JP2002017098A - Motor control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect an inverter and a capacitor against overvoltage without use of any resister for discharge or switching element for discharge control. SOLUTION: A relay control circuit 3 controls turn-on and-off of a heavy- current relay JB. A voltage detection circuit 2 detects the supply voltage of an inverter circuit 5 or the rectified voltage during regeneration, and a current detection circuit 4 detects the direction and value of current between a high- voltage power supply Vin and the inverter circuit 5. The detection circuits covey the result of detection to CPU 1, respectively. The CPU 1 decides from the direction of current whether the present state is in driving or regeneration. If any abnormal voltage is detected in a regeneration state, the CPU turns on the switching elements Q2, Q4, and Q6 in the inverter circuit 5 according to the rotational position detected by a position sensor 8 so that the plurality of the phases of the motor 6 are connected in series.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor control device, and more particularly to a motor control device having an abnormal voltage protection function during regeneration and a motor control device having a capacitor discharging function.

[0002]

2. Description of the Related Art In general, DC-AC converters (hereinafter, referred to as electric vehicles and electric-internal combustion engine hybrid vehicles) are used.
In general, a large-capacity capacitor is connected in parallel to a DC power supply terminal of the inverter (referred to as an inverter) to improve surge capacity absorption and transient large current supply capability due to a decrease in power supply impedance.

Power is supplied from a DC power supply such as a storage battery to the inverter and the capacitor via a power supply relay or the like to reduce power consumption while the vehicle is stopped and to ensure safety during maintenance work. In order to protect such an inverter and a capacitor from overvoltage, for example, Japanese Patent Application Laid-Open No. 10-262
No. 376 is provided.

This discharge circuit is provided in parallel with the capacitor and the inverter as a circuit in which a discharge resistor and a discharge control switching semiconductor are connected in series to protect the inverter and the capacitor from overvoltage. The discharge of the capacitor and the discharge of the capacitor after the power supply relay is turned off can be performed.

[0005]

However, in the above-described discharge circuit of the conventional motor control device, the excess energy accompanying the voltage rise at the time of abnormality is simply consumed by the discharge resistor. It is necessary to increase the withstand power of the discharge resistor and the discharge control switching element used in the above-described method, which causes a problem of miniaturization and cost reduction.

Further, the conventional motor control device has a problem that a long time is required until the discharge of the capacitor is completed after the power supply relay is turned off, and the maintenance work cannot be started immediately after the power supply relay is turned off.

[0007] In view of the above problems, an object of the present invention is to provide a motor control device capable of protecting an inverter and a capacitor from overvoltage without using a discharge resistor and a discharge control switching element. .

Another object of the present invention is to provide a small, lightweight and low-cost motor control device. It is a further object of the present invention to provide a motor control device capable of starting maintenance work immediately after a power relay is turned off.

[0009]

In order to achieve the above object, an invention according to claim 1 is a motor control device for controlling a motor capable of both a driving state and a regenerative state. A drive circuit for supplying a drive current of the motor from the motor and supplying a regenerative current from the motor to the power source when the motor is in a regenerative state, and detecting that the motor is in a regenerative state, and detecting a terminal of the motor when the motor is in a regenerative state. A control means for controlling the drive circuit when the voltage becomes equal to or higher than a predetermined value to supply a current to the electric motor is provided.

According to a second aspect of the present invention, there is provided a motor control device according to the first aspect, wherein the motor is a synchronous motor having a permanent magnet rotor, the drive circuit is an inverter circuit, The gist is that the control means forms a series circuit including a switching element of the inverter circuit and a plurality of phases of the induction motor when a terminal voltage of the motor in the regenerative state is equal to or higher than a predetermined value. I do.

According to a third aspect of the present invention, there is provided a motor control device according to the first aspect, wherein the motor is an induction motor, the driving circuit is an inverter circuit, and the control means is When the terminal voltage of the motor in the regenerative state is equal to or higher than a predetermined value, a series circuit is formed by a plurality of switching elements of the inverter circuit and a plurality of phases of the induction motor, and at least one of the switching elements is formed. Is to be duty controlled.

According to a fourth aspect of the present invention, there is provided an electric motor control device according to the third aspect, wherein the control means is configured to control the motor based on a magnitude of a terminal voltage of the electric motor.
The gist is to switch control modes having different duty ratios.

According to a fifth aspect of the present invention, there is provided a motor control device for controlling a motor capable of both a driving state and a regenerative state, wherein a driving circuit for driving the motor and a power supply for the driving circuit are provided. A capacitor connected in parallel between the terminals, a motor power relay connected in series between the DC power supply and the drive circuit, and detecting that the motor power relay has been turned off, even if a predetermined time has elapsed since the power was turned off. When the voltage between the terminals of the capacitor is equal to or higher than a predetermined value, a control means for controlling the drive circuit to flow a current to the electric motor is provided.

