JP2005143259A - Load driving device and computer-readable recording program for making computer run its operation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load driving device that can utilize electric power effectively and capable of discharging remaining electric charge of a capacitor provided at the input side of a drive device that drives a load. <P>SOLUTION: This load driving device 100 is provided with a limiting resistor 11 and a system relay SMR1 connected in series between a node N1 at the positive pole terminal side of a battery B and a node N2 at the high-tension side of a voltage raise converter 12. In starting the load driving device 100, the system relays SMR1, SMR3 are turned on and the battery B pre-charges the capacitor C2 via the limiting resistor 11. When the load driving device 100 is stopped or if a failure occurs to the voltage raise converter 12 or an inverter 14, the system relays SMR1, SMR2 are turned on and off, respectively, so that the electric power of the capacitor C2 is returned to the battery B. When a voltage across the capacitor C2 drops to a battery voltage, the remaining electric charge of the capacitor C2 is discharged by a discharging resistor 18. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a load driving device that drives a load and a computer-readable recording medium that records a program for causing a computer to execute the operation.

  Conventionally, a motor driving device that drives a motor includes an inverter, a capacitor, a chopper circuit, a reactor, and a battery. The inverter is connected between the positive bus and the negative bus. The capacitor is provided on the input side of the inverter, and is connected in parallel to the inverter between the positive bus and the negative bus. The chopper circuit includes an upper arm and a lower arm connected in series between a positive bus and a negative bus, and is provided between a reactor and a capacitor. The reactor has one end connected to the positive side of the battery and the other end connected between the upper arm and the lower arm of the chopper circuit. The chopper circuit and the reactor constitute a bidirectional converter.

  The battery outputs a DC voltage to the bidirectional converter. The bi-directional converter boosts and supplies the DC voltage from the battery to the capacitor by turning on / off the upper and lower arms of the chopper circuit according to control from the control circuit, and steps down the DC voltage from the inverter. Charge the battery. In this case, the bidirectional converter changes the boost level of the DC voltage according to the on-time of the lower arm. That is, if the lower arm on-time is increased, the bidirectional converter supplies a relatively high DC voltage to the capacitor, and if the lower arm on-time is decreased, the bidirectional converter has a relatively lower DC voltage. To the capacitor.

  The capacitor smoothes the DC voltage boosted by the bidirectional converter and supplies it to the inverter. The inverter converts the DC voltage from the capacitor into an AC voltage in accordance with control from the control circuit, and drives the motor. The inverter converts the AC voltage generated by the motor into a DC voltage and supplies it to the bidirectional converter.

As described above, the conventional motor driving device boosts the DC voltage from the battery to a DC voltage having a different voltage level to drive the motor, and converts the AC voltage generated by the motor into a DC voltage to charge the battery. (Patent Document 1).
Japanese Patent Application Laid-Open No. 8-214592 JP 2003-230269 A

  However, Patent Document 1 does not disclose a specific method for discharging the residual charge of the capacitor provided on the input side of the inverter. Therefore, in the conventional motor driving device, the discharge resistor is connected in parallel with the capacitor. The method of providing and discharging the residual charge of the capacitor has a problem that it is difficult to drive the motor by effectively using electric power.

  That is, in order to discharge the residual charge of the capacitor with the discharge resistor in a short time, it is necessary to set the discharge resistance low. However, if the discharge resistance is set low, the DC power reduces the discharge resistance during normal operation of the motor drive device. Therefore, it is difficult to effectively use the electric power stored in the battery and the electric power generated by the motor.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to effectively use electric power and to reduce the residual charge of a capacitor provided on the input side of a drive device that drives a load. It is to provide a load driving device capable of discharging.

  Another object of the present invention is to allow a computer to execute an operation of a load driving device that can effectively use electric power and can discharge a residual charge of a capacitor provided on an input side of a driving device that drives a load. It is providing the computer-readable recording medium which recorded the program for this.

  According to the present invention, the load driving device includes a power source, a capacitor, a voltage converter, an electrical path, a switch, and a limiting resistor. The capacitor is provided on the input side of the driving device that drives the load. The voltage converter performs voltage conversion between a power supply and a capacitor. The electrical path connects the high voltage side of the voltage converter to the positive side of the power supply. The switch opens and closes the electrical path. The limiting resistor is provided in the electrical path in series with the switch.

  Preferably, the load driving device further includes a control unit. The control means closes the electrical path when starting the load driving device, and controls the switch to open the electrical path when the voltage across the capacitor is precharged to a predetermined voltage.

  Preferably, the load driving device further includes a main switch. The main switch is provided between the power source and the voltage converter. Further, when the precharge is completed, the control means turns on the main switch and controls the voltage converter so as to boost the DC voltage from the power source.

  Preferably, the predetermined voltage is a power supply voltage of the power supply.

  Preferably, the load driving device further includes a discharge resistor and a control unit. The discharge resistor is connected in parallel to the capacitor and has a resistance value higher than a predetermined value. The control means controls the switch to close the electrical path when the load is stopped and open the electrical path when the voltage across the capacitor drops to a predetermined voltage.

  Preferably, the load driving device further includes a control unit. The control means closes the electrical path when the load is stopped, opens the electrical path when the voltage across the capacitor drops to a predetermined voltage, and controls the voltage converter to discharge the power stored in the capacitor To do.

  Preferably, the predetermined voltage is a power supply voltage of the power supply.

  Preferably, the load driving device further includes a discharge resistor and a control unit. The discharge resistor is connected to the capacitor in parallel and is composed of a variable resistor. The control means sets the resistance value of the variable resistor to be higher than a predetermined value during the operation of the load, and sets the resistance value of the variable resistor to a predetermined value or less when the load is stopped.

  Preferably, the load driving device further includes a control unit. The control means controls the switch so as to close the electrical path when the voltage converter fails.

  Preferably, the load driving device further includes a discharge resistor. The discharge resistor is connected in parallel to the capacitor and has a resistance value higher than a predetermined value. The control means further controls the switch so that the electric path is opened when the voltage across the capacitor is lowered to a predetermined voltage, and controls the driving device so that the electric power stored in the capacitor is discharged by the load.

  According to the present invention, the computer-readable recording medium recording a program to be executed by a computer is a computer-readable recording medium recording a program for causing the computer to execute an operation of the load driving device. . The load driving device includes a power source, a capacitor, a voltage converter, an electrical path, a switch, and a limiting resistor. The capacitor is provided on the input side of the driving device that drives the load. The voltage converter performs voltage conversion between a power supply and a capacitor. The electrical path connects the high voltage side of the voltage converter to the positive side of the power supply. The switch opens and closes the electrical path. The limiting resistor is provided in the electrical path in series with the switch. The program includes a first step of precharging the capacitor via the limiting resistor, a second step of controlling the voltage converter and the driving device to drive the load when the precharging is completed, and the load driving device. When stopping or when the voltage converter or the drive device is abnormal, the power stored in the capacitor is returned to the power source through the limiting resistor, and the residual charge of the capacitor is discharged when the voltage of the capacitor drops to a predetermined value. And let the computer run.

  Preferably, the third step includes a first sub-step for returning the power stored in the capacitor to the power source through the limiting resistor when the load driving device is stopped or when the voltage converter or the driving device is abnormal. And a second sub-step of discharging the residual charge of the capacitor when the voltage of the capacitor decreases to a predetermined value.

