JP2009040348A - Power source control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a hindrance in the steering assist control by inspecting an auxiliary power source device 50 with proper timing. <P>SOLUTION: This power source control section 62 inspects power source supplying ability of an auxiliary power source device 50 in the only case wherein a permission to inspect is output based on a determination that inspection is permitted. In this inspection, boosting operation of a booster circuit 40 is stopped, and power source supply to a motor driving circuit 30 is performed from the only auxiliary power source device 50 based on detection of the power source voltage vout and the discharging current isub. Inspection by the power source control section 62 is inhibited when the car speed Vx is an inhibition determining speed V1 or less, and permitted when the car speed Vx achieves the permission determining speed V2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply control device that supplies power to an electric actuator drive circuit using both a main power supply device and a sub power supply device.

2. Description of the Related Art Conventionally, for example, in an electric power steering apparatus, an electric motor has been 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 device uses an in-vehicle battery as its power source, but consumes a large amount of power. Therefore, for example, the device proposed in Patent Document 1 includes a sub power supply device that assists the in-vehicle battery. This sub power supply device is connected in parallel to the power supply line from the vehicle-mounted battery (hereinafter referred to as the main power supply device) to the motor drive circuit and is charged by the main power supply device, and the charged power is used to transfer the motor drive circuit. The power supply can be supplied. Further, a switch for switching power supply / non-power supply from the sub power supply device to the motor drive circuit and a switch for switching charge / non-charge from the main power supply device to the sub power supply device are provided.
JP2007-91122A

  In the device proposed in Patent Document 1, the state of charge of the sub power supply device is inspected by detecting the voltage between the terminals of the sub power source device, but the state of charge cannot be inspected very well. When inspecting the state of charge of the sub power supply device, a higher inspection accuracy can be obtained when power is supplied from the sub power supply device to the motor drive circuit. However, in this device, since the output line of the sub power supply device is connected to the power supply line to the motor drive circuit of the main power supply device, the output is balanced between the output voltage of the main power supply device and the output voltage of the sub power supply device. Power is supplied from the higher voltage power supply device to the motor drive circuit. For this reason, it is impossible to inspect the state of charge based on the timing at which power is supplied from the sub power supply device to the motor drive circuit. Moreover, even if it is going to detect the power supply voltage of a sub power supply device, it cannot detect appropriately by the influence of the power supply voltage of a main power supply device.

  Such a problem is that the power supply from the main power supply device is temporarily stopped, the circuit is switched so that power is supplied from only the sub power supply device to the motor drive circuit, and the charging state of the sub power supply device is checked in that state. This can be solved. However, when the power supply from the main power supply device to the motor drive circuit is stopped to check the state of charge, the following problems may occur depending on the timing.

  For example, if the power supply from the main power unit to the motor drive circuit is stopped when the steering operation is performed and the required power of the electric motor is increased, the steering assist torque that follows the steering operation due to power shortage Cannot be obtained. In this case, the driver feels resistance like being caught by the steering operation. In addition, the charge amount of the sub power supply device is greatly reduced.

  An object of the present invention is to cope with the above-described problem. By performing an inspection of the sub power supply device at an appropriate timing, an operation failure of the electric actuator is suppressed and the state of the sub power supply device is improved. There is to keep.

  In order to achieve the above object, a feature of the present invention includes a main power supply device and a sub power supply device charged by the main power supply device, and the main power supply device and the sub power supply device for an electric actuator drive circuit. Are connected in parallel to supply power to the electric actuator drive circuit from the main power supply device and the sub power supply device, and the power supply to the electric actuator drive circuit is performed only from the sub power supply device. When the power is supplied to the electric actuator drive circuit from only the sub power supply device prior to the inspection by the sub power supply inspection means, the sub power supply inspection means that switches to the state and inspects the power supply capability of the sub power supply device, A power shortage predicting means for predicting whether or not there is a possibility of insufficient power supply to the electric actuator drive circuit; and the power shortage When the measuring means is predicted that the situation that may cause the power supply shortage is to have a test inhibiting means for inhibiting the inspection by the secondary power supply checking means.

  In the present invention, the main power supply device and the sub power supply device are connected in parallel, and power is supplied from both power supply devices to the electric actuator drive circuit. When such a power supply configuration is adopted, if the sub power supply device deteriorates (decrease in power supply capability), the operation of the electric actuator is adversely affected. Therefore, in the present invention, a sub power supply inspection means for inspecting the power supply capability of the sub power supply device is provided. In order to inspect the power supply capability of the sub power supply device, it is necessary to switch to a state in which power supply to the electric actuator drive circuit is performed only from the sub power supply device. In other words, in the present invention, since the main power supply device and the sub power supply device are connected in parallel to the electric actuator drive circuit to supply power, the power supply voltage of the sub power supply device cannot be measured as it is. It is necessary to stop the power supply from the main power supply device to the electric actuator drive circuit.

  Therefore, the sub power supply inspection unit inspects the power supply capability of the sub power supply apparatus after switching to a state in which power supply to the electric actuator drive circuit is performed only from the sub power supply apparatus. In this case, prior to the inspection by the sub power supply inspection means, the power shortage prediction means predicts whether or not there is a possibility of insufficient power supply to the electric actuator drive circuit. That is, if power is supplied from only the sub power supply device to the electric actuator drive circuit before the power supply from the main power supply device to the electric actuator drive circuit is stopped, there is a risk of insufficient power supply to the electric actuator drive circuit. Predict whether the situation is. “Insufficient power supply to the electric actuator drive circuit” means that the electric power that can be supplied from the sub power supply device to the electric actuator drive circuit is insufficient with respect to the power required to drive the electric actuator. To do.

  And when it is predicted by the power shortage predicting means that the power supply may be insufficient, the inspection prohibiting means prohibits the inspection by the sub power supply inspection means. Therefore, the power supply from the main power supply device to the electric actuator drive circuit is not stopped. On the other hand, when it is predicted that there is no possibility of insufficient power supply to the electric actuator drive circuit, the inspection by the sub power supply inspection means is not prohibited. In this case, the sub power supply inspection unit switches the power supply to the electric actuator drive circuit from a state where only the sub power supply device is supplied, and inspects the power supply capability of the sub power supply device based on the power supply state.

  As a result, according to the present invention, it is possible to inspect the power supply capability of the sub power supply device at an appropriate timing, and an electric actuator operation failure occurs due to the inspection, or the charge amount of the sub power supply device is greatly reduced. Inconveniences such as this are reduced.

  Another feature of the present invention includes a booster circuit that boosts the output voltage of the main power supply device, and the electric actuator drive circuit is connected to the output side of the booster circuit, and the booster circuit, the electric actuator drive circuit, The sub power supply circuit is connected in parallel to each other, and the sub power supply inspection means stops the boosting of the booster circuit or lowers the boosted voltage, thereby supplying power to the electric actuator drive circuit. It is to switch to the state performed only from the sub power supply device.

  In the present invention, the output voltage of the main power supply device is boosted by the booster circuit and supplied to the electric actuator drive circuit. The sub power supply device is connected to the output side of the booster circuit, is charged by the main power supply device, and functions as a power supply device for the electric actuator drive circuit. Therefore, the electric actuator can be driven efficiently. That is, the output voltage of the main power supply device and the sub power supply device can be set to an appropriate voltage for efficiently operating the electric actuator.

