JPH10337072A - Energization control device for electric motor - Google Patents

Abstract

(57) [Summary] [Problem] Immediately discharge capacitor residual voltage immediately after turning off electric motor drive power. This is realized with substantially no power consumption during power-on and without the addition of a special discharge circuit. SOLUTION: A DC power supply PB is provided via a power switch PR.
Motor controller 18 for controlling the value of the current supplied to the electric motor 1; and, when the power switch PR is switched from closed to open, instructs the current controller to supply current. Discharge control means ECU is provided. The discharge control means ECU instructs energization for driving the motor in a direction opposite to the rotation of the motor. If the rotation speed is less than the set value, an instruction is made to energize all phases simultaneously. An instruction is given to energize the motor so that the sum of the torque generated by each motor phase is substantially zero. The target current value corresponding to the rotation angle of the motor is determined, and this energization is instructed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor energizing apparatus using a DC power supply for applying a DC voltage to a motor driver for energizing an electric motor, and more particularly to a motor driver immediately after a DC power supply is cut off. The present invention relates to discharge control of a voltage remaining in a power supply line. Although the present invention is not intended to be limited to this, the present invention is implemented, for example, for early discharge control of a voltage remaining in a power supply line to a motor driver that energizes chopping of a switched reluctance motor.

[0002]

2. Description of the Related Art With reference to the drawings, a switching circuit for energizing a switched reluctance motor will be described. Switched reluctance motor (hereinafter referred to as SR motor)
Generally has a rotor configured with a pole part protruding outward and a stator configured with a pole part protruding inward, and the rotor is configured by simply stacking iron plates. It is an iron core, and the stator has a coil wound around each pole. In this SR motor, each pole of the stator operates as an electromagnet, and the rotor rotates by attracting each pole of the rotor with the magnetic force of the stator. Therefore, the rotor can be rotated in a desired direction by sequentially switching the energized state of the coil wound around each pole of the stator according to the rotational position of each pole of the rotor. This type of SR motor is disclosed, for example, in Japanese Patent Application Laid-Open No. 1-298940.

In the SR motor, when each pole of the rotor is at a specific rotation position, on / off of energization to each pole of the stator is switched, so that the magnetic attraction force applied to the rotor at that time is switched. The size changes rapidly. Therefore, relatively large mechanical vibrations occur in the rotor and the stator. This vibration produces noise.

In the technique disclosed in Japanese Patent Application Laid-Open No. Hei 1-298940, a rotational position signal having a gradual rise and fall is generated, and the rise and fall of the current when the electric coil is energized on are generated using the rotational position signal. It has been practiced to moderate the fall of the current when the power is turned off. By doing so, it is possible to suppress the generation of vibration and noise of the SR motor. However, noise is suppressed when the rise of the current when the electric coil is energized and the fall of the current when the energization is off become substantially faster, such as during low-speed rotation because the rotation position signal is used. If the rise of the current when the energization of the electric coil is turned on and the fall of the current when the energization is turned off are substantially delayed, as in the case of high rotation, the energization on time per time is reduced. Since the length becomes shorter, the flowing current becomes very small, and the generated rotational torque becomes small. In addition, unless the timing of switching on / off of energization is changed according to the number of revolutions and the required torque, the efficiency is deteriorated and the required torque may not be sufficient.

[0005] JP-A-7-274569, JP-A-7-274569
Japanese Patent Application Laid-Open No. 298669/1990 and Japanese Patent Application Laid-Open No. 172793/1996 disclose that the motor conduction current is controlled by PWM using an H-type switching circuit, and that the rotation torque is increased. In order to improve the shortage, the switching mode is controlled.

For example, as shown in FIG. 11, an H-type switching circuit includes one end of an electric coil 1a of an electric motor and a first end.
The first switching element 18a inserted between the power supply line 18e and the second switching element 18 inserted between the other end of the electric coil 1a and the second power supply line 18f.
b, inserted between the one end and the second power supply line 18f;
A first diode D1, which allows current flow from the latter to the former;
And a second diode D interposed between the other end and the first power supply line 18e to allow current flow from the former to the latter.
2 inclusive.

As shown in FIG. 13A, when both the first and second switching elements 18a and 18b are turned on, a rotational drive current flows through the electric coil 1a, and when both are turned off, as shown in FIG. As shown, a feedback current to the power supply flows due to the induced voltage of the electric coil 1a. The pulsating current shown in FIG. 13C flows through the electric coil 1a by alternately repeating the above-described ON and OFF by the PWM control. This switching mode is called "hard chopping" in this document. FIG. 13 in this hard chopping
As shown in (b), both switching elements 18a, 18
b during the time interval in which both of the electric coils 1a are turned off.
Is generated is supplied to the first power supply line 18e (regeneration), and the current sharply decreases. Since the pulsation of the current due to the switching of the switching element on / off is large,
The pulsation of the magnetic attraction force applied to the rotor of the electric motor is large, causing vibration and generating large noise.

FIG. 14A (same as FIG. 13A)
As shown in FIG. 1, the first and second switching elements 18a,
14b, and then only the first switching element 18a is turned off and the second switching element 18b is kept on as shown in FIG. 14 (b), and the states (a) and (b) are changed. By repeating alternately, a current with relatively small pulsation shown in FIG. 14C flows through the electric coil 1a. This switching mode is called "soft chopping" in this document. In this soft chopping, the first switching element 18 shown in FIG.
In the period of a off and the second switching element 18b on,
The current gradually decreases, and the driving force of the motor and the radial suction force also gradually decrease. Therefore, when the motor is energized in the "soft chopping" mode, noise and vibration are relatively low.

The above-mentioned JP-A-7-274569, JP-A-7-298669 and JP-A-8-17279.
The electrification control device disclosed in Japanese Patent Publication No. 3 selects the above-mentioned "hard chopping" and "soft chopping" according to the rotation state of the SR motor, thereby realizing reduction of vibration and securing of high torque. doing.