  Preferably, the load driving device further includes a discharge resistor connected in parallel to the capacitor. Then, in the second sub-step of the program, the residual charge of the capacitor is discharged using the discharge resistance.

  Preferably, the residual charge of the capacitor is discharged only by the discharge resistor when the load driving device is stopped or when the driving device is abnormal.

  Preferably, the residual charge of the capacitor is discharged by the discharge resistor and the load when the voltage converter is abnormal.

  Preferably, the discharge resistor is a variable resistor. In the second sub-step of the program, the resistance value of the variable resistor is set to a value lower than a predetermined value.

  Preferably, in the second sub-step, the residual charge of the capacitor is discharged using a voltage converter.

  Preferably, the residual charge of the capacitor is discharged only by the voltage converter when the load driving device is stopped or when the driving device is abnormal.

  Preferably, the residual charge of the capacitor is discharged by the load when the voltage converter is abnormal.

  A load driving device according to the present invention includes a capacitor provided on the input side of a driving device that drives a load, a voltage converter that performs voltage conversion between the power source and the capacitor, and a high voltage side of the voltage converter that is connected to the power source. Since the electric path connected to the positive electrode side, the switch for opening and closing the electric path, and the limiting resistor provided in the electric path in series with the switch, the power stored in the capacitor is supplied via the limiting resistor and the switch. Can be returned to. The residual charge remaining in the capacitor when the voltage across the capacitor is lowered can be discharged by the discharge resistor. As a result, the resistance value of the discharge resistor can be set higher than the resistance value when the electric path, the switch, and the limiting resistor are not provided.

  Therefore, according to the present invention, electric power can be used effectively, and the residual charge of the capacitor provided on the input side of the drive device that drives the load can be discharged.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
1 is a schematic block diagram of a load driving apparatus according to Embodiment 1 of the present invention. Referring to FIG. 1, load driving apparatus 100 includes a battery B, system relays SMR1 to SMR3, voltage sensors 10 and 13, a limiting resistor 11, capacitors C1 and C2, a boost converter 12, and an inverter 14. , A discharge resistor 18, a current sensor 24, and a control device 30.

  AC motor M1 is a drive motor for generating torque for driving drive wheels of a hybrid vehicle or an electric vehicle. Alternatively, this motor has the function of a generator driven by an engine, and operates as an electric motor for the engine, for example, can be incorporated into a hybrid vehicle so that the engine can be started. Also good.

  Boost converter 12 includes a reactor L1, NPN transistors Q1, Q2, and diodes D1, D2.

  System relay SMR1 and limiting resistor 11 are connected in series between node N1 on the positive terminal side of battery B and node N2 on the high voltage side of boost converter 12. In this case, the limiting resistor 11 is provided on the node N1 side, and the system relay SMR1 is provided on the node N2 side.

  System relay SMR2 is connected between node N1 and reactor L1 of boost converter 12. System relay SMR3 is connected between the negative terminal of battery B and low-voltage side node N3 of boost converter 12.

  Capacitor C1 is connected in parallel between system relays SMR2 and SMR3 and boost converter 12. Reactor L1 has one end connected to system relay SMR2, and the other end connected to an intermediate point between NPN transistor Q1 and NPN transistor Q2, that is, between the emitter of NPN transistor Q1 and the collector of NPN transistor Q2.

  NPN transistors Q1 and Q2 are connected in series between node N2 on the positive bus of inverter 14 and node N3 on the negative bus. NPN transistor Q1 has a collector connected to node N2, and an emitter connected to the collector of NPN transistor Q2. NPN transistor Q2 has an emitter connected to node N3. Between the collector and emitter of each of the NPN transistors Q1 and Q2, diodes D1 and D2 that flow current from the emitter side to the collector side are respectively connected.

  Capacitor C <b> 2 is connected between the positive bus and the negative bus of inverter 14. Discharge resistor 18 is connected in parallel to capacitor C2 between the positive bus and the negative bus of inverter 14.

  Inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17. U-phase arm 15, V-phase arm 16, and W-phase arm 17 are provided in parallel between a positive bus and a negative bus.

  The U-phase arm 15 includes NPN transistors Q3 and Q4 connected in series, the V-phase arm 16 includes NPN transistors Q5 and Q6 connected in series, and the W-phase arm 17 includes NPN transistors Q7 and Q7 connected in series. Consists of Q8. Further, diodes D3 to D8 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the NPN transistors Q3 to Q8, respectively.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of AC motor M1. In other words, AC motor M1 is a three-phase permanent magnet motor, and is configured such that one end of three coils of U, V, and W phases is commonly connected to the middle point, and the other end of the U-phase coil is NPN transistor Q3. The other end of the V-phase coil is connected to the intermediate point of NPN transistors Q5 and Q6, and the other end of the W-phase coil is connected to the intermediate point of NPN transistors Q7 and Q8, respectively.

  The battery B is composed of a secondary battery such as nickel metal hydride or lithium ion. Voltage sensor 10 detects battery voltage Vb output from battery B, and outputs the detected battery voltage Vb to control device 30.

  System relays SMR1 to SMR3 are turned on / off by signals SE1 to SE3 from control device 30, respectively. More specifically, system relays SMR1 to SMR3 are turned on by H (logic high) level signals SE1 to SE3 from control device 30, respectively, and are turned off by L (logic low) level signals SE1 to SE3. .

  Capacitor C1 smoothes the DC voltage supplied from battery B and supplies the smoothed DC voltage to boost converter 12.

  Boost converter 12 boosts the DC voltage supplied from capacitor C1 and supplies it to capacitor C2, and steps down the DC voltage supplied from inverter 14 and supplies it to battery B. More specifically, boost converter 12 boosts a DC voltage according to a period during which NPN transistor Q2 is turned on by signal PWMU from control device 30 and supplies the boosted voltage to capacitor C2, and NPN transistor Q1 is turned on by signal PWMU. The battery B is charged by stepping down the DC voltage according to the period of time.

  Thus, boost converter 12 boosts the DC voltage from battery B and steps down the DC voltage from inverter 14, and thus has a bidirectional converter function.

  Capacitor C <b> 2 smoothes the DC voltage from boost converter 12 and supplies the smoothed DC voltage to inverter 14. The voltage sensor 13 detects the voltage across the capacitor C2, that is, the output voltage Vm of the boost converter 12 (corresponding to the input voltage to the inverter 14; the same applies hereinafter), and the detected output voltage Vm is controlled by the control device 30. Output to.

  When the DC voltage is supplied from the capacitor C2, the inverter 14 converts the DC voltage into an AC voltage based on the signal PWMI from the control device 30 and drives the AC motor M1. As a result, AC motor M1 is driven so as to generate torque specified by torque command value TR.

  Further, the inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage based on the signal PWMI from the control device 30 during regenerative braking of the hybrid vehicle or electric vehicle on which the motor drive device 100 is mounted, The converted DC voltage is supplied to boost converter 12 via capacitor C2. Note that regenerative braking here refers to braking with regenerative power generation when the driver driving a hybrid vehicle or electric vehicle performs foot braking, or turning off the accelerator pedal while driving, although the foot brake is not operated. This includes decelerating the vehicle (or stopping acceleration) while generating regenerative power.

