JP2015051718A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a motor controller capable of independently, simultaneously controlling two motors with one motor drive unit and greatly improving motor current detection accuracy without cost increase.SOLUTION: A motor controller includes: an H-bridge circuit that includes MOSFETs 400 to 403; a switching circuit that includes MOSFETs 4041 and 4042 each having a current detection function and that is connected to the H-bridge circuit in parallel; and one current detection resistor 500. A voltage across the current detection resistor 500 between the MOSFET 402 and a ground for connecting a first motor 200 between a connection point at which the MOSFETs 400 and 402 are connected to each other and a connection point at which the MOSFETs 4041 and 4042 are connected to each other, and a second motor 201 between a connection point at which the MOSFETs 401 and 403 are connected to each other and the connection point at which the MOSFETs 4041 and 4042 are connected to each other is input to a CPU 308. Information on a current flowing to a half-bridge IPD 404 is input to the CPU 308. The CPU 308 controls the MOSFETs 400 to 403, 4041, and 4042 to be turned on/off.

Description

  The present invention relates to a motor control device for a vehicle.

  There is a control device for a motor for a seat belt retractor mounted on a vehicle.

  In the prior art, a motor for a seat belt retractor and a control unit thereof are provided on each of a driver seat side and a passenger seat side of the vehicle.

  For this reason, a motor drive circuit is required for each of the two motors, the motor on the driver's seat side and the motor on the passenger's seat side, and a switching element is required for each of the motor drive circuits, resulting in an increase in cost. It was.

  Therefore, Patent Document 1 describes a technique for reducing the number of switching elements by using one control unit and one motor drive circuit as a common driver side motor and passenger side motor.

  Patent Document 1 discloses a motor driving device including one CPU and six switching elements.

JP 2012-96686 A

  However, in the technique described in Patent Document 1, since the driver seat side motor and the passenger seat side motor share one control unit and one motor drive circuit, the driver seat side and the passenger seat side are independent at the same time. It was difficult to control.

  In the technique described in Patent Document 1, since the motor drive current is estimated and controlled from the rotation speed of the belt reel, it is difficult to improve the current detection accuracy, and the motor drive accuracy is improved. There was a problem that it was difficult.

  In order to improve current detection accuracy, it is only necessary to provide a current detection resistor for each of the driver side motor and the passenger side motor. However, not only two current detection resistors are required, but also the CPU side has a current detection resistor. Two value input ports must be provided, which increases the cost.

  An object of the present invention is to provide a motor controller for a seat belt retractor for a vehicle that can improve the current detection accuracy of a motor without significantly increasing the cost while simultaneously controlling two motors independently by a single motor drive unit. Is to realize.

  In order to achieve the above object, the present invention is configured as follows.

  A motor control device for a seat belt retractor for a vehicle according to the present invention includes an H bridge circuit having four switching elements, a half bridge circuit having two switching elements, and a current detection resistor connected to the H bridge circuit. A first electric motor and a second electric motor are connected between the H-bridge circuit and the half-bridge circuit, and a motor driving unit that drives the first electric motor and the second electric motor, and the motor driving unit. A motor drive driver section that supplies a signal for turning on and off the switching elements of the H bridge circuit and the half bridge circuit to the motor drive section, and a control command section that generates a command for controlling the switching elements.

  The control command unit calculates a current flowing through the first electric motor and the second electric motor based on a current flowing through the current detection resistor and a current flowing through the half bridge circuit, and also includes the H bridge circuit and the half bridge circuit. A command for controlling the switching element of the bridge circuit is generated.

  According to the present invention, there is provided a motor control device for a seat belt retractor of a vehicle that can improve the current detection accuracy of the motor without significantly increasing the cost, while the two motors can be independently controlled simultaneously by one motor driving unit. Can be realized.

1 is a schematic configuration diagram of a general collision safety device and a seat belt device in a vehicle to which the present invention is applied. It is explanatory drawing of the seatbelt apparatus by the side of a driver's seat, and is a figure which shows the state by which the passenger | crew is restrained by the seatbelt. It is a figure which shows the motor drive device for seatbelt retractors used for one Example of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a general collision safety device and a seat belt device in a vehicle to which the present invention is applied.

  In FIG. 1, an obstacle sensor 102 that outputs a signal corresponding to a distance from an obstacle is attached to a vehicle 112 at the front part of the vehicle 112. The output signal of the obstacle sensor 102 is transmitted to the collision determination controller 106 that is electrically connected to the obstacle sensor 102.

  A signal from the wheel speed sensor 104 that outputs a signal corresponding to the speed of the vehicle 112 is also transmitted to the collision determination controller 106 that is electrically connected to the wheel speed sensor 104.

  The collision determination controller 106 determines whether or not the vehicle 112 collides with an obstacle based on signals from the obstacle sensor 102 and the wheel speed sensor 104. For example, when the distance to the obstacle obtained from the output signal of the obstacle sensor 102 is shorter than a predetermined value and the vehicle speed obtained from the output signal of the wheel speed sensor 104 is higher than the predetermined value, The collision determination controller 106 determines that the vehicle 112 collides with an obstacle. Before the vehicle 112 collides with the obstacle, the brake assist device 108 and the seat belt drive controller 110 (driver's seat side) and 114 (passenger seat side) A command signal is output.