[0010]

In order to reduce the power consumption of a battery on a vehicle, for example, when a large electric motor is used in an electric vehicle or the like, the motor is driven while the vehicle is stopped or parked. Shut off (turn off) the power and control power,
When the driving power supply is at a high voltage (approximately 300 V in an electric vehicle), after the driving power supply is turned off, the electric charge remaining in the motor driver power supply line or the capacitor in the motor driver, which is cut off from the driving power supply by the driving power switch, is removed. If the control power supply is turned off without discharging, the residual voltage of the capacitor may destroy the IC in the motor driver.

Conventionally, in order to discharge a capacitor residual voltage immediately after power-off, a resistor is generally incorporated so as to form a parallel circuit with the capacitor. However, if the resistance value is set small in order to shorten the discharge time, the power consumption during power-on increases due to the steady power consumption by the resistor. Also, a large resistor having a large power capacity is required for the resistor. When the resistance value is increased, the discharge time constant becomes large, so that the discharge cannot be performed immediately. In order to improve these, there is a discharge circuit in which a switching element is connected in series to the resistor, the switching element is turned on when the driving power is off, and the resistor is energized only when the driving power is off. According to this, there is substantially no power consumption by the resistor while the drive power is on. However, a large resistor having a large power capacity is required, and a discharge circuit (particularly, a switching element) requires a high withstand voltage, so that the cost is relatively high.

It is a first object of the present invention to quickly discharge a capacitor residual voltage immediately after a drive power supply is turned off.
A second object is to realize this without substantially consuming power while the power is on and without adding a special discharge circuit.

[0013]

[Means for Solving the Problems]

(1) An electric motor energization control device according to the present invention includes a motor driver (18, 19, 1A) connected to a DC power supply (PB) via a power switch (PR); Electric motor
(1) Motor current control for controlling the value of the current supplied to
And discharge control means (ECU) for instructing the motor current controller to energize when the power switch (PR) is switched from closed to open. In addition, in order to facilitate understanding, the symbols of the corresponding elements in the embodiments shown in the drawings and described later are added in the parentheses for reference.

According to this, when the power switch (PR) switches from the closed state to the open state, the discharge control means (ECU) instructs the motor current controller to energize, and thereby the motor driver
(18, 19, 1A) closes the electric motor energizing circuit and the power switch (PR) is open, so there is no DC power supply (PB), and the motor
The electric charge of the motor driver power supply line or the capacitor in the motor driver is discharged to the electric coil of the electric motor. As a result, the capacitor voltage disappears immediately.
It is not necessary to use a resistor having a low resistance value for discharging, and it is not necessary to add a special discharging circuit having a high withstand voltage.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) direction detection means (1d, 11) for detecting a rotation direction of the electric motor (1); and the discharge control means (ECU).
Instructs the motor current controller to energize the electric motor (1) in a direction opposite to the rotation of the electric motor (1).

According to this, when the electric motor is rotating when the power switch (PR) is switched from closed to open,
Alternatively, the discharge control means (ECU) controls the motor current control.
Command the energization of the motor, and in response to this,
The electric motor is energized through the motor driver by the motor, that is, the electric motor is discharged by the discharge current of the capacitor.
When the motor rotates, a current (capacitor discharge current) that rotates in a direction opposite to the direction of the rotation is supplied to the electric motor, and the rotation of the electric motor stops immediately. (3) speed detection means (1d, 11) for detecting the rotation speed and direction of the electric motor (1); Electric motor
The motor current controller is instructed to energize the motor (1) in a direction opposite to the rotation of the motor (1), and when the rotation speed is less than the set value, the electric motor (1) is turned on. Instructs 1) to energize all phases simultaneously.

According to this, when the rotation speed is such that rotation becomes a problem, the reverse drive energization is performed, and the electric motor is immediately decelerated. Discharge occurs rapidly in all the phase coils. When all phases are energized at the same time, the electric motor does not substantially generate a rotational torque, but rather acts as a brake to stop the rotation. Therefore, even if the discharge current is large, the electric motor does not rotate.

(4) The discharge control means (ECU) instructs the motor current controller to energize the electric motor (1) to make the sum of the torque generated by each phase substantially zero. . According to this, even if the discharge current is large, the electric motor does not rotate and the residual charge of the capacitor can be immediately discharged.

(5) Angle control means (1d) for detecting a rotation angle of the electric motor (1);
(ECU) determines the target current value corresponding to the rotation angle of the electric motor (1), and gives it to the motor current controller (4).

When the same current is applied to all phases of the electric motor, as shown in Tables 1a and 1b, the rotation angle of the rotor of the electric motor (in the table, simply referred to as "angle"). The unit is “°”, and the torque (N ·
m) are different.

[0021]

[Table 1a]

[0022]

[Table 1b]

When the current value is determined for each phase as shown in Tables 2a and 2b, the torque can be reduced to zero. That is, by supplying a current (A) corresponding to the rotation angle shown in Table 2a and Table 2b to each phase, the electric motor does not rotate.

[0024]

[Table 2a]

[0025]

[Table 2b]

(6) The electric discharge control means (ECU) is provided for controlling the rotation angle of the electric motor (1) to make the total of the torque generated by each phase of the electric motor (1) substantially zero. A current value corresponding to the rotation angle detected by the angle detecting means (1d) is read out from the memory, and the read current value is used as a target current value to set the motor current control. (5). According to this, by storing the current value group corresponding to the rotation angle and the phase corresponding to the rotation angle shown in Table 2a and Table 2b with the rotation angle as an address in the memory,
By giving the rotation angle to the memory and reading each phase current,
Energization with zero rotational torque can be set.

[0027] Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0028]

FIG. 1 shows an embodiment of the present invention. The apparatus shown in FIG. 1 is a main part of an electric motor system drive unit of a hybrid electric vehicle equipped with an internal combustion engine for driving wheels and a switched reluctance motor (hereinafter referred to as SR motor) for driving wheels. Is composed. FIG. 1 mainly shows a DC drive power supply circuit system below the on-vehicle battery PB for driving the SR motor. FIG. 2 shows a combination of the control system of the apparatus shown in FIG. In FIG. 2, the illustration of the DC drive power supply circuit system is omitted.

