JPS6349474B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor control device using a microcomputer, and particularly to a motor control device suitable for use in an electric vehicle.

The shunt motor used in electric vehicles is controlled by an armature and a field chopper. In this case, as a tipper control method, for example,
There is a chopper-on synchronous type in which the armature and the field chopper start at the same timing, as in the 157821 publication. This type of system has the drawback that the timing of both choppers being turned off may be the same, and the overvoltages generated when the choppers are turned off are superimposed, requiring the use of high-voltage elements.

The purpose of the present invention is to synchronize the time immediately before the armature chopper turns off and the time when the field chopper turns on to prevent superimposition of surge voltages when the armature and field chopper turn off, and to prevent the overlapping of surge voltages when the armature chopper and field chopper turn off. The aim is to provide a chip control method that can be used.

Embodiments of the present invention will be explained with reference to FIG. 1 and subsequent figures.
FIG. 1 is a basic configuration diagram of an electric vehicle control device according to an embodiment of the present invention. Reference numeral 1 designates a microcomputer, which includes a microprocessor 2, a random access memory 3, a read-only memory 4, an oscillator 5, and a bus line 6 for address, data, and control. 7 is an analog input circuit, which outputs analog electric signals ACA,
This is a circuit that converts a plurality of analog signals obtained from the detection signals of the operating states of the BRA and the main circuit 10 via the level conversion circuit 11 into digital signals and captures the digital signals, and one embodiment thereof is shown in FIG. The level conversion circuit 11 is composed of six circuits, including an amplifier 10 that amplifies the output IM of the armature current detector.
1. Amplifier 10 that amplifies the output of the field current detector
2. An amplifier 103 that amplifies the output TB of the battery temperature detector, an amplifier 104 that amplifies the output TM of the motor temperature detector, and an amplifier 104 that amplifies the output TT of the detector that detects the temperature of the main thyristor constituting the main circuit 10. It consists of an amplifier 105 and a voltage divider circuit 106 that lowers the battery voltage VB to a low voltage. In addition, the analog input circuit 7 is an analog multiplexer 1.
07, an A/D converter 108, a register 109, and an analog input control circuit 110. Now, when a signal is given from the microprocessor 2 to the AIC shown in FIG.
The analog input specified by AIC is sent to A/D converter 1.
The multiplexer 107 is operated to connect to 08. At the same time, the A/D converter 108 is activated to convert the specified analog quantity into a digital quantity,
It is held in register 109. As a result, by reading the AI value in microprocessor 2,
A specified analog amount can be imported.

12 is a digital input circuit, which receives a 1-bit accelerator switch signal ACD from the accelerator device 8 that indicates that the accelerator pedal has been depressed, and a 1-bit brake switch signal from the brake device 9 that indicates that the brake pedal has been depressed.
The signal KSD from the BRD and key switch 13 is taken in, and the signal is converted by the circuit shown in FIG. 3 to be input to the microcomputer.
That is, the digital input circuit 12 is a resistor connected to the power supply Vcc of the microcomputer 1.
It consists of R ₁ , R ₃ , R ₅ , resistors R ₂ , R ₄ , R ₆ and capacitors C ₁ , C ₂ , C ₃ that constitute a first-order lag filter. Now, when the accelerator switch SWA is open,
A voltage of Vcc is generated at DIA. Furthermore, when the accelerator switch SWA is closed, 0V is output to DIA. Note that the filter with R ₂ and C ₁ is for noise prevention. Similarly, brake switch SWB,
When key switch SWK operates, voltage Vcc or 0V is output to DIB and DIK depending on the operation.

The interrupt circuit 14 has a configuration as shown in FIG. In the example shown in FIG. 4, the circuit receives interrupt pulses INP1 to INP4 from four sources. Now, when a pulse is generated on INP1, the flip-flop circuit 111 is set and the output becomes the IND1 level. On the other hand, interrupt pulse INP1 is OR circuit 1
15, and provides an interrupt pulse INT to the microprocessor 2. As a result, microprocessor 2 imports the contents of IND and
Generates reset pulse INRE for flip-flops 111-114. Then, the contents of IND are checked, and if IND1 is at level 1, it is assumed that an interrupt has occurred in that part, and the interrupt processing is executed. The same applies when an interrupt pulse is input to INP2 to INP4.

Returning to FIG. 1, 15 is a conduction rate control circuit for the armature chopper and field chopper, and 2
The two square waves are divided by the pulse distribution circuit 16 into on-pulses and off-pulses of the armature chopper. These pulse signals are amplified by an amplifier circuit 17 and become control signals for the chopper in the main circuit 10. FIG. 5 shows the details of this portion of the circuit, and FIG. 6 shows some of its operating waveforms.

