JP2010178595A - Device for controlling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To safely and reliably discharge the accumulated charges of a smoothing capacitor on the occurrence of a collision of the vehicle, in a vehicle having the smoothing capacitor. <P>SOLUTION: At a discharge of the smoothing capacitor on the occurrence of a collision of the vehicle (when determining YES of S100), a first discharge treatment by a non-driving high-voltage equipment is preferentially executed (S120). When the smoothing capacitor cannot be fully discharged by the first discharge treatment (when determining NO of S140), a second discharge treatment by a driving high-voltage equipment is executed (S150). When the second discharge treatment is executed, the occurrence of vehicle movement is checked in parallel (S160). On the occurrence of the vehicle movement (when determining YES of S160), the discharge is stopped forcibly for safety (step S170). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle control device, and more specifically to control for safely and reliably discharging stored power in a smoothing capacitor in the event of a vehicle collision.

  Vehicles that can travel with a vehicle driving force by an electric motor, such as electric vehicles and hybrid vehicles, are widely used. A power supply system that applies an AC voltage to a DC voltage from a DC power source such as a battery by an inverter is applied to drive the vehicle driving motor. Such a power supply system generally has a configuration in which a smoothing capacitor is used on the input side (DC voltage side) of the inverter.

  In a vehicle equipped with the above power supply system, a configuration for reliably discharging the electric charge (accumulated electric power) stored in the smoothing capacitor is required in the event of a vehicle collision. For example, in Japanese Patent Application Laid-Open No. 2007-181308 (Patent Document 1), when a vehicle driven by an electric motor collides, an electric charge stored in a capacitor is converted to at least one of a horn and a headlight via an accessory converter. It is described that the battery is discharged.

  Japanese Patent Laying-Open No. 2004-222361 (Patent Document 2) basically describes a circuit configuration for consuming electric charge stored in a capacitor connected in parallel to an electric motor driving circuit for driving an electric motor. It is described that charges are consumed by a charge consuming circuit including an electric motor as a traveling motor, while charges are consumed by a DC / DC converter or an electric air conditioner when an abnormality is detected in the charge consuming circuit.

  Further, in Japanese Patent Laid-Open No. 2006-141158 (Patent Document 3), when it is detected that the vehicle has collided, the automatic transmission is set in the parking lock state and then accumulated in the smoothing capacitor by the motor zero torque process. It is described that it consumes charge. Japanese Patent Laying-Open No. 2006-224772 (Patent Document 4) newly provides a discharge relay that is energized when a vehicle crashes, and discharges the electric power charged in the smoothing capacitor to the energized state of the discharge relay. A configuration for disposing a discharge circuit is described.

JP 2007-181308 A JP 2004-222361 A JP 2006-141158 A JP 2006-224772 A

  Patent Documents 1-4 above all relate to charge discharge of a smoothing capacitor used in a power supply circuit for driving an electric motor. Among them, Patent Documents 1, 3 and 4 describe the accumulated charge of a smoothing capacitor at the time of a vehicle collision. It relates to discharge.

  However, in the configuration described in Patent Document 4, since a discharge relay and a discharge resistor are newly provided, there is a concern about an increase in circuit configuration and cost. Further, in Patent Document 1, only at least one of the horn and the headlight can be discharged, so there remains a concern as to whether or not the smoothing capacitor can be discharged quickly. Also in Patent Document 3, there remains a possibility that the smoothing capacitor cannot be discharged quickly only by the electric power consumption of the electric motor by the motor zero torque process in the parking lock state.

  The present invention has been made to solve such problems, and an object of the present invention is to safely and reliably discharge the accumulated charge of the smoothing capacitor at the time of a vehicle collision in a vehicle equipped with the smoothing capacitor. Is to execute.