Please refer to FIG. 1 and FIG. In this example, one SR motor 1 is provided as an electric drive source, and this SR motor 1 is an electric system controller E.
Controlled by the CU. System controller ECU
Controls the driving of the SR motor 1 based on information input from the shift lever, brake switch, accelerator switch, and accelerator opening sensor.

The SR motor 1 is provided with three-phase coils 1a, 1b, 1c for driving the SR motor and an angle sensor 1d for detecting the rotational position (angle) of the rotor. 3
The phase coils 1a, 1b and 1c are connected to motor drivers 18, 19 and 1A, respectively.
a and a driver 18, a wire connecting the coil 1 b and the driver 19, and a wire connecting the coil 1 c and the driver 1 A, respectively.
3 and 4 are installed. These current sensors 2, 3
And 4 output a voltage proportional to the current actually flowing through the coils 1a, 1b and 1c, respectively, as a current signal S6.

Inside the system controller ECU,
CPU (microcomputer) 11, input interface 12, direction detection circuit 5, current map memory 13
a, a waveform map memory 13b and a control power supply circuit 14, and the CPU 11 gives an energization command (target current value) to the current controllers 1, 2, and 3. The current controllers 1, 2, and 3 are each a motor driver 1
The currents supplied to the first phase electric coil 1a, the second phase electric coil 1b, and the third phase electric coil 1c of the electric motor 1 are controlled via 8, 19 and 1A.

The current controller 1 includes a current waveform generation circuit 15, a comparison circuit 16, and an output determination circuit 17. The configuration and function of the current controllers 2 and 3
It is the same as the current controller 1.

The electric power of the battery PB, which is a DC power supply for driving the electric motor on the vehicle, has a high voltage of about 288 V. When the driving power supply relay PR is turned on, the voltage of the battery PB is applied to the motor driver power supply line. A ripple absorption capacitor Cap and a resistor Res are connected to the power supply line. Since the motor drive current is as high as several hundred amps, the capacitance of the capacitor Cap is as large as about 8100 μF. However, the value of the resistor Res is high for reducing power consumption, and the discharge time constant of the parallel circuit of the capacitor Cap and the resistor Res is considerably large. Therefore, when the drive power supply relay PR is turned off with the motor drivers 18, 19 and 1A all turned off, the voltage of the capacitor Cap (the voltage of the motor driver power supply line) maintains a high value for a long time. In order to discharge this voltage in a short time, as will be described later, after turning off the drive power supply relay PR, the CPU 11 of the system controller ECU instructs the current controllers 1 to 3 to supply current, and Data drivers 18, 19,
1A is made conductive, and the electric charge of the capacitor Cap is discharged to the electric coils 1a to 1c of the SR motor 1.

In addition to the drive power supply circuit, a control power supply battery CB and a control power supply circuit 14 are also provided. The power supply circuit 14 is connected directly to the battery and constantly applies a constant voltage to the CPU 11 and consumes very little power. The power supply circuit 14 is connected to the battery CB when the control power supply relay-CR is turned on, and the current control circuit is connected to the battery CB. -Laters 1-3, motor driver 1
8, 19, and 1A (control voltage lines thereof), and a constant voltage circuit which supplies a constant voltage for control to each of the detectors and the detection circuits and consumes relatively large power.

The operating voltage is always supplied to the CPU 11 regardless of whether the control power supply relay-CR is on or off. CP
U11 responds to an on-vehicle power-on signal VSs indicating on / off of an ignition key switch VSC on the vehicle, and the signal VSs changes from a low level L indicating that the key switch VSC is off to a high level indicating on. When switching to level H,
Turn on the control power supply relay CR and turn on the drive power supply relay.
Turn on PR. When the on-vehicle power-on signal VSs is H (VS
When switching from C on) to L (VSC off), the drive power supply relay PR is turned off, and the insulation voltage conversion circuit VC
The output voltage of T is converted into a digital signal and read. If the output voltage is equal to or larger than a set value, the current controller 1 is instructed to supply current. When the output voltage of the insulation voltage conversion circuit VCT becomes lower than the set value, the power supply is stopped and the control power supply relay-CR is turned off.

The insulation voltage conversion circuit VCT is a sawtooth wave generating circuit, a voltage dividing resistor circuit for dividing the voltage of the capacitor Cap, and compares the divided voltage with the sawtooth wave to convert it into a PWM pulse (duty ratio thereof). A comparison circuit, a photocoupler that insulates and transmits the PWM pulse, and a pulse width / voltage conversion circuit that converts the insulated and transmitted pulse into an analog voltage. Give to D conversion input port. C
When the relay PR is on, the PU 11 A / D converts and reads the output analog voltage of the circuit VCT when drive power supply voltage information is required or at a predetermined cycle. Relay-PR
When the analog voltage is turned off, the analog voltage is repeatedly A / D converted and read.
Instructs the controllers 1 to 3 to energize the motor 1.

The system controller ECU is an electric motor
During normal operation of the motor 1 (during the drive power supply relay-PR on),
Shift lever, brake switch, accelerator switch,
And the required rotation direction, drive speed and drive torque of the SR motor 1 are sequentially calculated based on the information input from the accelerator opening sensor and the coil 1a of the SR motor 1 based on the calculation result. , 1b and 1c are controlled.

The angular velocity sensor 1d outputs an 11-bit binary signal indicating the absolute value of the angle from 0 to 360 degrees. The minimum resolution of the detection angle is 0.5 degrees. Direction detection circuit 5
Is based on the lower 2 bits of the signal output by the angle sensor 1d, and indicates the rotation direction (clockwise C) of the rotor of the SR motor 1.
W / counterclockwise CCW), and H at CW
(1) In the case of CCW, a direction detection signal S11 of L (0) is generated and supplied to the CPU 11 and the output determination circuit 17.

FIG. 3 shows a specific configuration of a main part of the circuits shown in FIGS. FIG. 3 shows only a circuit for controlling the energization of the first phase electric coil 1a of the SR motor 1, but the circuits shown in FIGS. 1 and 2 control the energization of the other coils 1b and 1c. Similar circuits are each included.

