JP2010188858A - Power supply control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure a safety characteristic of a vehicle even when a coating material for the electric wiring cable of a booster circuit is peeled by a collision of the vehicle. <P>SOLUTION: A boosting control unit 12 reads a collision discrimination signal (a collision information) outputted by an air-bag ECU at a step S11. When the collision discrimination signal is "no collision" signal (S12:No), a target boosting voltage V* is set to a high pressure VA (S13). While, when the collision discrimination signal inputted from the air-bag ECU is "a collision presence" signal, the target boosting voltage V* is set to a low pressure VB(<VA) (S14). Then, the boosting voltage of a booster circuit 40 is controlled to the target boosting voltage V* (S15). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply control device that boosts a voltage of a vehicle-mounted power supply by a booster circuit and supplies power to the vehicle-mounted electric actuator.

  2. Description of the Related Art Conventionally, for example, in an electric power steering apparatus, an electric motor is provided so as to apply a steering assist torque to a turning operation of a steering handle, and the steering assist torque is adjusted by performing energization control of the electric motor. Such an electric power steering apparatus is required to have a high output so that it can cope with high-speed steering and heavy and heavy vehicles. Therefore, for example, as shown in Patent Document 1, there is also known an electric power steering apparatus that includes a booster circuit that boosts the output voltage of an in-vehicle power supply and supplies the boosted power to a motor drive circuit.

Japanese Patent Laying-Open No. 2005-212659

  However, in an electric power steering apparatus equipped with a booster circuit, when a vehicle collides, the output side wiring cable of the booster circuit is covered, and a person touches the exposed portion or a conductor portion that is in contact with the exposed portion. there is a possibility.

  An object of the present invention is to cope with the above-described problem, and is to ensure safety even when the wiring cable of the booster circuit is covered by a vehicle collision.

  In order to achieve the above object, a feature of the present invention is that in a vehicle power supply control device for boosting an output voltage of an in-vehicle power source by a boost circuit and supplying the boosted power to the in-vehicle electric actuator, the presence or absence of a vehicle collision is detected. Collision information acquisition means for acquiring the collision information to be expressed, and when the acquired collision information is information indicating that the vehicle has collided, at the time of a collision that lowers the boosted voltage of the booster circuit from the boosted voltage at the time of non-collision And a boosting reduction means.

  In the present invention, the output voltage of the in-vehicle power supply is boosted by the booster circuit, and the boosted power supply is supplied to the in-vehicle electric actuator. Therefore, the on-vehicle electric actuator can be driven with high efficiency. An electric motor is suitable as the in-vehicle electric actuator. In the present invention, the collision information acquisition means and the collision pressure increase reduction means are provided so that safety can be ensured even if the vehicle collides and the output side wiring cable of the booster circuit is covered. The collision information acquisition means acquires collision information indicating the presence or absence of a vehicle collision. For example, collision information can be acquired from an airbag control device that deploys an airbag based on a signal from a vehicle collision sensor. Moreover, you may acquire the signal from a vehicle collision sensor directly. When the acquired collision information is information indicating that the vehicle has collided, the collision boosting means lowers the boosted voltage of the booster circuit from the boosted voltage during non-collision. Therefore, even if the cover of the output side wiring cable of the booster circuit is removed due to the collision, the output voltage is lowered, so that safety is improved.

It is a schematic block diagram of the power supply control apparatus which concerns on embodiment which applied this invention to the electric power steering apparatus. It is a flowchart showing a boost control routine. It is a graph showing the change of a target step-up voltage. It is a flowchart showing the pressure | voltage rise control routine as a 1st modification. It is a flowchart showing the pressure | voltage rise control routine as a 2nd modification. It is a flowchart showing the pressure | voltage rise control routine as a 3rd modification.

  Hereinafter, a power supply apparatus according to an embodiment of the present invention will be described. FIG. 1 is a system configuration diagram of a power supply unit in an electric power steering apparatus.

  This electric power steering device is assembled with a steering mechanism (not shown) for turning steered wheels by a steering operation of a steering wheel and generates a steering assist torque, and a motor for driving the electric motor 20 A drive circuit 30 and an assist electronic control device 10 (hereinafter referred to as an assist ECU 10) that controls an energization amount of the electric motor 20 in accordance with a driver's steering operation are provided. The assist ECU 10 includes a microcomputer including a CPU, a ROM, a RAM, and the like as a main part, and controls a motor control unit 11 that calculates an energization amount of the electric motor 20 and a boosted voltage of a booster circuit 40 that will be described later. The boost control unit 12 is roughly classified.