  In this case, the power supply device that supplies power to the electric actuator drive circuit is switched according to the balance between the output voltage of the booster circuit and the output voltage of the sub power supply device, and the sub power supply device is charged. When the output voltage of the booster circuit is lower than the output voltage of the sub power supply device, power is supplied from the sub power supply device to the electric actuator drive circuit. By utilizing this, the sub power supply inspection means switches the power supply to the electric actuator drive circuit from the sub power supply device only by stopping the boosting of the boosting circuit or lowering the boosted voltage, and The power supply capability of the sub power supply device is inspected based on the power supply state. Therefore, by using the booster circuit, both high-efficiency driving of the electric actuator and switching of the power supply device can be performed.

  Another feature of the present invention is that the sub power supply inspection means is configured to use the sub power supply based on a relationship between a power supply amount supplied from the sub power supply device to the electric actuator drive circuit and a power supply voltage drop of the sub power supply device. The purpose is to check the power supply capability of the device.

According to the present invention, it is possible to accurately inspect the power supply capability of the sub power supply apparatus.
For example, the inspection can be performed based on the power supply voltage drop amount of the sub power supply device with respect to the power supply amount supplied from the sub power supply device to the electric actuator drive circuit. In this case, the sub power supply inspection means may include voltage detection means for detecting the power supply voltage of the sub power supply apparatus, and current detection means for detecting the current flowing in the electric actuator drive circuit or the current flowing in the sub power supply apparatus.

  Another feature of the present invention is a power control device for an electric power steering device for a vehicle that assists the driver's steering operation by controlling the electric actuator drive circuit according to the driver's steering operation to generate a steering force. There is to use.

  The present invention is applied to a power supply control device of an electric power steering device for a vehicle that assists a driver's steering operation. In an electric power steering apparatus for a vehicle, for example, an electric motor is used as an electric actuator, but the power consumption is large, and the required power greatly varies depending on the steering operation state and the vehicle running state. For this reason, if the sub power supply device is inspected in a situation where the required power is large, the steering operation may be adversely affected, or the charge amount of the sub power supply device may be significantly reduced.

  Therefore, in the present invention, prior to the inspection of the sub power supply apparatus, it is predicted whether or not the power shortage predicting means is in a situation where there is a possibility of insufficient power supply to the electric actuator drive circuit. For example, it can be predicted by detecting a steering operation state or a vehicle behavior state. When it is predicted that there is a risk of insufficient power supply to the electric actuator drive circuit, the inspection prohibiting means prohibits the inspection by the sub power supply inspection means, so that the operation failure of the electric actuator is prevented. The driver does not feel uncomfortable during the steering operation. Moreover, the fall of the charge amount of a sub power supply device can be suppressed.

  For example, in the electric power steering apparatus, the target assist torque is calculated based on the steering torque detecting means for detecting the steering torque acting on the steering handle, the vehicle speed detecting means for detecting the vehicle speed, and at least the steering torque and the vehicle speed, It is preferable to provide assist control means for controlling the electric motor via a drive circuit so as to obtain the target assist torque.

  Another feature of the present invention includes vehicle speed acquisition means for acquiring vehicle speed information, wherein the power shortage prediction means is based on the vehicle speed information acquired by the vehicle speed acquisition means, and the vehicle speed is less than or equal to a reference speed. It is to predict that there is a risk of insufficient power supply to the electric actuator drive circuit.

  In the present invention, it is predicted that there is a possibility of insufficient power supply to the electric actuator drive circuit when the vehicle speed is equal to or lower than the reference speed. In the electric power steering apparatus, a large amount of electric power is required for the electric actuator during a steering operation during low speed traveling or stopping. Therefore, in such a situation, since the inspection by the sub power supply inspection unit is prohibited, it is possible to supply power to the electric actuator drive circuit from both the main power supply device and the sub power supply device. For this reason, when the steering operation is performed, the electric actuator can be appropriately operated, and the driver does not feel uncomfortable steering.

  Another feature of the present invention includes a steering speed acquisition means for acquiring steering speed information of a steering wheel, and the power shortage prediction means has a steering speed based on the steering speed information acquired by the steering speed acquisition means. It is to predict that there is a possibility of insufficient power supply to the electric actuator drive circuit when the reference steering speed is exceeded.

  In the present invention, it is predicted that there is a risk of insufficient power supply to the electric actuator drive circuit when the steering speed is equal to or higher than the reference steering speed. In the electric power steering apparatus, a large electric power is required for the electric actuator when the steering operation is performed quickly. Therefore, in such a situation, since the inspection by the sub power supply inspection unit is prohibited, it is possible to supply power to the electric actuator drive circuit from both the main power supply device and the sub power supply device. For this reason, an electric actuator can be operated appropriately and it does not give a driver an uncomfortable feeling of steering.

  Another feature of the present invention is provided with steering angle acquisition means for acquiring steering angle information of a steering wheel, and the power shortage prediction means has a steering angle based on the steering angle information acquired by the steering angle acquisition means. When the angle is equal to or greater than the reference steering angle, it is to be predicted that there is a possibility of insufficient power supply to the electric actuator drive circuit.

  In the present invention, when the steering angle is greater than or equal to the reference steering angle, it is predicted that there is a possibility of insufficient power supply to the electric actuator drive circuit. In the electric power steering device, a large electric power is required for the electric actuator when the steering handle is rotated to a large angular position with respect to the neutral position. Therefore, in such a situation, since the inspection by the sub power supply inspection unit is prohibited, it is possible to supply power to the electric actuator drive circuit from both the main power supply device and the sub power supply device. For this reason, an electric actuator can be operated appropriately and it does not give a driver an uncomfortable feeling of steering.

  Another feature of the present invention includes steering torque acquisition means for acquiring steering torque information acting on the steering wheel, wherein the power shortage prediction means is based on the steering torque information acquired by the steering torque acquisition means. Is to predict a situation where there is a risk of insufficient power supply to the electric actuator drive circuit when the value is equal to or greater than the reference steering torque.

  In the present invention, when the steering torque is equal to or higher than the reference steering torque, it is predicted that there is a possibility of insufficient power supply to the electric actuator drive circuit. In the electric power steering apparatus, when a large steering torque is applied to the steering wheel, a large electric power is required for the electric actuator. Therefore, in such a situation, since the inspection by the sub power supply inspection unit is prohibited, it is possible to supply power to the electric actuator drive circuit from both the main power supply device and the sub power supply device. For this reason, an electric actuator can be operated appropriately and it does not give a driver an uncomfortable feeling of steering.

  Hereinafter, a power supply control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an electric power steering device for a vehicle provided with a power supply control device as the embodiment.

  The electric power steering device for a vehicle according to the present embodiment includes a steering mechanism 10 that steers steered wheels by a steering operation of a steering handle 11, an electric motor 20 that is assembled to the steering mechanism 10 and generates steering assist torque, and an electric motor 20. A motor drive circuit 30 for driving the motor, a booster circuit 40 that boosts the output voltage of the main power supply device 100 and supplies power to the motor drive circuit 30, and a power supply circuit between the booster circuit 40 and the motor drive circuit 30 Are connected in parallel to each other, and an electronic control unit 60 that controls the operation of the electric motor 20 and the booster circuit 40 is provided as a main part.

  The steering mechanism 10 is a mechanism for turning the left and right front wheels FWL and FWR by a rotation operation of the steering handle 11, and includes a steering shaft 12 connected to the steering handle 11 so as to rotate integrally with the upper end. A pinion gear 13 is connected to the lower end of the steering shaft 12 so as to rotate integrally. The pinion gear 13 meshes with rack teeth formed on the rack bar 14 and constitutes a rack and pinion mechanism together with the rack bar 14. Knuckles (not shown) of the left and right front wheels FWL and FWR are steerably connected to both ends of the rack bar 14 via tie rods 15L and 15R. The left and right front wheels FWL and FWR are steered left and right according to the axial displacement of the rack bar 14 accompanying the rotation of the steering shaft 12 around the axis.