Referring to FIG. 3, one end of the coil 1a is
The other end of the coil 1a is connected via a switching transistor (IGBT) 18b to a low potential line 18f of the power supply via a switching transistor (IGBT) 18a. Further, the emitter of the transistor 18a and the low potential line 18
The diode 18c is connected between the transistor 18f and the transistor 18d, and the diode 18d is connected between the emitter of the transistor 18d and the high potential line 18e. Therefore, if both the transistors 18a and 18b are turned on (conductive state), a current flows between the power supply lines 18e and 18f and the coil 1a, and if one or both of them are turned off (non-conductive state). , The power supply to the coil 1a can be stopped.

The output judgment circuit 17 has two AND gates.
17a, 17b, 17c and an exclusion shevnogate 17d.

The exhaust vehicle 17c is based on information input from a shift lever, a brake switch, an accelerator switch, and an accelerator opening sensor.
A signal S10 (H: CW / C) indicating the required rotation direction of SR motor 1 determined by controller ECU, that is, the designated direction.
L: CCW) and the direction detection signal S11 of the direction detection circuit 5
When (H: CW / L: CCW) matches, that is, when the rotor of the motor is rotating in the same direction as the designated direction, H (meaning soft chopping is possible), the motor rotates in the opposite direction. And the mode designation signal of L (prohibition of soft chopping = designation of hard chopping)
c.

The output terminal of the AND gate 17a is connected to the gate terminal of the transistor 18b.
The output terminal of gate 17b is connected to the gate terminal of transistor 18a. Signals S72 and S5 and a mode switching instruction signal (17) are input to the input terminal of AND gate 17a.
c), and signals S71, S72 and S5 are input to the input terminal of the AND gate 17b. The signals S71 and S72 are binary signals output from the analog comparators 16a and 16b of the comparison circuit 16, respectively.
The signal S5 is a binary signal output from the current waveform generation circuit 15.

The comparison circuit 16 includes two analog comparators 16
a and 16b. The analog comparator 16a is
First reference voltage Vr1 output from current waveform generation circuit 15
And outputs the result of comparing the voltage of the signal S6 corresponding to the current detected by the current sensor 2 as a binary signal S71. The analog comparator 16b compares the second reference voltage Vr2 output by the current waveform generation circuit 15 with the second reference voltage Vr2. The comparison result of the voltage of the signal S6 corresponding to the current detected by the current sensor 2 is output as a binary signal S72. In this embodiment, Vr1 <
The relationship of Vr2 is established.

When the signal S5 is at a high level H, the signal S6
According to the magnitude relationship between the voltage Vs6 and the reference voltages Vr1 and Vr2, the states of the transistors 18a and 18b of the driver 18 are set to one of three types as shown below.

Table 1 Comparator Comparator EX-NOR AND AND Case classification 16a 16a 17d 17a 17b Tr Tr output Output output Output 18a 18b Vs6 ≦ Vr1 HHHH ON ON Vr1 <Vs6 ≦ Vr2 LH HHL Off On Vr1 <Vs6 ≦ Vr2 LHLL L Off Off Vs6> Vr2 LLL L L Off Off.

The above case is the state shown in FIG. 13A and FIG. 14A, and the above case is the state shown in FIG.
4 (b), and the above and the above cases are the states shown in FIG. 13 (b). The mode of alternately repeating the above is hard chopping, and the mode of alternately repeating the above is soft chopping.

In the case of Vr1 <Vs6 ≦ Vr2, as in the original case, 18a is turned off and 18b is turned on, as shown in FIG. Since the rotation direction of the rotor is opposite to the specified direction, the rotation is changed to 18a and 18b to prevent the transistors 18a and 18b from being destroyed.

That is, when Vr1 <Vs6.ltoreq.Vr2, the input to the AND gate 17c from the comparators 16a and 16b goes to the gate-on level. -D 17d
(H: soft chopping enabled / L: soft chopping disabled) is given, and if this mode designating signal is H, the above (soft chopping mode) is set, and the mode designating signal is If L, the above (hard chopping mode) is achieved.

As described above, the transistors 18a and 18a
There are a state in which both b are turned on, a state in which both are turned off, and a state in which one is turned on and the other is turned off. The state of Vs6 is lower than Vr1, Vr1
Between Vr2 and Vr2, or between three types of regions larger than Vr2, and when between Vr1 and Vr2, whether or not the rotation direction of the rotor of the motor is the same as the specified direction. .

When the signal S5 is at low level L, the outputs of the AND gates 17a and 17b are always at low level irrespective of the state of the signals S71 and S72 output from the comparison circuit 16, and the transistors 18a and 18a are at low level. 18b are both turned off.

The rise characteristic (speed of rise) of the current flowing through the coil 1a when both the transistors 18a and 18b are turned on is determined by the time constant of the circuit and cannot be changed by control. However, when the current is cut off, the falling characteristic (speed of falling) of the current depends on the case where both the transistors 18a and 18b are turned off and the case where the transistor 18a is turned off and the transistor 18b is kept on. Since it changes, it can be switched to adjust the fall speed of the current. That is, the transistor 18
When both a and 18b are turned off, the current changes rapidly,
The transistor 18a is turned off and the transistor 18a is turned off.
If b remains on, the current changes slowly.

When there is almost no change in the current target values (Vr1, Vr2), the deviation between the reference level (Vr1) and the actually flowing current level (Vs6) increases even when the current falling speed is slow. Therefore, the state of Vs6 <Vr2 is always maintained. Therefore, at this time, the fluctuation range of the current is small. Also, as in the case of switching the phase of the coil to be energized, the current target values (Vr1, Vr
When 2) is changed, if the current falls slowly,
Vs6> Vr2. In this case, since the two transistors 18a and 18b are both turned off, the falling speed of the current increases, and the current changes quickly following the target values (Vr1, Vr2). If the change in the target value stops, the deviation between the reference voltage Vr1 and the current level Vs6 decreases, so that the current fall speed slows down again.

Thus, not only can the delay of the current following the change of the target value be prevented, but also when the change of the target value is small, the speed of change of the current is slow, so that the generation of vibration and noise is suppressed.