  First, a power supply system to the electric motor 20 will be described. The electric motor 20 is supplied with power from the in-vehicle power source 100. The in-vehicle power source 100 is configured by connecting a battery and an alternator that generates electric power by rotating an engine in parallel, and supplies power not only to the electric power steering apparatus but also to other in-vehicle electric loads. A drive system power supply line 103 is connected to the plus pole of the in-vehicle power supply 100, and a ground line 105 is connected to the ground pole.

  A booster circuit 40 is connected to the in-vehicle power supply 100. The booster circuit 40 includes a capacitor 41 provided between the drive system power supply line 103 and the ground line 105, a booster coil 42 provided in series with the drive system power supply line 103 on the load side from the connection point of the capacitor 41, and a booster circuit. The first boost switching element 43 provided between the drive side power supply line 103 on the load side of the coil 42 and the ground line 105, and the drive side power supply line 103 on the load side from the connection point of the first boost switching element 43. Are connected in series to each other, and a capacitor 45 provided between the drive power supply line 103 on the load side of the second boost switching element 44 and the ground line 105. In the present embodiment, MOS-FETs are used as the boosting switching elements 43 and 44, but other switching elements can also be used.

  The step-up circuit 40 is subjected to step-up control by a step-up control unit 12 (described later) of the assist ECU 10. The step-up control unit 12 outputs a pulse signal having a predetermined cycle to the gates of the first and second step-up switching elements 43 and 44 to turn on and off both the switching elements 43 and 44, and the power supplied from the in-vehicle power supply 100 And a predetermined output voltage is generated on the boost power supply line 107 on the output side. In this case, the first and second boost switching elements 43 and 44 are controlled so that the on / off operations are reversed. The step-up circuit 40 turns on the first step-up switching element 43 and turns off the second step-up switching element 44 so that a current is passed through the step-up coil 42 for a short time to power the step-up coil 42 and immediately thereafter. The first boosting switching element 43 is turned off and the second boosting switching element 44 is turned on so that the power stored in the boosting coil 42 is output. The output voltage of the second boost switching element 44 is smoothed by the capacitor 45. Further, noise to the in-vehicle power supply 100 side is removed by the capacitor 41 provided on the input side of the booster circuit 40.

  The output voltage (boost voltage) of the booster circuit 40 can be adjusted by duty ratio control of the first and second booster switching elements 43 and 44. Accordingly, the boost voltage can be adjusted by adjusting the duty ratio of the gate signal output from the boost control unit 12 of the assist ECU 10.

  A voltage sensor 50 is provided on the boost power supply line 107 on the output side of the booster circuit 40. The voltage sensor 50 is connected to the boost control unit 12 of the assist ECU 10 and outputs a signal representing the boost voltage Vout that is an output voltage of the boost circuit 40 to the boost control unit 12.

  The power boosted by the booster circuit 40 is supplied to the motor drive circuit 30. The motor drive circuit 30 is a three-phase inverter circuit composed of six switching elements 31 to 36 made of MOS-FETs. The motor drive circuit 30 is provided with a current sensor 51 that detects a current flowing through the electric motor 20. The current sensor 51 detects a current flowing in each phase (U phase, V phase, W phase) and outputs a detection signal corresponding to the detected current value to the motor control unit 11 of the assist ECU 10. Hereinafter, the measured three-phase current values are collectively referred to as a motor current Iuvw.

  Each switching element 31 to 36 of the motor drive circuit 30 has a gate connected to the motor control unit 11 of the assist ECU 10, and the duty ratio is controlled by a PWM control signal output from the motor control unit 11. Thereby, the drive voltage of the electric motor 20 is adjusted to the target voltage.

  The motor control unit 11 of the assist ECU 10 connects a steering torque sensor 21, a motor rotation angle sensor 22, a vehicle speed sensor 23, and a current sensor 51, and a detection signal representing the steering torque Tr, the motor rotation angle θ, the vehicle speed v, and the motor current Iuvw. Enter. Based on the input detection signal, a command current (target current) to be passed through the electric motor 20 is calculated so that an optimum steering assist torque according to the steering operation of the driver can be obtained. The duty ratios of the switching elements 31 to 36 of the motor drive circuit 30 are controlled so as to flow in the flow. For example, a target assist torque that increases as the steering torque Tr increases and decreases as the vehicle speed v increases is calculated, and the command current is calculated by dividing the target assist torque by a torque constant. Then, the actual current actually flowing through the electric motor 20 is detected by the current sensor 51, the target voltage is set by feedback control using the deviation ΔI between the command current and the actual current, and the duty corresponding to the target voltage is set. The ratio PWM control signal is output to the motor drive circuit 30. Thus, a desired steering assist torque corresponding to the driver's steering operation can be obtained.

