively strongly, keeping the current constant with respect to variations
7702 00 1 of the mains voltage, battery voltage or other factors. The second stage starts when the battery starts to show a slight gas development and has reached a certain voltage, generally 2.35 volts per cell with a lead accumulator. From this point on, the battery voltage is kept constant and the charging current decreases accordingly. The output stage starts when the charging current has fallen to a certain final value. Thereafter, the current is held constant at this final value until charging is terminated by a timer set either for the total charge time or set for a given charge time during the last stage.
The need for a given end level of current in the above program is disadvantageous. It limits the range of battery sizes at which a given charger can be used, while further providing the possibility, for example in the case of an old battery, that the current does not drop to the given value before turning on the output stage to loading.
According to the present invention, the automatic electric battery charging device is provided with means for sensing the charging current and adjusting it to a given value, as well as means responsive to the battery voltage for gradually reducing this value according to a function of the battery voltage, so that the current is gradually reduced as the voltage increases gradually, at least during the part of the charge, in which gas development occurs and the battery voltage would rise relatively rapidly at constant current.
According to a further aspect of the present invention, the automatic electric battery charging device is of a voltage inverter, which varies in accordance with the current voltage of the motor voltage. means for repeatedly incrementing the reference voltage relative to the battery voltage when the control signal exceeds the reference voltage and means for decreasing the charging current in stepwise manner as the reference 770200 1 voltage increases stepwise. As a result, the control signal is kept in a constant relationship to the battery signal. The voltage steps can be almost the same.
The initial reference voltage is preferably chosen such that the signal of the battery voltage only reaches this value after most of the charging time has elapsed. Thus, as indicated above, the charge current can be kept at a constant maximum value during most of the charge, and only in the last part of the charge, if gas development occurs, should the charge current be reduced to avoid damaging the battery .
The means for generating a reference voltage may consist of a voltage comparator ft for comparing a signal proportional to the battery voltage with a reference voltage, a clock controlled by the inverter to transmit a pulse as the signal of the battery voltage exceeds the reference voltage and a digital-to-analog converter, which supplies an analog reference signal corresponding to the number of pulses emitted by the clock. The digital analog converter may consist of a binary weather tooth network connected to a binary reference counter for stepwise varying of the output voltage or the output current.
The device may further comprise an inverter for converting an ascending reference signal corresponding to the battery voltage into a descending reference signal, whereby the charging current is controlled. Also, the device can be provided with a voltage comparator for the current signal for comparing a signal corresponding to the actual charging current with the decreasing reference signal and decreasing the charging current when the first signal exceeds the latter and vice versa. ,
If the device is designed to charge lead-acid accumulators, the reference voltage may rise in steps no greater than 0.020 volts per cell.
If the device is provided with means for generating a reference signal and for doing it repeatedly
770200 1 If the reference voltage increases in accordance with a step relative to the battery voltage, if the control signal exceeds the reference voltage, this device can also be provided with means for starting the end stage of a charging phase if the time interval between the steps exceeds a certain value. This is described per se in German Offenlegungsschrift 2 50θ 395 · In general, the last time interval can be chosen such that an additional equalizing charge is not necessary, in which case the final phase is completely switched off. The duration of the last interval cannot be less than half an hour.
The means for terminating the charge (or a phase thereof) may consist of an interval time counter, which can be reset if the reference voltage rises in one step, and which is fed by an oscillator for counting the time and furthermore designed that the termination of a charging phase is started when a certain counting position is reached.
Preferably, the termination means remain in an inactive state until the battery voltage exceeds a given value, in the case of lead accumulators, for example, a value of 2.35 volts per cell.
If the charging current is diverted from an AC power source, which is normal practice, the strength of the charging current is controlled by the phase stringing of the ignition of one or more thyristors, in which case the charging termination can be accomplished by the ignition to end.
The device according to the invention may further comprise means responsive to the charging current for switching off the power supply if the charging current drops below a given value, for example by interrupting the connection to the battery. Switching off the power supply in this case can be controlled by the same thyristors, which control the strength of the charging current and, if desired, the end of the charge.
The invention will now be further elucidated with reference to the drawings, on which exemplary embodiments are shown.
Fig. 1 shows a block diagram of an automatic electrics
770200 1 battery charging device according to the invention;
Fig. 2 shows a more detailed circuit for the reference stage voltage generator and the interval time counter;
FIG. 3 is a schematic of a flow beat circuitry; FIG. 4 is a schematic diagram of a synchronization and phase angle driving circuit;
Fig. 5 shows a diagram of a power supply for thyristor control;
Fig. 6 shows a diagram of a current sensitive unit for switching off the power supply;
Fig. 7 shows curves of the battery voltage and the charging current plotted as a function of time.
