JP2006141158A - Control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently ensure safety in collision in a vehicle mounted with a smoothing capacitor. <P>SOLUTION: A vehicle is mounted with a battery; an inverter that converts direct-current power, supplied from the battery into alternating-current power; and a motor-generator that is rotated with alternating-current power from the inverter. The inverter is provided with a high-voltage smoothing capacitor. HV_ECU executes a program comprising a step (S100) at which it is detected based on a signal from a G sensor whether or not the vehicle has collided; a step (S110) at which, when it detected that the vehicle has collided (YES at S100), a command signal is outputted to ECT_ECU so as to bring an automatic transmission into parking lock state; and a step (S120) at which a command signal is outputted to MG_ECU so as to discharge the smoothing capacitor by motor zero torque processing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a vehicle driven by an electric motor, and more particularly to a control device for sufficiently ensuring safety when a vehicle having a high-voltage power storage mechanism collides.

  A vehicle equipped with a power train called a hybrid system combining an engine (for example, a known engine such as a gasoline engine or a diesel engine) and an electric motor has been developed and put into practical use. In such a vehicle, regardless of the amount of accelerator operation by the driver, the operation by the engine and the operation by the electric motor are automatically switched and controlled so as to obtain the highest efficiency. For example, when the engine is operated in a steady state to operate a generator that charges a secondary battery (battery), or the engine is operated intermittently during traveling according to the amount of charge of the secondary battery, etc. In such a case, the engine is repeatedly operated and stopped regardless of the amount of accelerator operation by the driver. That is, by operating the engine and the electric motor individually or in cooperation, it becomes possible to improve fuel consumption and significantly reduce exhaust gas.

  In such hybrid vehicles, electric vehicles, and fuel cell vehicles, the DC power of the battery is converted into AC power by an inverter, and power is supplied to a three-phase AC motor (motor generator). Further, at the time of power generation, contrary to such a flow of electric power, AC power generated by a three-phase AC motor (motor generator) is converted into DC power by an inverter to charge the battery. Further, in such a power conversion process, the voltage may be boosted or lowered, and a DC / DC converter may be provided for such step-up / step-down (transformation).

  In such an electric circuit (power line), a smoothing capacitor for reducing noise is provided. The smoothing capacitor is precharged with high voltage power and generates an action of reducing inrush current to the inverter. If an accident such as a collision occurs in a vehicle (hybrid vehicle, electric vehicle, fuel cell vehicle) equipped with such an electric circuit (that is, an electric circuit having a high-voltage storage mechanism), the adverse effects of this high voltage are eliminated. There is a need to.

  Japanese Patent Application Laid-Open No. 2004-129367 (Patent Document 1) discloses that even if power supply is stopped at the time of a collision or the like, power remains in the high-voltage power storage device. Disclosed is a vehicle control device that prevents the occurrence of adverse effects due to high voltage. This vehicle control device is a vehicle control device provided with a high-voltage power storage device, and a collision detection means for detecting a vehicle collision, and power supply to the power storage device is stopped when a vehicle collision is detected. And discharging means for forcibly discharging the electric power stored in the power storage device.

According to this vehicle control device, for example, in a vehicle having a high-voltage power storage device for corona discharge in an exhaust gas purification system, a motor drive of a hybrid vehicle, etc. Then, the electric power stored in the power storage device is forcibly discharged. As a result, even if it is assumed that a secondary accident due to disconnection of the high-voltage system wiring or the like will occur in the event of a vehicle collision, the high-voltage power storage device will be forcibly discharged, resulting in adverse effects due to the high voltage. Occurrence can be prevented.
JP 2004-129367 A

  When the high voltage storage mechanism is a smoothing capacitor provided in an inverter circuit, as a means for quickly discharging, for example, driving the motor in a zero torque state (driving so that no torque is generated on the axle), It is possible to discharge.

