JP2003230269A - Load driving device, discharge control method, and computer-readable recording medium storing a program for causing a computer to execute discharge control - Google Patents

Abstract

[PROBLEMS] To provide a load driving device capable of improving the durability of a system as a whole against a failure by discharging a residual charge when a main power supply is cut off to a load of an auxiliary system. SOLUTION: When an operation of turning off a main power supply is performed,
The control circuit 9 turns off the system main relay 2
Then, the drive system inverter 4 is stopped and the switching transistor 32 is turned off. Further, the control circuit 9 turns on the switching transistor 31 and turns on the A / C inverter 7.
Continue driving. Thus, the residual charge of the capacitor 5 is stepped down by the coil 35 via the converter 3 and further discharged to the A / C compressor 11 via the A / C inverter 7. Further, the control circuit 9 controls the node N
When it is determined that the voltage between node 1 and node N4 has become smaller than a predetermined value, switching transistor 31 is turned off.
Then, the A / C inverter 7 is stopped to end the discharge control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load drive device, a discharge control method, and a computer-readable recording medium in which a program for causing a computer to execute discharge control is recorded, and particularly to a drive motor in an electric vehicle or a hybrid vehicle. When driving and controlling an electric load such as an air conditioner or an air conditioner, a load driving device equipped with a discharge mechanism for discharging residual electric charge inside the device when the main power supply is cut off, a discharge control method, and a program for causing a computer to execute discharge control are recorded. The present invention relates to a computer-readable recording medium.

[0002]

2. Description of the Related Art Electric vehicles and hybrid vehicles have received a great deal of attention against the backdrop of energy-saving and environmental problems that have been increasing in recent years. Electric Vehicle,
Hereinafter referred to as EV. ) And hybrid vehicles (Hybrid V
vehicle, hereinafter referred to as HV. ) Runs by driving the motor with the main battery mounted in the automobile as the energy source.

As a motor used for EV and HV,
A three-phase induction motor or a synchronous motor is used. A technique is known in which a DC voltage output from a main power source such as a main battery mounted on an EV or HV is supplied to an inverter and converted into an AC voltage to drive the motor. A capacitor is provided at the input terminal of the inverter for smoothing the DC voltage input to the inverter, or for storing the DC voltage at least temporarily. The DC voltage output from the main power supply is smoothed by this capacitor and supplied to the inverter.

In order to drive an EV or HV using the above-mentioned motor, a direct current voltage of several tens to several hundreds of volts is used.
Voltages as high as V may be required. Therefore, after the power supply to the vehicle system is cut off, it is necessary to appropriately discharge the residual electric charge in the system such as the electric charge remaining in the capacitor.

Japanese Unexamined Patent Publication No. 9-121592 discloses an AC power source, a converter including a smoothing circuit, an inverter,
In a motor control device equipped with a motor, when the AC power is cut off, the residual charge of the smoothing capacitor in the converter is consumed by using the regenerative discharge resistance built in the motor control device instead of using a dedicated discharge resistance. A device has been proposed.

Further, in Japanese Patent Laid-Open No. 11-332248, in a storage type air conditioner, residual charge of a capacitor provided in a chopper portion is discharged to a storage battery when discharge of the storage battery is stopped, and further provided in parallel with the capacitor. There has been proposed a device that consumes electricity by a discharge resistance.

[0007]

However, the invention described in Japanese Patent Application Laid-Open No. 9-121592 is to discharge the residual electric charge in the motor control device, and the invention described in Japanese Patent Application Laid-Open No. 11-332248 is. The residual charge is discharged to a discharge resistor connected in parallel with the storage battery and the capacitor. These are all discharged in the drive system circuit which is the main device of the system,
Discharging in such a highly important device is not preferable because it increases the withstand voltage requirement of the system.

That is, since it becomes necessary to design the drive system circuit, which is a main device in the system, to withstand the discharge voltage when the power is cut off, various elements used in the drive system circuit have high withstand voltage performance. There is a risk that it will have to be made, and this will lead to higher system costs.

Further, the discharge of the residual charge must be surely performed in order to ensure the safety, and the circuit structure must be such that the failure of the element in the device is assumed as much as possible. I have to.

Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide a drive load and a drive system circuit which are highly important in the system when discharging residual charges. A load drive device capable of improving durability against failure in the entire system by performing the load on the auxiliary system without performing the load.

Another object of the present invention is to control the discharge of residual charges by performing the control on the load of the auxiliary system without performing it on the drive load and the drive system circuit which are highly important in the system. It is intended to provide a discharge control method capable of improving durability against failure in the entire system.

Still another object of the present invention is to control the discharge of residual charges by applying to a load of an auxiliary system, which is not performed in a drive load and a drive system circuit which are of high importance in the system, It is intended to provide a computer-readable recording medium in which a program for causing a computer to execute discharge control capable of improving durability against failure in the entire system is recorded.