  An electric motor 20 for steering assist is assembled to the rack bar 14. The rotating shaft of the electric motor 20 is connected to the rack bar 14 via the ball screw mechanism 16 so that power can be transmitted, and assists steering of the left and right front wheels FWL and FWR by the rotation. The ball screw mechanism 16 functions as a speed reducer and a rotation-linear converter, and decelerates the rotation of the electric motor 20 and converts it into a linear motion and transmits it to the rack bar 14.

  A steering torque sensor 21 is provided on the steering shaft 12. The steering torque sensor 21 outputs a signal corresponding to the steering torque that acts on the steering shaft 12 by the turning operation of the steering handle 11. Hereinafter, the value of the steering torque detected by the signal output from the steering torque sensor 21 is referred to as steering torque Tx. As for the steering torque Tx, the operating direction of the steering wheel 11 is identified by positive and negative values. In the present embodiment, the steering torque Tx when the steering handle 11 is steered in the right direction is indicated by a positive value, and the steering torque Tx when the steering handle 11 is steered in the left direction is indicated by a negative value. Therefore, the magnitude of the steering torque Tx is the absolute value thereof.

  The electric motor 20 is provided with a rotation angle sensor 22. The rotation angle sensor 22 is incorporated in the electric motor 20 and outputs a detection signal corresponding to the rotation angle position of the rotor of the electric motor 20. The detection signal of the rotation angle sensor 22 is used for calculation of the rotation angle and rotation angular velocity of the electric motor 20. On the other hand, since the rotation angle of the electric motor 20 is proportional to the steering angle of the steering handle 11, it is commonly used as the steering angle of the steering handle 11. Further, the rotational angular velocity obtained by differentiating the rotational angle of the electric motor 20 with respect to time is proportional to the steering angular velocity of the steering handle 11, and thus is commonly used as the steering speed of the steering handle 11. Hereinafter, the value of the steering angle of the steering wheel 11 detected by the output signal of the rotation angle sensor 22 is referred to as a steering angle θx, and the value of the steering angular velocity obtained by time differentiation of the steering angle θx is referred to as a steering speed ωx. The steering angle θx represents a steering angle in the right direction and the left direction with respect to the neutral position of the steering wheel 11 by using a positive or negative value. In the present embodiment, the neutral position of the steering handle 11 is set to “0”, the steering angle in the right direction with respect to the neutral position is indicated by a positive value, and the steering angle in the left direction with respect to the neutral position is indicated by a negative value.

  The motor drive circuit 30 includes a three-phase inverter circuit composed of six switching elements 31 to 36 made of MOSFETs. Specifically, a circuit in which a first switching element 31 and a second switching element 32 are connected in series, a circuit in which a third switching element 33 and a fourth switching element 34 are connected in series, a fifth switching element 35 and a first switching element A circuit in which 6 switching elements 36 are connected in series is connected in parallel, and a power supply line 37 to the electric motor 20 is drawn out between two switching elements (31-32, 33-34, 35-36) in each series circuit. Adopted.

  The drains of the first switching element 31, the third switching element 33, and the fifth switching element 35 are connected to a boost drive line 113, which will be described later, and the second switching element 32, the fourth switching element 34, and the sixth switching element 36 are connected. Each source is connected to the ground line 111. A current sensor 38 is provided in the power supply line 37 from the motor drive circuit 30 to the electric motor 20. The current sensor 38 detects (measures) the current flowing in each phase, and outputs a detection signal corresponding to the detected current value to the electronic control unit 60. Hereinafter, this measured current value is referred to as a motor current iuvw. The current sensor 38 is referred to as a motor current sensor 38.

  Each switching element 31 to 36 has a gate connected to an assist control unit 61 (described later) of the electronic control device 60, and a duty ratio is controlled by a PWM control signal from the assist control unit 61. Thereby, the drive voltage of the electric motor 20 is adjusted to the target voltage. Incidentally, as indicated by circuit symbols in the figure, the MOSFETs constituting the switching elements 31 to 36 are parasitically structured with diodes.

Next, a power supply system of the electric power steering apparatus will be described.
The electric power steering apparatus is supplied with power from the main power supply apparatus 100. The main power supply device 100 is configured by connecting in parallel a main battery 101 and an alternator 102 that generates electric power as the engine rotates. As the main battery 101, a general in-vehicle battery having a rated output voltage of 12V is used.

  The main power supply device 100 performs power supply not only to the electric power steering device but also to other in-vehicle electric loads. A power supply source line 103 connected to the power supply terminal (+ terminal) of the main battery 101 branches into a control system power supply line 104 and a drive system power supply line 105. The control system power supply line 104 functions as a power supply line for supplying power only to the electronic control device 60. The drive system power supply line 105 functions as a power supply line that supplies power to both the motor drive circuit 30 and the electronic control unit 60.

  An ignition switch 106 is connected to the control system power line 104. A power relay 107 is connected to the drive system power line 105. The power relay 107 is turned on by a control signal from the electronic control unit 60 to form a power supply circuit to the electric motor 20. The control system power supply line 104 is connected to the power supply + terminal of the electronic control device 60, and is provided with a diode 108 on the load side (electronic control device 60 side) of the ignition switch 106 in the middle. The diode 108 is a backflow prevention element that is provided with the cathode facing the electronic control device 60 side and the anode facing the main power supply device 100 side, and can be energized only in the power supply direction.

  The drive system power supply line 105 is provided with a connecting line 109 that branches from the power supply relay 107 to the control system power supply line 104 on the load side. The connection line 109 is connected to the electronic control device 60 side of the connection position of the diode 108 of the control system power supply line 104. A diode 110 is connected to the connecting line 109. The diode 110 is provided with the cathode facing the control system power line 104 and the anode facing the drive system power line 105. Accordingly, the circuit configuration is such that power can be supplied from the drive system power supply line 105 to the control system power supply line 104 via the connection line 109, but power cannot be supplied from the control system power supply line 104 to the drive system power supply line 105. . Drive system power supply line 105 and ground line 111 are connected to booster circuit 40. The ground line 111 is also connected to the ground terminal of the electronic control device 60.

  The booster circuit 40 includes a capacitor 41 provided between the drive system power supply line 105 and the ground line 111, a booster coil 42 provided in series with the drive system power supply line 105 on the load side from the connection point of the capacitor 41, and a booster. The first boosting switching element 43 provided between the drive-side power supply line 105 on the load side of the coil 42 and the ground line 111, and the drive-side power supply line 105 on the load side from the connection point of the first boosting switching element 43. Are connected in series to each other, and a capacitor 45 provided between the drive power supply line 105 and the ground line 111 on the load side of the second boost switching element 44. A boost power supply line 112 is connected to the secondary side of the booster circuit 40.

  In this embodiment, MOSFETs are used as the boosting switching elements 43 and 44, but other switching elements can also be used. Further, as indicated by circuit symbols in the figure, the MOSFETs constituting the boosting switching elements 43 and 44 are structurally parasitic diodes.