  However, when discharged in this way, if there is an abnormality in the motor drive circuit itself due to the impact at the time of collision (for example, if the rotation angle sensor of the motor is shifted), even if you intend to perform zero torque control, Actually, torque may be generated on the axle and the vehicle may move. On the other hand, when discharging from the high-voltage power storage mechanism with a discharge element instead of zero torque control, it takes time until the voltage of the smoothing capacitor becomes a sufficiently safe low voltage. The possibility of

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle control device that can sufficiently ensure safety at the time of collision in a vehicle equipped with a high-voltage power storage mechanism. That is.

  A vehicle control device according to a first aspect of the invention controls a vehicle that is driven by operating an electric device using electric power of a power storage device. The control device includes a detection unit for detecting a vehicle collision, a conversion unit for orthogonally converting the electric power of the power storage device, a blocking unit for blocking power transmission from the electric device to the drive wheels, and a conversion And control means for controlling the shut-off means. In this conversion means, electric power is stored in a high-voltage power storage mechanism provided inside the conversion means during the conversion operation. The control means includes a means for controlling the shut-off means so that the power transmission is shut off by the shut-off means when a collision of the vehicle is detected by the detection means, and an electric power using the conversion means after the power transmission is shut off. Means for controlling the conversion means to discharge the power of the high voltage power storage mechanism by supplying power to the device.

  In the vehicle control device according to the second invention, in addition to the configuration of the first invention, the power storage device is a secondary battery, the electrical device is a motor generator, the conversion means is an inverter, The high voltage storage mechanism is a smoothing capacitor provided in the inverter.

  According to the first or second invention, for example, when a vehicle is driven by a motor, from a secondary battery that is a power source in which DC power is stored, via an inverter that converts power from DC to AC, AC power is supplied to the three-phase AC motor. This inverter may be provided with a smoothing capacitor (high voltage power storage mechanism) for noise countermeasures. When the vehicle collides, it is necessary to quickly discharge the electric power stored in the smoothing capacitor from the viewpoint of preventing electric leakage and the like. In order to quickly discharge electric power from the smoothing capacitor, it is preferable to execute zero torque control that does not generate torque in the motor using an inverter. However, if a failure occurs such that the rotation angle sensor of the motor drive circuit does not react due to a collision, torque may be generated even if a zero torque control command signal is given to the inverter. The control means can discharge power from the smoothing capacitor as soon as possible by interrupting power transmission by the interruption means and then supplying electric power to the motor generator using an inverter by zero torque control or the like. As a result, it is possible to provide a vehicle control device that can sufficiently ensure safety at the time of collision in a vehicle equipped with a high-voltage power storage mechanism.

  According to a third aspect of the present invention, there is provided a vehicle control apparatus that controls a vehicle that is driven by increasing / decreasing the electric power of the power storage device and operating an electric device. The control device includes a detection unit for detecting a vehicle collision, a step-up / step-down unit for stepping up / down the electric power of the power storage device, a conversion unit for orthogonally converting the electric power of the power storage device, and a drive wheel from the electric device. And a control means for controlling the conversion means and the cutoff means. In the step-up / step-down means, electric power is stored in a high-voltage power storage mechanism provided inside the step-up / step-down means during the step-up / step-down operation. In the conversion means, electric power is stored in a high-voltage power storage mechanism provided inside the conversion means during the conversion operation. The control means includes a means for controlling the shut-off means so that the power transmission is shut off by the shut-off means when a collision of the vehicle is detected by the detecting means, and an electric device using the conversion means after the power transmission is shut off. A control apparatus for a vehicle, including means for controlling the conversion means so as to discharge the electric power of the high-voltage power storage mechanism by supplying electric power to the vehicle.

  In the vehicle control device according to the fourth invention, in addition to the configuration of the third invention, the power storage device is a secondary battery, the electrical device is a motor generator, the conversion means is an inverter, The high voltage storage mechanism is a smoothing capacitor provided in the inverter, the step-up / step-down means is a converter, and the high voltage storage mechanism is a smoothing capacitor provided in the inverter.