  In the vehicle control apparatus according to the present invention, the vehicle includes a smoothing capacitor connected to the power line and a plurality of electric devices that are operated by the power on the power line. The plurality of electric devices include a first electric device whose operation does not affect the driving force of the vehicle, and a second electric device that can generate the driving force of the vehicle by the operation. The control device activates the first electric device when a vehicle collision is detected by the collision detection means for detecting the collision of the vehicle, the voltage detection means for detecting the voltage of the power line, and the collision detection means. A first discharge processing means for consuming the stored power of the smoothing capacitor, a judging means for judging whether or not the discharge of the smoothing capacitor is completed based on the voltage detected by the voltage detecting means, In order to consume the accumulated power of the smoothing capacitor by operating the second electric device under the control of not generating the driving force when the discharge of the smoothing capacitor is not completed depending on the discharge processing means of 1. Second discharge processing means.

  According to the present invention, in a vehicle equipped with a smoothing capacitor, it is possible to safely and reliably execute discharging of the accumulated charge of the smoothing capacitor at the time of a vehicle collision.

It is a block diagram showing a power supply system configuration of a hybrid vehicle shown as an application example of a vehicle control device according to the present invention. FIG. 2 is a flowchart illustrating capacitor discharge processing when a vehicle collision occurs by the vehicle control apparatus according to the embodiment of the present invention.

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

  FIG. 1 is a block diagram showing a configuration of a hybrid vehicle shown as an application example of a vehicle control apparatus according to the present invention.

  Referring to FIG. 1, a hybrid vehicle to which a vehicle control apparatus according to the present invention is applied includes a battery 10, a hybrid ECU 15, a power control unit 20, motor generators MG1 and MG2, an engine ENG, and a power split mechanism. With PSD. Motor generator MG1, motor generator MG2 and engine ENG are connected to each other through power split mechanism PSD.

  The hybrid ECU 15 includes a CPU (Central Processing Unit) (not shown) and an electronic control unit (ECU) with a built-in memory. Based on a map and a program stored in the memory, a calculation process using detection values obtained by the sensors. Configured to perform. Alternatively, at least a part of the ECU may be configured to execute predetermined numerical / logical operation processing by hardware such as an electronic circuit.

  The battery 10 is shown as a typical example of a power storage device, and includes a secondary battery such as nickel metal hydride or lithium ion. Alternatively, a power storage device other than the secondary battery such as an electric double layer capacitor may be used in place of the battery 10.

  The hybrid ECU 15 comprehensively performs various controls related to the hybrid vehicle based on outputs 17 from various sensors (not shown) that indicate driving conditions and vehicle conditions. Particularly in the present embodiment, the sensor output 17 includes an output from an acceleration sensor and / or a vehicle speed sensor (not shown), and the hybrid ECU 15 performs a hybrid vehicle based on the output of the acceleration sensor and / or the vehicle speed sensor. It is possible to detect the occurrence of collision.

  Although motor generators MG1 and MG2 can function as both a generator and an electric motor, motor generator MG1 mainly operates as a generator, and motor generator MG2 mainly operates as an electric motor.

  Specifically, motor generator MG1 is used as a starter that starts engine ENG when an engine start request is made, such as during acceleration. At this time, the motor generator MG1 receives power supplied from the battery 10 via the power control unit 20 and is driven as an electric motor, and cranks and starts the engine. Further, after engine ENG is started, motor generator MG1 is rotated by the driving force of the engine transmitted through power split mechanism PSD and can generate electric power.

  Motor generator MG2 is driven by at least one of the electric power stored in battery 10 and the electric power generated by motor generator MG1. The driving force of motor generator MG2 is transmitted to a driving shaft (not shown). Thereby, motor generator MG2 assists the engine to run the hybrid vehicle, or runs the hybrid vehicle only by its own driving force.

  At the time of regenerative braking of the hybrid vehicle, motor generator MG2 operates as a generator by being driven by the rotational force of the wheels. At this time, the regenerative power generated by the motor generator MG2 is charged to the battery 10 via the power control unit 20.

  Power control unit 20 boosts the DC voltage from battery 10 in accordance with a control instruction from hybrid ECU 15 and converts the boosted DC voltage to an AC voltage in accordance with a control instruction from hybrid ECU 15 during motoring operation of motor generators MG1, MG2. It operates to drive and control MG1 and MG2.