  The booster circuit 40 is boosted and controlled by a power supply control unit 62 (described later) of the electronic control device 60. The power supply control unit 62 outputs a pulse signal having a predetermined cycle to the gates of the first and second boosting switching elements 43 and 44 to turn on and off the switching elements 43 and 44, and is supplied from the main power supply device 100. The power supply is boosted to generate a predetermined output voltage on the boost power supply line 112. 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. Therefore, a stable boost power supply is output from the boost power supply line 112. In this case, smoothing characteristics may be improved by connecting a plurality of capacitors having different frequency characteristics in parallel. Further, noise to the main power supply device 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 controlling the duty ratio of the first and second booster switching elements 43 and 44. The higher the on-duty ratio of the first booster switching element 43, the higher the on-duty ratio. The boost voltage becomes high. The booster circuit 40 in the present embodiment is configured such that the boosted voltage can be adjusted in the range of 20V to 50V, for example. Note that a general-purpose DC-DC converter can be used as the booster circuit 40.

  A voltage sensor 47 is provided on the boost power supply line 112 on the output side of the booster circuit 40. The voltage sensor 47 is connected to the power control unit 62 of the electronic control device 60 and outputs a signal representing the voltage vout that is a measured value to the power control unit 62.

  The boost power supply line 112 branches into a boost drive line 113 and a charge / discharge line 114. The boost drive line 113 is connected to the power input unit of the motor drive circuit 30. The charge / discharge line 114 is connected to the plus terminal of the sub power supply device 50.

  The sub power supply device 50 charges the power output from the booster circuit 40, and when the motor drive circuit 30 requires a large amount of power, the auxiliary power supply 50 assists the main power supply device 100 and supplies power to the motor drive circuit 30. Device. Therefore, the sub power supply device 50 is configured by connecting a plurality of power storage cells in series so that a voltage corresponding to the output voltage of the booster circuit 40 can be maintained. The ground terminal of the sub power supply device 50 is connected to the ground line 111.

  In this circuit configuration, since the boost power supply line 112 and the charge / discharge line 114 are connected, the measured value of the voltage sensor 47 is the higher voltage of the output voltage of the booster circuit 40 and the power supply voltage of the sub power supply device 50. Value. Hereinafter, the detection voltage of the voltage sensor 47 is referred to as an output voltage vout.

  The charge / discharge line 114 is provided with a current sensor 51 that detects a current flowing through the sub power supply device 50. The current sensor 51 is connected to the power control unit 62 of the electronic control device 60, and outputs a signal representing the current isub that is a measured value to the power control unit 62. In the present embodiment, the current sensor 51 detects the discharge current flowing from the sub power supply device 50 toward the motor drive circuit 30. However, even if the current sensor 51 detects the charge current and the discharge current by distinguishing the direction of the current. good. Hereinafter, the current value measured by the current sensor 51 is referred to as a discharge current isub.

  The electronic control unit 60 includes a microcomputer including a CPU, a ROM, a RAM, and the like as a main part, and is roughly divided into an assist control unit 61 and a power supply control unit 62 in terms of functions. The assist control unit 61 and the power supply control unit 62 are provided so as to be able to exchange control commands and control data with each other. The assist control unit 61 connects the steering torque sensor 21, the rotation angle sensor 22, the motor current sensor 38, and the vehicle speed sensor 23, and inputs sensor signals representing the steering torque Tx, the steering angle θx, the motor current iuvw, and the vehicle speed Vx. Based on these sensor signals, the assist control unit 61 outputs a PWM control signal to the motor drive circuit 30 to drive-control the electric motor 20 and assist the driver's steering operation.

  The power control unit 62 connects the voltage sensor 47 and the current sensor 51, and inputs sensor signals representing the output voltage vout and the discharge current isub. The power supply control unit 62 outputs a PWM control signal to the booster circuit 40 so that the target boosted voltage is obtained based on the detected output voltage vout. The booster circuit 40 controls the boosted voltage to the target voltage by controlling the duty ratio of the first and second boosting switching elements 43 and 44 in accordance with the input PWM control signal. The power supply control unit 62 performs boosting control by the boosting circuit 40 during the assist control performed by the assist control unit 61, but stops the boosting operation only when checking the state of the sub power supply device 50 described later.

  In addition, the power supply control unit 62 is connected to a notification device 63 for notifying the driver of the abnormality. Although the indicator 63 such as a lamp is used as the notification device 63 of the present embodiment, it may be notified to the driver by sound.

  Next, a steering assist control process performed by the assist control unit 61 of the electronic control device 60 will be described. FIG. 2 shows a steering assist control routine executed by the assist control unit 61, and is stored as a control program in the ROM of the electronic control device 60. The steering assist control routine is activated by turning on (turning on) the ignition switch 106 and is repeatedly executed at a predetermined short cycle.

  When this control routine is started, the assist control unit 61 first reads the vehicle speed Vx detected by the vehicle speed sensor 23 and the steering torque Tx detected by the steering torque sensor 21 in step S11.

  Subsequently, in step S12, with reference to the assist torque table shown in FIG. 3, the basic assist torque Tas set according to the input vehicle speed Vx and steering torque Tx is calculated. The assist torque table is stored in the ROM of the electronic control unit 60, and is set so that the basic assist torque Tas increases as the steering torque Tx increases, and increases as the vehicle speed Vx decreases. . The assist torque table in FIG. 3 represents the characteristic of the basic assist torque Tas with respect to the steering torque Tx in the right direction, but the characteristic in the left direction is the same when viewed in absolute values only in the opposite direction.

  Subsequently, in step S13, the assist control unit 61 adds the compensation torque to the basic assist torque Tas to calculate the target command torque T *. This compensation torque is a return torque corresponding to a return force to the basic position of the steering shaft 12 that increases in proportion to the steering angle θx and a resistance force that opposes the rotation of the steering shaft 12 that increases in proportion to the steering speed ωx. Is calculated as the sum of This calculation is performed by inputting the rotation angle of the electric motor 20 detected by the rotation angle sensor 22 (corresponding to the steering angle θx of the steering handle 11). Further, the steering speed ωx is obtained by differentiating the steering angle θx of the steering handle 11 with respect to time. The steering speed ωx may be estimated from the counter electromotive force generated by the electric motor 20.

  Next, in step S14, the assist control unit 61 calculates a target current ias * proportional to the target command torque T *. The target current ias * is obtained by dividing the target command torque T * by the torque constant.

  Subsequently, the assist control unit 61 reads the motor current iuvw flowing through the electric motor 20 from the motor current sensor 38 in step S15. Subsequently, in step S16, a deviation Δi between the motor current iuvw and the previously calculated target current ias * is calculated, and a target command voltage v * is calculated by PI control (proportional integral control) based on the deviation Δi.

  Then, in step S17, the assist control unit 61 outputs a PWM control signal corresponding to the target command voltage v * to the motor drive circuit 30, and once ends this control routine. This control routine is repeatedly executed at a predetermined fast cycle. Therefore, by executing this control routine, the duty ratios of the switching elements 31 to 36 of the motor drive circuit 30 are controlled, and a desired assist torque corresponding to the driver's steering operation is obtained.

  During the execution of such steering assist control, a large amount of electric power is required particularly when a steering wheel operation is performed at a low speed or a fast steering wheel rotation operation is performed. However, it is not preferable to increase the capacity of the main power supply device 100 in preparation for temporary large power consumption. Therefore, the electric power steering apparatus according to the present embodiment includes the auxiliary power supply device 50 that assists the power supply during temporary large power consumption without increasing the capacity of the main power supply device 100. Further, in order to efficiently drive the electric motor 20, a booster circuit 40 is provided, and a system for supplying the boosted power to the motor drive circuit 30 and the sub power supply device 50 is configured.