  According to the third or fourth invention, for example, when the vehicle is driven by a motor, the power of the secondary battery, which is a power source in which DC power is stored, is boosted by the converter, and then the boosted DC power is The boosted AC power is supplied to the three-phase AC motor via an inverter that converts AC power. If it does in this way, even if it is a secondary battery of a small physique, a big output can be obtained from a motor. This inverter may be provided with a smoothing capacitor (high voltage power storage mechanism) for noise countermeasures. Also, this converter may be provided with a smoothing capacitor (high voltage power storage mechanism). When the vehicle collides, it is necessary to quickly discharge the electric power stored in the smoothing capacitor from the viewpoint of preventing electric leakage and the like. In order to quickly discharge electric power from the smoothing capacitor, it is preferable to execute zero torque control that does not generate torque in the motor using an inverter. However, if a failure occurs such that the rotation angle sensor of the motor drive circuit does not react due to a collision, torque may be generated even if a zero torque control command signal is given to the inverter. The control means can first quickly discharge the electric charge from the smoothing capacitor by interrupting the power transmission by the interruption means and then supplying electric power to the motor generator using an inverter by zero torque control or the like. As a result, it is possible to provide a vehicle control device that can sufficiently ensure safety at the time of collision in a vehicle equipped with a high-voltage power storage mechanism.

  In the vehicle control apparatus according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the blocking means is realized by a parking lock mechanism.

  According to the fifth aspect of the present invention, torque is generated from the motor when the parking lock mechanism of the transmission is actuated by the control means and the zero torque control is executed when the electric power stored in the high voltage power storage mechanism is discharged immediately. Even so, the torque generated in the drive wheels is not transmitted and the vehicle does not start to move.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A control block diagram of a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIG. The present invention is not limited to the hybrid vehicle shown in FIG. It may be a hybrid vehicle having another aspect. Further, it may be an electric vehicle or a fuel cell vehicle.

  The hybrid vehicle includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as a gasoline engine or a diesel engine, and a motor generator (MG) 140 as drive sources. In FIG. 1, for convenience of explanation, the motor generator 140 is expressed as a motor 140A and a generator 140B (or a motor generator 140B), but the motor 140A functions as a generator depending on the traveling state of the hybrid vehicle. The generator 140B functions as a motor.

In addition to this, the hybrid vehicle transmits a power generated by the engine 120 and the motor generator 140 to the drive wheels 160, and a reduction gear 180 that transmits the drive of the drive wheels 160 to the engine 120 and the motor generator 140, and the engine 120. Power split mechanism (for example, planetary gear mechanism) 200 that distributes the generated power to two paths of drive wheel 160 and generator 140B, travel battery 220 that charges power for driving motor generator 140, and travel Inverter 240 that performs current control while converting the direct current of battery 220 and the alternating current of motor 140A and generator 140B, and a battery control unit (hereinafter referred to as a battery ECU (Electronic Control Unit)) that manages and controls the charge / discharge state of traveling battery 220 260) and En Engine ECU controlling an operation state of the emission 120
280 and MG_ECU 300 that controls motor generator 140, battery ECU 260, inverter 240, etc., and battery ECU 260, engine ECU 280, MG_ECU 300, etc. according to the state of the hybrid vehicle are mutually managed and controlled so that the hybrid vehicle can operate most efficiently. HV_ECU 320 and the like for controlling the entire hybrid system.

  In the present embodiment, converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the motor 140A or the motor generator 140B, and therefore when the power is supplied from the traveling battery 220 to the motor 140A or the motor generator 140B, the converter 242 boosts the power. To do. This converter 242 has a built-in smoothing capacitor, and when the converter 242 performs a boosting operation, electric charge is stored in this smoothing capacitor.

  In FIG. 1, each ECU is configured separately, but may be configured as an ECU in which two or more ECUs are integrated (for example, MG_ECU 300 and HV_ECU 320, as shown by a dotted line in FIG. 1). An example is an integrated ECU).

