JPH0334311B2 - - 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.

In electric vehicle control devices using microcomputers, various analog signals such as command values from command devices such as accelerator pedals and brake pedals, motor current, battery voltage, and motor/control device temperature are A/D converted. The data is controlled by a microcomputer via a device. (For example, Japanese Unexamined Patent Publication No. 53-96117) As a method of taking in these signals, for example, there is a method of providing an independent A/D converter for each signal. However, this method requires a large number of A/D converters and increases the price of the control device, so generally only one A/D converter is used, and the input signal is switched by a multiplexer to receive several types of signals. method is used.

By the way, A/D converters with fast conversion times are expensive. Also, if you use a cheap one, A/
This is not preferable since the D conversion time becomes long. This is particularly a problem in motor control, which requires a fast program processing time.

An object of the present invention is to avoid increasing the number of A/D converters for acquiring various analog signals, and to
Even when using a method with relatively slow conversion time,
The object of the present invention is to provide a means for taking in many necessary input signals while minimizing the time required for A/D conversion.

A feature of the present invention is that in a control device using a chopper, an interrupt is generated in synchronization with the chopper cycle, each analog signal is detected for each interrupt, and the number of times each signal is captured is weighted according to its importance. The reason is that the signal acquisition is performed.

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 receives analog electric signals ACA and ACA corresponding to the amount of depression of the accelerator device 8 and the brake device 9, respectively;
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 of the battery temperature detector, an amplifier 104 that amplifies the output TM of the motor temperature detector, and an amplifier that amplifies the output TT of the detector that detects the temperature of the main thyristor constituting the main circuit 10. 105, it is composed of a voltage dividing circuit 106 that lowers the battery voltage VB to a low voltage. Further, the analog input circuit 7 is an analog multiplexer 10.
7, 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 A/D converter 108
The multiplexer 107 is operated to connect to. Also, at the same time, start up the A/D converter 108,
The designated analog quantity is converted into a digital quantity and held in the register 109. As a result, the microprocessor 2 can take in the specified analog amount by reading the AI value.

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 at INP1, the flip-flop circuit 111 is set and the output becomes the IND1 level. On the other hand, the interrupt pulse INP1 also serves as an input to the OR circuit 115, and provides the microprocessor 2 with an interrupt pulse INT. As a result, the microprocessor 2 takes in the contents of IND and generates a 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 the 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 includes a counter 116, registers 117, 118, a digital comparator 119,
120 and a matching circuit 121. counter 11
6 counts the clock pulses CLO generated by the oscillator 5. However, the counter 116 is a down counter. As a result, the output of the counter 116
COUT exhibits sawtooth wave characteristics as shown in FIG.
The output COUT of this counter 116 is, as shown in FIG.
17,118 value and digital comparator 119,1
It is compared with 20. And digital comparator 1
When the values in the registers 117 and 118 become larger than the counter value COUT, the square wave signals 19 and 120 become 1 level. Also, counter 1
The output COUT of 16 becomes the input of the matching circuit 121, and the value of COUT becomes COUTL as shown in FIG.
When this happens, a pulse INP1 of a constant width is generated. This INP1 pulse becomes the interrupt pulse shown in FIG. 4 described above, and interrupts the microprocessor 2.
Further, as shown in the operating waveform of FIG. 6, the pulse of INP1 is generated a certain period of time before the pulse of APF is generated.

Specifically, the time from the on-pulse to the off-pulse when the flow rate of the chopper is at its minimum (usually
300 μsec to 500 μsec) before a specific time ΔT (arbitrarily set).

Furthermore, each of the interrupt cause pulses INP1 to INP4 becomes an input to the OR gate circuit 115 and is directly applied to the interrupt terminal of the microprocessor 2 as INT.