  The brake assist device 108 and the seat belt drive controllers 110 and 114 are electrically connected to the collision determination controller 106, and each execute a predetermined operation based on a command signal from the collision determination controller 106.

  The seat belt drive controller 110 is electrically connected to the retractor 100 and controls power feeding to the retractor 100. The seat belt drive controller 114 is electrically connected to the retractor 116 and controls power feeding to the retractor 116.

  FIG. 2 is an explanatory diagram of the seat belt device on the driver's seat side, and shows a state where an occupant is restrained by the seat belt.

  In FIG. 2, the retractor 100 is provided with a motor 200, and the seat belt can be wound by rotating the electric motor 200. For example, let us consider a case where the occupant 202 is moving in the forward direction of the vehicle while the occupant 202 is driving the vehicle 112, and a gap is generated between the occupant 202 and the seat 204.

  In such a situation, when the vehicle 112 collides with an obstacle, the occupant 202 is not restrained by the seat 204 and is therefore strongly hit against the seat 204.

  However, the seat belt device can eliminate the gap between the occupant 202 and the seat 204 by operating the motor 200 attached to the retractor 100 and winding the seat belt 206 before the vehicle 112 and the obstacle collide. Is possible. Accordingly, when the vehicle 112 and the obstacle collide with each other, the passenger 202 is already restrained by the seat 204, so that the impact on the passenger 202 can be reduced.

  FIG. 3 is a view showing a seat belt retractor motor driving device 302 used in one embodiment of the present invention. The motor drive device 302 may be mounted inside the housing of the seat belt retractor 100 or 116, or may be installed inside the vehicle physically separated from the seat belt retractor 100.

  Further, the motor driving device 302 shown in FIG. 3 can be replaced with two controllers of the seat belt driving controllers 110 and 114 shown in FIG. Control the operation of the two motors, the passenger side motor.

  The motor driving device 302 includes a custom IC 304 and a motor driving unit 600.

  The custom IC 304 includes a CPU (control command unit) 308 that controls signal processing, a power supply circuit 306 connected to the power supply 300, a motor drive driver unit 312, and an A / D conversion unit 316.

  In addition, the motor driving unit 600 includes switching elements 400, 401, 402, and 403 that switch power supply states to the two motors 200 and 201, a half-bridge circuit IPD 404 having a current detection function (a switching element 4041 of a high-side bridge, Low-side bridge switching element 4042) and one current detection resistor 500.

  Note that, instead of the half-bridge IPD 404 having a current detection function, it is also possible to configure with two switching elements and one current detection resistor.

  The switching elements 400 to 403 of the motor driving unit 600 are MOSFETs, the source of the MOSFET 400 is connected to the power supply 300, and the drain of the MOSFET 400 is connected to the drain of the MOSFET 402.

  The source of the MOSFET 402 is grounded via the current detection resistor 500.

  The source of the MOSFET 401 is connected to the power supply 300, and the drain of the MOSFET 401 is connected to the drain of the MOSFET 403.

  The source of the MOSFET 403 is grounded.

  The switching elements 4041 and 4042 of the half-bridge IPD 404 are MOSFETs, the source of the MOSFET 4041 is connected to the power supply 300, and the drain of the MOSFET 4041 is connected to the drain of the MOSFET 4042. The source of the MOSFET 4042 is grounded.

  The drains of the MOSFETs 400 and 402 are connected to the drains of the MOSFETs 4041 and 4042 via the motor 200. The drains of the MOSFETs 401 and 403 are connected to the drains of the MOSFETs 4041 and 4042 via the electric motor 201.

  The CPU 308 instructs the motor drive driver unit 312 to turn on and off the MOSFETs 400 to 403, 4041, and 4042 of the motor drive unit 600. The motor drive driver unit 312 performs on / off operation of the MOSFETs 400 to 403, 4041, and 4042 according to the on / off command of the MOSFETs 400 to 403, 4041, and 4042 from the CPU 308.

  The DO2 terminal of the motor driver unit 312 outputs the PWM signal (B) to the gate of the MOSFET 4041 and outputs the PWM signal (B) to switch the MOSFET 4041 on and off in synchronization with the PWM signal (B).

Further, the D04 terminal of the motor drive driver unit 312 outputs a high signal (D) to the gate of the MOSFET 402, whereby the MOSFET 402 is turned on. As a result, the current I ₄₀₂ flows from the MOSFET 4041 of the half-bridge IPD to the MOSFET ₄₀₂ , so that the motor 200 rotates in the forward rotation direction.

  At the same time, the DO6 terminal of the motor drive driver unit 312 outputs a high signal (F) to the gate of the MOSFET 4023, so that the MOSFET 403 is turned on. Rotate to.