  In addition, when regenerative braking of motor generators MG1 and MG2, power control unit 20 charges battery 10 by converting the AC voltage generated by motor generators MG1 and MG2 into a DC voltage in accordance with a control instruction from hybrid ECU 15. Operate.

Next, the configuration of the power control unit will be described in detail.
Power control unit 20 includes system main relays SMR1 and SMR2, converter 110, smoothing capacitors C1 and C2, inverters 131 and 132 corresponding to motor generators MG1 and MG2, respectively, and MGECU (Electronic Control Device) 140. . The MGECU 140 is configured by an electronic control unit (ECU), similar to the hybrid ECU 15.

  System main relays SMR1 and SMR2 conduct / shut off the power supply path from battery 10 to converter 110. Specifically, system main relay SMR 1 is connected between the positive electrode of battery 10 and power supply line 101. System main relay SMR <b> 2 is connected between the negative electrode of battery 10 and ground line 102. System main relays SMR1 and SMR2 are turned on / off (on / off) by signal SE from MGECU 140, respectively.

  Smoothing capacitor C <b> 1 is connected between power supply line 101 and ground line 102, and smoothes voltage fluctuations between power supply line 101 and ground line 102. Voltage sensor 120 detects voltage VL across smoothing capacitor C1 and outputs the detected voltage VL to MGECU 140.

  For example, converter 110 includes a step-up / step-down chopper circuit, and includes a reactor L1, power semiconductor switching elements (hereinafter also simply referred to as switching elements) Q1 and Q2, and diodes D1 and D2. As the switching element in this embodiment, for example, an IGBT (Insulated Gate Bipolar Transistor) is applied.

  Converter 110 performs bidirectional DC voltage conversion between power supply line 101 and power supply line 103 corresponding to the “power line”. Converter 110 is basically controlled such that switching elements Q1 and Q2 are complementarily and alternately turned on and off within each switching period. By controlling the ON period ratio (duty) with respect to the switching period of the switching elements Q1 and Q2 by the switching control signal PWMC that controls the on / off of the switching elements Q1 and Q2, a voltage conversion ratio (VH / VL) is controlled.

  A smoothing capacitor C <b> 2 is connected between the power supply line 103 and the earth line 102. Smoothing capacitor C2 smoothes the DC voltage from converter 110 and supplies the smoothed DC voltage to inverters 131 and 132. Voltage sensor 122 detects voltage VH across smoothing capacitor C2 and outputs the detected voltage VH to MGECU 140.

  Inverter 131 returns electric power generated by motor generator MG1 to converter 110 by the rotational torque transmitted from the crankshaft of engine ENG.

  Inverter 131 includes switching elements Q3 and Q4 constituting a U-phase arm, switching elements Q5 and Q6 constituting a V-phase arm, and switching elements Q7 and Q8 constituting a W-phase arm. Further, anti-parallel diodes D3 to D8 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the switching elements Q3 to Q8, respectively. Switching elements Q3 to Q8 are subjected to on / off control, that is, switching control, based on switching control signal PWMI1 from MGECU 140.

  Motor generator MG1 is a three-phase permanent magnet motor configured by commonly connecting a U-phase coil, a V-phase coil, and a W-phase coil to a neutral point. An intermediate point of switching elements Q3 and Q4 where a U-phase voltage is generated by switching control is electrically connected to a U-phase coil. Similarly, the intermediate point of switching elements Q5 and Q6 where the V-phase voltage is generated is electrically connected to the V-phase coil. Furthermore, the intermediate point of switching elements Q7 and Q8 where the W-phase voltage is generated is electrically connected to the W-phase coil.

  Motor generators MG1 and MG2 are attached with rotation angle sensors 161 and 162 for detecting the rotational position of the rotor, respectively. The rotation angle sensors 161 and 162 are typically constituted by resolvers.

  Inverter 132 is connected to converter 110 in parallel with inverter 131. Inverter 132 converts the DC voltage output from converter 110 into a three-phase AC voltage and outputs the same to motor generator MG2. Inverter 132 returns the electric power generated in motor generator MG2 to converter 110 as a result of regenerative braking.