  The inverter 14 includes six drive circuits (not shown) for driving the NPN transistors Q3 to Q8 corresponding to the NPN transistors Q3 to Q8, and each of the six drive circuits includes a corresponding NPN transistor. When an overcurrent flows through, a fail signal is generated. Therefore, when a fail signal is generated by at least one of the six drive circuits, inverter 14 outputs a fail signal FLI indicating that inverter 14 cannot operate normally to control device 30.

  Discharge resistor 18 has a resistance value higher than a resistance value (predetermined value) when there is no electrical path from node N1 to node N2. Then, the discharge resistor 18 discharges the residual charge of the capacitor C2. By providing the electric path from the node N1 to the node N2, the limiting resistor 11 and the system relay SMR1, the power stored in the capacitor C2 is transferred to the battery via the limiting resistor 11 and the system relay SMR1 when the load driving device 100 is stopped. Returning to B, after the voltage Vm across the capacitor C2 drops to the battery voltage Vb, the residual charge of the capacitor C2 can be discharged by the discharge resistor 18. Therefore, even if the resistance value of the discharge resistor 18 is set higher than the resistance value when there is no electrical path from the node N1 to the node N2, the residual charge of the capacitor C2 can be discharged in a short time. Therefore, the resistance value of the discharge resistor 18 is set higher than the resistance value when there is no electrical path from the node N1 to the node N2.

  As a result, the power usage rate of the load driving device 100 can be made higher than when there is no electrical path from the node N1 to the node N2. That is, when the load driving device 100 drives the AC motor M1 in the power running mode, the inverter 14 receives a DC voltage from the capacitor C2 via the discharge resistor 18, so that a part of the electric power stored in the capacitor C2 is discharged. The resistor 18 is discharged. Further, when the load driving device 100 drives the AC motor M1 in the regeneration mode, the inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage, and the converted DC voltage is converted into a capacitor via the discharge resistor 18. Since it is supplied to C2, a part of the generated power is discharged by the discharge resistor 18. However, since the resistance value of the discharge resistor 18 is set higher than the resistance value when there is no electrical path from the node N1 to the node N2, the discharge power when the AC motor M1 is driven in the power running mode or the regeneration mode is The discharge power is lower than when there is no electrical path from the node N1 to the node N2, and the power usage rate of the load driving device 100 is higher than the power usage rate when there is no electrical path from the node N1 to the node N2. Become.

  Current sensor 24 detects motor current MCRT flowing through AC motor M <b> 1 and outputs the detected motor current MCRT to control device 30.

  The control device 30 includes a torque command value TR and a motor rotational speed MRN input from an externally provided ECU (Electrical Control Unit), a battery voltage Vb from the voltage sensor 10, an output voltage Vm from the voltage sensor 13, and a current. Based on the motor current MCRT from the sensor 24, a signal PWMU for driving the boost converter 12 and a signal PWMI for driving the inverter 14 are generated by a method described later, and the generated signal PWMU and signal PWMI are respectively generated. Output to boost converter 12 and inverter 14.

  Signal PWMU is a signal for driving boost converter 12 when boost converter 12 converts the DC voltage from capacitor C1 into output voltage Vm. When boost converter 12 converts the DC voltage to output voltage Vm, control device 30 feedback-controls output voltage Vm, and drives boost converter 12 so that output voltage Vm becomes commanded voltage command Vdc_com. The signal PWMU for generating is generated. The signal PWMU is a signal for driving the boost converter 12 when the boost converter 12 steps down the DC voltage from the inverter 14. A method for generating the signal PWMU will be described later.

  Control device 30 generates signals SE1 to SE3 for turning on / off system relays SMR1 to SMR3 and outputs the signals to system relays SMR1 to SMR3, respectively. A sequence in which control device 30 turns system relays SMR1 to SMR3 on / off will be described later.

  FIG. 2 is a functional block diagram of the control device 30 shown in FIG. Referring to FIG. 2, control device 30 includes inverter control means 301, converter control means 302, and switch control means 303.

  Inverter control means 301 receives torque command value TR from the external ECU, motor current MCRT from current sensor 24, and voltage Vm from voltage sensor 13. When the inverter control unit 301 receives the signal PCH indicating that the precharge of the capacitor C2 is completed from the switch control unit 303, the inverter control unit 301 performs a signal based on the torque command value TR, the motor current MCRT, and the voltage Vm by a method described later. PWMI is generated and output to the inverter 14. Further, when the inverter control means 301 receives the signal DCH for discharging the residual charge of the capacitor C2 from the switch control means 303, the inverter PWM means 301 outputs a signal PWMI_D (a kind of signal PWMI) for discharging the residual charge of the capacitor C2 by the AC motor M1. ) And output to the inverter 14.

  Converter control means 302 receives torque command value TR and motor rotation speed MRN from an external ECU, receives battery voltage Vb from voltage sensor 10, and receives voltage Vm from voltage sensor 13. The converter control means 302 generates a signal PWMU by a method to be described later based on the torque command value TR, the motor rotation speed MRN, the battery voltage Vb and the voltage Vm in accordance with the signal PCH from the switch control means 303 to generate a boost converter. 12 is output.

  Further, converter control means 302 determines whether or not boost converter 12 can operate normally by a method described later, based on torque command value TR, motor rotational speed MRN, and voltage Vm. When the converter control unit 302 determines that the boost converter 12 cannot operate normally, the converter control unit 302 generates a fail signal FLU indicating that the boost converter 12 cannot operate normally and outputs it to the switch control unit 303. To do.

  Upon receiving a signal IGON from the external ECU indicating that the ignition key of the hybrid vehicle or electric vehicle on which the load driving device 100 is mounted is turned on, the switch control means 303 generates H level signals SE1 and SE3, respectively. Output to system relays SMR1 and SMR3.

  Further, switch control means 303 generates H level signals SE1 and SE3 and outputs them to system relays SMR1 and SMR3, respectively, and then whether or not voltage Vm from voltage sensor 13 is equal to battery voltage Vb from voltage sensor 10 or not. It is determined whether or not the capacitor C2 is precharged. When it is determined that the capacitor C2 is precharged, the switch control unit 303 generates an H level signal SE2 and outputs the signal to the system relay SMR2, and subsequently generates an L level signal SE1 to generate the system relay SMR1. Output to. When the switch control unit 303 determines that the capacitor C2 is precharged, the switch control unit 303 generates a signal PCH indicating that the precharge of the capacitor C2 is completed, and outputs the signal PCH to the inverter control unit 301 and the converter control unit 302.

  Further, the switch control means 303 generates an H level signal SE1 when receiving a fail signal FLI from the inverter 14 or when receiving a signal IGOFF indicating that the ignition key is turned off from the external ECU. The signal is output to SMR1, and subsequently an L level signal SE2 is generated and output to system relay SMR2. Thereafter, when voltage Vm drops to battery voltage Vb, switch control means 303 generates L level signals SE1 and SE3 and outputs them to system relays SMR1 and SMR3, respectively.

  Further, when receiving the fail signal FLU from the converter control means 302, the switch control means 303 generates an H level signal SE1 and outputs it to the system relay SMR1, and subsequently generates an L level signal SE2 to generate a system. Output to relay SMR2. Thereafter, when the voltage Vm decreases to the battery voltage Vb, the switch control means 303 generates L level signals SE1 and SE3 and outputs them to the system relays SMR1 and SMR3, respectively, and also generates the signal DCH to generate the inverter control means 301. Output to.