[0013]

According to the present invention, a load drive device is connected to a main circuit including a load drive circuit for driving a first electric load, and operates a second electric load. An auxiliary machine circuit for controlling and a control circuit are provided.
When the main power supplied to the main circuit is cut off, the load drive circuit is stopped, and after the main power is cut off, the main circuit is controlled so as to supply the residual charge of the main circuit to the auxiliary circuit.

Preferably, the main circuit is connected between the converter for boosting the DC voltage supplied from the main power source and outputting it to the load drive circuit, and between the load drive circuit and the converter.
And a smoothing circuit for smoothing the DC voltage boosted by the converter, wherein the auxiliary circuit is connected between the main power source and the converter, and after the main power source is cut off, the control circuit causes the remaining of the smoothing circuit to remain. The converter is controlled to supply the charge to the auxiliary circuit through the converter, and the converter is
The voltage generated by the residual charge of the smoothing circuit is stepped down and output to the auxiliary circuit.

Preferably, the main circuit further includes another smoothing circuit connected between the main power source and the converter, and after the main power source is cut off, the residual charge of the other smoothing circuit is an auxiliary circuit. Is supplied to.

[0016] Preferably, the converter has a first switching transistor having a collector connected to the first node connected to the load driving circuit, an emitter connected to the second node, and a collector connected to the second node. A second switching transistor connected to the third node having an emitter connected to the load driving circuit and a negative node of the main power supply; an anode connected to the second node; and a cathode connected to the first node. A first diode connected, an anode connected to the third node, a cathode connected to the second node, and a second diode connected to the second node and one connected to the second node; And a coil connected to the positive electrode node of the control circuit, the control circuit turns on the first switching transistor after the main power is cut off, and
Turn off the switching transistor.

Preferably, the control circuit detects the input voltage of the auxiliary device circuit, and turns off the first switching transistor when it determines that the input voltage becomes lower than a predetermined value after the main power supply is cut off, Stop the accessory circuit.

Preferably, the second electric load is an on-vehicle air conditioner, the auxiliary circuit includes an inverter for driving the on-vehicle air conditioner, and the first electric load is a drive motor for generating a driving force of the vehicle. The load drive circuit is an inverter that drives a drive motor.

Preferably, the second electric load is an auxiliary power supply, and the auxiliary circuit includes another converter for converting the input electric power into a predetermined voltage and outputting it to the auxiliary power supply. The first electric load is a drive motor that generates a driving force of the vehicle, and the load drive circuit is an inverter that drives the drive motor.

According to the present invention, the discharge control method is a discharge control method in a load drive device including a main circuit and an auxiliary circuit connected to the main circuit, wherein the main circuit is the first circuit. Connected to the load drive circuit for driving the electric load, the converter for boosting the DC voltage supplied from the main power source and outputting the boosted DC voltage to the load drive circuit, and the DC voltage boosted by the converter. A smoothing circuit for smoothing the voltage, the auxiliary circuit is connected between the main power supply and the converter to operate the second electric load, and the discharge control method is supplied to the main circuit and the auxiliary circuit. The first step of stopping the load drive circuit when the main power source is cut off, and the step of stepping down the voltage generated by the residual charge of the smoothing circuit by the converter and outputting it to the auxiliary circuit after the load drive circuit is stopped. 2's And step, when the remaining charge in the smoothing circuit is discharged to the auxiliary circuit in the second step, a third step of detecting the input voltage of the auxiliary circuit,
When it is judged that the detected input voltage is lower than the predetermined value,
A fourth step of shutting down the converter and the accessory circuit.

Further, according to the present invention, the recording medium is a computer recording a program for causing a computer to execute discharge control in a load drive device including a main circuit and an auxiliary circuit connected to the main circuit. A readable recording medium, wherein a main circuit includes a load drive circuit that drives a first electric load, a converter that boosts a DC voltage supplied from a main power source and outputs the DC voltage to the load drive circuit, and a load drive circuit. A smoothing circuit for smoothing the DC voltage boosted by the converter, the auxiliary circuit being connected between the main power supply and the converter for operating the second electric load. , The recording medium, the first step of stopping the load drive circuit after the main power supply to the main circuit and the auxiliary circuit is cut off, and after the load drive circuit is stopped,
A second step of stepping down the voltage generated by the residual charge of the smoothing circuit by the converter and outputting the stepped voltage to the auxiliary circuit;
When the residual charge of the smoothing circuit is discharged to the auxiliary circuit in the step of, the third voltage for detecting the input voltage of the auxiliary circuit is detected.
And a fourth step of stopping the converter and the auxiliary circuit when it is determined that the detected input voltage is lower than a predetermined value.

According to the load drive device and the discharge control method of the present invention, in discharging the residual charge inside the device when the main power supply is cut off, the drive system, which is the main circuit of the system, is not discharged, and the auxiliary system Since the second electric load is discharged, the durability of the first electric load and the drive system circuit, which are highly important in the system, can be improved.

Further, according to the load driving device of the present invention, the second electric load of the auxiliary system, which is the discharge destination of the residual charge, is connected to the opposite side of the first electric load via the converter. Therefore, even if the converter fails, it is possible to avoid the situation in which the smoothing capacitor for the main battery, which is equipped on the input side of the converter, cannot be discharged at all, and it is considered to be safer. Has become.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference characters and description thereof will not be repeated.