The conduction rate control circuit 15 has counters 116a, 1
16b, registers 117 and 118, digital comparators 119 and 120, and a matching circuit 121.
Counters 116a and 116b count the clock pulses CLO generated by oscillator 5. However, the counter 116a is a down counter, and the counter 116a is a down counter.
6b is an up counter. As a result, the output COUT1 of the counter 116a exhibits sawtooth wave characteristics as shown in FIG. The output of this counter 116a
As shown in FIG. 5, COUT1 is the value of the register 117 holding the armature chopper current duty command DUA given by the microcomputer 2, and the value of the register 117 in the digital comparator 119 is greater than the value of the counter COUT1. When it gets bigger, 1
Generates a square wave signal AP that becomes the level. Further, the output COUT1 of the counter 116a is output from the coincidence circuit 12.
1 input, and as shown in Figure 6, COUT
When the value of 1 becomes COUTL, constant width pulse INP
Generates 1. This INP1 pulse is the fourth pulse mentioned above.
This becomes the interrupt pulse shown in the figure, and the microprocessor 2
interrupt. On the other hand, the field chopper is controlled by the microcomputer 2, as shown in Figure 5.
A digital comparator 120 compares the value of the register 118 holding the field chopper current duty command DUF given by . The output COUT2 of the field chopper counter 116b is the interrupt pulse INP.
It is reset by 1. At that time, a square wave signal output FP for the field chopper is generated. The value COUT2 of the counter 116b continues to count up, and the register 1 holding the conduction rate command DUF continues to count up.
Comparator 120 compares the values of register 11.
When the value of 8 becomes smaller than the value COUT2 of the counter 116b, the square wave signal output FP is made zero. That is, as shown in Fig. 6, the square wave signal FP is synchronized with the rising edge of the interrupt pulse INP1, and is generated at Δt immediately before the armature chopper signal output AP turns OFF.
Outputting ahead of time.

In the example shown in FIG. 6, only INP1 is used for interrupts. Therefore, INP2 to INP4 in FIG. 4 are not used in this example, but can be used depending on the purpose. For example, since the field current response is slower than the armature current, INP1 detects only the armature current,
Alternatively, commutation failure may also be detected, and the field current may be detected only once every plurality of chopper cycles or asynchronously at INP2, which is interrupted. Further, the INP 3 may be made to perform an interruption to give priority to processing for emergencies.

The pulse distribution circuit 16 shown in FIG. 1 is constructed as shown in FIG. A monostable circuit 122 that generates a constant width pulse in synchronization with the rising edge of the output square wave of the digital comparator 407, a monostable circuit 123 that generates a constant width pulse in synchronization with the falling edge, and two AND gate circuits. It consists of 124 and 125. SUP, which is one input of the AND gate circuits 124 and 125, sets this signal to 0 level when the microcomputer 2 wants to stop generating pulses. Now, when SUP is at 1 level, the outputs of the monostable circuits 122 and 123 directly become the outputs of the AND gate circuits 124 and 125, resulting in signals such as APO and APF in FIG. The outputs of the AND gate circuits 124 and 125 are amplified by pulse amplifiers 126 and 127,
These become the ON gate pulse APGO and OFF gate pulse APGF of the armature current control thyristor chopper, which will be described later. Further, the output square wave of the digital comparator 408 is amplified by the amplifier 128, and becomes a base drive signal of a field current control transistor chopper, which will be described later.

The main circuit 10 has the configuration shown in FIG. A battery 130 is used as a power source, and a thyristor chopper circuit 131 controls the armature current of the shunt motor 132, and a transistor chopper circuit 133 controls the current flowing through the field winding 134 of the shunt motor 132. The thyristor chopper circuit 131 includes a main thyristor 135, an auxiliary thyristor 136, a diode 137, a commutating capacitor 138, and a commutating reactor 139. The commutating capacitor 138 includes an auxiliary charging diode 140 and a resistor 1.
41 is connected. Furthermore, 142 is a flywheel diode for the shunt motor 132 and the DC reactor 144. Furthermore, 143 is a flywheel diode for the field winding. 145 is a power supply/disconnection switch, which is turned on with a manual lever installed in the driver's seat, and the signal is turned on.
Use FFT to pull it apart and release it. 146A and 146B are the contacts of the contactor 146, and when the contactor control signal CON is at 0 level, the state shown in FIG. C.B.
Connected to CBM. This contactor 146 performs switching between power running and regeneration. In other words, the state shown in Fig. 7 shows the regeneration mode.
When the thyristor chopper circuit 131 is turned on, the induced voltage of the shunt motor 132 flows into the DC reactor 144.
When the shunt motor 132 and DC reactor 144 are short-circuited and turned off after a certain period of time, the induced voltage in the shunt motor 132 and the DC reactor 144 is regenerated to the battery 130 via the flywheel diode 142. During this time, the field current is controlled by the chopper circuit 133. In this way, regeneration operation is performed. On the other hand, when the contactor excitation signal CON becomes 1 level and the contactor 146 operates, terminals CA and CAM are connected to terminals CB and CBM.
is connected. When the thyristor chopper circuit 131 is turned on in this state, the voltage of the battery 130 is applied to the shunt motor 132, and the voltage of the battery 130 is applied to the shunt motor 132.
The current flowing through 2 increases. Also, when the thyristor chopper circuit 132 is turned off, the shunt motor 13
The current flowing through the DC reactor 144,
The power action is attenuated through the flywheel diode 142.