  FIG. 3 is a functional block diagram of the inverter control means 301 shown in FIG. Referring to FIG. 3, inverter control means 301 includes a motor control phase voltage calculation unit 40 and an inverter PWM signal conversion unit 42.

  The motor control phase voltage calculation unit 40 receives the signal PCH from the switch control means 303, receives the output voltage Vm of the boost converter 12, that is, the input voltage to the inverter 14 from the voltage sensor 13, and supplies each phase of the AC motor M1. The flowing motor current MCRT is received from the current sensor 24, and the torque command value TR is received from the external ECU. Then, upon receiving the signal PCH from the switch control means 303, the motor control phase voltage calculation unit 40 applies it to the coils of each phase of the AC motor M1 based on the output voltage Vm, the torque command value TR, and the motor current MCRT. The voltage is calculated, and the calculated result is supplied to the inverter PWM signal converter 42.

  Based on the calculation result received from motor control phase voltage calculation unit 40, inverter PWM signal conversion unit 42 generates a signal PWMI that actually turns on / off each NPN transistor Q3-Q8 of inverter 14, and generates the signal PWMI. The signal PWMI is output to the NPN transistors Q3 to Q8 of the inverter 14.

  Thereby, each NPN transistor Q3-Q8 is switching-controlled, and controls the electric current sent through each phase of AC motor M1 so that AC motor M1 may output the commanded torque. In this way, the motor drive current is controlled, and a motor torque corresponding to the torque command value TR is output.

  Whether the inverter 14 is driven in the power running mode or the regenerative mode by the signal PWMI is determined by the motor rotational speed MRN and the torque command value TR. That is, when the relationship between the motor rotational speed MRN and the torque command value TR exists in the first quadrant or the second quadrant in the orthogonal coordinates with the motor rotational speed on the horizontal axis and the torque command value on the vertical axis, the AC motor M1 is in the power running mode, and AC motor M1 is in the regeneration mode when the relationship between motor rotational speed MRN and torque command value TR exists in the third quadrant or the fourth quadrant. Therefore, when the motor control phase voltage calculation unit 40 receives the motor rotation speed MRN and the torque command value TR existing in the first quadrant or the second quadrant from the external ECU, the inverter PWM signal conversion unit 42 Is generated in the power running mode, and the motor control phase voltage calculation unit 40 receives the motor rotational speed MRN and the torque command value TR existing in the third quadrant or the fourth quadrant from the external ECU. The inverter PWM signal converter 42 generates a signal PWMI for driving the inverter 14 in the regeneration mode.

  Further, when the inverter PWM signal conversion unit 42 receives the signal DCH from the switch control means 303, the AC motor M1 discharges the residual charge of the capacitor C2 regardless of the calculation result from the motor control phase voltage calculation unit 40. The signal PWMI_D is generated and output to the inverter 14. For example, the signal PWMI_D is a signal for turning on all the NPN transistors Q3 to Q8 of the inverter 14. The signal PWMI_D is not limited to a signal for turning on all the NPN transistors Q3 to Q8. Generally, the residual charge of the capacitor C2 flows to at least two of the U-phase coil, the V-phase coil, and the W-phase coil of the AC motor M1. Thus, any signal that turns on the NPN transistors Q3 to Q8 may be used.

  FIG. 4 is a functional block diagram of converter control means 302 shown in FIG. Referring to FIG. 4, converter control means 302 includes an inverter input voltage command calculation unit 50, a feedback voltage command calculation unit 52, a duty ratio conversion unit 54, and a determination unit 56.

  When receiving the signal PCH indicating that the precharge of the capacitor C2 has been completed from the switch control means 303, the inverter input voltage command calculation unit 50 receives the optimum value (inverter input voltage) based on the torque command value TR and the motor rotational speed MRN ( Target value), that is, the voltage command Vdc_com is calculated, and the calculated voltage command Vdc_com is output to the feedback voltage command calculation unit 52 and the determination unit 56.

  Feedback voltage command calculation unit 52 sets output voltage Vm to voltage command Vdc_com based on output voltage Vm of boost converter 12 from voltage sensor 13 and voltage command Vdc_com from inverter input voltage command calculation unit 50. The feedback voltage command Vdc_com_fb is calculated, and the calculated feedback voltage command Vdc_com_fb is output to the duty ratio converter 54.

  The duty ratio conversion unit 54 outputs from the voltage sensor 13 based on the battery voltage Vb from the voltage sensor 10, the output voltage Vm from the voltage sensor 13, and the feedback voltage command Vdc_com_fb from the feedback voltage command calculation unit 52. To calculate a duty ratio for setting voltage Vm to feedback voltage command Vdc_com_fb from feedback voltage command calculation unit 52, and to turn on / off NPN transistors Q1 and Q2 of boost converter 12 based on the calculated duty ratio The signal PWMU is generated. Then, duty ratio converter 54 outputs the generated signal PWMU to NPN transistors Q1 and Q2 of boost converter 12.

  Note that increasing the on-duty of the NPN transistor Q2 on the lower side of the boost converter 12 increases the power storage in the reactor L1, so that a higher voltage output can be obtained. On the other hand, increasing the on-duty of the upper NPN transistor Q1 lowers the voltage of the positive bus. Therefore, the voltage of the positive bus can be controlled to an arbitrary voltage equal to or higher than the output voltage of the battery B by controlling the duty ratio of the NPN transistors Q1 and Q2.

  Based on output voltage Vm from voltage sensor 13 and voltage command Vdc_com from inverter input voltage command calculation unit 50, determination unit 56 determines whether boost converter 12 has become unable to operate normally. More specifically, determination unit 56 calculates the difference between output voltage Vm and voltage command Vdc_com, and when the calculated difference is equal to or greater than a predetermined value for a predetermined period, boost converter 12 can operate normally. Judge that it is gone. When the determination unit 56 determines that the boost converter 12 cannot operate normally, the determination unit 56 generates a fail signal FLU and outputs it to the switch control unit 303. When boost converter 12 is operating normally, output voltage Vm gradually approaches voltage command Vdc_com. However, when boost converter 12 cannot operate normally, the difference between output voltage Vm and voltage command Vdc_com continues for a predetermined period and exceeds a predetermined value. Therefore, it is determined whether or not the boost converter 12 is operating normally by determining whether or not the difference between the output voltage Vm and the voltage command Vdc_com is continuously greater than or equal to a predetermined value. Is.

  FIG. 5 is a flowchart for explaining the operation of the load driving device 100 shown in FIG. Referring to FIG. 5, when a series of operations is started, switch control means 303, when receiving signal IGON from an external ECU (step S1), generates H-level signals SE1 and SE3 and system relay SMR1. And output to SMR3.

  System relays SMR1 and SMR3 are turned on by H level signals SE1 and SE3 from control device 30, respectively, and battery B supplies a DC voltage to capacitor C2 via limiting resistor 11 and system relays SMR1 and SMR3. C2 is precharged (step S2). In this case, since the battery B supplies the DC voltage to the capacitor C2 via the limiting resistor 11, an inrush current to the capacitor C2 can be prevented.

  Thereafter, the switch control means 303 determines whether or not the voltage Vm from the voltage sensor 13 matches the battery voltage Vb from the voltage sensor 10 (step S3), and when the voltage Vm matches the battery voltage Vb, the capacitor It is determined that C2 is precharged.