  When such a power supply system is configured, the regular performance (assist performance) of the electric power steering device can be fully exhibited by using both the main power supply device 100 and the sub power supply device 50. For this reason, in order to ensure regular assist performance, it is necessary to keep the charged state of the sub power supply device 50 favorable. Therefore, in this embodiment, when the power supply capability of the sub power supply device 50 is inspected and it is detected that the power supply capability has become insufficient due to deterioration of the sub power supply device 50 or the like, the driver is notified of the sub power supply device 50. Encourage exchange.

  Hereinafter, the sub power supply state inspection process performed by the power supply control unit 62 of the electronic control device 60 will be described. FIG. 4 shows a sub power supply state inspection routine executed by the power supply control unit 62, and is stored as a control program in the ROM of the electronic control unit 60. The sub power supply state inspection routine starts when a predetermined inspection timing comes when the ignition switch 106 is turned on. And after starting once, it repeats with a very short period, and is complete | finished when a test result is output. In addition, the inspection timing is set so that the sub power supply state inspection routine is started every time a predetermined time elapses (for example, every 5 minutes elapses) from the end of the previous sub power supply state inspection routine.

  When the sub power supply state inspection routine starts, the power supply control unit 62 performs inspection permission determination processing in step S20. This inspection permission determination process will be described later. Subsequently, in step S31, the power supply control unit 62 determines whether or not the inspection permission is output by the inspection permission determination process. Here, a case where inspection permission is output will be described first.

  When the inspection permission is output (S31: YES), the operation of the booster circuit 40 is stopped in step S32. That is, the first and second boosting switching elements 43 and 44 of the booster circuit 40 are held off. In this case, the secondary side voltage (output voltage) of the booster circuit 40 becomes lower than the power supply voltage of the sub power supply device 50 by stopping the operation of the booster circuit 40. Therefore, the power supply to the motor drive circuit 30 is performed only from the sub power supply device 50.

  Subsequently, the power supply control unit 62 reads the output voltage vout detected by the voltage sensor 47 and the discharge current isub detected by the current sensor 51 in step S33. In this case, the output voltage vout detected by the voltage sensor 47 represents the power supply voltage of the sub power supply device 50. The discharge current isub detected by the current sensor 51 represents the value of the discharge current flowing from the sub power supply device 50 to the motor drive circuit 30.

  Subsequently, in step S34, the power supply controller 62 determines whether or not the initial voltage vout0 is stored. The initial voltage vout0 represents the output voltage vout detected first after the boosting operation of the booster circuit 40 is stopped. If the initial voltage vout0 is not stored (S34: NO), the output voltage vout at that time is stored as the initial voltage vout0 in step S35. If the initial voltage vout0 is stored (S34: YES), the process of step S35 is not performed. In this sub power supply state inspection routine, the detection of the output voltage vout and the discharge current isub is repeated after the boosting operation of the booster circuit 40 is stopped, but the processing of steps S34 and S35 stores the initial output voltage vout. It is something to be made.

  Subsequently, in step S <b> 36, the power supply control unit 62 calculates the amount of power supplied from the sub power supply device 50 to the motor drive circuit 30 after the booster circuit 40 is stopped. In the present embodiment, the power supply amount Σisub is obtained by integrating the discharge current isub repeatedly detected at a predetermined cycle. This power supply amount Σisub is calculated by adding the value every time the discharge current isub is read, and is stored and updated in the RAM.

  Next, the power supply controller 62 calculates the voltage drop Δv in step S37. This voltage drop Δv is obtained from the difference (vout0−vout) between the initial voltage vout0 and the current output voltage vout. When the boosting operation of the booster circuit 40 is stopped, the output voltage vout represents the power supply voltage of the sub power supply device 50. Therefore, here, a decrease in the power supply voltage of the sub power supply device 50 is obtained.

  Subsequently, in step S38, the power supply controller 62 determines whether or not the voltage drop Δv has reached a preset set value A. When the voltage drop Δv is less than the set value A (S38: NO), the sub power supply state inspection routine is temporarily ended. This sub power supply state inspection routine is repeatedly executed at a predetermined short cycle. Accordingly, detection of the output voltage vout and the discharge current isub, calculation of the power supply amount Σisub, and calculation of the voltage drop Δv are performed each time. When the power supply control unit 62 repeats such processing and determines that the voltage drop Δv has reached the preset setting value A (S38: YES), the processing proceeds to step S39.

  In step S39, the power supply control unit 62 determines whether or not the power supply amount Σisub is lower than the reference power amount B. The power supply voltage of the sub power supply device 50 gradually decreases as power is supplied to the motor drive circuit 30. In the case where the sub power supply device 50 is deteriorated, the power supply voltage quickly decreases with respect to an increase in the amount of power supplied to the motor drive circuit 30. On the other hand, when the power supply capability is high, the rate of decrease in the power supply voltage is slow with respect to the increase in the amount of power supplied to the motor drive circuit 30.

  That is, as the sub power supply device 50 is deteriorated, the voltage drop Δv reaches the set value A when the amount of power supplied to the motor drive circuit 30 is small. Therefore, when the power supply amount Σisub is lower than the reference power amount B in step S39, the power supply control unit 62 determines that the power supply capability of the sub power supply device 50 is low, and turns on the alarm 63 in step S40. Let Thus, the driver can recognize that it is time to replace the sub power supply device 50. On the other hand, if the power supply amount Σisub is greater than or equal to the reference power amount B in step S39, it is determined that the power supply capability of the sub power supply device 50 is appropriate. When the result of the inspection of the sub power supply device 50 is obtained in the determination of step S39, the sub power supply inspection routine is terminated. The sub power supply inspection routine is started again after a predetermined time has elapsed (for example, 5 minutes).

  On the other hand, if the inspection permission is not output in step S31, the booster circuit 40 is operated as usual in step S41. That is, a PWM control signal is output to the booster circuit 40 based on the deviation between the output voltage vout detected by the voltage sensor 47 and the target booster voltage, and the duty ratios of the first and second booster switching elements 43 and 44 are controlled. As a result, the boosted voltage is controlled to the target boosted voltage. Therefore, the power supply to the motor drive circuit 30 is maintained in a state where it can be performed from both the main power supply device 100 and the sub power supply device 50.

  Subsequently, in step S42, it is determined whether the initial voltage vout0 and the power supply amount Σisub are stored. If they are stored (S42: YES), the initial voltage vout0 and the power supply amount Σisub are cleared in step S43. To do. That is, when the inspection permission is stopped in the middle of the inspection of the sub power supply device 50, the data indicating the initial voltage vout0 and the electric energy isub is stored in the RAM, and thus the data is deleted. If it is determined in step S42 that the initial voltage vout0 and the power supply amount Σisub are not stored, the sub power supply state inspection routine is temporarily terminated as it is.

  While the inspection permission is not output, the processes in steps S41 to S43 are repeated. When the inspection permission is output in step S31, the process proceeds to the process from step S32 described above. Thereby, the operation of the booster circuit 40 is stopped (S32), and the power supply voltage of the sub power supply device 50 can be detected by the voltage sensor 47. As described above, the power supply control unit 62 calculates the power supply amount Σisub and the voltage drop Δv of the sub power supply device 50 and repeats the calculation process until the voltage drop Δv reaches the set value A. When the voltage drop Δv reaches the set value A, the inspection result of the power supply capability of the sub power supply device 50 is output according to the power supply amount Σisub at that time. That is, the alarm device 63 is activated when the power supply capability of the sub power supply device 50 is low.