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 AP of the digital comparator 119, a monostable circuit 123 that generates a constant width pulse in synchronization with the falling edge of the output square wave AP, and two AND gates. It consists of circuits 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 level 1, monostable circuits 122 and 12
The output of 3 is sent directly to the AND gate circuit 124,1
25, resulting in signals such as APO and APF in Fig. 6. AND gate circuits 124, 125
The outputs of are amplified by pulse amplifiers 126 and 127, and are used to generate ON gate pulses APGO and thyristor chopper for armature current control, respectively, which will be described later.
Becomes the off gate pulse APGF. Also, the output square wave FP of the digital comparator 120 is outputted by the amplifier 128.
The signal is amplified by , and becomes a base drive signal for 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. 7 is reached.
When the contactor excitation signal CON is at 1 level, each contact operates, terminal CA becomes CAM, terminal CB
is 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 the signal SUP for suppressing the gate pulse shown in FIG. 5, and the 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, a counter 157 for counting the output pulse PLP of the pulse generator 20, and a counter 157 that holds the output of the counter 157 at regular intervals. It consists of a register 158. 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 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. If the key switch is off, step 2
02 is performed, a stop designation is performed, 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. If the accelerator is being depressed, a power running mode is specified in step 204.
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 command is issued and the process returns to step 202. When the brake switch is on, the regeneration mode is specified in step 205.

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

Further, in step 211, the level conversion circuit 11,
If the value of battery voltage VB previously taken in by the interrupt program via the analog input circuit 7 is too low to continue operating the electric vehicle, an abnormality is determined in step 212, and step 212 is performed. 209, 210 protection and alarm display. Next, in step 213, the rotational speed of the electric motor is acquired via the speed detection circuit 19. If this rotational speed is abnormally high, it is determined in step 214 that overspeeding has occurred, and protection and warning display are performed. Also, if it is not over-speed, it will operate normally and proceed to step 2.
Calculate the armature current command and field current command based on the accelerator pedal depression amount or brake pedal depression amount detected in 15, 216, and the motor rotation speed,
The process returns to step 202. This kind of behavior
The MAIN program is executed repeatedly.

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 specifying stop, step 302
Moving on to the processing, the power digital output circuit 18
Set SUP to 0 level via , and stop the pulse of Chiyotsupa. If there is no stop instruction, the process moves to step 303 and the armature current value IM is taken into the microcomputer 1 via the analog input circuit 7. If the value is extremely large, it is abnormal, so the switch 145 shown in FIG. Panel 21 through 20
A warning will be displayed. If there is no overcurrent, the process moves to step 307 and the field current value IF is taken into the microcomputer 1 via the analog input circuit 7. If this value is very large, it is abnormal, so the process moves to steps 305 and 306, opens the switch 145, displays an alarm, ends the interrupt program, and returns to the MAIN program. If there is no overcurrent, the process moves to step 309, where various analog signals, which will be described in detail later, are taken in.
Next, proceed 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,
A control calculation is performed to match the command value of the actually flowing current, and the values of the conductivity obtained as a result are set as DUA and DUF in the register 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.

In the INT program shown in Figure 10, step 31
It ends when the first process is completed and is always running.
Performs the action of returning to the MAIN program.

The first example of the startup sequence of these two programs is shown in comparison with the field chopper operation.
Figure 1. When an interrupt pulse is generated in synchronization with the field chopper ON, the interrupt program is executed and after completion returns to the main program, which is repeated.

FIG. 12 shows step 309 explained in FIG.
FIG. 3 is a detailed diagram of the selection and detection processing of various analog signal acquisitions. Steps 309a and 30 in FIG.
Detection of the armature current and field current at 9b is the same as that shown in steps 303 and 307 of FIG. 10, and is shown in FIG. 12 for explanatory purposes. In FIG. 12, the armature current is inputted in step 309a, and the field current value is inputted in step 309b to the analog input circuit 7.
The data is imported into the microcomputer 1 via the microcomputer 1. In the next step 309c, steps 309d to 30
Select which of the analog values up to 9h (accelerator opening command, brake command, battery voltage, battery temperature, motor/control device temperature) to be imported.
For example, when acquiring an accelerator opening command, the data is acquired in step 309d, and then in step 30.
At step 9i, data to be taken in by the next interrupt program is specified, and the process moves to step 310. In the next interrupt program execution, another data specified in step 309i is fetched during the previous interrupt program execution. FIG. 13 shows a series of operation sequences for such data acquisition. The armature current and field current, which require fast processing, are captured every interrupt.
Data for accelerator opening commands and brake commands is taken in once every three interrupt processings, and data for battery voltage, temperature, etc., which can be processed slowly, is taken in once in every interrupt processing. In this way, in interrupt program processing synchronized with the chopper cycle, the A/D conversion time can be shortened by weighting the analog input acquisition according to the importance of the data and changing the number of data acquisitions. can. Therefore, even if a relatively slow A/D converter is used, it is possible to capture many input signals.