When the falling speed of the current is switched by the signals S71 and S72 output from the comparison circuit 16 shown in FIG. 3, the actual switching tends to be slightly delayed from the optimal timing as the switching timing. . That is, when the target value sharply decreases, it is ideal that the fall of the current is accelerated. However, if the current deviation does not actually increase, the signal S72 does not become L, so that a time delay occurs. . For this reason, when the target value changes very quickly, there is a possibility that the responsiveness of the current to the target value is insufficient only by the automatic switching of the change speed by the signals S71 and S72.

Therefore, in this embodiment, by controlling the signal S5, regardless of the magnitude of the current (Vs6),
The falling speed of the current can be increased. That is, when the signal S5 is set to the low level L, the transistors 18a and 18b are simultaneously turned off irrespective of the signals S71 and S72, so that the current falling speed is increased.

Referring to FIG. 3, current waveform generating circuit 15
Outputs two kinds of reference voltages Vr1 and Vr2 and a binary signal S5. Reference voltages Vr1, Vr2 and binary signal S5
Are the memories (RAM) 15b, 15a and 1
5c is generated based on the information stored in 5c. Memory 1
5b, 15a and 15c hold 8-bit, 8-bit and 1-bit data at each address. The 8-bit data read from the memory 15a is
The voltage is converted into an analog voltage by the D / A converter 15e, and becomes the reference voltage Vr2 through the amplifier 15g. Similarly, 8-bit data read from the memory 15b is converted to an analog voltage by the D / A converter 15f, and becomes the reference voltage Vr1 through the amplifier 15h. In addition, amplifiers 15g, 15
h is input to the analog signal S1 output from the CPU 11.
Are added. By adjusting the level of the signal S1, the reference voltages Vr1 and Vr2 can be finely adjusted. The 1-bit data output from the memory 15c passes through the AND gate 15i to become a signal S5. A binary signal (start / stop signal) S3 output from the CPU 11 is applied to one input terminal of the AND gate 15i. When the SR motor 1 is being driven, the signal S3 is always at the high level H, so that the output signal of the memory 15c becomes the binary signal S5 as it is.

Each of the memories 15a, 15b and 15c has a large number of addresses.
The rotation position (angle) of the rotor R is associated with each (in units of one degree). The address decoder 15d outputs a signal S9 of the rotational position of the rotor detected by the angle sensor 1d.
To generate address information. This address information
The data is simultaneously input to the address input terminals of the three sets of memories 15a, 15b and 15c. Therefore, when the SR motor 1 rotates, the memories 15a, 15b and 15c sequentially output data held at addresses corresponding to the rotational position of the rotor. Therefore, the states of the reference voltages Vr1, Vr2 and the binary signal S5 can change for each rotational position.

Actually, in order to cause a current having a waveform as shown in FIG. 4 to flow through the three-phase coil, the memories 15a and 15b hold information of an energization map as shown in FIG. 8, respectively. That is, the target value of the current to be set at that position is held at the address associated with each rotational position (in this example, every 0.5 degrees). Since the information in the memories 15a and 15b corresponds to the reference voltages Vr2 and Vr1, respectively, the memories 1a and 15b satisfy the relationship of Vr2> Vr1.
The contents of 5a and the contents of memory 15b are slightly different. As described above, since the level of the current flowing through the coil 1a changes so as to follow the reference voltage Vr1, the waveform of the current desired to flow through the coil 1a is changed to the reference voltages Vr1 and Vr1.
By registering 2 in the memories 15b and 15a, a current can flow as shown in FIG.

In this embodiment, the three-phase coils 1a, 1b
And 1c must be switched every time the rotor rotates 30 degrees as shown in FIG.
Is registered in the memories 15b and 15a, the switching between energization and non-energization every 30 degrees is automatically performed by the signals S71 and S72. That is,
It is not necessary for the CPU 11 to switch between energization and non-energization of each coil.

In the memory 15c, the information of "1" corresponding to the high level H of the signal S5 is held in most of the addresses, but the current target values (Vr1, Vr
At the address corresponding to the angle at which 2) sharply decreases, information of "0" (forcible cutoff information) corresponding to the low level L of the signal S5 is held. That is, the target value of the current (Vr
1, Vr2), at the rotational position where the slope of the descent is steep and the current change rate is expected to be faster at the start of the fall of the waveform of (1, Vr2), the automatic switching by the signal S72 is performed. Without waiting, the signal S5 is switched to the low level L by the information stored in the memory 15c, and the current changing speed is forcibly increased. As a result, it is possible to avoid a time delay in switching the current change speed, and the follow-up of the current to the target value is further improved.

The memories 15a, 15b and 15c are capable of writing and reading, and can execute writing and reading simultaneously. The memories 15a, 15b and 15c
It is connected to the CPU 11 via the signal line S2,
U11 stores the memories 15a, 15b and 15 as necessary.
Update the contents of c.

The operation of the CPU 11 is schematically shown in FIGS.
Shown in First, referring to FIG. 6, when the power is turned on (operating voltage is applied to the CPU 11 by the battery CB and the power supply circuit 14), initialization is executed in step 51. That is, C
After the initialization of the internal memory of the PU 11 and the mode setting such as the internal timer and the interrupt, the system is diagnosed. If there is no abnormality, the process proceeds to the next process.

In step 52, the state of the signal output from each of the shift lever, the brake switch, the ignition key switch VSC, the accelerator switch, and the accelerator opening sensor is read via the input interface 12 and driven. The voltage Vp (output analog voltage of the insulation voltage conversion circuit VCT) is read, and the state data and the voltage value data are stored in the internal memory.

Then, at step 61, the ignition key switch Vsc is turned on / off (H / L of the signal VSs).
And if it is on (H), step 6
In step 2, it is determined whether or not this time is the switching from off to on by referring to the data of the register Fvsc (1 if already on, 0 if not on). If it is determined that this time is switching from off to on, steps 54 and 55 are performed.
Then, the status is checked for normal / abnormal with reference to the status data. If the status is normal, the control power supply relay CR is turned on, the drive power supply relay PR is turned on, and 1 is written into the register Fvsc. To light the ready lamp (steps 56 to 5).
9). In the following, the word "step" is omitted in parentheses, and only the step display symbol is described.