[0014]

According to the first aspect of the present invention, in a motor control device for controlling a motor capable of both a driving state and a regenerative state, a driving current for the motor is supplied from a power supply when the motor is in a driving state. A drive circuit for supplying a regenerative current from the motor to the power source when the motor is in the regenerative state, and detecting that the motor is in the regenerative state, and when the motor is in the regenerative state, the terminal voltage of the motor has become a predetermined value or more. Control means for controlling the drive circuit in the case to flow a current to the motor, and by controlling the drive circuit when the terminal voltage of the motor becomes an overvoltage in the regenerative state to flow the current to the motor. Overvoltage can be suppressed, and abnormal voltage can be suppressed without providing a dedicated discharge circuit as in the prior art, contributing to downsizing and cost reduction of the motor control device. There is a result.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the motor is a synchronous motor having a permanent magnet rotor, the drive circuit is an inverter circuit, and the control The means is arranged such that when the terminal voltage of the motor in the regenerative state is equal to or higher than a predetermined value, a series circuit is formed by a switching element of the inverter circuit and a plurality of phases of the synchronous motor. There is an effect that overvoltage protection can be performed while suppressing heat generation of the motor and the inverter circuit.

According to the third aspect of the present invention, in addition to the effects of the first aspect, the motor is an induction motor, the drive circuit is an inverter circuit, and the control means is the regenerative state. When the terminal voltage of the motor becomes equal to or higher than a predetermined value, a series circuit including a plurality of switching elements of the inverter circuit and a plurality of phases of the induction motor is formed, and at least one of the switching elements is set to duty. Since control is performed, there is an effect that overvoltage protection can be performed while suppressing heat generation of the induction motor and the inverter circuit.

According to a fourth aspect of the present invention, in addition to the effect of the third aspect, the control means switches control modes having different duty ratios based on the magnitude of the terminal voltage of the electric motor. As a result, the components of the inverter circuit can be operated in a safe area within the safe operation area, and the reliability of the motor control device can be maintained high.

According to a fifth aspect of the present invention, in a motor control device for controlling a motor capable of both a driving state and a regenerative state, a driving circuit for driving the motor and a power supply terminal of the driving circuit are connected in parallel. The connected capacitor, a motor power relay connected in series between the DC power supply and the drive circuit, and detects the off of the motor power relay, and the terminal of the capacitor even if a predetermined time has elapsed since the off. Control means for controlling the drive circuit to supply a current to the motor when the inter-voltage is equal to or higher than a predetermined value, so that the capacitor voltage may not exceed the predetermined value even if a predetermined time has elapsed after the power supply relay was turned off. For example, by supplying a discharge current from a capacitor using a motor as a resistive load, when a service is received, the worker can start the work without worrying about the work of discharging the residual charge of the capacitor. That reason, maintainability is the effect of greatly improved.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings. [First Embodiment] FIG. 1 is a system configuration diagram showing a configuration of a first embodiment of a motor control device according to the present invention. For convenience of explanation, a DC voltage is supplied to an inverter circuit and regenerative power is supplied to the inverter circuit. 1 includes a high-voltage power supply such as a battery charged with a permanent magnet rotor type synchronous motor (motor) to be controlled.

In FIG. 1, the motor control device includes a high-voltage relay JB for controlling current supply from a high-voltage power supply Vin to the inverter circuit 5, and a large-capacity electrolytic capacitor connected in parallel to the power supply input side of the inverter circuit 5. C1, C2,
A discharge resistor RL for discharging the electric charge of C1 and C2 when the high-voltage relay JB is turned off, and a microcomputer which controls the entire motor control device and also serves as the first and second control means described in the claims. Hereinafter, abbreviated as CPU) 1, a voltage detection circuit 2 for detecting a power supply voltage or a regenerative voltage of the inverter circuit 5, a relay control circuit 3 for controlling the high voltage relay JB, and a connection between the high voltage power supply Vin and the inverter circuit 5. A current detection circuit 4 for detecting the current direction and current value of the current, a DC voltage of the high-voltage power supply Vin is converted into an AC three-phase voltage and supplied to the motor 6, and a regenerative AC current generated when the motor 6 is in a regenerative state is rectified. An inverter circuit 5 for charging the high-voltage power supply Vin, and a position sensor 8 for detecting the rotational position of the rotor.