  On the other hand, when the voltage Vm does not match the battery voltage Vb, the series of operations proceeds to step S10.

  When it is determined that the capacitor C2 is precharged, the switch control unit 303 generates the signal PCH and outputs it to the inverter control unit 301 and the converter control unit 302. Then, the switch control means 303 generates an H level signal SE2 and outputs it to the system relay SMR2, and subsequently generates an L level signal SE1 and outputs it to the system relay SMR1. Thereby, battery B supplies a DC voltage to boost converter 12 via system relays SMR2 and SMR3.

  Thereafter, inverter input voltage command calculation unit 50 of converter control means 302 calculates voltage command Vdc_com based on torque command value TR and motor rotational speed MRN from the external ECU in accordance with signal PCH from switch control means 303. To the feedback voltage command calculation unit 52 and the determination unit 56.

  The feedback voltage command calculation unit 52 calculates the feedback voltage command Vdc_com_fb by the above-described method based on the voltage command Vdc_com from the inverter input voltage command calculation unit 50 and the voltage Vm from the voltage sensor 13, and the duty ratio conversion unit. To 54. Then, duty ratio converter 54 generates signal PWMU by the above-described method based on feedback voltage command Vdc_com_fb, battery voltage Vb, and voltage Vm, and outputs the signal PWMU to boost converter 12.

  In addition, the motor control phase voltage calculation unit 40 of the inverter control unit 301 determines the AC motor M1 based on the torque command value TR and the motor rotational speed MRN from the external ECU in response to the signal PCH from the switch control unit 303. The voltage applied to each phase is calculated, and the calculation result is output to the inverter PWM signal converter 42. The inverter PWM signal conversion unit 42 generates a signal PWMI based on the calculation result from the motor control phase voltage calculation unit 40 and outputs the signal PWMI to the inverter 14.

  Boost converter 12 boosts the DC voltage from battery B by signal PWMU from control device 30 and supplies the boosted voltage to capacitor C2. Capacitor C <b> 2 smoothes the DC voltage from boost converter 12 and supplies it to inverter 14. The inverter 14 converts the DC voltage from the capacitor C2 into an AC voltage by the signal PWMI from the control device 30, and drives the AC motor M1. That is, the inverter 14 drives the AC motor M1 in the power running mode.

  Further, during regenerative braking of a hybrid vehicle or an electric vehicle on which the load driving device 100 is mounted, the AC motor M1 generates an AC voltage. The inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage by the signal PWMI from the control device 30 and supplies it to the capacitor C2.

  Capacitor C2 smoothes the DC voltage from inverter 14 and supplies the boosted voltage to boost converter 12. Boost converter 12 steps down DC voltage from capacitor C2 by signal PWMU from control device 30 to charge battery B.

  Thus, the load driving device 100 performs voltage conversion between the battery B and the capacitor C2, and drives the AC motor M1 in the power running mode or the regeneration mode (step S4).

  Thereafter, determination unit 56 of converter control means 302 determines whether or not the difference between voltage command Vdc_com and voltage Vm continues for a predetermined period and is equal to or greater than a predetermined value, so that boost converter 12 cannot operate normally. It is determined whether or not (step S5).

  When it is determined that boost converter 12 cannot operate normally, the series of operations proceeds to step S9. In step S5, when the difference between voltage command Vdc_com and voltage Vm is smaller than a predetermined value, determination unit 56 determines that boost converter 12 is normal.

  Then, the switch control means 303 determines whether or not the inverter 14 cannot operate normally by determining whether or not the fail signal FLI is received from the inverter 14 (step S6). When the switch control unit 303 receives the fail signal FLI from the inverter 14, the switch control unit 303 determines that the inverter 14 cannot operate normally. Thereafter, the series of operations proceeds to step S8.

  On the other hand, in step S6, when the switch control means 303 does not receive the fail signal FLI from the inverter 14, it determines that the inverter 14 is normal. Then, the switch control means 303 determines whether or not the signal IGOFF is received from the external ECU (step S7). When the switch control means 303 does not receive the signal IGOFF, steps S4 to S7 are repeatedly executed.

  When it is determined in step S6 that the inverter 14 cannot operate normally, or when it is determined in step S7 that the signal IGOFF has been received, the switch control means 303 generates an H level signal SE1 to the system relay SMR1. Then, an L level signal SE2 is generated and output to the system relay SMR2.

  Then, system relay SMR1 is turned on in response to H level signal SE1, and system relay SMR2 is turned off in response to L level signal SE2. Then, the electric power stored in the capacitor C2 is returned to the battery B via the system relay SMR1 and the limiting resistor 11, and the voltage Vm across the capacitor C2 decreases.

  Thereafter, when voltage Vm drops to battery voltage Vb, switch control means 303 generates L level signals SE1 and SE3 and outputs them to system relays SMR1 and SMR3, respectively. System relays SMR1 and SMR3 are turned off in response to L level signals SE1 and SE3, respectively.

  Then, the residual charge of the capacitor C2 is discharged through the discharge resistor 18 (step S8).

  On the other hand, when it is determined in step S5 that the boost converter 12 cannot operate normally, the determination unit 56 generates a fail signal FLU and outputs it to the switch control means 303. Switch control means 303 generates H level signal SE1 in response to fail signal FLU from converter control means 302 and outputs it to system relay SMR1, and subsequently generates L level signal SE2 to generate system relay SMR2. Output to.

  Then, system relay SMR1 is turned on in response to H level signal SE1, and system relay SMR2 is turned off in response to L level signal SE2. Then, the electric power stored in the capacitor C2 is returned to the battery B via the system relay SMR1 and the limiting resistor 11, and the voltage Vm across the capacitor C2 decreases.

  Thereafter, when the voltage Vm decreases to the battery voltage Vb, the switch control means 303 generates L level signals SE1 and SE3 and outputs them to the system relays SMR1 and SMR3, respectively, and also generates the signal DCH to generate the inverter control means 301. Output to.

  Then, system relays SMR1 and SMR3 are turned off in response to L level signals SE1 and SE3, respectively. Then, the inverter PWM signal conversion unit 42 of the inverter control unit 301 generates a signal PWMI_D according to the signal DCH from the switch control unit 303 and outputs it to the inverter 14. Inverter 14 supplies the residual charge of capacitor C2 to AC motor M1 in response to signal PWMI_D from control device 30.

  Thereby, the residual charge of the capacitor C2 is discharged by the discharge resistor 18 and the AC motor M1 (step S9).

  Further, in step S3, when the voltage Vm does not match the voltage Vb, that is, when the precharge of the capacitor C2 is not completed, it is determined that a disconnection has occurred in the electrical path from the node N1 to the node N2 (step S3). S10).

  And after any of step S8, step S9, and step S10, a series of operation | movement is complete | finished.

  As described above, in load driving device 100, when signal IGON indicating that the ignition key is turned on is received from the external ECU, system relays SMR1 and SMR3 are turned on and capacitor C2 is connected to battery voltage via limiting resistor 11. Precharge to Vb (see steps S1 and S2). Therefore, when the load driving device 100 is started, the inrush current can be prevented to precharge the capacitor C2, and the system relay SMR1 can be prevented from being welded.