The embodiment to be described comprises important parts of the device described above. In the following, a charging device is described in which the charging (or its phase) is terminated in response to the rise rate of a control signal, according to the battery voltage which is compensated for variations of the AC voltage of the power supply. The device therefore automatically switches off the charging device when the battery is almost fully charged, regardless of significant variations in the supply voltage.
This is achieved in the previous device without the need to control the voltage, thereby avoiding the extra expense for a stabilized voltage supply, which can become extra expensive if the current to be controlled involves kilowatts in power. However, there are applications in which it is important to terminate a charge as soon as possible, or a charge must be able to be completed within a given time, regardless of fluctuations in the AC voltage supplied. Thus, as in the aforementioned known apparatus, if the charging current and therefore the time for ending a charge varies with the AC voltage supplied, the charging device must be designed so that the charging current can be processed at the maximum supply voltage, without the battery or the damage the loading device. However, for the termination of a charge within time, this can only be relied on at the minimum supply
770 2 00 1 AC voltage. '
The present invention relates to the control of the charging current in such a way that it is virtually independent of the supplied alternating voltage over a very wide range thereof and modifies this charging current as the charge progresses, so that the current decreases in accordance with the increase in the battery voltage.
Fig. 1 of the drawings shows a block diagram in which the reference numbers indicate the different connections between the different blocks or parts of the circuit, as well as the signals passing through these connections, while the different blocks, which are also with reference numbers indicated in more detail in Figures 2 to 6.
The charging device basically consists of a transformer of conventional type, a choke and a rectifying device 20. The current flowing to the charging device from an alternating current source 21 is controlled by two oppositely connected thyristors 22 and 23, which are connected in such a way that the AC input voltage to the transformer is controlled.
The signal indicating the battery voltage is taken from the charger from the output terminals 1-2 while the signal indicating the charging current is taken from a shunt resistor between the points 3-4, which is connected in series with the charging cables .
Thyristors 22 and 23 are fired by current pulses in each of the two gate circuits 14, 15 and 16, 17. These pulses 25 are generated by a thyristor controller 24 (FIG. 5). The starting point for each pulse in the period of the mains voltage is controlled such that the phase angle of the ignition of the thyristors is varied in order to set the average voltage applied to the primary winding of the transformer according to the desired charging current. .
The thyristor control unit 24 receives three signals 11, 12 and 13. The signals 11 and 12 are low power voltage pulses which turn on the gate current pulses at an appropriate point of the mains voltage period. The pulses are supplied 35 by a synchronization and phase control unit 25 (Fig. 4). It
770200 J signal 15 occurs when the battery is turned off and stops supplying current pulses to the thyrite port. The signal is supplied by a current sensitive trip unit 26 (FIG. 6) and occurs in the form of a short circuit across the inputs for signals 11 and 12.
The synchronization and phase angle control unit 25 itself receives two signals 10 and 7. The signal 10 is a DC voltage, the amplitude of which controls the moment at which the signals 11 and 12 occur in the period of the mains voltage. It is supplied by a current signal comparator 27 (Fig. 3). The signal 7 is the signal indicating the end of charging and occurs in the form of a short circuit across the input for the signal 10. It is provided by a dV / dt unit 28 (Fig. 2).
The current signal comparator 27 forms part of the logic current control circuit 29 (Fig. 3), which also includes a current signal amplifier 3θ connected across the load current shunt resistor
3-4, as well as a stage signal inverter and a current draw control circuit 31, which receives a signal 5 from the dV / dt unit 28. The comparator 27 compares the DC voltage in the outputs of the other two units 3θ1n 31, which represents the charging current and represent the reverse battery voltage, and sets the signal 10 according to the result of the equation to vary the charging current to maintain a balance between its two inputs. In addition, the output voltage signal 9 from the current signal amplifier 30 is used as the operating signal for the current sensitive power switching unit 26 (FIG. 6).
The dV / dt unit 28 (Fig. 2) receives the signal 1 regarding the battery voltage and supplies three output signals 5, 6 and
7. The signal 5 supplied to the current control circuit 29 is in the form of a gradually increasing stepped reference voltage, which is then inverted by the stepping inverter and the current draw rate controller 31 to form a gradually decreasing stepped reference voltage. The rate of decrease depends on the controller 31 θη of the rate of rise of the battery voltage. Signals 6 and 7
7702 00 1
I ............ '... J i
are digital voltage signals which occur in antiphase with each other and each operate an orange and a green indicator lamp J2 and 33, respectively, the signal 7 additionally ending charging.