The high-voltage relay JB controls the supply of current from the high-voltage power supply Vin to the inverter circuit 5, and its contact is designed to intermittently connect the positive electrode of the high-voltage power supply Vin and the power supply input of the inverter circuit 5. Has become. One end of the coil of the high-power relay JB is connected to the 12 V power supply Vign, and the other end is connected to the relay control circuit 3, so that the relay control circuit 3 controls the drive current of the high-power relay JB.

The large-capacity electrolytic capacitors C1 and C2 reduce the power supply impedance of the inverter circuit 5 to improve the AC current driving capability of the inverter circuit 5, and absorb abnormal voltage applied to the inverter circuit 5 by absorbing surge voltage. Works to lower the peak value of. In the present embodiment, it is not always necessary to connect C1 and C2 in parallel.
If either one of C1 and C2 satisfies the required capacity, the other is unnecessary.

The CPU 1 has an input terminal A1 connected to the voltage detection circuit 2, an input terminal A2 connected to the current detection circuit 4, and transistors Q1 to Q6 of the inverter circuit 5.
, And an output terminal O7 for driving the relay control circuit 3.

The CPU 1 also functions as the first and second control means described in the claims. That is,
When the motor 6 is in the driving state of the load, the first control means controls the inverter circuit 5 to supply current to the windings of each phase of the motor 6 so as to control the rotation of the motor 6.
Is in the state of regenerative rotation energy of the load, when detecting an abnormality in which the regenerative voltage becomes equal to or higher than a predetermined value, the second control means controls the inverter circuit 5 to flow a current to the motor 6 to consume the regenerative energy. Control.

The voltage detecting circuit 2 is a circuit for detecting the power supply voltage of the inverter circuit 5, and includes voltage dividing resistors R3 and R4 for dividing the power supply voltage, a smoothing capacitor C3 connected in parallel to R4, and the voltage dividing circuit. Limiter diodes D7 and D8 for limiting the amplitude of the divided voltage between Vcc and GND, and the divided voltage is input to the A1 terminal of the CPU 1.

The relay control circuit 3 includes a complementary connected transistor Q7 that amplifies the output current from the output terminal O7 of the CPU 1 to the drive current of the high-power relay JB.
Q8 is provided.

The current detection circuit 4 includes capacitors C1, C2
A current sensor between the positive terminal of the inverter circuit 5 and the power supply input terminal of the inverter circuit 5 and its current value. The current sensor Isen using a Hall element or the like and the current detected by the current sensor Isen are converted into a voltage. An operational amplifier IC for converting and inputting to the A2 terminal of the CPU 1 and a Vref for supplying a reference voltage to the operational amplifier IC are provided.

The inverter circuit 5 is connected to the motor iu, i
transistors (IGBT) Q1, Q3, Q5 for supplying currents to the respective terminals of v, iw, and iu, iv, iw
Transistors (I
GBT) Three phases by Q2, Q4, and Q6, and flyback diodes D1 to D6 that connect each terminal of iu, iv, and iw to the power supply terminal and the ground terminal of the inverter circuit 5 and rectify an AC current during regeneration. Configured as a bridge, Q
1 to Q6 are connected to the CPU 1
Output terminals O1 to O6.

The motor 6 is a motor capable of rotating and driving the load and regenerating the rotational energy of the load as electric energy. A permanent magnet rotor type three-phase AC synchronous motor or a brushless three-phase DC motor is used. I have. Specifically, it corresponds to a motor for an electric vehicle or a motor for a hybrid vehicle.

The position sensor 8 detects the rotational position of the rotor of the motor 6 using an optical encoder or a magnetic encoder. The detected rotational position is C
The drive current is transmitted from the inverter circuit 5 to the coil having a phase corresponding to the rotational position of the rotor and transmitted to the PU1, whereby the rotor of the motor 6 is synchronously driven.

Next, the operation of the first embodiment will be described.
First, during normal driving, the high voltage supplied from the high-voltage power supply Vin is supplied to the capacitors C1 and C2 via the high-voltage relay JB.
And is supplied to the power supply terminal of the inverter circuit 5. Therefore, the current direction detected by the current detection circuit 4 is the minus direction in FIG. is there. At this time, CP based on the rotational position detected by the position sensor 8 is used.
U1 determines which phase of u, v, or w should be driven, and selectively drives transistors Q1 to Q6 of inverter circuit 5. Thus, the rotation of the rotor and the rotation of the magnetic field formed by the drive coil are synchronized.

At the time of normal energy regeneration, the three-phase AC voltage generated at the terminals iu, iv, iw of the motor 6 in the energy regenerating state is subjected to three-phase bridge rectification by the flyback diodes D1 to D6 of the inverter circuit 5, and the capacitor is turned on. C1, C2 and the high voltage power supply Vin are charged. Therefore, the current direction detected by the current detection circuit 4 is the + direction (the direction from the inverter circuit 5 to the high-voltage power supply Vin) in FIG.