[First Embodiment] FIG. 1 is a circuit diagram showing a circuit configuration of a load driving device mounted on an EV or an HV according to the first embodiment.

Referring to FIG. 1, the load driving device 100 is
System main relay 2 (hereinafter referred to as SMR2), converter 3, drive system inverter 4, capacitors 5, 6, 8 and air conditioner inverter 7 (hereinafter referred to as A / C inverter 7) .)When,
A control circuit 9 and nodes N1 to N4 are provided. Moreover, the converter 3 includes switching transistors 31, 32.
And diodes 33, 34 and a coil 35.

The main battery 1 comprises a motor generator 10 and an air conditioner compressor 11 (hereinafter,
It is called the A / C compressor 11. ) Is a direct current power supply for supplying power to.

The motor / generator 10 is a three-phase AC induction motor or a synchronous motor for running an EV or HV, and the driving force of the motor / generator 10 is EV.
Or it is transmitted to the wheel of HV. The motor / generator 10 is also used as a generator when the EV or HV is decelerated, and steps down the voltage generated by the power generation action (regenerative power generation) during deceleration using the converter 3 described later,
It can be supplied to the main battery 1 or to auxiliary machines such as an A / C compressor 11 described later.

The motor generator 10 is an EV
If it is HV, it is arranged in a drive system that can give a drive torque to a drive shaft or wheels (not shown), and if it is HV, it is connected to an engine (not shown).

The A / C compressor 11 is an electric A / C compressor that operates by the electric power supplied from the main battery 1. The A / C compressor 11 operates by the electric power supplied from the main battery 1 and, as described later, when the SMR 2 is turned off, the capacitors 5, 6, 8
It is used as a discharge destination of the residual charge of.

The SMR 2 is connected between the main battery 1 and the capacitor 6, and is connected from the main battery 1 to the motor generator 10.
And the main relay of the system that supplies and cuts off power to the A / C compressor 11. SMR2
When an ignition key (hereinafter, referred to as IG key) is turned on, turns on based on a command from the control circuit 9 and connects the main battery 1 to the nodes N1 and N4. Further, when the IG key is turned off, the SMR 2 turns off based on a command from the control circuit 9 and shuts off the power output from the main battery 1.

The converter 3 is a chopper type converter and is connected between the capacitors 6 and 5. When SMR 2 is turned on, converter 3 boosts the DC voltage from main battery 1 and supplies it to drive system inverter 4 based on a command from control circuit 9. When the SMR 2 is turned off, the converter 3 steps down the residual charge of the capacitor 5 connected in parallel between the converter 3 and the drive system inverter 4 based on a command from the control circuit 9, as described later. And discharges to the A / C compressor 11.

Switching transistor 31 has a collector connected to node N3 and an emitter connected to node N2, and receives a command from control circuit 9 at its gate to perform a switching operation.

Switching transistor 32 has a collector connected to node N2 and an emitter connected to node N4, and receives a command from control circuit 9 at its gate to perform a switching operation.

The anode of the diode 33 is the node N2.
In addition, the cathodes are connected to the node N3, respectively, and are energized when the converter 3 operates as a boost converter.

The diode 34 has an anode at the node N4.
In addition, the cathodes are connected to the node N2, respectively, and are energized when the converter 3 operates as a step-down converter.

The coil 35 operates as a reactor for storing energy and is connected between the node N1 connected to the positive electrode of the main battery 1 and the node N2 connected to the switching transistors 31, 32 and the diodes 33, 34. To be done.

The drive system inverter 4 is a conversion circuit that converts the DC voltage boosted by the converter 3 into a three-phase AC voltage and supplies it to the motor generator 10.

The capacitors 5, 6 and 8 are connected in parallel to the drive system inverter 4, the main battery 1 and the A / C inverter 7, respectively, and reduce the influence on each device due to voltage fluctuation. Is a smoothing capacitor for

The A / C inverter 7 is a conversion circuit that converts a DC voltage supplied from the main battery 1 into an AC voltage and supplies the AC voltage to the A / C compressor 11, and is connected between the SMR 2 and the converter 3. It In addition, the A / C inverter 7
A continues to operate based on a command from the control circuit 9 even after the power supply from the main battery 1 is cut off, and the residual charge of the capacitors 5, 6 and 8 is converted into an alternating current, which is the discharge destination A.
/ C Output to the compressor 11.

The control circuit 9 is a CPU (Central Processi).
ng Unit), RAM (Random AccessMemory), ROM
A microcomputer including a (Read Only Memory) and an input / output device (both of which are not shown).

When determining that the IG key is ON, the control circuit 9 turns ON the SMR 2 and connects the main battery 1 to the nodes N1 and N4. As a result, power is supplied from the main battery 1 to the load driving device 100. Then, the control circuit 9 controls the converter 3 and the drive system inverter 4 in order to cause the motor / generator 10 to generate a torque according to the motor torque command based on the electric power supplied from the main battery 1. The control of the motor torque will be described later. Further, the control circuit 9 controls the A / C inverter 7, which drives the A / C compressor 11.