  The power split mechanism 200 uses a planetary gear mechanism (planetary gear) in order to distribute the power of the engine 120 to both the drive wheel 160 and the motor generator 140B. By controlling the rotation speed of motor generator 140B, power split device 200 also functions as a continuously variable transmission. The rotational force of the engine 120 is input to the planetary carrier (C), which is transmitted to the motor generator 140B by the sun gear (S) and to the motor and the output shaft (drive wheel 160 side) by the ring gear (R). When the rotating engine 120 is stopped, since the engine 120 is rotating, the kinetic energy of this rotation is converted into electric energy by the motor generator 140B, and the rotational speed of the engine 120 is reduced.

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, the hybrid vehicle travels only by the motor 140 </ b> A of the motor generator 140 when the engine 120 is inefficient, such as when starting or running at a low speed. During normal travel, for example, the power split mechanism 200 divides the power of the engine 120 into two paths, and on the other hand, the drive wheels 160 are directly driven, and on the other hand, the generator 140B is driven to generate power. At this time, the motor 140A is driven by the generated electric power to assist driving of the driving wheels 160. Further, at the time of high speed traveling, electric power from the traveling battery 220 is further supplied to the motor 140A to increase the output of the motor 140A and to add driving force to the driving wheels 160. On the other hand, at the time of deceleration, motor 140 </ b> A driven by drive wheel 160 functions as a generator to perform regenerative power generation, and the collected power is stored in traveling battery 220. When the amount of charge of traveling battery 220 decreases and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by generator 140B to increase the amount of charge for traveling battery 220. Of course, control is performed to increase the drive amount of the engine 120 as necessary even during low-speed traveling. For example, it is necessary to charge the traveling battery 220 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 120 to a predetermined temperature.

  Further, G sensor (acceleration sensor) 1000, which is an example of a sensor for detecting a vehicle collision, is connected to HV_ECU 320. When the acceleration received by the vehicle is detected by the G sensor 1000 and an acceleration greater than a predetermined acceleration is received, it can be determined that the vehicle has collided. Note that the sensor for detecting the collision of the vehicle is not limited to the G sensor 1000.

  ECT (Electronically Controlled Automatic Transmission) _ECU 1100 controls an automatic transmission in which a part of the power split mechanism 200 mounted on the vehicle (stepless transmission at the forward travel position) is realized. In particular, the parking lock mechanism can be operated or released by an electrical control signal from the ECT_ECU 1100. When the parking lock mechanism is operated, the operating state of the automatic transmission is changed to the parking position, and torque is not transmitted from the engine 120 or the motor generator 140 that is a driving source to the driving wheels 160.

  The motor drive circuit in FIG. 1 is shown in FIG. Referring to FIG. 2, motor drive circuit includes a traveling battery 220, system relays SR (1) and SR (2), capacitors C (1) and C (2), and a converter 242 that steps up and down the voltage. The voltage sensor 310 and the inverter 240 are provided.

  The traveling battery 220 outputs a DC voltage. When system relays SR (1) and SR (2) are turned on by HV_ECU 320, DC voltages from battery for traveling 220 are supplied to capacitor C (1). Capacitor C (1) smoothes the DC voltage supplied from traveling battery 220 via system relays SR (1) and SR (2) and supplies the smoothed DC voltage to converter 242.

  Converter 242 includes a reactor 311, NPN transistors 312 and 313, and diodes 314 and 315. Reactor 311 has one end connected to the power supply line of battery for traveling 220 and the other end connected to the intermediate point between NPN transistor 312 and NPN transistor 313, that is, between the emitter of NPN transistor 312 and the collector of NPN transistor 313. Is done. NPN transistors 312 and 313 are connected in series between the power supply line of inverter 240 and the ground line. The collector of the NPN transistor 312 is connected to the power supply line, and the emitter of the NPN transistor 313 is connected to the ground line. In addition, diodes 314 and 315 for passing a current from the emitter side to the collector side are connected between the collector and emitter of each NPN transistor 312 and 313.