  The boost control unit 12 of the assist ECU 10 connects the voltage sensor 50 and the airbag ECU 200, and inputs the boost voltage Vout and vehicle collision information. The airbag ECU 200 connects a plurality of vehicle collision sensors 210 (for example, acceleration sensors), determines a vehicle collision based on signals from the vehicle collision sensors 210, and deploys the airbag. The airbag ECU 200 outputs a collision determination signal indicating the presence or absence of a vehicle collision to the boost control unit 12 of the assist ECU 10.

  Here, boost control executed by the boost controller 12 of the assist ECU 10 will be described. FIG. 2 is a flowchart showing a boost control routine executed by the boost control unit 12. The boosting control routine is repeated at a predetermined short cycle while an ignition switch (not shown) is turned on.

  When the ignition switch is turned on and the boost control routine is started, the boost control unit 12 first reads the collision information from the airbag ECU 200 in step S11. Airbag ECU 200 always performs vehicle collision determination and outputs a collision determination signal. That is, when a vehicle collision is not detected, a “no collision” signal is output, and when a collision is detected, a “collision present” signal is output. In step S12, the boost control unit 12 determines whether a vehicle collision is detected based on the collision information (collision determination signal). When the vehicle collision is not detected (S12: No), the target boost voltage V * of the booster circuit 40 is set to VA in step S13. This VA is a boosted voltage value set to drive the electric motor 20 with high output and high efficiency, and is set to 40 V, for example.

  When the target boost voltage V * is set, the boost control unit 12 obtains the target boost voltage V * in step S15, that is, the boost voltage Vout detected by the voltage sensor 50 is equal to the target boost voltage V *. The duty ratio of the pulse signal output to the first and second boost switching elements 43 and 44 of the booster circuit 40 is controlled so as to be equal. As a result, the boosted voltage of the booster circuit 40 is maintained at the target boosted voltage V *.

  This boost control routine is repeatedly executed. If a vehicle collision is detected (S12: Yes), the target boost voltage V * of the booster circuit 40 is set to VB. This VB is a value lower than VA, and is set to a voltage value at which the driver can safely drive. When the target boost voltage V * is set to VB, VB may be set to the same value as the output voltage of the in-vehicle power supply 100 so that the boost operation by the boost circuit 40 is not performed. Further, once a vehicle collision is detected, the target boost voltage V * is maintained at VB until the ignition switch is turned off. Therefore, as shown in FIG. 3, the target boost voltage V * is switched from the high voltage VA to the low voltage VB at the time t1 when the vehicle collision is detected.

  As a result, according to the present embodiment, safety can be ensured even if the output wiring cable of the booster circuit 40 is covered due to a vehicle collision. Note that the booster circuit 40 and the boost controller 12 in the present embodiment correspond to the power supply control device of the present invention. Moreover, the structure which combined the motor drive circuit 30 and the electric motor 20 in this embodiment is equivalent to the vehicle-mounted electric actuator of this invention. Moreover, the process of the pressure | voltage rise control part 12 which reads collision information in step S11 of this embodiment corresponds to the collision information acquisition means of this invention. Moreover, the process of step S12-step S15 of this embodiment is equivalent to the pressurization reduction means at the time of a collision of this invention.

  Next, a modified example related to boost control will be described. FIG. 4 shows a boost control routine as a first modification. In the first modified example, a nonvolatile memory (not shown) is provided in the assist ECU 10 and is configured to store a history of vehicle collisions. In the following description, the same step numbers are assigned to the same processing as the boost control routine (FIG. 2) of the embodiment, and the description is omitted.

  When the ignition switch is turned on and the boost control routine is started, first, in step S21, the collision history is read from the nonvolatile memory. Subsequently, in step S22, it is determined whether or not a collision history indicating “collision present” is stored. If a collision history indicating “collision present” is not stored, the processing from step S11 is performed. That is, based on the collision determination signal output from the airbag ECU 200, the target boost voltage V * is set and the boost voltage of the boost circuit 40 is controlled.

  When the “collision present” signal is received from the airbag ECU 200 during the repetition of these processes (S12: Yes), in step S23, data representing “collision present” is written in the non-volatile memory. In step S14, the target boost voltage V * is switched to VB. Therefore, when the ignition switch is turned off and this routine is finished, and then the ignition switch is turned on again and this routine is started, the target boost voltage V * Is set to VB. Thereby, the pressure | voltage rise control (V * = VB) at the time of a vehicle collision can be continued.