  Although the internal configuration of inverter 132 is not shown, it is similar to inverter 131, and detailed description will not be repeated. Switching elements constituting each phase arm of inverter 132 are subjected to switching control based on switching control signal PWMI2 from MGECU 140.

  Similar to motor generator MG1, motor generator MG2 is a three-phase permanent magnet motor configured by commonly connecting a U-phase coil, a V-phase coil, and a W-phase coil to a neutral point. An intermediate point of each phase arm of inverter 132 is electrically connected to a U-phase coil, a V-phase coil, and a W-phase coil of motor generator MG2.

  Based on the pedal operation and various sensor outputs 17, hybrid ECU 15 generates operation commands for motor generators MG1 and MG2 and outputs them to MGECU 140 so that desired driving force generation and power generation are performed. This operation command includes an operation permission / prohibition instruction, a torque command value, a rotation speed command, and the like of each motor generator MG1, MG2.

  The MGECU 140 is controlled by the hybrid ECU 15 by feedback control based on a current sensor (not shown) disposed in the motor generator MG1 and the motor drive current of each phase from the rotation angle sensors 161 and 162 and the detected value of the rotation angle of the rotor. The switching control signal PWMI1 for controlling the switching operation of the switching elements Q3 to Q8 is generated so that the motor generator MG1 operates according to the operation command.

  Further, MGECU 140 receives feedback from hybrid ECU 15 by feedback control based on the detected values of the motor drive current of each phase and the rotation angle of the rotor from a current sensor and a position sensor (both not shown) arranged in motor generator MG2. A switching control signal PWMI2 for controlling the switching operation of switching elements Q3 to Q8 is generated so that motor generator MG2 operates in accordance with the operation command.

  Further, MGECU 140, based on the operation command from hybrid ECU 15, motor operation voltage for increasing the efficiency of motor generators MG1 and MG2, that is, voltage command of DC voltage VH corresponding to the DC side voltage of inverters 131 and 132, Calculate the value. During normal operation, the duty of converter 110 is feedforward and / or feedback controlled so that DC voltage VH matches the voltage command value.

  MGECU 140 generates switching control signal PWMC so as to step down DC voltage (motor operating voltage VH) supplied from inverters 131 and 132 during regenerative braking of the hybrid vehicle. That is, at the time of regenerative braking, converter 110 turns on and off switching elements Q1 and Q2 in response to switching control signal PWMC, thereby stepping down motor operating voltage VH and causing DC voltage VL to fall between power supply line 101 and ground line 102. Output. Battery 10 is charged by DC voltage VL from converter 110.

  Power control unit 20 further includes a DC / DC converter 130 and an auxiliary battery SB. The DC / DC converter 130 is connected between the power supply line 101 and the earth line 102 and steps down DC power from the converter 110 to a predetermined DC voltage and supplies it to the auxiliary battery SB and low-voltage auxiliary machines (not shown). To do. The low-voltage auxiliary machines are a general term for auxiliary machines that operate at a lower pressure than the output voltage of the battery 10, and as an example, ECU related to controlling the traveling of the vehicle such as the hybrid ECU 15, a lighting device, and an ignition device. Including electric pumps.

  Auxiliary battery SB is composed of, for example, a lead storage battery, and is connected to the output side of DC / DC converter 130 and charged with DC power from DC / DC converter 130, while the electric power stored in low-voltage auxiliary machines is stored. Supply.

  A high-voltage device 200 is further connected to the power supply line 103 and the earth line 102. The high-voltage device 200 includes, for example, an electric air-conditioning device (electric A / C), an electric power steering mechanism, an active stabilizer, and the like. The high voltage device 200 is a general term for electric devices driven by the DC voltage VH on the power supply line 103. If necessary, these high-voltage devices may be driven by a converter that converts the DC voltage VH into an AC voltage or converts the DC voltage VH. In other words, in the configuration shown in FIG. 1, high-voltage device 200 and motor generators MG <b> 1 and MG <b> 2 correspond to “a plurality of electrical devices” that are operated by electric power on power supply line 103.

  FIG. 2 is a flowchart illustrating capacitor discharge processing when a vehicle collision occurs by the vehicle control apparatus according to the embodiment of the present invention. Each step shown in FIG. 2 is basically realized by software or hardware processing by the MGECU 140.