Next, the routine proceeds to the steady-state control of the SR motor shown in FIG. 7, and thereafter, steps 52-61-62-FIG. 7-6 until the ignition key switch Vsc is turned off.
3-69, 6A-52 -... in FIG.
Over the loop.

In step 63 of FIG. 7, if there is any change in the state detected in step 52, the process proceeds from step 63 to step 64. If there is no change, the process proceeds from step 63 to step 65.

In step 64, a required driving direction (designated direction) of the SR motor 1 is determined based on the various states detected in step 62, and a signal S10 indicating the driving direction is determined.
(H: CW / L: CCW)
To the target 17d to determine the target value of the driving torque. For example, when the accelerator opening detected by the accelerator opening sensor increases, the target value of the driving torque also increases. Here, a torque change flag indicating a change in the target torque is set.

At step 65, the rotational speed of the SR motor 1 is detected. In this embodiment, the bit data of the angle detection data (11 bits) of the angle sensor 1d changes according to the rotation of the rotor of the SR motor, and the change cycle is inversely proportional to the rotation speed. The CPU 11 calculates the motor rotation speed by measuring the change period of the lower bits. Data of the calculated rotation speed is stored in the internal memory.

If there is a change in the rotation speed of the SR motor 1, the process proceeds from step 66 to step 68, and if there is no change in the rotation speed, the process proceeds to step 67. In step 67, the state of the torque change flag is checked. When the flag is set, that is, when there is a change in the target torque, the process proceeds to step 68, and when there is no change in the torque, step 6 is performed.
Return to 2.

In step 68, the current map memory 13
Data is input from a, and in the next step 69, data is input from the waveform map memory 13b. In this embodiment, the current map memory 13a and the waveform map memory 13
b is a read-only memory (ROM) in which various data are registered in advance. The data as shown in FIG. 8 is stored in the current map memory 13a, and the waveform map memory 13b is stored in the waveform map memory 13b. Data as shown in FIG. 12 is held.

That is, the current map memory 13a stores a large number of data Cnm (n: columns corresponding to torques) corresponding to various target torques and various rotational speeds (rotational speeds of the motor). , M: numerical value in a row corresponding to the number of rotations), and one set of data Cnm includes a power-on angle, a power-off angle, and a current target value. For example, when the torque is 20 [N · m] and the rotation speed is 500
The content of the data C34 at the time of [rpm] is 52.5 degrees,
82.5 degrees and 200 [A]. That is, within the range of the rotation position of 0 to 90 degrees, 52.5
A current of 200 A flows in the range of
In the range of 2.5 degrees and the range of 82.5 to 90 degrees, it means that the current is interrupted. In step 68, a set of data of Cmn selected according to the torque and the rotation speed at that time is set.
Input data.

However, the target value of the current actually supplied to the coil does not change in a general rectangular waveform but has a gentle rising and falling waveform. This waveform is determined based on the waveform map memory 13b.

As shown in FIG. 12, the waveform map memory 1
3b includes a large number of data D1n and D2n corresponding to various rotation speeds (rotational speeds of the motor).
(N: numerical value of the row corresponding to the number of rotations) is held.
Data D1n is the required rise angle, and indicates the amount of change in the rotation angle from when the current rises from a low level (0 [A]) to a high level (for example, 200 [A]). Data D
2n is a required fall angle, which indicates a rotation angle change amount from when the current falls from a high level (for example, 200 [A]) to a low level (0 [A]).

For example, when the data of C34 in the current map shown in FIG. 8 is used, the rise of the current target value is started from a position D1n before the energization ON angle of 52.5 degrees. The waveform of the current target value is changed so that it gradually rises to 100% at 52.5 degrees, and the fall of the current target value starts from a position D2n before 82.5 degrees which is the energization off angle. Then, the current target value is gently changed so that the fall is completed at 82.5 degrees.

Data D1n, D2n of waveform map memory
Is predetermined so that the rise and fall of the current change at the optimum time (angle) for each rotation speed [rpm]. That is, if the rise and fall are too fast, the differential value of the magnetic flux at the time of switching the excitation becomes large, and the vibration and noise increase.If the rise and fall are too slow, the driving torque is significantly reduced and the driving efficiency is also reduced. D1n and D2n are determined such that the vibration and noise can be sufficiently suppressed and the driving efficiency is not significantly reduced. In particular, D
The rise time corresponding to 1n and the fall time corresponding to D2n are both set to be longer than a half cycle of the natural vibration frequency (resonance frequency) of the SR motor 1.
In this way, the frequency of the vibration generated when the excitation is switched becomes lower than the natural vibration frequency of the SR motor 1, so that the resonance is prevented and the increase in the vibration and noise levels is suppressed.

At step 69 in FIG. 7, one set of data D is stored from the waveform map memory 13b according to the rotation speed at that time.
1n and D2n are selected and their data are input to the CPU 11. For example, when the rotation speed [rpm] is 500, the data D14 and D24 are selected and input.

In the next step 6A, based on the data Cnm input in step 68 and the data D1n and D2n input in step 69, data of an energization map as shown in FIG. 9 is generated. With this latest energization map,
The memories 15a and 15b of the current waveform generation circuit shown in FIG.
15c is updated (rewritten). Of course, in addition to writing the energization map to the memories 15a, 15b, and 15c for one phase shown in FIG. 2, energization maps are created for all three phases of memory, and the data is written to each memory. .

In practice, the energization map is created as follows. In the case of the third phase, the current target value at the angular position A1 obtained by subtracting the required rise angle D1n from the energization ON angle Aon included in the data Cnm is 0, and the position of the energization ON angle Aon is included in Cnm. Current target value (for example, 200
[A]), and data is interpolated between the angular positions A1 and Aon so as to connect them with a smoothly rising curve. That is, a value approximating the curve is calculated and obtained every 0.5 degree of the rotor angle, and the calculated value is used as a current target value at each angle. Similarly, at the angular position A2 obtained by subtracting the required fall angle D2n from the energization off angle Aoff included in the data Cnm, the current target value is set to the current target value (for example, 200 [A]) included in Cnm. , Energization off angle Ao
The current target value at the position ff is set to 0, and the angular positions A2 and Ao
Between ff and ff, data is interpolated so as to be connected by a smoothly falling curve. That is, a value approximating the curve is calculated and obtained every 0.5 degree of the rotor angle, and the calculated value is used as a current target value at each angle. In other angular positions, 0 is written as a current target value.