  In load driving device 100, system relays SMR1 and SMR3 are turned on when boost converter 12 or inverter 14 cannot operate normally (referred to as “abnormal”, hereinafter the same), or when the ignition key is turned off. Then, the electric power stored in the capacitor C2 is returned to the battery B via the limiting resistor 11. When the voltage Vm across the capacitor C2 drops to the battery voltage Vb, the residual charge of the capacitor C2 is discharged by the discharge resistor 18 or the discharge resistor 18 and the AC motor M1 (see steps S5 to S9).

  Therefore, the power stored in the capacitor C2 is returned to the battery B by using the limiting resistor 11 that prevents the inrush current from flowing into the capacitor C2 and the welding of the system relay SMR1, and the voltage Vm across the capacitor C2 is reduced in a short time. Can be reduced.

  Further, after the voltage Vm at both ends of the capacitor C2 has dropped to the battery voltage Vb, the residual charge of the capacitor C2 is discharged by the discharge resistor 18. Therefore, even if the resistance value of the discharge resistor 18 is set high, the residual charge of the capacitor C2 Can be discharged in a short time and the power utilization efficiency during normal operation of the load driving device 100 can be increased. More specifically, when the load driving device 100 is mounted on a hybrid vehicle or an electric vehicle, the load driving device 100 drives the AC motor M1 with the charging power charged in the battery B during normal operation to drive the hybrid vehicle or Drives the drive wheels of an electric vehicle. Since the resistance value of the discharge resistor 18 is set high, the amount of discharge by the discharge resistor 18 is small during the driving of the AC motor M1. Therefore, the charging travel distance can be increased.

  Further, when the load driving device 100 drives the AC motor M1 in the regeneration mode, the inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage, and the boost converter 12 converts the DC voltage from the inverter 14 into the DC voltage. The battery B is charged by stepping down. Also in this case, the amount of discharge by the discharge resistor 18 can be reduced. Therefore, the energy recovery rate can be increased.

  As described above, in the load driving device 100, the electric power can be effectively used and the residual charge of the capacitor C2 can be discharged in a short time.

  Note that control of the load driving device 100 in the control device 30 is actually performed by a CPU (Central Processing Unit), and the CPU reads a program including each step of the flowchart shown in FIG. 5 from a ROM (Read Only Memory). Then, the read program is executed to control the operation of the load driving device 100 according to the flowchart shown in FIG. Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program including each step of the flowchart shown in FIG. 5 is recorded.

  The path from the node N1 to the node N2 constitutes an “electrical path” that connects the high voltage side of the boost converter to the positive side of the battery.

  Converter control means 302 and switch control means 303 constitute “control means”.

  Further, in the above, after the system relays SMR1 and SMR3 are turned on and the electric power stored in the capacitor C2 is returned to the battery B, the timing at which the residual charge of the capacitor C2 is discharged by the discharge resistor is the voltage across the capacitor C2. Although it has been described that Vm has dropped to the battery Vb, the present invention is not limited to this, and when the voltage Vm reaches a voltage Vb + α higher than the battery voltage Vb, the residual charge of the capacitor C2 is caused to discharge by the discharge resistor 18. You may make it discharge. Α is set to a value at which the discharge time by the discharge resistor 18 is approximately the same as the discharge time when there is no electrical path from the node N1 to the node N2.

[Embodiment 2]
FIG. 6 is a schematic block diagram of the load driving device according to the second embodiment. Referring to FIG. 6, load drive device 100 </ b> A is obtained by replacing discharge resistor 18 of load drive device 100 with variable resistor 28, and control device 30 with control device 30 </ b> A. Is the same.

  The variable resistor 28 is connected in parallel to the capacitor C2 between the positive bus and the negative bus. In addition to the function of the control device 30 of the load driving device 100, the control device 30A sets the signal RS1 for setting the resistance value of the variable resistor 28 higher than a predetermined value and the resistance value of the variable resistor 28 below the predetermined value. And the signal RS1 or RS2 thus generated is output to the variable resistor 28. The predetermined value is a resistance value of the discharge resistance when there is no electrical path from the node N1 to the node N2.

  FIG. 7 is a functional block diagram of control device 30A shown in FIG. Referring to FIG. 7, control device 30 </ b> A is obtained by adding resistance control means 304 to control device 30, and the rest is the same as control device 30. In control device 30A, determination unit 56 of converter control means 302 outputs generated fail signal FLU to switch control means 303 and resistance control means 304.

  When the resistance control unit 304 receives the signal IGON from the external ECU, the resistance control unit 304 generates the signal RS1 and outputs the signal RS1 to the variable resistor 28. Further, the resistance control unit 304 generates the signal RS2 when receiving the signal IGOFF from the external ECU, when receiving the fail signal FLI from the inverter 14, or when receiving the fail signal FLU from the converter control unit 302. Output to the variable resistor 28.

  That is, the resistance control unit 304 sets the resistance value of the variable resistor 28 to be higher than a predetermined value when the load driving device 100A is started, and the boost converter 12 or the inverter 14 is normally operated when the load driving device 100A is stopped. When the operation becomes impossible, the resistance value of the variable resistor 28 is set low.

  FIG. 8 is a flowchart for explaining the operation of the load driving apparatus 100A shown in FIG. The flowchart shown in FIG. 8 is obtained by inserting step S1A between step S1 and step S2 of the flowchart shown in FIG. 5 and replacing steps S8 and S9 with steps S8A and S9A, respectively. It is the same as the flowchart shown in FIG.

  Referring to FIG. 8, after step S <b> 1, resistance control unit 304 generates signal RS <b> 1 in response to signal IGON and outputs it to variable resistor 28. Then, the resistance value of the variable resistor 28 is set higher than a predetermined value (step S1A). Then, step S2-step S7 and step S10 which were mentioned above are performed.

  When it is determined in step S6 that the inverter 14 cannot operate normally, or when it is determined in step S7 that the signal IGOFF has been received, the switch control means 303 generates an H level signal SE1 to the system relay SMR1. Then, an L level signal SE2 is generated and output to the system relay SMR2.

  Then, system relay SMR1 is turned on in response to H level signal SE1, and system relay SMR2 is turned off in response to L level signal SE2. Then, the electric power stored in the capacitor C2 is returned to the battery B via the system relay SMR1 and the limiting resistor 11, and the voltage Vm across the capacitor C2 decreases.

  Thereafter, when voltage Vm drops to battery voltage Vb, switch control means 303 generates L level signals SE1 and SE3 and outputs them to system relays SMR1 and SMR3, respectively. System relays SMR1 and SMR3 are turned off in response to L level signals SE1 and SE3, respectively. Further, the resistance control means 304 generates a signal RS2 according to the fail signal FLI from the inverter 14 and outputs it to the variable resistor 28.

  Then, the residual charge of the capacitor C2 is discharged through the variable resistor 28 whose resistance value has dropped below a predetermined value (step S8A).

  On the other hand, when it is determined in step S5 that the boost converter 12 cannot operate normally, the determination unit 56 generates a fail signal FLU and outputs it to the switch control means 303. Switch control means 303 generates H-level signal SE1 in response to fail signal FLU from converter control means 302 and outputs it to system relay SMR1, and subsequently generates L-level signal SE2 and system relay SMR2. Output to.