On the other hand, when the control circuit 9 determines that the IG key is off, it turns off the SMR 2 to cut off the power supplied from the main battery 1. Then, the control circuit 9 turns off the switching transistor 32 and stops the drive system inverter 4. The control circuit 9 also turns on the switching transistor 31 in order to discharge the residual charge of the capacitor 5 to the A / C compressor 11 connected to the low voltage side of the converter 3. Then, the control circuit 9 detects the voltage VC applied between the node N1 and the node N4, and when it determines that the discharging of the capacitors 5, 6, 8 is completed based on the detected voltage VC, it turns off the switching transistor 31. Then, the A / C inverter 7 is stopped.

The control circuit 9 controls the duty ratio of ON / OFF of the switching transistors 31 and 32, so that the DC voltage can be stepped up / down mutually in the converter 3. In Embodiment 1 and Embodiment 2 described later, converter 3 boosts the voltage of main battery 1 and outputs the boosted voltage to drive system inverter 4, and capacitor 5 provided on the input side of drive system inverter 4 includes It describes the control of stepping down and outputting the voltage.

Although not shown in FIG. 1, a DC / DC converter is connected between the main battery 1 and the SMR 2, and D
Electric power is supplied to an auxiliary system (not shown) via the C / DC converter. In this case, this auxiliary system is activated or deactivated by another switch (not shown) such as a well-known accessory switch.

FIG. 2 is a functional block diagram for functionally explaining the torque control of the motor generator 10 by the control circuit 9.

Referring to FIG. 2, the control circuit 9 includes a motor control phase voltage calculator 91, an inverter PWM signal converter 92, an inverter input voltage command calculator 93, and a converter duty ratio calculator 94. And converter PW
And an M signal calculator 95.

The motor control phase voltage calculator 91 inputs the motor torque command value, the current value of each phase of the motor generator 10 and the input voltage of the drive system inverter 4 to input each phase of the motor generator 10. Calculate the voltage of the coil,
It outputs to the PWM signal conversion part 92 for inverters.

Here, the motor torque command value is given, for example, as a motor torque value necessary to achieve the required power calculated from the opening degree of the accelerator pedal.
For example, in the case of the parallel HV, the motor torque command value is given so that the sum of the engine torque and the motor torque is output as the drive shaft torque.

The current value of each phase of the motor / generator 10 is detected by a current sensor (not shown). The input voltage of the drive system inverter 4 is detected by a voltage sensor (not shown).

The inverter PWM signal conversion unit 92 generates a PWM signal for turning on / off each transistor (not shown) in the drive system inverter 4 based on the calculation result by the motor control phase voltage calculation unit 91. , To the drive system inverter 4.

Based on this PWM signal, each transistor is switched, the drive current of each phase of the motor generator 10 is controlled, and the motor torque control according to the motor torque command value is performed.

On the other hand, the inverter input voltage command calculator 93
Calculates the optimum value (target value) of the input voltage of the drive system inverter 4 by inputting the motor torque command value and the motor rotation speed described above.

The converter duty-ratio calculation unit 94
The target value of the input voltage of the drive system inverter 4 calculated by the inverter input voltage command calculation unit 93, the input voltage of the drive system inverter 4, and the voltage of the main battery 1 are input to determine the input voltage of the drive system inverter 4. The duty ratio for achieving the target value is calculated. That is, the converter duty ratio calculation unit 94 determines that the input voltage of the drive system inverter 4 (that is, the output voltage of the converter 3) is the target value of the input voltage of the drive system inverter 4 calculated by the inverter input voltage command calculation unit 93. ON / OFF of the switching transistors 31 and 32 included in the converter 3
The duty ratio of OFF is calculated.

The converter PWM signal converter 95 turns ON / OFF the switching transistors 31 and 32 of the converter 3 based on the calculation result of the duty ratio calculated by the converter duty ratio calculator 94.
A WM signal is generated and output to the converter 3.

The switching transistors 31 and 32 are switched based on this PWM signal, and the input voltage of the drive system inverter 4 is controlled to the target value.

By increasing the on-duty ratio of the switching transistor 32, the coil 35
Since the stored power of 1 is increased, converter 3 can further boost the power supply voltage supplied from main battery 1 and output it to drive system inverter 4. On the other hand, when the on-duty ratio of the switching transistor 31 is increased, the voltage of the power supply line (node N3 shown in FIG. 1) decreases.
Therefore, by controlling the duty ratio of these switching transistors 31 and 32, the voltage of the power supply line can be arbitrarily controlled to a voltage higher than that of the main battery 1. In particular, the motor / generator 10 can generate power by regeneration, but since the voltage of the power supply line increases during regeneration, the switching transistor 31 is turned on by PWM control and the voltage of the power supply line is maintained at a predetermined value.