Thus, the orange lamp 32 indicates that the charge is in progress, while the green lamp 33 indicates that the charge is complete. 5 t
The dV / dt unit 28 is provided with a number of sections.
The battery voltage 1 is supplied to the two voltage comparators, a stage comparator 34, which compares the voltage to the rising stage voltage 5 and a time comparator 35, which compares the voltage to a fixed reference voltage of 2.35 volts per cell. The rising step voltage 5 is obtained from the output of a digital-analog converter 36 (D-Α) connected to the outputs of the binary counter 41<sup>me</sup>t stair generator. The last counter receives clock pulses from a staircase clock generator 37, which in turn is turned on by the output voltage of the staircase voltage comparator 34 whenever the battery voltage 1 exceeds the staircase output voltage 5 of the LA converter. The step voltage 5 therefore follows very closely the signal 1 of the battery voltage.
The time comparator 35 turns on a clock 3θ, thereby energizing a binary interval counter 42 when the battery voltage 1 reaches the equivalent of 2.35 volts per cell. This counter then adds up at a fixed repetition rate during the periods that the stair generator clock 37 is turned off. Whenever a new voltage step is generated by the pedometer 41, the time counter 42 is reset to zero through a reset gate 39. The latter therefore counts the intervals between the stepping voltage steps. The counting speed of the clock 3θ and the counter 42 is preset such that after a step interval of a certain duration, the last stage of the counter 42 changes from a low state 0 ”30 to a high state 1” thereby turning the green lamp 32 switched on and the charge is switched off via a switch-off port 40 and the orange lamp 33 is switched off (as described above).
Two stabilized power supplies 45 and 44 are used, 35 with the first running on battery power and the second running on net7702 00 1 power. The battery power supply 45 provides power (indicated by + ν ^) for the counters and the cooperating digital logical gates and resistance networks, so that each count is maintained during mains interruptions. The power supply unit 44 supplies the power (designated + V) for the remainder of the logic control circuits in which no memory or other states are required.
Reference stage voltage generator and step interval timer circuit (dV / dt unit 28) - fig. 2
The battery voltage 1 is supplied by a resistance proportioning network 45 »to provide the voltage equivalent of two cells to the non-inverting inputs of two operational amplifiers, which form the stage and time comparators 34 and 35 to control the operation of two programmable unijunction oscillators which form the clocks 37 ®π 3θ. The inverting input of the comparator 34 receives the output stage voltage 5 from the DA converter 36, the initial value of which, when the count in counter 41 is zero, is set by a potential divider 46 for starting the clock 37 when the battery voltage 1 is the desired decreasing starting voltage reached. The inverting input of comparator 35 receives a reference voltage set by a potential divider 47 for starting the clock 3θ at a battery voltage of 2.35 volts per cell. The two clocks operate the binary step counter 41 and the binary time counter 42, and are of the complementary MOS (C / MOS) type.
The binary counter 41 receives clock pulses from the clock 37 and starts adding up to generate the ascending pedaling curve before when the output of the comparator 34 is in the high state 1, that is, if the hot thaw of the battery voltage in the non-inverting input do what ovoruohrljdt of the pedaling voltage in the inverting input. The stage voltage increases by a step of, for example, 22 millivolts after each set of 32 clock pulses as stage 6 (Q6) of counter 41 changes state. The state change Q6 coincides with the change from a state 1 to a state 0 of the stage 5 (Q5), thereby supplying a negative transient voltage signal
770200 1 that operates the reset port 59 connected to the binary time counter 42 '. Thus, whenever a step is performed on the stairs, a reset pulse is supplied to the reset input of the time counter 42.
The time counter 42 continuously receives clock pulses from the clock 3-5 when the battery voltage 1 exceeds 2.35 volts per cell and continues to add up to change the state of step 14 (Q14) to terminate charging. This requires a total count of 8,192, and at the clock speed used in the present case, this corresponds to a total time of 10 minutes. Charging is thus terminated when the time between countdown pulses and thus the step duration of the step voltage is 32 minutes or more.