  Next, the inspection permission determination process in step S20 will be described. As described above, when the power supply capability of the sub power supply device 50 is inspected, it is necessary to stop the power supply from the main power supply device 100 to the motor drive circuit 30. Therefore, when the motor drive circuit 30 requires a large amount of power due to the steering assist control, the electric motor 20 may not be driven properly. In addition, the charge amount of the sub power supply device 50 may be significantly reduced.

  Therefore, in the present embodiment, when the electric motor 20 is driven only from the sub power supply device 50, it is predicted whether or not there is a possibility of insufficient power supply, and there is a possibility of insufficient power supply. In this case, the inspection of the power supply capability of the sub power supply device 50 is prohibited. Hereinafter, the inspection of the power supply capability of the sub power supply device 50 is simply referred to as inspection of the sub power supply device 50.

  FIG. 5 is a flowchart showing an inspection permission determination routine. This inspection permission determination routine is incorporated as the process of step S20 of the above-described sub power supply state inspection routine. In this inspection permission determination routine, first, the vehicle speed Vx detected by the vehicle speed sensor 23 is read in step S21. The vehicle speed Vx is data used for assist control processing performed by the assist control unit 61. Therefore, the power control unit 62 reads the vehicle speed Vx from the assist control unit 61.

  Subsequently, in step S22, the power supply control unit 62 determines whether or not the flag F is set to “0”. This flag F indicates whether the inspection of the sub power supply apparatus 50 is permitted (F = 0) or prohibited (F = 1). Is set to "0".

  If it is determined in step S22 that the flag F is set to “0”, it is determined in step S23 whether or not the vehicle speed Vx is equal to or lower than the prohibition determination speed V1. If the vehicle speed Vx is equal to or lower than the prohibition determination speed V1, the flag F is set to “1” in step S24. If the vehicle speed Vx exceeds the prohibition determination speed V1, the setting of the flag F is not changed. That is, in the processes of steps S23 to S24, it is determined whether or not the prohibition condition for the inspection of the sub power supply device 50 is satisfied. When the vehicle speed Vx is equal to or lower than the prohibition determination speed V1, the prohibition condition is satisfied. The flag F is set to “1”.

  On the other hand, if it is determined in step S22 that the flag F is set to “1”, it is determined in step S25 whether or not the vehicle speed Vx is equal to or higher than the permission determination speed V2. If the vehicle speed Vx is equal to or higher than the permission determination speed V2, the flag F is set to “0” in step S26, and if the vehicle speed Vx is less than the permission determination speed V2, the setting of the flag F is not changed. That is, in the processes of steps S25 to S26, it is determined whether or not the prohibition cancellation condition for the inspection of the sub power supply device 50 is satisfied, and the prohibition cancellation condition is satisfied when the vehicle speed Vx is equal to or higher than the permission determination speed V2. The flag F is set to “0”. The permission determination speed V2 is set to a value (high speed) larger than the prohibition determination speed V1.

  When the flag F is set in this way, subsequently, in step S27, the setting state of the flag F is confirmed. If the flag F is set to “1”, an inspection prohibition command is issued in step S28. Output. On the other hand, if the flag F is set to “0”, an inspection permission command is output in step S29. This instruction is read in step S31 in the sub power supply state inspection routine, and is used to determine whether or not inspection is permitted.

  Since this inspection permission determination routine is incorporated as the process of step S20 of the sub power supply state inspection routine, it is repeated at a predetermined short cycle.

  According to the inspection permission determination routine described above, the inspection permission / prohibition of the auxiliary power supply device 50 is determined according to the vehicle speed Vx. That is, an inspection prohibition command is output when the vehicle speed Vx is equal to or lower than the prohibition determination speed V1, and an inspection permission command is output when the vehicle speed Vx increases to the permission determination speed V2 or higher. Therefore, when the vehicle is traveling at low speed or stopped (hereinafter referred to as low-speed traveling including when stopped), inspection of the sub power supply device 50 is prohibited.

  The energy required to steer the steered wheels FWL and FWR increases as the traveling speed of the vehicle decreases. Further, a lighter operating performance is required at low speeds than at high speeds. Therefore, the required power of the electric motor 20 that assists the driver's steering operation also increases as the traveling speed of the vehicle decreases. Therefore, in the present embodiment, when the vehicle speed Vx is equal to or lower than the prohibition determination speed V1 (corresponding to the reference speed of the present invention), it is predicted that there is a possibility of insufficient power supply to the motor drive circuit 30. Thus, the inspection of the sub power supply device 50 is prohibited. Thus, the power supply control unit 62 continues the boosting control of the boosting circuit 40 in preparation for the steering operation, and maintains a state where both the main power supply device 100 and the sub power supply device 50 can supply power to the motor drive circuit 30. At this time, when the charge amount of the sub power supply device 50 is insufficient, the sub power supply device 50 is charged from the booster circuit 40, so that the charge amount of the sub power supply device 50 can be increased. When a steering operation is performed from this state, power is supplied to the motor drive circuit 30 from the main power supply device 100 and the sub power supply device 50.

  As a result, even if a steering operation is performed during low-speed traveling, the necessary power can be supplied to the motor drive circuit 30, and the steering assist by the assist control unit 61 can be performed appropriately. Further, at the time of the capacity test of the sub power supply device 50, the power supply from the main power supply device 100 is stopped, but the power required to be supplied to the motor drive circuit 30 is small. Can be performed properly. Further, the charge amount of the sub power supply device 50 is not significantly reduced.

  In addition, since hysteresis is provided in the determination speed when switching inspection permission / prohibition of the sub power supply device 50, a problem that the prohibition command and the permission command are frequently switched is prevented. In other words, the permission determination speed V2 is set to a value larger than the prohibition determination speed V1, so that after the prohibition command is output based on the prohibition determination speed V1, the vehicle speed Vx does not increase to the permission determination speed V2. The prohibition order continues. Further, after the permission command is output, the permission command is continued unless the vehicle speed Vx decreases to the prohibition determination speed V1. Thus, when the vehicle speed Vx takes a value between the prohibition determination speed V1 and the permission determination speed V2, hysteresis is provided so as not to change the command.

  According to the electric power steering apparatus provided with the power supply control apparatus of the present embodiment described above, the auxiliary power supply apparatus 50 is inspected at an appropriate timing according to the vehicle speed Vx. can get. Further, the amount of charge of the sub power supply device 50 is not significantly reduced.

  Further, as the power supply device to the electric power steering device, the main power device 100 and the sub power device 50 are used so that the steering assist performance can be fully exhibited. can do. Further, the electric motor 20 can be efficiently driven by the booster circuit 40. Further, by reducing the boosted voltage of the booster circuit 40, the power supply from the main power supply device 100 is stopped and the power supply is switched from the sub power supply device 50 only, so that a special switching switch or circuit is required. do not do.

  Further, since the power supply capability of the sub power supply device 50 is inspected from the relationship between the power supply amount Σisub and the power supply voltage drop Δv, high inspection accuracy can be obtained. In addition, since hysteresis is provided in the determination speed when switching inspection permission / prohibition of the sub power supply device 50, a problem that the prohibition command and the permission command are frequently switched is prevented.

  Next, a first modification of the inspection permission determination process will be described. FIG. 6 is a flowchart showing an inspection permission determination routine as a first modification. In the first modified example, the processes of steps S51, S53, and S55 are performed instead of the processes of steps S21, S23, and S25 of the inspection permission determination routine of the above-described embodiment. Hereinafter, the same processes as those in the above-described embodiment are denoted by the same step symbols in the drawings, and description thereof is omitted.