Further, regarding the first phase and the second phase, the third phase
The phase energization map data shifted by 30 degrees and 60 degrees, respectively, is used as it is. Thus, FIG.
Is generated as shown in FIG. The energization map shown in FIG. 10 shows only the data (Vr1) written in the memory 15b, and the data (Vr2) written in the memory 15a has a value slightly larger than the value of the energization map in FIG. .

In this embodiment, the memories 15a, 15b,
Since the current flowing through the electric coil 1a is controlled based on the data of the memory 15c, the CPU 11 stores the memory (15 for three phases).
a, 15b, 15c) only by writing the energization map,
In accordance with this, the excitation switching of each coil is automatically performed by a hardware circuit.

The CPU 11 executes the above steps 62 to 6A
Is repeatedly executed. Then, the detected SR mode
If the rotation speed and torque of the motor are constant, step 6
6-67-62, but when the rotation speed changes or the torque changes, steps 68-69-6 are performed.
Since A is executed, the energization maps on the memories 15a, 15b, and 15c are updated.

According to the above-described embodiment, even when the condition for performing soft chopping (Vr1 <Vs6 ≦ Vr2) is satisfied and the transistor 18a is turned off and the transistor 18b is originally turned off, the CPU 11 specifies the signal S10. The direction detection circuit 5 detects the signal S for the motor rotation direction.
When the actual rotation directions represented by 11 are different,
The output of the exclusive gate 17d becomes L and the output of the AND gate 17c is constrained to L, whereby the output of the AND gate 17a is constrained to L and the transistor 18b is turned off. As a result, immediately after the transistor is turned off, the electric motor is fed back (regenerated) to the power supply line 18e as shown in FIG. 11B, so that an excessive current does not flow through the transistor 18b and there is no fear of destruction. .

The signal VSs, which is read in step 52 and indicates the on / off state of the ignition key switch VSC, is at L
When the state is switched to (OFF), the process proceeds from step 61 to step 53, where the data in the register Fvsc is 1 (drive power supply relay-PR on), so that the drive power supply relay-PR is turned off. (71). And the drive power supply voltage V
It is checked whether p (the output voltage of the insulation voltage conversion circuit VCT) is less than 1 V (72), and if it is 1 V or more, the target value of each phase current is set to 20 A (77). That is, data indicating 20 A is written in each phase register for storing the target value of each phase current. Next, the rotation speed of the SR motor 1 is 1 rp.
It is checked whether it is less than m (78). If it is less than 1 rpm, the currents of the first to third phases corresponding to the rotation angles at that time are obtained from the capacitor discharge current value table of the current map memory 13a. The values are read and updated and written to each phase register (82).

The current values in Table 2a and Table 2b are written in the capacitor discharge current value table of the current map memory 13a in correspondence with the rotation angle.
Is the rotation angle of the rotor of the SR motor 1 at that time (0 to 0)
(360 degrees) is read. When the rotation angle is 0 to 45 degrees, the memory access address is determined by the rotation angle data. When the rotation angle is 46 to 90 degrees, a value obtained by subtracting 45 degrees from the value is obtained. It is a value obtained by subtracting 135 degrees when it is 136 to 180 degrees, and a value obtained by subtracting 180 degrees from it when it is 181-225 degrees.
When it is 270 degrees, it is a value obtained by subtracting 225 degrees from it.
In the case of 271 to 315 degrees, a value obtained by subtracting 270 degrees from it, and in the case of 316 to 360 degrees, 3 is subtracted therefrom.
A memory access address is determined by a value obtained by subtracting 15 degrees.

The CPU 11 stores the data written in each phase register in step 83 in step 82 in the controller 1.
To 3 and write to the memory 15b.
The data for continuous energization is transferred to c, and the signal S3 is set to H. The controllers 1 to 3 output the transferred target current value data to the D / A converter 15f via the memory 15b, and output the energization designation data via the memory 15c to the AND gate 15i. Output to As a result, current values shown in Tables 2a and 2b flow through the electric coils 1a to 1c of each phase of the SR motor 1. However, this is when the residual voltage of the capacitor Cap is high enough to flow the current value. When the residual voltage drops rapidly and the coil current becomes smaller than the target current value, the output of the comparator S71 remains at H, and chopping as in the steady driving does not appear.

When it is determined in step 78 that the motor rotation speed is 1 rpm or more, the CPU 11
In response to the rotation direction of the motor, an energization command for performing a rotation in the opposite direction is given to controllers 1 to 3 together with a target current value (here, 20 A) (80, 81). The energization command at this time is the same as that at the time of the above-described steady drive, and differs only in that the target current value is fixed at 20A.

When the voltage of the capacitor Cap becomes less than 1 V due to the above-described motor energization, the CPU 11 writes the target current value 0A into each phase register (72, 73) and supplies it to the controllers 1 to 3. Command to stop power supply (74). Then, the control power supply relay-CR is turned off (7
5), the register Fvsc is cleared (76), and thereafter,
It waits for the ignition key switch VSC to be turned on in steps 52-61-53-52.

The above-mentioned SR motor 1 has a maximum torque of 165 N · m and a maximum output of 45 KW. Capacitor C
When the battery voltage is 288 V, the residual charge Q of ap becomes Q = CV = 8100 μF × 288 V. If this charge is discharged with a constant current I within 150 msec,
I = CV / t = 15.6A, and it is sufficient to conduct electricity of 15.6A or more. From this viewpoint, first, the current target value is set to 20 A (77 in FIG. 6).

The values in Tables 1a, 1b, 2a and 2b are calculated values (estimated values) for the SR motor 1 described above.
In a graph, the estimated 20A torques in Tables 1a and 1b are as shown in FIG. "Electrified current" shown in Tables 2a and 2b is as shown in FIG.
17 are as shown in FIG.