The output Q14 of the time counter 42 provides a voltage signal 6 for operating the green lamp 32 and the signal 15
7, via the switch-off port 40, to switch off the charging and the orange lamp 33 · The switch-off port 40 comprises a transistor buffer circuit to prevent feedback from the mains supply in the battery supply part when the battery is switched off. Control circuit 29 for the charging current - fig. 5 20
This section basically consists of two operational amplifiers 48 and 49, which form the stage inverter unit and the current draw control unit 31, as well as the current signal comparator 27 and the current signal amplifier 30 in the form of two further operational amplifiers. 25
The amplifier 30 with its two inputs is connected to the charging current shunt resistor 3-4®n amplifies the signal of the shunt voltage with a factor 22. The output signal of the amplifier is smoothed, so that the signal 9 becomes forkrogon.
The amplifier 4 as a voltage follower has been invented on von 30 a buffer between the stage output of the DA converter 36 and the logic current sections, in order to avoid loading of the latter by the converter.
The amplifier 49 is designed as an inverting amplifier with variable, low gain and three functions. First, this amplifier reverses the rising portion of the hot trap 770 voltage signal 5 from the DA buffer stage 48, so that it becomes a falling stage voltage. Second, the initial value of the falling step voltage is applied to its non-inverting input by the adjustment of a potential divider 5 voor, for setting the value of the constant current during the first step of the formed charging characteristic. Third, it determines the size of the descending stair steps, by setting a variable resistor 51 in its negative feedback loop, thereby determining the size of the current steps and thus the rate at which the characteristic formed drops.
The amplifier 27 compares the falling step voltage signal of the amplifier 49 with the amplified current signal of the amplifier 30 and produces a high output voltage 1 or a low output voltage O, depending on whether the step signal is at a higher voltage level than the amplified current signal. The digital nature of the output signal of the amplifier 27 is integrated by the resistor capacitor network 52 into its output to provide the thyristor phase angle control voltage 10. If the step voltage is lower than the voltage of the amplified current signal, the control voltage 10 decreases, causing the phase of thyristors 22 and 23 to decrease and the charging current to decrease and vice versa. Control unit 25 for synchronization and phase angle - fig. 4
This unit includes two identical sections for alternately supplying a control pulse to the thyristor during each half period of a mains voltage cycle. The synchronization by the mains voltage frequency is obtained by a phase transformer 53 with two secondary windings. The time variation of a thyristor gate pulse over a half period is obtained by coincidence of the control DC voltage 10 with a negative sawtooth voltage which is present for half a period.
Any negative sawtooth voltage changing is supplied by a capacitor 54 or 54 'in series with a resistor 55 or 55'. Transistor 56 or 56 'which is controlled by? 70200 1 the phase transformer short-circuits the capacitor 54 or 54' during each half period and allows it to be charged again
I becomes to provide the negative sawtooth voltage during the other half period. The transistor connections to the two secondary windings of the phase transformer 53 are arranged such that the negative slopes of the two sections of the sawtooth occur during alternating half periods. The negative sawtooth voltage is applied to the inverting inputs of two voltage comparators 57 and 57 'acting as operational amplifiers. The control DC voltage 10 is applied to the non-inverting inputs. Thus, when coincidence occurs, the output voltage of 57 (or 57 ') changes from a low state "0" to a high state "1. This change in DC voltage level is converted into a short positive pulse by a capacitor and resistor differentiating network JQ or 5 "connected to the output of the voltage comparator.
The load end signal 7 reduces the control signal 10 to a value below that achieved by the negative sawtooth voltage at the limit of its deflection and thus prevents the occurrence of gate pulses 11 and 12.
Power supply unit 24 for the thyrlstor port - fig. 5
This unit amplifies thyristor gate pulses 11 and 12 so that they have sufficient power and duration to reliably control thyristors 22 and 2J in the presence of allowable self-inductance in the load circuit.
The thyristor gate signals 11 and 12 turn on a pair of transistors 59 and 59 'to supply an energy pulse through the cooperating pulse transformers 60 and 60'. These pulse transformers 60 and 60 'turn on a pair of small thyristors 61 and 61' included in a transformer auxiliary power supply 62 to provide energy-rich gate pulses that last for the remainder of the half-period.
The predominant signal 13 of the current sensitive switching circuit 26 reduces the thyristor gate signals 11 and 12 to below the value required to operate the transistors 59
770200 ?
and 59 'and thereby immediately turn off charging, Current Sensitive Power Switch Hero 26 - Fig. 6
This unit, which in itself forms part of British patent application 9401/76, suppresses ignition of the main thyristors 22 and 23, so that the output plug becomes electrically dead when the battery is switched off. The unit operates as soon as the charging current drops below a predetermined threshold value.