When an abnormal voltage is generated during energy regeneration, the voltage detection circuit 2 detects an abnormally high voltage and transmits it to the terminal A1 of the CPU 1. The CPU 1 turns off the high voltage relay JB to prevent charging of the high voltage power supply Vin due to the abnormal voltage.
Output to the relay control circuit 3 so that
In order that the abnormal voltage is absorbed by the motor 6, outputs O2, O4, and O6 are output so that Q2, Q4, and Q6 are selectively turned on in accordance with the rotational position detected by the position sensor 8. For example, if an abnormal voltage is now generated in the u phase, by conducting Q2, iu → Q2 → D4
(Or D6) → Current flows through the path of iv (or iw), and the energy causing abnormal high voltage is
Is consumed by the coil resistance.

At this time, Q2, Q4 and Q6 may be simply turned on until the abnormal voltage disappears, or a certain DUT
Pulse driving that repeats ON / OFF at the Y ratio may be used. At the time of pulse driving, it is preferable to limit the ON time per operation in consideration of the current and voltage applied to the element based on the standard of the safe operation area (ASO) as the switching element.

[Second Embodiment] FIG. 2 is a system configuration diagram showing a configuration of a second embodiment of a motor control device according to the present invention. For convenience of explanation, a DC voltage is supplied to an inverter circuit. The drawing also includes a high-voltage power supply such as a battery charged with regenerative power and an induction motor (motor) to be controlled.

In FIG. 2, the motor control device includes a high-voltage relay JB for controlling current supply from a high-voltage power supply Vin to the inverter circuit 5, and a large-capacity electrolytic capacitor connected in parallel to the power supply input side of the inverter circuit 5. C1, C2,
A discharge resistor RL for discharging the electric charge of C1 and C2 when the high-voltage relay JB is turned off, and a microcomputer which controls the entire motor control device and also serves as the first and second control means described in the claims. Hereinafter, abbreviated as CPU) 1, a voltage detection circuit 2 for detecting a power supply voltage or a regenerative voltage of the inverter circuit 5, a relay control circuit 3 for controlling the high voltage relay JB, and a connection between the high voltage power supply Vin and the inverter circuit 5. A current detection circuit 4 for detecting the current direction and current value of the current, a DC voltage of the high-voltage power supply Vin is converted into an AC three-phase voltage and supplied to the motor 6, and a regenerative AC current generated when the motor 6 is in a regenerative state is rectified. And an inverter circuit 5 for charging the high-voltage power supply Vin.

The high-voltage relay JB controls the current supply from the high-voltage power supply Vin to the inverter circuit 5, and its contact is provided so that the positive electrode of the high-voltage power supply Vin and the power supply input of the inverter circuit 5 can be connected and disconnected. Has become. One end of the coil of the high-power relay JB is connected to the 12 V power supply Vign, and the other end is connected to the relay control circuit 3, so that the relay control circuit 3 controls the drive current of the high-power relay JB.

The large-capacity electrolytic capacitors C1 and C2 reduce the power supply impedance of the inverter circuit 5 to improve the AC current driving capability of the inverter circuit 5, and absorb an abnormal voltage applied to the inverter circuit 5 by absorbing a surge voltage. Works to lower the peak value of.

The CPU 1 has an input terminal A1 connected to the voltage detection circuit 2, an input terminal A2 connected to the current detection circuit 4, and transistors Q1 to Q6 of the inverter circuit 5.
, And an output terminal O7 for driving the relay control circuit 3.

The CPU 1 also functions as the first and second control means described in the claims. That is,
When the motor 6 is in the driving state of the load, the first control means controls the inverter circuit 5 to supply current to the windings of each phase of the motor 6 so as to control the rotation of the motor 6.
Is in the state of regenerative rotation energy of the load, when detecting an abnormality in which the regenerative voltage becomes equal to or higher than a predetermined value, the second control means controls the inverter circuit 5 to flow a current to the motor 6 to consume the regenerative energy. Control.

The voltage detecting circuit 2 is a circuit for detecting the power supply voltage of the inverter circuit 5, and includes voltage dividing resistors R3 and R4 for dividing the power supply voltage, a smoothing capacitor C3 connected in parallel to R4, and the voltage dividing circuit. Limiter diodes D7 and D8 for limiting the amplitude of the divided voltage between Vcc and GND, and the divided voltage is input to the A1 terminal of the CPU 1.