Referring again to FIG. 1, the load driving device 100
In the above, the A / C inverter 7 drives the A / C compressor 11 by the power source supplied from the main battery 1, and after the power source supplied from the main battery 1 is cut off, A / C compressor 1 for residual charge
It has the function of discharging to 1. Here, the capacitor 6 is
Since the capacitor 3 is connected between the converter 3 and the main battery 1, while the capacitor 5 is connected between the converter 3 and the drive system inverter 4, the A / C inverter 7 is connected to the load driving device 100. There are two possible configurations: one connected between the converter 3 and the drive system inverter 4, and one connected between the converter 3 and the main battery 1.

Here, in EV, a system in which A / C is connected to a drive system circuit and is operated by using electric power from a main battery is described in Japanese Patent Laid-Open No. 2000-59919. Japanese Patent Laid-Open No. 2000-59919 discloses a main battery,
A drive inverter driven by a DC voltage output from the main battery, a capacitor connected between the main battery and the drive inverter, and an A / C connected in parallel with the capacitor.
Disclosed is a system configuration including an inverter, an A / C relay connected between a main battery and an A / C inverter, and a charging circuit for charging the main battery from an external charger via the A / C relay. Has been done.

The object of the invention described in Japanese Patent Laid-Open No. 2000-59919 is to provide A / A when an overvoltage occurs during charging.
The purpose is to protect the circuit of the motor drive system by shutting off the charging circuit by the C relay, which is different from the purpose of the present invention intended to discharge the residual charge of the capacitor to the A / C of the auxiliary system. is there.

In the system described in Japanese Patent Laid-Open No. 2000-59919, the drive system inverter and the A / C inverter are connected to a common capacitor. When discharging C,
A similar system configuration causes problems.

That is, in the load driving device 100,
When the A / C inverter 7 is connected to the nodes N3 and N4 and the drive system inverter 4 and the A / C inverter 7 are connected to the common capacitor 5, the residual charge of the capacitor 5 is A
Although the / C compressor 11 can be discharged (however, a step-down circuit is required in the discharge path), if the diode 33 included in the converter 3 fails, the residual charge of the capacitor 6 is no longer present. In addition, neither of the motor / generator 10 can be discharged.

On the other hand, if the A / C inverter 7 is connected to the nodes N1 and N4 as described above, the above-mentioned problem does not occur. In this case, if the switching transistor 31 fails, the residual charge of the capacitor 5 is
It becomes impossible to discharge to the A / C compressor 11 via
In this case, if a function of discharging the motor / generator 10 is provided as a backup as the final means when an abnormality occurs, the situation in which the residual charge cannot be discharged at all does not occur.

Further, since the capacitor 5 is provided on the high voltage side of the converter 3, it is necessary to step down the voltage in order to discharge it to the A / C compressor 11.
If the converter 3 is used as a step-down converter at the time of discharging, it is not necessary to separately provide a step-down circuit, and the device configuration becomes simple.

From the above, in the load driving device 100, the A / C inverter 7 is connected between the converter 3 and the main battery 1.

In the load driving device 100, when the IG key is turned on, the control circuit 9 turns on the SMR 2 and power is supplied from the main battery 1. Then, the converter 3 receives the PWM received from the control circuit 9 as described above.
Based on the signal, the DC voltage output from the main battery 1 is boosted to the target value of the input voltage of the drive system inverter 4 and output to the drive system inverter 4. The drive system inverter 4 receives the DC voltage output from the converter 3 and smoothed by the capacitor 5, converts it into a three-phase AC voltage based on the PWM signal received from the control circuit 9 as described above, and converts the DC voltage into a three-phase AC voltage. Output to the generator 10. As a result, the motor / generator 10 is driven.

The A / C inverter 7 receives the DC voltage output from the main battery 1 and smoothed by the capacitor 8, and receives the AC voltage corresponding to the A / C compressor 11 based on a command from the control circuit 9. The voltage is converted and output to the A / C compressor 11.

On the other hand, when the IG key is turned off, the control circuit 9 turns off the SMR 2 and the power supply from the main battery 1 is cut off. Then, the PW received from the control circuit 9
Based on the M signal, the drive system inverter 4 is stopped, the switching transistor 32 is turned off, and the switching transistor 31 is turned on. As a result, the residual charge of the capacitor 5 is not discharged to the drive system inverter 4 and passes through the switching transistor 31 to the node N2.
Flows to the A / C compressor 11 via the A / C inverter 7 after being stepped down by the coil 35. Further, the residual charges of the capacitors 6 and 8 are similarly discharged to the A / C compressor 11 via the A / C inverter 7.

During discharging, the control circuit 9 causes the detection voltage VC to rise.
The discharge state of the capacitors 5, 6 and 8 is monitored based on the A / C until the discharge of the capacitors 5, 6 and 8 is completed.
The inverter 7 is driven. When the control circuit 9 determines that the discharge has ended, the PW from the control circuit 9
The output of the M signal is stopped, and the converter 3 and the A / C inverter 7 are stopped. Therefore, the A / C compressor 1
1 also stops.