  Then, system relay SMR1 is turned on in response to H level signal SE1, and system relay SMR2 is turned off in response to L level signal SE2. Then, the electric power stored in the capacitor C2 is returned to the battery B via the system relay SMR1 and the limiting resistor 11, and the voltage Vm across the capacitor C2 decreases.

  Thereafter, when the voltage Vm decreases to the battery voltage Vb, the switch control means 303 generates L level signals SE1 and SE3 and outputs them to the system relays SMR1 and SMR3, respectively, and also generates the signal DCH to generate the inverter control means 301. Output to. Further, the resistance control unit 304 generates a signal RS2 according to the fail signal FLU from the converter control unit 302 and outputs the signal RS2 to the variable resistor 28.

  Then, system relays SMR1 and SMR3 are turned off in response to L level signals SE1 and SE3, respectively. Then, the inverter PWM signal conversion unit 42 of the inverter control unit 301 generates a signal PWMI_D according to the signal DCH from the switch control unit 303 and outputs it to the inverter 14. Inverter 14 supplies the residual charge of capacitor C2 to AC motor M1 in response to signal PWMI_D from control device 30A.

  As a result, the residual charge in the capacitor C2 is discharged by the AC motor M1 and the variable resistor 28 whose resistance value has dropped below a predetermined value (step S9A).

  Thus, in the load driving device 100A, the resistance value of the variable resistor 28 is set to be higher than a predetermined value at the time of start-up and normal operation, and the boost converter 12 or the inverter 14 cannot operate normally at the time of stop. At this time, the resistance value of the variable resistor 28 is set to a predetermined value or less.

  Therefore, the residual charge of the capacitor C2 can be discharged in a short time, and the power utilization efficiency during the normal operation of the load driving device 100A can be further increased.

  Note that the control of the load driving device 100A in the control device 30A is actually performed by the CPU, and the CPU reads a program including each step of the flowchart shown in FIG. 8 from the ROM and executes the read program. The operation of the load driving device 100A is controlled according to the flowchart shown in FIG. Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program including each step of the flowchart shown in FIG. 8 is recorded.

  Further, the variable resistor 28 constitutes a “discharge resistor”.

  Others are the same as in the first embodiment.

[Embodiment 3]
FIG. 9 is a schematic block diagram of the load driving device according to the third embodiment. Referring to FIG. 9, load drive device 100B is the same as load drive device 100 except that discharge resistor 18 of load drive device 100 is deleted and control device 30 is replaced with control device 30B. .

  In addition to the function of control device 30 of load driving device 100, control device 30B has a function of controlling boost converter 12 so as to discharge the residual charge of capacitor C2.

  FIG. 10 is a functional block diagram of the control device 30B shown in FIG. Referring to FIG. 10, control device 30B is the same as control device 30 except that converter control means 302 of control device 30 is replaced with converter control means 302A. In control device 30B, switch control means 303 generates signal DCH and outputs it to inverter control means 301 or converter control means 302A when voltage Vm drops to battery voltage Vb.

  In addition to the function of converter control means 302 of control device 30, converter control means 302A has a function of controlling boost converter 12 so as to discharge the residual charge of capacitor C2 in accordance with signal DCH from switch control means 303.

  FIG. 11 is a functional block diagram of converter control means 302A shown in FIG. Referring to FIG. 11, converter control means 302A is the same as converter control means 302 except that duty ratio conversion unit 54 of converter control means 302 is replaced with duty ratio conversion unit 54A.

  In addition to the function of the duty ratio conversion unit 54, the duty ratio conversion unit 54A receives the signal DCH from the switch control unit 303, and changes the residual charge of the capacitor C2 regardless of the feedback voltage command Vdc_com_fb from the feedback voltage command calculation unit 52. A signal PWMU_D (a kind of signal PWMU) for controlling boost converter 12 so as to discharge is generated and output to boost converter 12.

  For example, the signal PWMU_D is a signal that limits the current flowing through the NPN transistor Q1 by lowering the voltage applied to the base of the NPN transistor Q1 than in the normal operation and turns off the NPN transistor Q2.

  FIG. 12 is a flowchart for explaining the operation of the load driving device 100B shown in FIG. The flowchart shown in FIG. 12 is the same as the flowchart shown in FIG. 5 except that steps S8 and S9 in the flowchart shown in FIG. 5 are replaced with steps S8B and S9B, respectively.

  When it is determined in step S6 that the inverter 14 cannot operate normally, or when it is determined in step S7 that the signal IGOFF has been received, the switch control means 303 generates an H level signal SE1 to the system relay SMR1. Then, an L level signal SE2 is generated and output to the system relay SMR2.

  Then, system relay SMR1 is turned on in response to H level signal SE1, and system relay SMR2 is turned off in response to L level signal SE2. Then, the electric power stored in the capacitor C2 is returned to the battery B via the system relay SMR1 and the limiting resistor 11, and the voltage Vm across the capacitor C2 decreases.

  Thereafter, when voltage Vm drops to battery voltage Vb, switch control means 303 generates L level signals SE1 and SE3 and outputs them to system relays SMR1 and SMR3, respectively. System relays SMR1 and SMR3 are turned off in response to L level signals SE1 and SE3, respectively. Further, switch control means 303 generates signal DCH and outputs it to converter control means 302A.

  Duty ratio converter 54A of converter control means 302A generates signal PWMU_D in accordance with signal DCH and outputs the signal to boost converter 12.

  Then, boost converter 12 causes a direct current to flow from capacitor C2 in the direction of reactor L1 via NPN transistor Q1 in accordance with signal PWMU_D from control device 30B, and discharges the residual charge in capacitor C2 (step S8B).

  On the other hand, when it is determined in step S5 that the boost converter 12 cannot operate normally, the determination unit 56 of the converter control unit 302A generates a fail signal FLU and outputs it to the switch control unit 303. Switch control means 303 generates H level signal SE1 in response to fail signal FLU from converter control means 302A and outputs it to system relay SMR1, and subsequently generates L level signal SE2 to generate system relay SMR2. Output to.

  Then, system relay SMR1 is turned on in response to H level signal SE1, and system relay SMR2 is turned off in response to L level signal SE2. Then, the electric power stored in the capacitor C2 is returned to the battery B via the system relay SMR1 and the limiting resistor 11, and the voltage Vm across the capacitor C2 decreases.

  Thereafter, when the voltage Vm decreases to the battery voltage Vb, the switch control means 303 generates L level signals SE1 and SE3 and outputs them to the system relays SMR1 and SMR3, respectively, and also generates the signal DCH to generate the inverter control means 301. Output to.

  Then, system relays SMR1 and SMR3 are turned off in response to L level signals SE1 and SE3, respectively. Then, the inverter PWM signal conversion unit 42 of the inverter control unit 301 generates a signal PWMI_D according to the signal DCH from the switch control unit 303 and outputs it to the inverter 14. Inverter 14 supplies the residual charge of capacitor C2 to AC motor M1 in response to signal PWMI_D from control device 30B.

  Thereby, the residual electric charge of the capacitor C2 is discharged by the AC motor M1 (step S9B).

  As described above, when the load driving device 100B is stopped or when the boost converter 12 or the inverter 14 cannot operate normally, the residual charge of the capacitor C2 is discharged by the boost converter 12 or the AC motor M1 without using the discharge resistor. To do.

  Therefore, the power utilization efficiency during normal operation of the load driving device 100A can be further increased, and the residual charge of the capacitor C2 can be discharged without providing a discharge resistor.