  In converter 242, NPN transistors 312 and 313 are turned on / off by HV_ECU 320, and the DC voltage supplied from capacitor C (1) is boosted and the output voltage is supplied to capacitor C (2). Converter 242 steps down the DC voltage generated by motor generator 140 and converted by inverter 240 during regenerative braking of a hybrid vehicle or electric vehicle equipped with a motor drive circuit, and supplies the voltage to capacitor C (1). .

  Capacitor C (2) smoothes the DC voltage supplied from converter 242 and supplies the smoothed DC voltage to inverter 240. Voltage sensor 310 detects the voltage on both sides of capacitor C (2), that is, output voltage VH of converter 242.

  When the DC voltage is supplied from capacitor C (2), inverter 240 converts DC voltage into AC voltage based on control from HV_ECU 320 to drive motor generator 140. Thereby, motor generator 140 is driven to generate torque specified by the torque command value. The inverter 240 converts the AC voltage generated by the motor generator 140 into a DC voltage based on control from the HV_ECU 320 during regenerative braking of a hybrid vehicle or an electric vehicle equipped with a motor drive circuit, and the converted DC voltage Is supplied to the converter 242 via the capacitor C (2).

  In particular, when the voltage is boosted by converter 242 (for example, when the vehicle is accelerated, the engine is assisted by the motor generator), electric power is supplied from battery 220 to capacitor C (1) and capacitor C (2), and electric charge is stored. On the other hand, since the voltage is not boosted by converter 242 when the vehicle is stopped, no electric charge is stored in capacitor C (1) and capacitor C (2).

  A technical feature of the present embodiment is that, in the event of a vehicle collision, the motor generator 140 is used to quickly discharge the charges of the capacitor C (1) and the capacitor C (2) that are stored during driving. Is subjected to zero torque control (control for operating the motor drive circuit without generating torque from the rotating shaft of the motor generator 140). At this time, if the motor drive circuit itself is damaged, torque may be generated even though the command signal is a zero torque command signal. In such a case, the vehicle starts to move. For this reason, in the present embodiment, before executing the zero torque control, the automatic transmission is set in the parking lock state, and even if the torque is generated from the motor generator 140 even if it is a zero torque command signal. However, torque is not transmitted to the drive wheels 160.

  With reference to FIG. 3, the control structure of the vehicle collision process performed by HV_ECU 320 will be described.

  In step (hereinafter step is abbreviated as S) 100, HV_ECU 320 determines whether or not the vehicle has collided. This determination is made based on a signal from G sensor 1000 input to HV_ECU 320. For example, it is determined that a collision has occurred when the acceleration detected by the G sensor 1000 is equal to or greater than a predetermined acceleration. If it is detected that the vehicle has collided (YES in S100), the process proceeds to S110. Otherwise (NO in S100), this process ends.

  In S110, HV_ECU 320 outputs a parking lock command signal to ECT_ECU 1100. The ECT_ECU 1100 that has received this signal changes, for example, the forward travel position (D position) of the automatic transmission to the parking position (P position). At this time, the automatic transmission is changed to the parking position by an electrical control signal from the ECT_ECU 1100.

  In S120, HV_ECU 320 outputs a smoothing capacitor discharge processing signal to MG_ECU 300. The MG_ECU 1100 that has received this signal controls the motor generator 140 with zero torque while the power supply from the battery 220 is cut off, and stores it in the smoothing capacitor C1 (1) of the converter 242 and the smoothing capacitor C (2) of the inverter 240. The generated charge is discharged.

  The operation of the vehicle equipped with the control device according to the present embodiment based on the structure and flowchart as described above will be described.

  If the vehicle collides with another vehicle or a fixed object while traveling (YES in S100), ECT_ECU 1100 outputs a parking lock command signal to the automatic transmission, and the automatic transmission enters the parking lock state. In this state, torque is not transmitted to the drive wheels 160 from the motor generator 140 or the engine 120 that is the drive source of the vehicle.