FIG. 3 is a flow chart for explaining the discharge control process by the control circuit 9 when the IG key is turned off. Referring to FIG. 3, when the IG key is turned off, control circuit 9 turns off SMR2 (step S1). Then, the control circuit 9 turns off the switching transistor 32, stops the drive system inverter 4 (step S2), and switches the switching transistor 31.
Is turned on (step S3). Then, the control circuit 9
The A / C inverter 7 is continuously driven even after the SMR 2 is turned off. As a result, the residual charges of the capacitors 5, 6, 8 are discharged to the A / C compressor 11 and consumed (step S4).

When the control circuit 9 determines that the detected voltage VC is equal to or higher than the predetermined voltage V0 which is a small value and the discharge from the capacitors 5, 6 and 8 is not completed sufficiently ( In step S5), the discharge control is continued.

On the other hand, when the control circuit 9 determines in step S5 that the detected voltage VC becomes smaller than the predetermined voltage V0 and the discharging from the capacitors 5, 6, 8 is completed, the switching transistor 31 is turned off. At the same time, the A / C inverter 7 is stopped (step S6),
Discharge control ends.

In this way, the residual charges of the capacitors 5, 6, 8 are discharged to the A / C compressor 11.

In the above description, when the residual charge in the capacitor 5 is discharged, the switching transistor 31 is turned on based on the instruction from the control circuit 9, the voltage is reduced by the coil 35 and the A / C compressor 11 is discharged. However, it is also possible to control the switching of the switching transistor 31 by the control circuit 9 to discharge the voltage while lowering the voltage more accurately.

Further, the main battery 1 described above may be one that finally functions as a DC power source, and may be, for example, a secondary battery, a fuel cell, or a power capacitor. Further, the main battery 1 may be a system capable of supplying a DC voltage generated by converting an AC voltage into a DC.

Further, in the HV, since not only the motor but also the combustion engine (engine) is provided, the IG key can be selected as a switch for starting the system.
In an EV that does not have a combustion engine, the SMR 2 may be turned on / off by turning on / off the travel permission switch.

As described above, according to the load drive device 100 according to the first embodiment, in discharging the residual charge in the load drive device 100 when the main power supply is turned off, the drive system that is the main circuit of the system is discharged. It is designed to discharge the A / C compressor 11 of the auxiliary system without performing the operation.
The durability of the generator 10 and the drive system circuit can be improved.

Further, the load driving device 1 according to the first embodiment
00, the A / C compressor 11, which is the discharge destination of the residual charge, is connected between the converter 3 and the main battery 1. Therefore, even if the diode 33 in the converter 3 fails, the main battery It is possible to avoid a situation in which the capacitor 6 which is the smoothing capacitor for 1 becomes isolated and discharge is impossible at all, and the safety is further taken into consideration.

[Second Embodiment] In the second embodiment, in addition to the A / C compressor, an auxiliary system battery and a power steering motor (hereinafter referred to as power) are used as a discharge destination of the residual charge of the capacitor in the load driving device. For steering, it is also referred to as P / S).

FIG. 4 is a circuit diagram showing a circuit configuration of a load driving device mounted on an EV or HV according to the second embodiment.

Referring to FIG. 4, the load driving device 101 is
In addition to the load driving device 100, the DC / DC converter 2
01, capacitors 202 and 204, and a P / S controller 203.

The DC / DC converter 201 is connected in parallel with the A / C inverter 7, and converts the DC voltage supplied from the main battery 1 into a predetermined voltage corresponding to the auxiliary system battery 205 to convert the auxiliary system battery. Output to 205. Also, DC / DC
The converter 201 continues its operation based on the command from the control circuit 9 even after the power supply from the main battery 1 is cut off, and the residual electric charge of the capacitors 5, 6, 202 is used as a discharge destination thereof. Output to the machine system battery 205.

The P / S controller 203 is a controller for driving the P / S motor 206 that electrically assists steering, and inputs the DC voltage supplied from the main battery 1 to the P / S motor 206. It outputs the driving power and the driving signal of. In addition, the P / S controller 203
Even after the power supply from the main battery 1 is cut off, the control circuit 9
Operation is continued based on the command from
The residual charge of 6,204 is used as the discharge destination of P
/ S output to the motor 206.

The capacitors 202 and 204 are respectively D
C / DC converter 201 and P / S controller 2
It is a smoothing capacitor connected in parallel in the immediate vicinity of 03 to remove the influence of ripple on each device.

The auxiliary system battery 205 is a battery for a headlight and other auxiliary machines, and is a rechargeable 12V battery. The auxiliary system battery 205 is connected to the DC / DC converter 201,
The motor / generator 10, the A / C compressor 11, etc. store the surplus of the DC power supplied from the main battery 1 and the residual electric charge discharged from the capacitors 5, 6, 202 when the main power is shut off. The auxiliary system battery 205 is also charged with electric power generated by the motor / generator 10 when the motor / generator 10 is operating as a generator during braking.