The relay control circuit 3 includes a complementary connected transistor Q7 that amplifies the output current from the output terminal O7 of the CPU 1 to the drive current of the high-power relay JB.
Q8 is provided.

The current detection circuit 4 includes capacitors C1 and C2
A current sensor between the positive terminal of the inverter circuit 5 and the power supply input terminal of the inverter circuit 5 and its current value. The current sensor Isen using a Hall element or the like and the current detected by the current sensor Isen are converted into a voltage. An operational amplifier IC for converting and inputting to the A2 terminal of the CPU 11 and Vref for supplying a reference voltage to the operational amplifier IC are provided.

The inverter circuit 5 is connected to the iu, i
transistors (IGBT) Q1, Q3, Q5 for supplying currents to the respective terminals of v, iw, and iu, iv, iw
Transistors (I
GBT) Three phases by Q2, Q4, and Q6, and flyback diodes D1 to D6 that connect each terminal of iu, iv, and iw to the power supply terminal and the ground terminal of the inverter circuit 5 and rectify an AC current during regeneration. Configured as a bridge, Q
1 to Q6 are connected to the CPU 1
Output terminals O1 to O6.

The motor 6 is a motor for starting the engine and supplying regenerative electric power, and a three-phase AC induction motor is used.

Next, the operation of this embodiment will be described. In the normal control, first, a current component Iq necessary for realizing a torque value (torque command) to be output from the motor for starting the engine, and an excitation current component Id determined according to a predetermined motor rotation speed are described. And the motor current command value Is is set to C
It is calculated by PU1.

Current command value Is = √ (Id ² + Iq ² ) In addition to the current command value, the CPU 1 determines the rotational frequency Wr of the motor and the slip frequency Ws determined by the motor load.
, And the control pattern of each phase is determined from these to control the inverter circuit 5.

On the other hand, at the time of regeneration, the three-phase AC current generated by the motor 6 is DC-converted by the flyback diodes D1 to D6 of the inverter circuit 5, and is returned to the high-voltage power source Vin as a battery and the capacitors C1 and C2.

At this time, for example, the vehicle is always regenerated on a downhill,
In addition, when the battery is fully charged, excessive regenerative energy may be generated, and the power supply terminal voltage of the inverter circuit 5 may become an abnormal voltage.

In the present invention, in order to suppress abnormal voltage during engine start-up and regeneration, (1) the direction of line current flowing from the high-voltage power supply Vin is compared with the result of judgment by the CPU to judge the presence or absence of a current abnormality. I do. That is, in Table 1 shown below,
At the time of 3, it is determined that the current is abnormal.

[0051]

[Table 1] (2) Only in the state 4 of Table 1, that is, when the motor is in the regenerative state and the current flows from the motor to the high-voltage power supply Vin,
Measure the terminal voltage, and judge whether high voltage or low voltage is abnormal. Here, when the low voltage Vign is abnormal, it is determined that the power supply is abnormal (low voltage).

(3) High voltage abnormality and normal control during regeneration (three-phase AC current generated by the motor is directly converted by the inverter, and the battery is a high voltage power supply Vin and electrolytic capacitors C1 and C2 Is stopped, and the ON / OFF pattern of the inverter circuit 5 is changed based on the direction in which the line current flows from the high-voltage power supply Vin, the magnitude of the generated voltage, and the determination result of the control device. Switching to the abnormal voltage suppression control using the motor 6 as a resistance load is performed without returning to the capacitors C1 and C2.

(4) In the actual operation of the abnormal voltage suppression control, only the current component Iq is applied. Further, the amount of generated energy is estimated from the magnitude of the generated voltage of the terminal voltage, and the abnormal voltage suppression control is performed. , 2 are switched.

[Abnormal Voltage Suppression Control 1] When the voltage generated at the terminal voltage is equal to or higher than a predetermined value, for example, Q1 is kept ON, and Q4 is turned on / off (PWM control), so that the motor 6 and the inverter are controlled. While suppressing the heat generation of the circuit 5,
Excess energy is consumed by the resistance of the motor.

[Abnormal voltage suppression control 2] When the voltage generated at the terminal voltage is equal to or less than the specified value, Q1 and Q4 are set to the specified time O
The voltage is suppressed while keeping N.

In either case, the control returns to the normal control after the terminal voltage returns to the normal state. When the terminal voltage is more than a specified number of times (for example, three times or more), and when the terminal voltage is NG, the power supply is abnormal (high voltage). It is judged as.

Here, an example of a specified voltage and a specified time (control time) used for switching between the abnormal voltage suppression controls 1 and 2 will be described.

The specified voltage is set based on the lower one of the withstand voltage of each element of the inverter circuit 5 and the maximum working voltage of the motor 6 and the voltage value of the high voltage power supply Vin applied to the inverter circuit 5.