  Note that the control of the load driving device 100B in the control device 30B is actually performed by the CPU, and the CPU reads a program including each step of the flowchart shown in FIG. 12 from the ROM, and executes the read program. The operation of the load driving device 100B is controlled according to the flowchart shown in FIG. Therefore, the ROM corresponds to a computer (CPU) readable recording medium that records a program including the steps of the flowchart shown in FIG.

  Others are the same as in the first embodiment.

  The embodiment disclosed this time should 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 scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a load driving device that can effectively use electric power and can discharge a residual charge of a capacitor provided on the input side of the driving device that drives a load. According to another aspect of the present invention, there is provided a program for causing a computer to execute an operation of a load driving device that can effectively use electric power and discharge a residual charge of a capacitor provided on an input side of a driving device that drives a load. It is applied to a recorded computer-readable recording medium.

1 is a schematic block diagram of a load driving device according to Embodiment 1 of the present invention. It is a functional block diagram of the control apparatus shown in FIG. It is a functional block diagram of the inverter control means shown in FIG. It is a functional block diagram of the converter control means shown in FIG. It is a flowchart for demonstrating operation | movement of the load drive device shown in FIG. FIG. 6 is a schematic block diagram of a load driving device according to a second embodiment. It is a functional block diagram of the control apparatus shown in FIG. It is a flowchart for demonstrating operation | movement of the load drive device shown in FIG. FIG. 6 is a schematic block diagram of a load driving device according to a third embodiment. It is a functional block diagram of the control apparatus shown in FIG. It is a functional block diagram of the converter control means shown in FIG. 10 is a flowchart for explaining the operation of the load driving device shown in FIG. 9.

Explanation of symbols

  10, 13 Voltage sensor, 11 Limit resistor, 12 Boost converter, 14 Inverter, 15 U phase arm, 16 V phase arm, 17 W phase arm, 18 Discharge resistance, 24 Current sensor, 28 Variable resistor, 30, 30A, 30B Control device, 40 motor control phase voltage calculation unit, 42 inverter PWM signal conversion unit, 50 inverter input voltage command calculation unit, 52 feedback voltage command calculation unit, 54, 54A duty ratio conversion unit, 56 determination unit, 100, 100A , 100B load drive device, 301 inverter control means, 302, 302A converter control means, 303 switch control means, 304 resistance control means, C1, C2 capacitor, L1 reactor, B battery, M1 AC motor, N1-N3 nodes, SMR1- SMR3 Temurire, Q1~Q8 NPN transistor, D1~D8 diode.

Claims (19)

Power supply,
A capacitor provided on the input side of the driving device for driving the load;
A voltage converter that performs voltage conversion between the power source and the capacitor;
An electrical path connecting the high voltage side of the voltage converter to the positive side of the power source;
A switch for opening and closing the electrical path;
A load driving device comprising a limiting resistor provided in the electrical path in series with the switch.   The controller further includes a control unit that controls the switch to close the electrical path when the load driving device is activated and to open the electrical path when the voltage across the capacitor is precharged to a predetermined voltage. 2. The load driving device according to 1. A main switch provided between the power source and the voltage converter;
3. The load driving device according to claim 2, wherein when the precharge is completed, the control unit further turns on the main switch to control the voltage converter so as to boost a DC voltage from the power source.   The load driving device according to claim 2, wherein the predetermined voltage is a power supply voltage of the power supply. A discharge resistor connected in parallel to the capacitor and having a resistance value higher than a predetermined value;
The control means for controlling the switch to close the electrical path when the load is stopped and to open the electrical path when the voltage across the capacitor drops to a predetermined voltage. Load drive device.   The voltage converter closes the electrical path when the load is stopped, opens the electrical path when the voltage across the capacitor drops to a predetermined voltage, and discharges the electric power stored in the capacitor. The load driving device according to claim 1, further comprising a control means for controlling   The load driving apparatus according to claim 5, wherein the predetermined voltage is a power supply voltage of the power supply. A discharge resistor composed of a variable resistor connected in parallel to the capacitor;
Control means for setting a resistance value of the variable resistor to be higher than a predetermined value during operation of the load, and setting a resistance value of the variable resistor to be equal to or less than the predetermined value when the load is stopped; The load driving device according to claim 1.   The load driving device according to claim 1, further comprising control means for controlling the switch so as to close the electrical path when the voltage converter is faulty. A discharge resistor connected in parallel to the capacitor and having a resistance value higher than a predetermined value;
The control means further controls the switch so that the electrical path is opened when the voltage across the capacitor is lowered to a predetermined voltage, and the drive is performed so that the electric power stored in the capacitor is discharged by the load. The load driving device according to claim 9, wherein the load driving device controls the device. A computer-readable recording medium recording a program for causing a computer to execute an operation of a load driving device,
The load driving device includes:
Power supply,
A capacitor provided on the input side of the driving device for driving the load;
A voltage converter that performs voltage conversion between the power source and the capacitor;
An electrical path connecting the high voltage side of the voltage converter to the positive side of the power source;
A switch for opening and closing the electrical path;
A limiting resistor provided in the electrical path in series with the switch,
The program is
A first step of precharging the capacitor via the limiting resistor;
A second step of controlling the voltage converter and the driving device to drive the load when the precharge is completed;
When the load driving device is stopped, or when the voltage converter or the driving device is abnormal, the power stored in the capacitor is returned to the power source through the limiting resistor, and the voltage of the capacitor is reduced to a predetermined value. A computer-readable recording medium recording a program for causing a computer to execute a third step of discharging a residual charge of the capacitor. The third step includes
A first sub-step of returning the electric power stored in the capacitor to the power source via the limiting resistor when the load driving device is stopped or when the voltage converter or the driving device is abnormal;
The computer-readable recording medium which recorded the program for making the computer perform of Claim 11 including the 2nd substep which discharges the residual charge of the said capacitor when the voltage of the said capacitor falls to a predetermined value. The load driving device further includes a discharge resistor connected in parallel to the capacitor,
The computer-readable recording medium recording the program for causing the computer to execute according to claim 12, wherein in the second sub-step of the program, the residual charge of the capacitor is discharged using the discharge resistance. .   The computer-readable program recording a program to be executed by a computer according to claim 13, wherein the residual charge of the capacitor is discharged only by the discharge resistor when the load driving device is stopped or when the driving device is abnormal. Possible recording media.   14. The computer-readable recording medium storing a program for causing a computer to execute according to claim 13, wherein the residual charge of the capacitor is discharged by the discharge resistor and the load when the voltage converter is abnormal. The discharge resistor comprises a variable resistor,
The computer according to any one of claims 13 to 15, wherein in the second sub-step of the program, the resistance value of the variable resistor is set to a value lower than a predetermined value. A computer-readable recording medium on which the program is recorded.   The computer-readable recording medium storing a program for causing a computer to execute according to claim 12, wherein in the second sub-step, the residual electric charge of the capacitor is discharged using the voltage converter.   The computer recorded with the program for causing the computer to execute according to claim 17, wherein the residual charge of the capacitor is discharged only by the voltage converter when the load driving device is stopped or when the driving device is abnormal. A readable recording medium.   The computer-readable recording medium storing a program for causing a computer to execute according to claim 17, wherein the residual charge of the capacitor is discharged by the load when the voltage converter is abnormal.

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