The P / S motor 206 is a motor for electrically operating the P / S instead of the conventional hydraulic type.
The P / S motor 206 is connected to the P / S controller 203 and operates by using the DC power supplied from the main battery 1 as a power source.
It is used as a discharge destination of the residual charge discharged from 6,204.

Also in the load driving device 101, as in the load driving device 100, the IG key is O
Then, the control circuit 9 turns on the SMR 2 and the main battery 1
The electric power is supplied from the motor generator 10 to the A / C compressor 11.

In the load driving device 101, S
When the MR2 is turned on, the auxiliary system battery 205 and the P / S converter 203 are connected via the DC / DC converter 201 and the P / S controller 203 which are connected in parallel with the A / C inverter 7.
Electric power is further supplied from the main battery 1 to the S motor 206.

On the other hand, also in the second embodiment, like the first embodiment, when the IG key is turned off, the control circuit 9
Turns off the SMR2, and the power supply from the main battery 1 is cut off. Then, the control circuit 9 stops the drive system inverter 4 and turns off the switching transistor 32.
Then, the switching transistor 31 is turned on. Then, as in the first embodiment, the residual charge of the capacitor 5 is not discharged to the drive system inverter 4 but flows to the node N2 via the switching transistor 31 and the coil 3
Although it is stepped down by 5 and flows to the node N1, in the second embodiment, in addition to the A / C compressor 11, the auxiliary system battery 205 and the P / S motor 206 are also dispersed and discharged. Also, the capacitors 6, 8, 202, 20
Similarly, the residual charge of No. 4 is also dispersed and discharged to the A / C compressor 11, the auxiliary system battery 205, and the P / S motor 206.

Then, the control circuit 9 monitors the discharge state of the capacitors 5, 6, 8, 202, 204 based on the detection voltage VC, and the discharge of the residual charge of the capacitors 5, 6, 8, 202, 204 is completed. Until A / C inverter 7, D
C / DC converter 201 and P / S controller 2
Drive 03. Then, the control circuit 9 detects the detection voltage VC
If it is determined that the discharge is completed, the switching transistor 31 is turned off, and the A / C inverters 7, D
C / DC converter 201 and P / S controller 2
Stop 03. As a result, the A / C compressor 11
And the P / S motor 206 is stopped, and the auxiliary system battery 205
Also ends charging.

In the second embodiment described above,
The A / C inverter 7 and the DC / DC converter 201 are connected in parallel, but the A / C inverter 7 is connected in series at the subsequent stage of the DC / DC converter 201, and the A / C compressor 11 is connected to the auxiliary system voltage. May be driven by. Similarly, for the P / S controller 203,
The P / S controller 203 may be connected in series after the DC / DC converter 201.

As described above, according to the load driving device 101 according to the second embodiment, when the main power source is turned off, the residual electric charge in the load driving device 101 is discharged by the driving system that is the main circuit of the system. A / C compressor 11 and P / S motor 2 in the auxiliary system without performing
06 and the auxiliary system battery 205 are discharged, the durability of the motor / generator 10 and the drive system circuit, which are highly important in the system, can be improved, and the load at the discharge destination can be dispersed. By
The residual charge can be discharged more quickly.

Further, the load driving device 1 according to the second embodiment.
According to 01, the A / C compressor 11, the P / S motor 206, and the auxiliary system battery 205, which are the discharge destinations of the residual charge,
Are connected in parallel between the converter 3 and the main battery 1, respectively, so that even if the diode 33 in the converter 3 fails, the smoothing capacitor 6 for the main battery 1 is isolated and discharged. It is possible to avoid a situation in which the above becomes impossible at all, and the safety is taken into consideration as in the first embodiment.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a circuit configuration of a load driving device according to a first embodiment of the present invention.

2 is a functional block diagram for functionally explaining torque control of a motor / generator by a control circuit in the load driving device shown in FIG. 1. FIG.

FIG. 3 is a flowchart for explaining a discharge control process by a control circuit in the load driving device shown in FIG.

FIG. 4 is a circuit diagram showing a circuit configuration of a load driving device according to a second embodiment of the present invention.

[Explanation of symbols]

1 main battery, 2 SMR, 3 converter, 4 drive system inverter, 5, 6, 8, 202, 204 capacitor, 7 A / C inverter, 9 control circuit, 10 motor generator, 11 A / C compressor, 31, 3
2 switching transistors, 33, 34 diodes, 35 coils, 91 motor control phase voltage calculator,
92 inverter PWM signal converter, 93 inverter input voltage command calculator, 94 converter duty ratio calculator, 95 converter PWM signal converter, 10
0,101 load drive device, 201 DC / DC converter, 203 P / S controller, 205 auxiliary system battery, 206 P / S motor, N1 to N4 nodes.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H115 PA08 PA15 PC06 PG04 PI16                       PU08 PV09 QA01 QE12 TR14                       TU01 TU04 TW08                 5H730 AA14 AS04 AS13 BB14 BB57                       DD02 FD01 FD11 FG05 FG23                       XC20

Claims (9)