Since the "energized current" data of Tables 2a and 2b are written in the capacitor discharge current value table of the current map memory 13a, all phases are simultaneously energized (83 in FIG. 6). However, there may be a case where the motor torque does not definitely become zero. However, if the SR motor is rotating when the drive power supply relay is turned off, or if it is assumed that the motor starts rotating by all-phase simultaneous energization (83 in FIG. 6), the rotation speed is 1 rpm. If it is equal to or more than 1 rpm, the reverse energization is performed (8
0, 81), the motor rotation is reliably suppressed. Actually, the total sum of the torques does not become zero due to the simultaneous energization of all phases (83 in FIG. 6), and a torque corresponding to the rotation angle is generated.
However, the maximum torque is extremely small at 4 N · m, and the energizing time is as short as approximately 50 msec (approximately 150 msec / 3 because three phases are energized).
Rotation is barely perceptible to human senses.

Therefore, the "calculation of the current value corresponding to the angle" in step 82 of FIG. 6 may be omitted, and the set 20A (step 77) may be used as it is for "simultaneous energization of all phases" (83). Even in this case, it is inferred that rotation is hardly perceived by human senses, but microscopically, it is estimated that motor rotation during capacitor discharge is slightly larger than in the above-described embodiment.

[Brief description of the drawings]

FIG. 1 is a block diagram mainly showing a drive power supply circuit of a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram mainly showing a control system configuration of the embodiment shown in FIG. 1;

FIG. 3 is a block diagram showing a specific configuration of only a one-phase drive circuit among three-phase drive circuits of a main part of the control system shown in FIG. 2;

FIG. 4 is a time chart showing a waveform example of an excitation current instruction when the SR motor 1 shown in FIG. 1 is driven.

FIG. 5 is a time chart showing a change according to a driving condition of an exciting current waveform supplied to the SR motor 1 shown in FIG. 1;

FIG. 6 is a flowchart showing a part of an operation outline of a CPU 11 shown in FIG. 1;

7 is a flowchart showing the rest of the outline of the operation of the CPU 11 shown in FIG.

8 is a map showing the contents of a part of data of a current map memory 13a shown in FIG.

FIG. 9 is a map showing a part of data written in memories 15a, 15b and 15c shown in FIG.

FIG. 10 is a time chart showing current, magnetic flux, and magnetic flux change when general energization control is performed in an SR motor.
It is.

FIG. 11 is a time chart showing a current, a magnetic flux, and a magnetic flux change when the rise and fall of the current of the SR motor are gradually changed.

FIG. 12 is a map showing contents of a part of data of a waveform map memory 13b shown in FIG. 2;

FIG. 13 is a view showing a motor current in a hard chopping mode of the inverter 18 shown in FIG. 3;
(A) shows the current flowing direction when the driving current is flowing through the motor, (b) shows the current flowing direction when the supply of the driving current is cut off, and (c) shows the time-series current waveform. The outline of is shown.

14 is a view showing a motor current in a soft chopping mode of the inverter 18 shown in FIG. 2,
(A) shows the current flowing direction when the driving current is flowing through the motor, (b) shows the current flowing direction when the supply of the driving current is cut off, and (c) shows the time-series current waveform. The outline of is shown.

FIG. 15 is a graph showing estimated phase torques shown in Tables 1a and 1b.

FIG. 16 is a graph showing the current flowing through each phase shown in Tables 2a and 2b.

FIG. 17 is a graph showing each phase torque shown in Tables 2a and 2b.

[Explanation of symbols]

1: SR motors 1a, 1b, 1c:
Electric coil 1d: Angle sensor 2, 3, 4: Current sensor 11: CPU 12: Input interface
Face 13a: Current map memory 13b: Waveform map memory 14: Power supply circuit 15: Current waveform generation circuit 15a, 15b, 15c: Memory 15d: Address decoder 15e, 15f: D / A converter 15g, 15h: Amplifier 16: Comparison circuit 16a, 16b: Analog comparator 17: Output determination circuit 17a to 17c: AND gate 17d: Excitation gate 18, 19, 1A: Each phase driver 18a, 18b: Transistor (IGBT) 18c, 18d : Diode 18e, 18f: Power supply line Vr1, Vr2: Reference voltage

Claims (6)

[Claims] 1. A motor driver connected to a DC power supply via a power switch; and an electric motor via the motor driver.
Motor current controller for controlling the value of the current supplied to the motor;
And a discharge control means for instructing the motor current controller to supply power when the power switch is switched from closed to open. 2. The electric motor according to claim 1, further comprising: direction detecting means for detecting a rotation direction of the electric motor;
2. An electric motor energization control device according to claim 1, wherein an energization for rotating and driving the electric motor in a direction opposite to the rotation of the motor is instructed to the motor current controller. 3. The electric motor according to claim 1, further comprising: speed detecting means for detecting a rotation speed and a direction of the electric motor, wherein the discharge control means reverses the rotation of the electric motor when the rotation speed is higher than a set value. An instruction is given to the motor current controller to energize the electric motor to rotate in the direction, and if the rotational speed is less than a set value, an instruction is made to energize the electric motor simultaneously for all phases;
An energization control device for an electric motor as described in the above. 4. An electric motor according to claim 1, wherein said electric discharge control means includes means for energizing said electric motor so that the sum of torque generated by each phase of said electric motor is substantially zero.
The electric motor energization control device according to claim 1, wherein an instruction is given to a motor current controller. 5. An electric motor according to claim 1, further comprising an angle detecting means for detecting a rotation angle of the electric motor, wherein the discharge control means determines a target current value corresponding to the rotation angle of the electric motor, and determines the target current value. 5. An electric motor energization control device according to claim 4, which is provided to a motor current controller. 6. The discharge control means includes a memory storing a current value corresponding to a rotation angle of the electric motor for making the sum of torque generated by each phase of the electric motor substantially zero. 6. An electric motor energization control according to claim 5, wherein a current value corresponding to the rotation angle detected by the angle detecting means is read out from the memory, and the read out current value is given to the motor current controller as a target current value. apparatus.