An operational amplifier 63 compares the amplified current signal voltage 9 with a low reference voltage of about 60 millivolts. For example, if the maximum charging current is 100 A, this reference voltage can be the equivalent of about 3.5 A charging current. When the charging current drops to a correspondingly low value, the output of the amplifier 63 changes from the low state 'O' to a high state 1.
When the output of amplifier 63 is in the low state, the loading of a resistor 64 on the anode of a programmable unijunction transistor 65 is prevented, thereby preventing this device from being pulled to the on position. In the off state, the voltage on the gate of transistor 65 is sufficient to drive a two-stage transistor amplifier 66 so that the output 13 is in the high state and does not affect the thyristor firing circuit 24.
Once the battery is turned off, the output of the amplifier 63 goes to the high state and capacitor 64 of the programmable unijunction trigger circuit is charged to the trigger voltage for pulling transistor 65 into the switched-on state. In this state, the gate voltage of transistor 65 is too low to drive transistor amplifier 66, so that the signal 13 is converted to a low state to terminate the thyristor gate pulses and turn off the charger.
The loading device according to the invention is also provided with a device that takes network interruptions into account. It consists of an inverter port 67 controlled by the positive terminal 1 of the battery through a resistive capacitor delay network 68 to operate transistor 69, which is connected
770200 1 over a portion of the programmable capacitor unijunotion charging circuit. When the mains voltage returns, transistor 69 delays the operation of the last circuit until the various other capacitors in the control circuit are charged again. So if a battery is connected, e
Charging continues and the charging current signal prevents the trigger circuit from operating. If no battery is connected, the trigger circuit operates after a further short delay and turns off the charger. Thus, the present device provides a short time of about three seconds to examine whether or not a battery is connected after a brief mains interruption occurs.
This circuit and its operation are described in more detail in the above-mentioned British Patent Application 9401/76.
It is believed that the operation of the device is generally apparent from the above description.
At the beginning of the charging process, the initial output signal of the stage signal inverter 31 is provided to provide the desired high constant current value for most of the duration of the charge. The reference voltage supplied by the potential divider 47 has been chosen in accordance with a value of 2.35 volts per cell, so that for the longest duration of the charging process this voltage is above the signal of the battery voltage, until the battery voltage increases and gas development occurs. performance. From this point, the reference stage output signal 5 gradually increases in steps and the inverter output also gradually decreases in steps, at a rate determined by its gain set by the variable resistor 51, while the charging current gradually decreases. Although not to scale, this is shown in fig. 7 showing the rising battery voltage along a solid line, the reference voltage along a dotted line and the falling charging current also in solid lines. When the current and the battery voltage finally become constant and remain this for 32 minutes, the signal 7 switches off the charging device.
During charging, the power becomes oon gogovon wuardo ln
770 2 oo 1 controlled at a certain stage, so that full charging within a considerable area is independent of the mains voltage. Therefore, the time required to recharge a given battery will always be the same in a given state of discharge.
Likewise, the charging current in a given charging state will not vary significantly by factors such as the mains voltage, so that the charging device can be designed to provide maximum discharge current that the battery can still safely handle at any time of the charge, without that an increase in the mains voltage would lead to a current which will damage the battery.
By using the reference voltage in the form of a step-wise rising voltage to terminate the charging process and by de-energizing it to control the current, instead of using separate components, the number of components can be significantly reduced thereby furnishing becomes cheaper. In addition, by using the same thyristors to control the strength of the charging current during charging and to turn off the power supply device at the end of the charge and to switch off the device when the battery is turned off, a reduction of the number of parts reached.
It goes without saying that the invention is not limited to the device shown and discussed above, but that additions and changes are possible without departing from the scope of the invention.
8 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8
6 members in 5 offices; this record represents the family
Priority claims1
| Document | Office | Kind | Date |
|---|---|---|---|
| 939376 | United Kingdom | A |
Members6
| Document | Office | Kind | |
|---|---|---|---|
| NL7702001AThis record | Netherlands (Kingdom of the) | A | |
| DE2709863A1 | Germany | A1 | |
| FR2344163A1 | France | A1 | |
| US4146830A | United States of America | A | |
| GB1578332A | United Kingdom | A | |
| FR2344163B1 | France | B1 |
1 legal event, as the office reported them to INPADOC
Events
| Event | Code | |
|---|---|---|
| The patent application has lapsedLapsedBV | BV |
Numbers
- Application
- 7702001
Titles2
- English
- ELECTRIC BATTERY CHARGER.
- Dutch
- ELEKTRISCHE BATTERIJLAADINRICHTING.
Classification
- CPC, 2
- H02J7/96
- Y10S320/19
- IPC, 1
- H02J7 00