  In this torque transmission cut-off state and in the system main relay cut-off state, the motor generator 140 is subjected to zero torque control using the electric charge (electric power) stored in the smoothing capacitor of the inverter 240 and / or the smoothing capacitor of the converter 242. At this time, even if the rotation angle sensor, which is an example of the motor drive circuit, is damaged and torque is generated from the motor generator 140, the automatic transmission is in the parking lock state. No torque is transmitted to 160 and the vehicle does not move.

  As described above, according to the vehicle control apparatus of the present embodiment, the motor drive circuit is damaged when a collision or the like occurs in a vehicle including a drive circuit having a capacitor that stores high-voltage charges. Even if the vehicle does not move, the electric charge of the capacitor can be discharged quickly and safely without causing a problem due to electric leakage or the like.

  In the above-described embodiment, the motor drive circuit has been described as having a converter, but a motor drive circuit having only an inverter may be used.

  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.

It is a control block diagram of the hybrid vehicle which concerns on embodiment of this invention. It is the elements on larger scale of FIG. It is a flowchart which shows the control structure of the vehicle collision process performed by MG_ECU.

Explanation of symbols

  120 engine, 140 motor generator, 140A motor, 140B generator, 160 driving wheel, 180 speed reducer, 200 power split mechanism, 220 battery, 240 inverter, 242 converter, 260 battery ECU, 280 engine ECU, 300 MG_ECU, 320 HV_ECU, 1100 ECT_ECU, 1000 G sensor.

Claims (5)

A control device for a vehicle driven by operating an electric device using electric power of a power storage device,
Detection means for detecting a collision of the vehicle;
Conversion means for orthogonally converting the power of the power storage device;
A blocking means for blocking power transmission from the electric device to the drive wheel;
Control means for controlling the conversion means and the blocking means,
In the conversion means, electric power is stored in a high-voltage power storage mechanism provided inside the conversion means during the conversion operation,
The control means includes
Means for controlling the shut-off means to shut off power transmission by the shut-off means when a collision of a vehicle is detected by the detecting means;
Means for controlling the conversion means so as to discharge the electric power stored in the high-voltage power storage mechanism by supplying electric power to the electric device using the conversion means after the power transmission is interrupted; A vehicle control device. The power storage device is a secondary battery,
The electrical device is a motor generator,
The conversion means is an inverter,
The vehicle control device according to claim 1, wherein the high-voltage power storage mechanism is a smoothing capacitor provided in the inverter. A control device for a vehicle that is driven by raising and lowering the electric power of a power storage device to operate an electric device,
Detection means for detecting a collision of the vehicle;
Step-up / step-down means for stepping up / down the electric power of the power storage device;
Conversion means for orthogonally converting the power of the power storage device;
A blocking means for blocking power transmission from the electric device to the drive wheel;
Control means for controlling the conversion means and the blocking means,
In the step-up / step-down means, electric power is stored in a high-voltage power storage mechanism provided inside the step-up / step-down means during the step-up / step-down operation,
In the conversion means, electric power is stored in a high-voltage power storage mechanism provided inside the conversion means during the conversion operation,
The control means includes
Means for controlling the shut-off means to shut off power transmission by the shut-off means when a collision of a vehicle is detected by the detecting means;
Means for controlling the conversion means so as to discharge the electric power stored in the high-voltage power storage mechanism by supplying electric power to the electric device using the conversion means after the power transmission is interrupted; A vehicle control device. The power storage device is a secondary battery,
The electrical device is a motor generator,
The conversion means is an inverter, and the high voltage storage mechanism is a smoothing capacitor provided in the inverter,
The step-up / step-down means is a converter, and the high-voltage power storage mechanism is a smoothing capacitor provided in the inverter.
The vehicle control device according to claim 3.   The vehicle control device according to claim 1, wherein the blocking means is realized by a parking lock mechanism.

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