[Claims] 1. A control circuit comprising: a main circuit including a load drive circuit for driving a first electric load; an auxiliary circuit connected to the main circuit for operating a second electric load; and a control circuit. The circuit stops the load drive circuit when the main power supply to the main circuit is cut off, and supplies the residual charge of the main circuit to the auxiliary circuit after the main power supply is cut off. A load drive device for controlling the main circuit. 2. The main circuit is connected between a converter that boosts a DC voltage supplied from the main power supply and outputs the boosted DC voltage to the load drive circuit, and between the load drive circuit and the converter.
And a smoothing circuit that smoothes the DC voltage boosted by the converter, the auxiliary circuit is connected between the main power supply and the converter, and after the main power supply is cut off, the control circuit Controls the converter to supply the residual charge of the smoothing circuit to the auxiliary circuit via the converter, and the converter steps down the voltage generated by the residual charge of the smoothing circuit to reduce the voltage of the auxiliary circuit. The load driving device according to claim 1, wherein the load driving device outputs the load to the load driving device. 3. The main circuit further includes another smoothing circuit connected between the main power source and the converter, and the residual charge of the other smoothing circuit after the main power source is cut off. The load drive device according to claim 2, wherein is supplied to the auxiliary circuit. 4. The first converter has a collector connected to a first node connected to the load driving circuit and an emitter connected to a second node.
A second switching transistor whose collector is connected to the second node and whose emitter is connected to a third node which connects the load drive circuit and a negative node of the main power supply; A first diode connected to the second node and having a cathode connected to the first node; and a second diode having an anode connected to the third node and a cathode connected to the second node And a coil, one of which is connected to the second node and the other of which is connected to a positive electrode node of the main power supply, wherein the control circuit is configured to operate the first power supply after the main power supply is cut off.
The load drive device according to claim 2 or 3, wherein the switching transistor is turned on and the second switching transistor is turned off. 5. The first switching transistor when the control circuit detects an input voltage of the auxiliary circuit and determines that the input voltage becomes lower than a predetermined value after the main power supply is cut off. The load drive device according to claim 4, wherein the load drive device is turned off to stop the auxiliary circuit. 6. The second electric load is a vehicle-mounted air conditioner, the auxiliary circuit includes an inverter that drives the vehicle-mounted air conditioner, and the first electric load is a drive that generates a driving force of the vehicle. The load drive device according to claim 1, wherein the load drive circuit is a motor, and the load drive circuit is an inverter that drives the drive motor. 7. The second electric load is an auxiliary power supply, and the auxiliary circuit is another converter that converts input electric power into a predetermined voltage and outputs the voltage to the auxiliary power supply. The first electric load is a drive motor that generates a driving force of a vehicle, and the load drive circuit is an inverter that drives the drive motor. The load drive device according to the item. 8. A discharge control method in a load drive device comprising a main circuit and an auxiliary circuit connected to the main circuit, wherein the main circuit is a load drive circuit for driving a first electric load. A converter that boosts a DC voltage supplied from the main power source and outputs the boosted DC voltage to the load drive circuit, and is connected between the load drive circuit and the converter,
A smoothing circuit for smoothing the DC voltage boosted by the converter, wherein the auxiliary circuit is connected between the main power source and the converter to operate the second electric load, and the discharge control The method includes a first step of stopping the load driving circuit when the main power supplied to the main circuit and the auxiliary circuit is cut off, and a step of remaining the smoothing circuit after the load driving circuit stops. A second step of stepping down a voltage generated by electric charges by the converter and outputting the stepped voltage to the auxiliary machine circuit; and when the residual electric charge of the smoothing circuit is discharged to the auxiliary machine circuit in the second step, the auxiliary circuit A third step of detecting an input voltage of a mechanical circuit; and a fourth step of stopping the converter and the auxiliary circuit when it is determined that the detected input voltage is lower than a predetermined value.
And a discharge control method. 9. A computer-readable recording medium in which a program for causing a computer to execute discharge control in a load driving device including a main circuit and an auxiliary circuit connected to the main circuit is recorded. The main circuit includes a load drive circuit that drives a first electric load, a converter that boosts a DC voltage supplied from the main power source and outputs the DC voltage to the load drive circuit, and the load drive circuit and the converter. Connected in between,
A smoothing circuit for smoothing the DC voltage boosted by the converter, wherein the auxiliary circuit is connected between the main power source and the converter to operate the second electric load, and the recording medium. A first step of stopping the load drive circuit after the main power supplied to the main circuit and the auxiliary circuit is cut off; and a residual charge of the smoothing circuit after the load drive circuit is stopped. The step of stepping down the voltage generated by the converter by the converter and outputting the stepped voltage to the auxiliary circuit, and when the residual charge of the smoothing circuit is discharged to the auxiliary circuit in the second step, A third step of detecting an input voltage of the circuit; and a fourth step of stopping the converter and the auxiliary circuit when it is determined that the detected input voltage is lower than a predetermined value.
And a computer-readable recording medium recording a program for causing a computer to execute the steps of.