Note that 147 and 148 are fuses for protection. Further, 149 and 150 are a shunt resistor for armature current detection and a shunt resistor for field current detection, respectively, and are connected to the amplifiers 101 and 10 in FIG.
The value is taken into the microcomputer 1 via the microcomputer 2. 151, 152, and 153 are thermistors that detect the temperatures of the battery 130, the main thyristor 135, and the shunt motor 132, respectively, and the amplifiers 103, 104, and 1 of FIG.
The value is taken into the microcomputer 1 via the microcomputer 05.

Returning to FIG. 1, 18 is a power digital output circuit, which generates a signal SUP for suppressing the gate pulse shown in FIG. 5, and excitation signals CON and FFT for the contactor 146 and switch 145 shown in FIG. do.

19 is a speed detection circuit, and a pulse generator 2 generates pulses corresponding to the rotational position and whose frequency is proportional to the speed of the shunt motor 132.
The speed is digitally detected based on the zero output pulse train PLP and is input into the microcomputer 1.

An embodiment of the speed detection circuit is shown in FIG. a counter 155 for generating pulses at time intervals serving as a reference for measuring speed;
A monostable circuit 156 that generates a pulse of a constant width in synchronization with the falling edge of the overflow pulse of , a counter 157 for counting the output pulse PLP of the pulse generator 20, and a register that holds the output of the counter 157 at regular intervals. It consists of 158 pieces. Since the counter 157 is reset at fixed time intervals by the output pulses of the monostable circuit 156, the speed can be detected from the number of pulses that have arrived at a fixed time, that is, the output of the counter. Note that the output of the counter is set in the register 158 by the overflow pulse of the counter 155 immediately before the reset pulse is input. The microcomputer 1 can detect the speed by reading the contents of this register 158. Note that the clock pulse of the counter 155 is the reference pulse of the oscillator 5 in FIG.
I am using CLO.

Returning to FIG. 1 again, 21 is a digital output circuit, which is provided to light up a lamp on a panel 22 provided at the driver's seat.

All operations of the control device shown in FIG. 1 are performed by sequentially processing the contents of the program written in the read-only memory 4. The details of this process will be explained below.

There are roughly two types of programs written in the read-only memory 4 shown in FIG. The first program is a MAIN program that is constantly executed, and its processing contents are shown in FIG.
The second program is an INT program that is activated by the generation of an interrupt pulse, and its processing contents are shown in FIG. 9 and 10 will be explained in relation to FIG. 1.

When the power is turned on to the microcomputer 1, the process of step 200 in FIG. 9 is first performed to set the initial values of each register and the random access memory 3 shown in FIG. Next, the key switch signal KSD, accelerator switch signal ACD, and brake switch signal BRD are taken in via the digital input circuit 12, and a key switch determination is made in step 201.
When the key switch is off, the process of step 202 is performed, a stop designation is made, and the process returns to the key switch determination. When the key switch is turned on, the state of the accelerator switch is checked in step 203.
When the accelerator is depressed, the step
At step 204, the power running mode is designated, and at the same time, the analog output ACA of the accelerator device 8 is taken in via the analog input circuit 7. On the other hand, when the accelerator switch is in the off state, the state of the brake switch is determined in step 205. When the brake switch is off, a stop is designated and the process returns to step 202. When the brake switch is on, the regeneration mode is specified in step 205, and the analog output BRA of the brake device 9 is taken in via the analog input circuit 7.