  It should be noted that the collision history stored in the non-volatile memory may be deleted only when the dealer requests deletion. The erasure request may be made at the time of system initialization.

  Next, a second modification example regarding the boost control will be described. FIG. 5 shows a boost control routine as a second modification. In the second modified example, the boost control unit 12 is configured to input engine information indicating the operating state of the engine from the engine ECU 300 (shown by a broken line in FIG. 1) and input vehicle speed information from the vehicle speed sensor 23. Has been. In the following description, the same step numbers are assigned to the same processing as the boost control routine (FIG. 2) of the embodiment, and the description is omitted.

  When the ignition switch is turned on and the boost control routine is started, first, collision information (collision determination signal) is read from the airbag ECU 200, and it is determined whether or not a vehicle collision is detected (S11, S12). If no vehicle collision is detected, the target boost voltage V * is set to VA in step S13.

  On the other hand, if a vehicle collision is detected, it is determined in step S31 whether or not the engine is off based on the engine information output from engine ECU 300. If the engine is off, the boosting operation of the booster circuit 40 is stopped in step S33. If the engine is not off, it is determined in step S32 whether or not the vehicle speed v detected by the vehicle speed sensor 23 is zero. If the vehicle speed v is zero, the step-up operation of the step-up circuit 40 is stopped in step S33. If the engine is not off and the vehicle speed v is not zero, the target boost voltage V * is set to VB in step S14.

  According to the boost control routine of the second modification, the boost operation is stopped when the engine is off and the vehicle speed is zero, so that safety can be further improved.

  Next, a third modification example regarding the boost control will be described. FIG. 6 shows a boost control routine as a third modification. In the third modification, the case where the engine information and the vehicle speed information cannot be received in the second modification is considered. In the following description, the same step number is assigned to the same step as the step-up control routine (FIG. 5) of the second modified example, and the description is omitted.

  When the ignition switch is turned on and the boost control routine is started, first, collision information (collision determination signal) is read from the airbag ECU 200, and it is determined whether or not a vehicle collision is detected (S11, S12). If no vehicle collision is detected, the target boost voltage V * is set to VA in step S13.

  On the other hand, if a vehicle collision is detected, it is determined in step S41 whether or not both engine information and vehicle speed information are unreceivable. If the engine information cannot be received from the engine ECU 300 and the vehicle speed information cannot be received from the vehicle speed sensor 23 (S41: No), the step-up operation of the step-up circuit 40 is stopped in step S33. If the determination in step S41 is “No”, it is determined in step S42 whether only engine information can be received. If only engine information can be received, it is determined in step S31 whether or not the engine is off. If the engine is off, the boost operation of the booster circuit 40 is stopped in step S33, and the engine If not in the off state, the target boost voltage V * is set to VB in step S14.

  If it is determined in step S42 that the vehicle speed information can be received, it is determined in step S32 whether or not the vehicle speed v detected by the vehicle speed sensor 23 is zero. If the vehicle speed v is zero, the step-up operation of the step-up circuit 40 is stopped in step S33, and if the vehicle speed v is not zero, the target boost voltage V * is set to VB in step S14.

  According to the boost control routine of the third modified example, even when the engine information and the vehicle speed information cannot be received, the appropriate boost control is performed, so that safety can be further improved.

  The electric power steering apparatus including the power supply control apparatus according to this embodiment has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention. It is.

  For example, in the present embodiment, the power supply control device applied to the electric power steering device has been described, but the present invention is not limited to application to the electric power steering device. For example, the present invention can be applied to a power supply control device such as an electric active stabilizer device, a by-wire type electric steering device, and an electromagnetic suspension device. Moreover, you may make it take in the signal of the vehicle collision sensor 210 directly as collision information not via airbag ECU200.

  DESCRIPTION OF SYMBOLS 10 ... Assist ECU, 11 ... Motor control part, 12 ... Boost control part, 20 ... Electric motor, 23 ... Vehicle speed sensor, 30 ... Motor drive circuit, 40 ... Boost circuit, 50 ... Voltage sensor, 100 ... In-vehicle power supply, 200 ... Airbag ECU, 210 ... vehicle collision sensor, 300 ... engine ECU.

Claims (1)

In the vehicle power supply control device for boosting the output voltage of the in-vehicle power source by the boost circuit and supplying the boosted power source to the in-vehicle electric actuator,
Collision information acquisition means for acquiring collision information indicating the presence or absence of a vehicle collision;
When the acquired collision information is information indicating that the vehicle has collided, the apparatus includes a collision boosting reduction unit that reduces the boosted voltage of the booster circuit below the boosted voltage in a non-collision state. Vehicle power supply control device.

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