For example, if the breakdown voltage of the element is 150 V, Vin =
If the voltage is 42 V and the maximum operating voltage of the motor is 300 V, the specified voltage is Vth = Vin × 2 + (150−Vin × 2) / in consideration of erroneous determination due to ON / OFF noise.
2 = 117V.

Next, at the voltage calculated above, Q1,
Q4 is turned on, and the motor 6 and the driving transistors Q1 to Q6 are turned on.
The control time (the time during which both Q1 and Q4 are turned on) is set by obtaining the time during which no failure occurs from an experiment.

When the voltage is higher than the above-mentioned voltage, the amount of generated heat is controlled by varying the DUTY according to the applied voltage with the breakdown voltage of the element as an upper limit (abnormal voltage suppression control 1).

For example, control time = 500 μs, Ron =
Assuming that 100 mΩ and Vth = 117 V, the generated power P ₀ = (Vtn / Ron) ² × Ron × 500 μs
= 68.4 W, and with the rise in the generated voltage, Q4 is turned on / off to make the amount of power per cycle variable and controlled so that it does not exceed P ₀ , thereby suppressing heat generation and suppressing abnormal voltage. Can be suppressed.

Specifically, the ON / OFF frequency f = 10
KHz, Vth = 150V, (150/100
mΩ) ² × 100 mΩ × T = 68.4 W, T = 30
4 μST: Total application time In other words, the above-mentioned 500 μs
Should be reduced to 60.8%, that is, since the control cycle per cycle is 100 μs, D
This can be realized by reducing UTY to 60.8%.

(∵ Since the number of times of application is five, six in one cycle)
0.8 μs. (That is, DUTY is 60.8%.) Finally, after turning off the high voltage relay JB, the specified time (τ
= (C1 + C2) × RL), when the terminal voltage is equal to or higher than the specified voltage (ex. Vin × 0.8), Q1 and Q4 are turned on.
The electric charge can be discharged quickly.

Next, referring to the flowchart of FIG.
The operation of the present embodiment will be described. First, when an ignition (IGN) switch is turned on (step 10,
Hereinafter, steps are abbreviated as S), and an initial diagnosis is performed (S1).
2) When the initial diagnosis is completed normally, the high voltage relay JB
Is turned on and the capacitors C1 and C2 are charged. When the charging is completed, the inverter circuit 5 becomes operable (S1).
4).

Next, normal control for the motor 6 is started (S16), and it is determined whether or not the vehicle is running (S1).
8). If it is not running, it is stopped (high power relay is OFF
F) is determined (S20). If the vehicle is stopped, the process returns to S16 to prepare for start and continues the normal control. If the high-voltage relay JB is OFF, it is determined whether or not the terminal voltages of the capacitors C1 and C2 are equal to or lower than a specified value after the high-current relay is turned off (S22).

If it is not less than the specified value in S22, C
By turning on the transistors Q1 and Q4 of the inverter circuit 5 from the PU, the terminals of the plurality of phases of the motor 6 are connected in series to form a discharge path for the electric charges of the capacitors C1 and C2 (S24). Next, it is determined whether or not the terminal voltage of the capacitor has decreased to a specified value (S26). If not, the process returns to S24. If it has fallen to the specified value, it is determined that the discharge is completed, and the process proceeds to an end process (not shown).

If it is determined in step S18 that the vehicle is running, then it is determined whether the current direction is from the motor to the battery (S2).
8) If it is the direction from the motor to the battery, it is determined whether the terminal voltage is normal (S32), and if it is normal, the process proceeds to S18.

If it is determined in S28 that the current direction is not the direction from the motor to the battery, the CPU determines whether or not the power running control is determined (S30).
Returning to step 8, if the power running is not determined, it is determined that the current is abnormal, and a current abnormal process (not shown) is performed.

If the terminal voltage is not normal in the determination in S32, it is determined whether the type of power failure is a high voltage (S3).
4) If it is not a high voltage, the process proceeds to a low voltage power supply abnormality process not shown.

If it is determined in step S34 that the type of power supply abnormality is high voltage, it is determined whether normal control can be exited (S3).
6) If not removed, the process proceeds to a high-voltage power supply abnormality process not shown.

If it is determined in step S36 that normal control can be exited, it is determined whether or not the generated voltage is equal to or higher than a specified voltage (determination value for switching between abnormal voltage controls 1 and 2) (S38). In order to perform abnormal voltage suppression control 1,
Transistor for ON / OFF control is connected to inverter circuit 5
(S40). Next, the selected power supply side transistor (for example, Q1) is turned on.
(S42), and a ground-side transistor (for example, Q
4) ON / OF by PWM control to control DUTY
F control is performed (S44), and the routine goes to S50. At the time of this DUTY control, for example, a DUT as shown in FIG.
Y control is performed.