  When the inspection permission determination routine of the first modification is activated, the power supply control unit 62 first reads the steering speed ωx from the assist control unit 61 in step S51. The steering speed ωx is calculated by time-differentiating the detection signal (representing the steering angle θx) of the rotation angle sensor 22 when the assist control unit 61 is performing assist control. Accordingly, in step S51, the steering speed ωx used in the assist control is read.

  When the flag F is set to “0” (S22: YES), the power supply control unit 62 determines whether or not the steering speed ωx is equal to or higher than the prohibition determination steering speed ω1 in step S53. If the steering speed ωx is equal to or higher than the prohibition determination steering speed ω1, the flag F is set to “1” in step S24. If the steering speed ωx is lower than the prohibition determination steering speed ω1 (S53: NO), the flag F Do not change the setting. That is, in the processes of steps S53 and S24, it is determined whether or not the prohibition condition for the inspection of the sub power supply device 50 is satisfied, and the prohibition condition is satisfied when the steering speed ωx is equal to or higher than the prohibition determination steering speed ω1. The flag F is set to “1”.

  On the other hand, when the flag F is set to “1” (S22: NO), the power supply control unit 62 determines whether or not the steering speed ωx is equal to or lower than the permission determination steering speed ω2 in step S55. . If the steering speed ωx is equal to or lower than the permission determination steering speed ω2, the flag F is set to “0” in step S26, and if the steering speed ωx exceeds the permission determination steering speed ω2 (S55: NO), the flag Do not change F setting. That is, in the processes of steps S55 and S26, it is determined whether or not the prohibition cancellation condition for the inspection of the sub power supply device 50 is satisfied. When the steering speed ωx is equal to or lower than the permission determination steering speed ω2, the prohibition cancellation condition is As a result, the flag F is set to “0”. The permission determination steering speed ω2 is set to a value (low speed) smaller than the prohibition determination steering speed ω1.

  According to the inspection permission determination routine as the first modified example described above, whether the inspection of the sub power supply device 50 is permitted or prohibited is determined according to the steering speed ωx. That is, when the steering speed ωx is equal to or higher than the prohibition determination steering speed ω1, the inspection prohibition command is output, and when the steering speed ωx is decreased to the permission determination steering speed ω2 or lower, the inspection permission command is output. Therefore, when the steering handle 11 is operated at a fast rotation, the inspection of the sub power supply device 50 is prohibited.

  In order to rotate the steering handle 11 quickly, a large steering operation force is required for the driver. For this reason, the required electric power of the electric motor 20 which assists a driver | operator's operation also increases. Therefore, in the present modification 1, when the steering speed ωx is equal to or higher than the prohibition determination steering speed ω1 (corresponding to the reference steering speed of the present invention), there is a possibility of insufficient power supply to the motor drive circuit 30. The sub power supply device 50 is prohibited from being inspected in anticipation of being present. Thereby, the same effect as the above-described embodiment can be obtained. In addition, since the determination steering speed is provided with a hysteresis when switching the capability test of the auxiliary power supply device 50 between permission and prohibition, a problem that the prohibition command and the permission command are frequently switched is prevented.

  Next, a second modification of the inspection permission determination process will be described. FIG. 7 is a flowchart showing an inspection permission determination routine as a second modification. In the second modification, steps S61, S63, and S65 are performed instead of the steps S21, S23, and S25 of the inspection permission determination routine of the above-described embodiment. Hereinafter, the same processes as those in the above-described embodiment are denoted by the same step symbols in the drawings, and description thereof is omitted.

  When the inspection permission determination routine of the second modification is started, the power supply control unit 62 first reads the steering angle θx from the assist control unit 61 in step S61. The steering angle θx is obtained from the detection signal of the rotation angle sensor 22 when the assist control unit 61 is performing assist control. Accordingly, in step S61, the steering angle θx used in the assist control is read.

  When the flag F is set to “0” (S22: YES), the power supply control unit 62 determines whether or not the steering angle θx is greater than or equal to the prohibition determination steering angle θ1 in step S63. If the steering angle θx is equal to or greater than the prohibition determination steering angle θ1, the flag F is set to “1” in step S24. If the steering angle θx is less than the prohibition determination steering angle θ1 (S63: NO), the flag F Do not change the setting. That is, in the processing of steps S63 and S24, it is determined whether or not the prohibition condition for the inspection of the sub power supply device 50 is satisfied, and the prohibition condition is satisfied when the steering angle θx is equal to or greater than the prohibition determination steering angle θ1. The flag F is set to “1”.

  On the other hand, when the flag F is set to “1” (S22: NO), the power supply control unit 62 determines whether or not the steering angle θx is equal to or smaller than the permission determination steering angle θ2 in step S65. . If the steering angle θx is less than or equal to the permission determination steering angle θ2, the flag F is set to “0” in step S26, and if the steering angle θx exceeds the permission determination steering angle θ2 (S65: NO), the flag Do not change F setting. That is, in the processing of steps S65 and S26, it is determined whether or not the prohibition cancellation condition for the inspection of the sub power supply device 50 is satisfied, and when the steering angle θx is equal to or smaller than the permission determination steering angle θ2, the prohibition cancellation condition is As a result, the flag F is set to “0”. The permission determination steering angle θ2 is set to be smaller than the prohibition determination steering angle θ1.

  According to the inspection permission determination routine as the second modified example described above, whether the inspection of the auxiliary power supply device 50 is permitted or prohibited is determined according to the steering angle θx. That is, the inspection prohibition command is output when the steering angle θx is equal to or greater than the prohibition determination steering angle θ1, and the inspection permission command is output when the steering angle θx becomes smaller than the permission determination steering angle θ2. Therefore, when the steering handle 11 is operated at a large steering angle, the inspection of the sub power supply device 50 is prohibited.

  In order to rotate the steering handle 11 to a large steering angle position, a large steering operation force is required for the driver due to steering characteristics. For this reason, the required electric power of the electric motor 20 which assists a driver | operator's operation also increases. Therefore, in the second modification, when the steering angle θx is equal to or greater than the prohibition determination steering angle θ1 (corresponding to the reference steering angle of the present invention), there is a possibility that power supply to the motor drive circuit 30 may be insufficient. The sub power supply device 50 is prohibited from being inspected in anticipation of being present. Thereby, the same effect as the above-described embodiment can be obtained. In addition, since hysteresis is provided in the determination steering angle when switching inspection permission / prohibition of the sub power supply device 50, a problem that the prohibition command and the permission command are frequently switched is prevented.

  Next, a third modification of the inspection permission determination process will be described. FIG. 8 is a flowchart showing an inspection permission determination routine as a third modification. In the third modified example, steps S71, S73, and S75 are performed instead of the steps S21, S23, and S25 of the inspection permission determination routine of the above-described embodiment. Hereinafter, the same processes as those in the above-described embodiment are denoted by the same step symbols in the drawings, and description thereof is omitted.

  When the inspection permission determination routine of the third modification is started, the power supply control unit 62 first reads the steering torque Tx from the assist control unit 61 in step S71. The steering torque Tx is detected by the steering torque sensor 21 when the assist control unit 61 is performing the assist control. In this step S71, the steering torque Tx used in the assist control is read.

  When the flag F is set to “0” (S22: YES), the power supply control unit 62 determines whether or not the steering torque Tx is equal to or greater than the prohibition determination steering torque T1 in step S73. If the steering torque Tx is equal to or greater than the prohibition determination steering torque T1, the flag F is set to “1” in step S24. If the steering torque Tx is less than the prohibition determination steering torque T1 (S73: NO), the flag F Do not change the setting. That is, in the processes of steps S73 and S24, it is determined whether or not a prohibition condition for the inspection of the sub power supply device 50 is satisfied, and the prohibition condition is satisfied when the steering torque Tx is equal to or greater than the prohibition determination steering torque T1. The flag F is set to “1”.