Next, in step 208, the values of the motor, main thyristor, and battery temperatures TM, TT, and TB are taken in via the level conversion circuit 11 and analog input circuit 7, and if the values are abnormal, the process moves to step 209. A protective operation such as reducing the current command is performed, and an alarm is displayed on the lamp of the panel 21 via the digital output circuit 20.

Furthermore, in step 211, the battery voltage VB is taken in via the level conversion circuit 11 and analog input circuit 7. If the battery voltage is too low to continue operating the electric vehicle, an abnormality is determined in step 212, and protection and warning display are performed in steps 209 and 210. Next, in step 213, the number of rotations of the motor is taken in via the speed detection circuit 19. If this rotation speed is abnormally high, the step
214 determines that the engine is overspeeding, and provides protection and a warning display.
Also, when it is not over-speeding, it operates normally,
The armature current command and field current command are calculated based on the accelerator pedal depression amount or brake pedal depression amount and the motor rotation speed detected in steps 215 and 216, and the process returns to step 202. This kind of operation is executed repeatedly in the MAIN program.

If the interrupt pulse shown at INP1 in Figure 5 is input while such a MAIN program is being executed, the first
Execute the INT program shown in Figure 0. In the INT program, it is first determined whether a stop specification has been made. When a stop is specified, the process moves to step 302, where SUP is set to 0 level via the power digital output circuit 18, and the pulse of the chopper is stopped. Step when there is no stop instruction
Moving to the process 303, the armature current value IM is taken into the microcomputer 1 via the analog input circuit 7. If the value is very large, it is abnormal, so the power digital output circuit 18
The switch 145 shown in FIG. 7 is opened via the switch 145 in FIG.
An alarm is displayed on the panel 21 via the digital output circuit 20. When there is no overcurrent, the step
Moving to 307, the field current value IF is taken into the microcomputer 1 via the analog input circuit 7.
It is abnormal when this value is very large, so
Moving on to steps 305 and 306, the switch 145 is opened,
Displays a warning and terminates the interrupt program.
Return to MAIN program. Also, if there is no overcurrent, the process moves to steps 309 and 310,
Based on the armature current command and field current command given in advance in the MAIN program and the detected values of the armature current IM and field current IF detected earlier,
Perform control calculations to match the actually flowing current with the command value, and use the resulting conductivity values as DUA and DUF in the registers 117 and 117 in FIG.
Set to 118. As a result, the conduction rate control circuit 15 and the pulse distribution circuit 16 generate gate pulses and base driving square waves for the thyristor chopper circuit 131 and the transistor chopper circuit 133, respectively, according to the set conduction rate command. do.

These signals are amplified and the thyristors and transistors are operated to control the current flowing through the armature and field of the motor.

The INT program in Figure 10 ends when the processing in step 310 is completed, and is always running.
Performs the action of returning to the MAIN program. The first part shows the startup sequence of these two programs in correspondence with the operation of the armature and field chopper.
Figure 1. The program operation moves from MAIN to INT program by the generation of interrupt pulse INP1. At the same time, the square wave signal of the field chopper is output,
The field chopper is turned on and field current i _F flows. On the other hand, the armature chopper generates an off pulse Δt time after the generation of interrupt pulse INP1, turning off the chopper.
let The current acquisition timing at this time is performed in synchronization with the interrupt pulse INP1. That is, the field current is the current value of _IF immediately after the field chopper is turned on, and the armature current is taken into the computer as the value of I _M immediately before the armature chopper is turned off. In addition to the program operations described above, the INT program executes the program shown in the flowchart of Figure 10, for example,
After 20~30ms, when the INT program finishes
Repeat the operation to return to the MAIN program.

When controlling an electric motor with the configuration described above, since a microprocessor is used, the control performance is less likely to change due to changes in temperature and environment, and a highly reliable and compact device can be realized. Further, by generating and controlling interrupt pulses at the timing shown in FIG. 11, the following effects are brought about. 1st, 11th
As shown in the figure, since the armature and field chopper are synchronized and the field chopper is turned on a certain period of time immediately before the armature chopper is turned off, the effect of the circuit inductance when the armature chopper is turned off is The thyristor's jump voltage V _ap and the transistor's jump voltage V _fp when the field chopper is OFF do not appear at the same time. Conventional armature and field chopper asynchronous type and chopper ON
In the time-synchronized type, the OFF timings of both choppers may overlap, so the jump voltage may also overlap. Therefore, the elements used for both choppers required high voltage elements capable of withstanding this voltage.

As described above, the present invention turns on the field chopper.
Since the rear armature chopper is turned off, the withstand voltage of the element only needs to be able to tolerate the surge voltage when both choppers themselves turn off. Transistors are often used in field choppers because they have a small capacity. Therefore, the ability to use elements with low breakdown voltages has great effects, such as simplifying the surge absorption circuit and reducing the cost of the elements.