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. Furthermore, by generating and controlling interrupt pulses at the timing shown in FIG. 11, the following effects are brought about. Since calculation of conduction rate is started for each interrupt processing, control with good responsiveness to commands and load changes is possible.

In addition, in an electric vehicle, the response after stepping on the accelerator pedal is relatively slow, so the calculation of the current command is performed in the MAIN program once every few chopper cycles. Therefore, INT
There are fewer processing programs in the program,
Since the processing time is also shortened, processing can be performed on a relatively slow microcomputer.

As explained above, according to the present invention, an interrupt is generated in synchronization with the chopper cycle, and the analog input signal acquisition method in the interrupt processing program is changed every time for each interrupt for signals of high importance, and several times for signals of low importance. Import once per interrupt,
By weighting the acquired signals, many signals can be acquired without increasing the number of A/D converters. Furthermore, since the A/D conversion time in the interrupt processing program can be reduced, there is an effect that a large number of input signals can be taken in even if an A/D converter with a relatively slow conversion time is used.

[Brief explanation of the drawing]

1 is a block diagram showing an embodiment of an electric vehicle control device to which the present invention is applied; FIG. 2 is a block diagram showing an embodiment of the analog input control circuit of FIG. 1;
The figure is a circuit diagram showing an embodiment of the digital input circuit in Fig. 1, Fig. 4 is a circuit diagram showing an embodiment of the interrupt circuit in Fig. 1, and Fig. 5 is a circuit diagram showing an embodiment of the interrupt circuit in Fig. 1. A circuit diagram showing an embodiment of the circuit and pulse distribution circuit, 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. 1 is a circuit diagram showing an embodiment of the speed detection circuit, FIG. 9 is a flowchart of an embodiment of the MAIN program showing the control operation of FIG. 1, and FIG. 10 is an INT program showing the control operation of FIG. 1. A flowchart of an example of the program, Figure 11 shows the MAIN program and
A time chart showing an example of the starting sequence of the INT program, FIG. 12 is a detailed explanatory diagram of the signal acquisition method in FIG. 10, and FIG. 13 is a time chart showing the operation of FIG. 12. DESCRIPTION OF SYMBOLS 1... Microcomputer, 8... Accelerator device, 9... Brake device, 10... Main 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 current control circuit that synchronizes and drives the operating points of the slave chopper and the field chopper, and inputs signals corresponding to at least the armature current, the amount of depression of the accelerator and the brake device, and performs A/D conversion; It has an analog input circuit that outputs a signal to the random access memory when operated by a microcomputer, and a digital input circuit that inputs at least an accelerator switch signal and a brake switch signal and outputs a signal to the random access memory when operated by the microcomputer. In the device, the signals of the armature current and the field current are transmitted to the interrupt pulse generated in synchronization with the ON or OFF cycle of the chopper circuit, and for each interrupt processing executed in synchronization with the pulse. means for capturing into a random access memory; and after capturing the armature current and field current signals, at least an accelerator opening;
Means for sequentially selecting a brake command, a battery voltage signal, and an accelerator switch signal according to a predetermined priority order, performing a logical operation based on the signals obtained based on the priority order, and controlling the chopper based on the result of the operation. 1. A direct current motor control device comprising a control means.