  Referring to FIG. 2, MGCU 140 determines whether or not a collision has occurred in the vehicle based on a signal from hybrid ECU 15 in step S100. As described above, the hybrid ECU 15 can detect a vehicle collision based on the output of the acceleration sensor and / or the vehicle speed sensor. That is, the processing in step S100 corresponds to “collision detection means”.

  When a vehicle collision does not occur (NO in S100), the MGECU 140 does not execute the following steps S110 to S170 because the discharge process of the smoothing capacitor C2 is unnecessary.

  On the other hand, when a vehicle collision occurs (YES in S100), MGECU 140 issues an opening command to system main relays SMR1 and SMR2 in step S110. Thereby, the power supply from the battery 10 to the power control unit 20 is cut off.

  Further, the MGECU 140 executes the first discharge process by the non-drive high-voltage device in step S120. Specifically, by operating a high-voltage device (a device using DC voltage VH as a power source) whose operation does not affect the vehicle driving force among the “plural electrical devices” that are operated by electric power on the power supply line 103, The accumulated charge in the smoothing capacitor C2 is consumed. For example, an operation command is issued to the high voltage device 200 shown in FIG. In other words, the processing in step S120 corresponds to “first discharge processing means”.

  The operation command at this time may be different from the normal operation command. In other words, it is possible to set an operation command in the first discharge process so that power consumption becomes larger than usual within a range where no abnormality occurs in each device.

  In the configuration of FIG. 1, the motor generator MG1 does not generate a vehicle driving force directly, so the motor generator MG1 is operated in a state where the output torque is controlled to 0 for safety in the first discharge process. It is also possible to make it.

  In step S130, the MGECU 140 determines whether or not the first discharge process in step S120 has been executed for a predetermined time. And until predetermined time passes (at the time of NO determination of S130), MGECU140 continues the primary discharge process by step S120.

  On the other hand, when the primary discharge is executed for a predetermined time (when YES is determined in S130), the MGECU 140 proceeds to step S140 and determines whether or not the discharge of the smoothing capacitor C2 is completed. The determination is made based on the DC voltage VH detected by the voltage sensor 122. That is, the voltage sensor 122 corresponds to “voltage detection means”, and the processing in step S140 corresponds to “determination means”.

  When it is determined that the DC voltage VH has sufficiently decreased and the discharge of the smoothing capacitor C2 has ended (when YES is determined in S140), the MGECU 140 performs the discharge process without performing the subsequent processes. Exit.

  On the other hand, when it is determined that the DC voltage VH has not decreased and the discharge of the smoothing capacitor C2 has not been completed (NO in S140), the MGECU 140 performs the secondary operation using the driving high-voltage device. A discharge process is executed. Specifically, by operating motor generator MG2, which is a driving high-voltage device capable of generating vehicle driving force during operation, out of “a plurality of electric devices” that are operated by electric power on power supply line 103, smoothing is achieved. The accumulated charge in the capacitor C2 is consumed. That is, the process in step S150 corresponds to “second discharge processing means”.

  In the second discharge process, similarly to the zero torque process in Patent Document 2, the motor generator MG2 is operated in a state where the inverter is controlled so that the output torque = 0. For example, the zero torque process can be realized by controlling inverter 132 such that only the d-axis current flows to motor generator MG2.

  Then, during the second discharge process, MGECU 140 determines whether vehicle movement has occurred before the control cycle in step S160. The determination in step S160 can be executed based on, for example, a rotation speed sensor provided on the wheel.

  At the time of a vehicle collision, there is a possibility that the zero torque process cannot be properly executed due to the influence of the position of the rotation angle sensor 162 being shifted due to the impact at the time of the collision. When a component failure occurs, it can be recognized that the discharge (zero torque processing) by the motor generator MG2 cannot be executed, but in the situation where the sensor output is incorrect although it does not cause damage, the zero torque processing is executed. As a result, torque may be generated and vehicle driving force may be generated.

  For this reason, during the secondary discharge process using the driving high-voltage device, the control structure is configured to confirm that no vehicle movement has occurred in step S160.