If it is determined in step S38 that the generated voltage is not equal to or higher than the specified voltage, the ON / OFF control is performed to perform the abnormal voltage suppression control 2.
The transistor to be turned off is selected from the transistors Q1 to Q6 of the inverter circuit 5 (S46), the selected power supply side transistor (for example, Q1) and the ground side transistor (for example, Q4) are turned on (S48), and the process proceeds to S50.

In S50, it is determined whether or not the terminal voltage has returned to the normal value. If the terminal voltage has returned to the normal value, the abnormal voltage suppression is ended, and the process proceeds to the normal control. If it is determined in S50 that the terminal voltage has not returned to the normal value, it is determined whether or not the number of times is equal to or more than a specified number of times (for example, three times) (S52).
Repeat 38. If it is the specified number of times, the process proceeds to a high voltage power supply abnormality process not shown.

As described above, according to the present invention, in the motor control device for a motor having a driving (powering) state and a regenerative state, the ON / OFF pattern of the inverter circuit for controlling the motor is controlled by the motor power supply. From the direction in which the line current flows from the motor, the magnitude of the generated voltage, and the result of the power running / regeneration determination by the microcomputer, the switching to the abnormal voltage suppression control provided separately from the normal control is determined, and the motor is used as a resistive load. This can suppress abnormal voltage without having a special energy absorption circuit, and can contribute to downsizing.

Further, the amount of generated energy is estimated from the magnitude of the generated abnormal voltage, and a plurality of phases of the motor are simply connected in series to absorb the abnormal voltage, or the series-connected plural phases are subjected to DUTY control by an inverter. Switching between ON / OFF control while reducing the heat generation of the motor and inverter circuit. When the terminal voltage is higher than the specified voltage even after the specified time after turning off the high-voltage relay, the control is provided separately from the normal control. And quickly discharging the electric charge using the motor as a resistance load, it is possible to improve the maintainability.

[Third Embodiment] FIG. 5 is a system configuration diagram showing a configuration of a third embodiment of a motor control device according to the present invention. For convenience of explanation, a DC voltage is supplied to an inverter circuit. The drawing also includes a high-voltage power supply such as a battery charged with regenerative power and an induction motor (motor) to be controlled.

The difference between FIG. 5 showing the configuration of the third embodiment and FIG. 2 showing the configuration of the second embodiment is that, in FIG. 5, a switch for switching the connection state of the electrolytic capacitors C1 and C2 between parallel and series. SW1 to SW3 and an energy absorbing circuit 7 are added. Other configurations are
Since the second and third embodiments are the same, duplicate description will be omitted.

The energy absorbing circuit 7 is connected between the power input terminal of the inverter circuit 5 and the ground, and has an energy absorbing resistor R9 having one end connected to the power input terminal and a collector connected to the other end of the energy absorbing resistor R9. And a transistor Q9, which is connected to
9, a Zener diode ZD1 having an anode connected to the base and a cathode connected to the power input terminal, and a resistor R10 connected between the base of the transistor Q9 and ground.
It is composed of

Next, the operation of the third embodiment will be described.
The energy absorbing circuit 7 is a circuit for limiting the power supply terminal voltage of the inverter circuit 5 to the Zener voltage of the Zener diode DZ1 (hereinafter, abbreviated as VZ). No current flows, and the voltage across R10 is 0, so transistor Q9 is off. When abnormal, the terminal voltage is VZ
Current starts to flow through the Zener diode ZD1, and when the voltage drop of R10 exceeds the emitter-base conduction start voltage of the transistor Q9, the transistor Q9
Is turned on, and a current flows through the resistor R9. Thereby, the energy due to the abnormal voltage is absorbed.

SW1 to SW3 are capacitors C1 and C2
Is switched between parallel connection and series connection according to the operation patterns shown in Table 2 below.

[0082]

[Table 2] In the third embodiment, the connection of a large-capacity electrolytic capacitor can be converted from parallel to series connection by SW1, 2, and 3, thereby increasing the breakdown voltage of the large-capacity capacitor at the time of abnormal voltage. It responds without changing the withstand voltage and further improves reliability.

(1) Normal operation During normal operation, large-capacity electrolytic capacitors C1 and C2
Are connected in parallel.

(2) Residual charge discharge At the time of residual charge discharge after the strong electric relay JB is turned off, SW1 to SW1
By switching SW3, the two capacitors C1 and C2 are serially reconnected, the discharge time is reduced to half, and the maintainability is greatly improved.