  On the other hand, when the flag F is set to “1” (S22: NO), the power supply control unit 62 determines whether or not the steering torque Tx is equal to or less than the permission determination steering torque T2 in step S75. . If the steering torque Tx is equal to or smaller than the permission determination steering torque T2, the flag F is set to “0” in step S26, and if the steering torque Tx exceeds the permission determination steering torque T2 (S75: NO), the flag Do not change F setting. That is, in the processes of steps S75 and S26, it is determined whether or not the prohibition cancellation condition for the inspection of the sub power supply device 50 is satisfied. When the steering torque Tx is equal to or less than the permission determination steering torque T2, the prohibition cancellation condition is As a result, the flag F is set to “0”. The permission determination steering torque T2 is set to a value smaller than the prohibition determination steering torque T1.

  According to the inspection permission determination routine as the third modified example described above, whether the inspection of the auxiliary power supply device 50 is permitted or prohibited is determined according to the steering torque Tx. That is, when the steering torque Tx becomes equal to or greater than the prohibition determination steering torque T1, an inspection prohibition command is output, and when the steering torque Tx decreases below the permission determination steering torque T2, an inspection permission command is output. Therefore, when the steering handle 11 is steered with a large torque, the inspection of the sub power supply device 50 is prohibited.

  In order to rotate the steering handle 11 with a large torque, a large steering operation force is required for the driver. For this reason, the required power of the electric motor 20 that assists the driver's operation also increases. Therefore, in the third modification, when the steering torque Tx is equal to or greater than the prohibition determination steering torque T1 (corresponding to the reference steering torque of the present invention), there is a possibility of insufficient power supply to the motor drive circuit 30. The sub power supply device 50 is prohibited from being inspected in anticipation of being present. Thereby, the same effect as the above-described embodiment can be obtained. Further, since the hysteresis is provided in the determination steering torque when switching the inspection permission / prohibition of the sub power supply device 50, a problem that the prohibition command and the permission command are frequently switched is prevented.

  As mentioned above, although the electric power steering apparatus provided with the power supply control apparatus was demonstrated as embodiment of this invention, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the objective of this invention. Is possible.

  For example, in this embodiment, when the sub power supply device 50 is inspected, the boosting operation of the booster circuit 40 is stopped. However, the target boost voltage is set to be higher than the power supply voltage (normal target boost voltage) of the sub power supply device 50. Alternatively, the boosting operation may be continued by setting a lower voltage.

  In this embodiment, the power supply amount Σisub is calculated from the discharge current isub detected by the current sensor 51. However, the power supply amount may be calculated from the motor current iuvw detected by the motor current sensor 38.

  The application of the power supply control device is not limited to the electric power steering device, and can be applied to various devices. For example, the present invention can be applied to various devices such as an electrically controlled brake device, an electrically controlled suspension device, and an electrically controlled stabilizer device mounted on a vehicle. In addition, as a steering device for applying a steering force to a wheel, a steering wheel and a wheel steering shaft are mechanically separated from each other, and a by-wire type steering that steers the wheel only by the power of an electric motor that operates according to a steering operation. It can also be applied to devices.

It is a schematic structure figure of an electric power steering device provided with a power supply control device concerning an embodiment of the present invention. It is a flowchart showing a steering assist control routine. It is a graph showing an assist torque table. It is a flowchart showing a sub-power supply state inspection routine. It is a flowchart showing an inspection permission determination routine. 10 is a flowchart illustrating an inspection permission determination routine according to a first modification. 10 is a flowchart illustrating an inspection permission determination routine according to Modification 2. 10 is a flowchart illustrating an inspection permission determination routine according to Modification 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Steering mechanism, 20 ... Electric motor (electric actuator), 21 ... Steering torque sensor, 22 ... Rotation angle sensor, 23 ... Vehicle speed sensor, 30 ... Motor drive circuit (electric actuator drive circuit), 40 ... Booster circuit, 47 ... Voltage sensor, 50 ... sub power supply device, 51 ... current sensor, 60 ... electronic control device, 61 ... assist control unit, 62 ... power supply control unit, 100 ... main power supply device, 101 ... main battery, 102 ... alternator, FWL, FWR ... left and right front wheels.

Claims (8)

A main power supply;
A sub-power supply device charged by the main power supply device, wherein the main power supply device and the sub-power supply device are connected in parallel to the electric actuator drive circuit, and the main power supply device and the sub-power supply device In the power supply control device for supplying power to the electric actuator drive circuit,
Sub power supply inspection means for inspecting the power supply capability of the sub power supply device by switching to a state in which power supply to the electric actuator drive circuit is performed only from the sub power supply device,
Prior to the inspection by the auxiliary power supply inspection means, it is predicted whether or not there is a possibility of insufficient power supply to the electric actuator drive circuit when power is supplied to the electric actuator drive circuit only from the auxiliary power supply device. Power shortage prediction means,
Power supply control, comprising: an inspection prohibiting means for prohibiting the inspection by the sub power supply inspection means when the power shortage prediction means predicts that the power supply shortage may occur. apparatus. A booster circuit for boosting the output voltage of the main power supply device; the electric actuator drive circuit is connected to an output side of the booster circuit; and the sub power supply device is provided between the booster circuit and the electric actuator drive circuit. Configure the power supply circuit connected in parallel,
2. The sub power supply inspection unit switches to a state in which power supply to the electric actuator drive circuit is performed only from the sub power supply device by stopping boosting of the boosting circuit or lowering the boosted voltage. The power supply control device described.   The sub power supply inspection unit inspects the power supply capability of the sub power supply device based on the relationship between the power supply amount supplied from the sub power supply device to the electric actuator drive circuit and the power supply voltage drop of the sub power supply device. The power supply control device according to claim 1, wherein the power supply control device is a power supply control device.   The electric power steering device for a vehicle that assists the driver's steering operation by controlling the electric actuator drive circuit according to the driver's steering operation to generate a steering force and using the electric actuator driving circuit. The power supply control device according to any one of claims 1 to 3. Vehicle speed acquisition means for acquiring vehicle speed information;
Based on the vehicle speed information acquired by the vehicle speed acquisition unit, the power shortage prediction unit predicts that there is a risk of insufficient power supply to the electric actuator drive circuit when the vehicle speed is equal to or lower than a reference speed. The power supply control device according to claim 4, wherein: Steering speed acquisition means for acquiring steering speed information of the steering wheel;
The power shortage predicting means may cause a shortage of power supply to the electric actuator drive circuit when the steering speed is equal to or higher than a reference steering speed based on the steering speed information acquired by the steering speed acquisition means. The power supply control device according to claim 4, wherein the power supply control device is predicted to be A steering angle acquisition means for acquiring steering angle information of the steering wheel;
The power shortage predicting means may cause a shortage of power supply to the electric actuator drive circuit when the steering angle is greater than or equal to a reference steering angle based on the steering angle information acquired by the steering angle acquiring means. The power supply control device according to claim 4, wherein the power supply control device is predicted to be Steering torque acquisition means for acquiring steering torque information acting on the steering wheel;
The power shortage predicting means may cause a shortage of power supply to the electric actuator drive circuit when the steering torque is greater than or equal to a reference steering torque based on the steering torque information acquired by the steering torque acquiring means. The power supply control device according to claim 4, wherein the power supply control device is predicted to be

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