  The MGECU 140 continues the secondary discharge process in step S150 until it is determined in step S140 that the discharge of the smoothing capacitor C2 has been completed when no vehicle movement has occurred (NO in S160). Run it.

  On the other hand, when the vehicle movement is generated by the secondary discharge process in step S150 (when YES is determined in S160), MGECU 140 proceeds to the process in step S170, forcibly stops the discharge, and ends the process. .

  As described above, according to the vehicle control apparatus of the present embodiment, the first discharge process by the non-drive high-voltage device is preferentially executed for discharging the smoothing capacitor C2 at the time of the vehicle collision, and the first When the smoothing capacitor C2 cannot be sufficiently discharged in the primary discharge process, the control configuration is such that the second discharge process is performed by the driving high-voltage device while confirming the occurrence of vehicle movement. As a result, in consideration of the possibility that the discharge process by the high-voltage drive device (motor generator MG2) may not be executed normally due to a sensor error that occurs during a vehicle collision, the accumulated charge of the smoothing capacitor C2 during the vehicle collision Discharging can be performed safely and reliably.

  In particular, whether motor generators MG1 and MG2 are classified as non-drive high-voltage equipment or drive high-voltage equipment is not necessarily fixedly determined, and the vehicle situation at the time of the vehicle collision is further determined. It can be appropriately determined by reflecting.

  For example, since motor generator MG1 in FIG. 1 does not directly generate vehicle driving force when normal, it is basically classified as “non-driving high-voltage equipment”. However, if the engine shaft is locked for some reason, the output of motor generator MG1 may act as a vehicle driving force. Therefore, when such a failure state is detected based on a diagnosis code or the like, motor generator MG1 should be classified as a “high voltage device for driving”.

  The motor generator MG2 for driving the vehicle is also classified as “non-drive high-voltage equipment” by disengaging the clutch when the clutch is provided in the path from the motor rotation shaft to the vehicle section coaxial. Can be done. That is, in such a vehicle configuration, the vehicle driving motor (motor generator MG2) can be classified into either “driving high-voltage device” or “non-driving high-voltage device” according to the state of the clutch.

  Further, the application of the present invention is not limited to the configuration illustrated in FIG. 1, and the present invention can be applied to smoothing in a power supply system mounted on a hybrid vehicle, an electric vehicle, a fuel vehicle, or the like having another hybrid configuration. The point which can be applied to the discharge treatment of the capacitor will be described in a confirming manner.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10 battery, 15 hybrid ECU, 17 sensor output, 20 power control unit, 101, 103 power supply line, 102 ground line, 110 converter, 120, 122 voltage sensor, 130 converter, 131, 132 inverter, 140 MGECU, 161, 162 rotation Angle sensor, 200 high voltage equipment, C1 smoothing capacitor, C2 smoothing capacitor (discharge target), D1 to D8 antiparallel diode, ENG engine, L1 reactor, MG1 motor generator, MG2 motor generator (high voltage equipment for driving), PSD power split mechanism , PWMC, PWMI1, PWMI2 switching control signal, Q1-Q8 power semiconductor switching element, SB auxiliary battery, SMR1, SMR2 system main relay , VH DC voltage, VL DC voltage.

Claims (1)

A vehicle control device comprising a smoothing capacitor connected to a power line, and a plurality of electric devices operated by power on the power line,
The plurality of electric devices include a first electric device whose operation does not affect the driving force of the vehicle, and a second electric device that can generate the driving force of the vehicle by the operation,
The control device includes:
A collision detection means for detecting a collision of the vehicle;
Voltage detection means for detecting the voltage of the power line;
A first discharge processing means for consuming the stored power of the smoothing capacitor by operating the first electrical device when a vehicle collision is detected by the collision detection means;
Determining means for determining whether or not the discharge of the smoothing capacitor is completed based on the voltage detected by the voltage detecting means;
When the discharge of the smoothing capacitor is not completed depending on the first discharge processing means, the second electric device is operated under a state controlled so as not to generate the driving force. A vehicle control device comprising: second discharge processing means for consuming stored power.

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