Second, as can be seen from the operating waveforms of the armature and field current in Figure 11, when the armature current decreases (when the armature chopper is OFF), the field current is increased (when the field chopper is ON). Since the phases of both currents are shifted in this way, the combined torque ripple is reduced.

Thirdly, since the operation timings of the armature and the field chopper can be set at arbitrary timings in association with each other, it is possible to capture the current value at a certain timing during one cycle of the chopper.

Fourth, the armature current can be detected not only by directly detecting the armature current, but also by using the signal of the shunt 149, which detects the battery current flowing through the armature, as shown in Fig. 7. . If a shunt is placed at a position such as shunt 149' in FIG. 7, the motor current will flow through the diode 142 even after the chopper is turned off, so that the armature current can be detected.

However, it is necessary to connect one end of shunt 149' to the battery's ground terminal. shant 14
Position 9 has the advantage that no special ground line is required.

Fifth, since the instantaneous current value immediately after the chopper is turned on is used to calculate the conduction rate for the next chopper cycle from the timing just before the chopper turns off, control with good responsiveness to commands and load changes is possible. becomes.
Furthermore, since the current control, which has a quick response, is processed every chopper cycle, the response is even better. On the other hand, in electric vehicles, the response after stepping on the accelerator pedal is relatively slow, so the calculation of the current command is
The MAIN program is configured to perform this once every few cycles of the chip. Therefore, the number of processing programs in the INT program is small and the processing time is shortened, which has the effect of making it possible to perform processing on a relatively slow microcomputer.

In the embodiment, a method of turning on the field chopper immediately before turning off the armature chopper has been described, but this order can be applied in the same way even if the order is reversed.

Further, in the embodiment, an example in which the chopper period is constant is shown, but it can be similarly applied to a variable period one.

Furthermore, in the control of series-wound motors, when bypass contactor closing control is performed to short-circuit the chopper to obtain maximum output, the chopper is stopped when the contactor is closed; All you have to do is to interrupt it.

As described above, according to the present invention, the OFF times of the armature and the field chopper do not overlap, so there is an advantage that elements with low breakdown voltages can be used in the chopper circuit.

[Brief explanation of the drawing]

1 is a block diagram showing an embodiment of an electric vehicle control device according to the present invention, FIG. 2 is a block diagram showing an embodiment of the analog input control circuit of FIG. 1, and FIG. 3 is a block diagram of an embodiment of the analog input control circuit of FIG. 4 is a circuit diagram showing an embodiment of the input circuit. FIG. 4 is a circuit diagram showing an embodiment of the interrupt circuit in FIG. 1. FIG. 5 is a circuit diagram showing an embodiment of the interrupt circuit in FIG. 1. A circuit diagram showing an embodiment, FIG. 6 is an operation waveform diagram of FIG. 5, FIG. 7 is a circuit diagram showing an embodiment of the main circuit of FIG. 1, and FIG. 8 is a diagram of the speed detection circuit of FIG. 1. A circuit diagram showing one embodiment, FIG.
Figure 10 is a flowchart of an embodiment of the INT program showing the control operations shown in Figure 1. Figure 11 is a startup sequence of the MAIN program and INT program. This is a time chart showing an example. DESCRIPTION OF SYMBOLS 1...Microcomputer, 2...Microprocessor, 8...Accelerator device, 131...Thyristor chopper circuit, 132...Shunt motor.

Claims (1)

[Claims] 1. A shunt motor having a field winding, a battery that supplies power to the motor, an armature chopper that controls the armature current of the motor, a field chopper that controls the field current of the motor, and the electric machine. A chopper conduction rate control circuit that synchronizes and drives the operating points of a child chopper and a field chopper, and the conduction rate control circuit includes an up counter and a down counter that count a clock pulse signal CLO from an oscillator. and a pulse signal for resetting the up counter when the output value from the down counter matches the time width of the interrupt pulse that determines the period of the duty ratio control circuit stored in advance. a digital comparator that compares the value of the down counter with the value of a first register holding the armature chopper duty command value, and a matching circuit that compares the value of the up counter with the value of the field chopper. and another digital comparator that compares the conduction rate command value with a second register value holding the conduction rate command value, and determines when the field chopper is turned on or the armature chopper is turned on based on the output of the conduction rate control circuit. 1. A motor control device characterized in that said armature chopper or field chopper is turned off with a delay of a time Δt shorter than an on time of said field chopper or armature chopper.