(3) Abnormal Voltage Suppression The high-voltage power supply Vin whose current direction is from the motor 6 to the battery
When the terminal voltage is higher than the specified value in the direction, it is possible to make the withstand voltage × 2 without increasing the withstand voltage of each capacitor by connecting the capacitors that affect the size especially in series connection. To prevent the capacitor from becoming large, and to set the voltage (detection voltage) of the energy absorption circuit.
By setting also high, the load factor of the energy absorption resistance can be reduced. Thus, the abnormal voltage is suppressed while improving the reliability and reducing the size.

[Reduction of Load Ratio] Next, an example of reduction of the load ratio of the energy absorption resistance will be described. For example, when the abnormality occurrence voltage is set to 90 V and suppressed to 45 V, when the resistance value of the energy absorption resistor R9 to be used is set to 100Ω,
The required withstand power is 20.2 W according to the following equation.

P = (90−45) ² / R9 = 2025 /
R9 = 20.2W On the other hand, if the capacitors C1 and C2 are connected in series and the breakdown voltage is to be suppressed at 75V by improving the withstand voltage, P = (90−75) ² /R9=225/R9=2.25
W 2, which is about 1/9 of the power resistance, and the resistance R9 can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a configuration of a first embodiment of a motor control device according to the present invention.

FIG. 2 is a system configuration diagram showing a configuration of a second embodiment of the motor control device according to the present invention.

FIG. 3 is a flowchart illustrating operations of abnormal voltage suppression and residual charge discharge in a second embodiment.

FIG. 4 is a graph showing a relationship between an abnormal voltage and a transistor duty DUTY according to a second embodiment.

FIG. 5 is a system configuration diagram showing a configuration of a third embodiment of the motor control device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Voltage detection circuit 3 Relay control circuit 4 Current detection circuit 5 Inverter circuit 6 Motor 7 Energy absorption circuit 8 Position sensor Vin High voltage power supply (battery) Vign 12V power supply JB High voltage relay C1, C2 Electrolytic capacitor RL Discharge resistance Q1 Q6 Power transistor (IGBT) D1 to D6 Flyback diode Q7, Q8 Transistor D7, D8 Diode R1 to R8 Resistance Isen Current sensor Vref Reference voltage IC Operational amplifier

Continued on front page F term (reference) 5H007 AA17 BB01 BB06 CA01 CB05 CC01 DA05 DA06 DB01 DB12 DC02 DC05 FA01 FA12 FA19 5H115 PA08 PC06 PG04 PI16 PU09 PU10 PU19 PV09 PV23 QE10 QI04 QN02 QN05 RB22 SE03 TD17 TO13 TR01 BB05 A05 BB05 A05 BB07 CC02 DD02 DD04 DD07 EE01 EE09 HA04 HB02 JJ03 LL22 LL24 LL30 LL41 LL55 MM03 MM06

Claims (5)

[Claims] 1. A motor control device for controlling a motor capable of both a driving state and a regenerative state, comprising: supplying a driving current for the motor from a power source when the motor is in a driving state; A drive circuit for supplying a regenerative current to the power supply, and a motor for detecting that the motor is in a regenerative state, and controlling the drive circuit when the terminal voltage of the motor becomes a predetermined value or more in the regenerative state. A motor control device, comprising: control means for causing a current to flow through the motor. 2. The motor is a synchronous motor having a permanent magnet rotor; the drive circuit is an inverter circuit; and the control means is such that the terminal voltage of the motor in the regenerative state is equal to or higher than a predetermined value. 2. The motor control device according to claim 1, wherein in such a case, a series circuit is formed by a switching element of the inverter circuit and a plurality of phases of the induction motor. 3. The motor is an induction motor, the drive circuit is an inverter circuit, and the control means is configured to control the inverter when a terminal voltage of the motor in the regenerative state becomes equal to or higher than a predetermined value. The motor control device according to claim 1, wherein a series circuit is formed by a plurality of switching elements of a circuit and a plurality of phases of the induction motor, and duty control of at least one of the switching elements is performed. 4. The motor control device according to claim 3, wherein the control unit switches between control modes having different duty ratios based on the magnitude of the terminal voltage of the motor. 5. A motor control device for controlling a motor capable of both a driving state and a regenerative state, comprising: a driving circuit for driving the motor; a capacitor connected in parallel between power terminals of the driving circuit; And a motor power relay connected in series between the drive circuit and the power supply relay, and when the voltage between the terminals of the capacitor is equal to or higher than a predetermined value even when a predetermined time has elapsed since the motor power relay was turned off. And a control means for controlling the drive circuit to flow a current to the motor.