  The half bridge IPD 404 is provided with a current detection information output terminal for the current flowing through the half bridge IPD 404, and the current detection information G from the current detection information output terminal is input to the CPU 308 via the A / D conversion unit 316. The

As a result, the CPU 308 detects the current value I _404a flowing through the MOSFET 4041. Further, the potential difference of the current detection resistor 500 connected between the source of the MOSFET ₄₀₂ and the ground is input to the CPU 308 via the A / D conversion unit 316, so that the CPU 308 detects the current value I ₄₀₂ flowing through the MOSFET _402. Can do.

Further, the value of the current flowing through the MOSFET ₄₀₃ can be detected by the CPU 308 calculating I _404a -I ₄₀₂ .

  The D05 terminal of the motor driver section 312 outputs the PWM signal (E) to the gate of the MOSFET 4042, thereby switching the MOSFET 4042 on and off in synchronization with the PWM signal (E). When the D01 terminal of the motor drive driver unit 312 outputs a high signal (A) to the gate of the MOSFET 400, the MOSFET 400 is turned on, and a current flows from the MOSFET 400 to the MOSFET 4042 of the half bridge IPD 404, whereby the motor 200 rotates in the reverse direction. To do. At the same time, when the DO3 terminal of the motor drive driver unit 312 outputs a high signal (C) to the gate of the MOSFET 401, the MOSFET 401 is turned on, and a current flows from the MOSFET 401 to the MOSFET 4042 of the half bridge IPD 404, whereby the motor 201 rotates in the reverse direction. To do.

  Here, it is also possible to perform current detection in the reverse rotation direction by connecting current detection resistors between the MOSFET 400 and the half-bridge IPD 404 and between the MOSFET 401 and the half-bridge IPD 404, respectively.

  As described above, according to one embodiment of the present invention, an H bridge circuit including the MOSFETs 400, 401, 402, and 403, which are four switching elements, and the MOSFET 4041 and the MOSFET 4042 having a current detection function, And an IPD (switching circuit) connected in parallel with each other and one current detection resistor.

  Then, the first motor 200 is connected to the mutual connection point of two MOSFETs 400 and 402 connected in series forming an H-bridge circuit and from the two MOSFETs 4041 and 4042 connected in series forming a half-bridge IPD 404. The second motor 201 is connected in series with each other, and the second motor 201 is connected in series with the other two MOSFETs 401 and 403 connected in series to form an H-bridge circuit and with each other to form a half-bridge IPD 404. The two connected MOSFETs 4041 and 4042 are connected to each other's connection point.

  Further, the current detection resistor 500 is connected between the MOSFET 402 of the H bridge circuit and the ground, and the voltage across the current detection resistor 500 is input to the CPU 308. Further, the current information flowing through the half bridge IPD 404 is input to the CPU 308.

  The MOSEFTs 400 to 403, 4041, 4042 are turned on and off by a command from a CPU (control command unit) 308.

  Therefore, a motor for a seat belt retractor for a vehicle that can improve the current detection accuracy of the motors 200 and 201 without significantly increasing the cost while the two motors 200 and 201 can be independently controlled simultaneously by one motor driving unit 600. The control device 302 can be realized.

  The MOSFETs 400 to 403, 4041, and 4042 can be composed of other switching elements such as transistors.

  DESCRIPTION OF SYMBOLS 100,116 ... Retractor, 102 ... Obstacle sensor, 104 ... Wheel speed sensor, 106 ... Collision judgment controller, 108 ... Brake assist device, 112 ... Vehicle, 200, 201 ..Motor, 202 ... occupant, 204 ... Seat, 206 ... Seat belt, 300 ... Power supply, 302 ... Motor controller for seat belt retractor, 304 ... Custom IC, 306 ..Power supply circuit, 308... CPU (control command unit), 312... Motor drive driver unit, 316... A / D conversion unit, 400, 401, 402, 403, 4041, 4042d. 500 ... Current detection resistor, 600 ... Motor drive unit

Claims (4)

An H-bridge circuit having four switching elements, a half-bridge circuit having two switching elements, and a current detection resistor connected to the H-bridge circuit, and between the H-bridge circuit and the half-bridge circuit A motor drive unit connected to the first electric motor and the second electric motor, and driving the first electric motor and the second electric motor;
A motor drive driver for supplying a signal for turning on and off the switching elements of the H bridge circuit and the half bridge circuit of the motor drive to the motor drive;
Based on the current flowing through the current detection resistor and the current flowing through the half bridge circuit, the current flowing through the first electric motor and the second electric motor is calculated, and switching elements of the H bridge circuit and the half bridge circuit are provided. A control command unit that generates a command to control;
A motor control device for a seat belt retractor of a vehicle. The motor control device for a seat belt retractor for a vehicle according to claim 1,
The H bridge circuit of the motor driving unit includes a first switching element, a second switching element and a first series circuit having a current detection resistor connected in series with each other, a third switching element and a fourth switching element connected in series with each other. A second series circuit having a switching element,
The half-bridge circuit includes a third series circuit having a fifth switching element and a sixth switching element connected in series with each other,
The first series circuit, the second series circuit, and the third series circuit are connected in parallel to each other, the connection point between the first switching element and the second switching element, the fifth switching element, and the sixth switching element. The first electric motor is connected between the third switching element and the fourth switching element and the second electric motor is connected between the fifth switching element and the sixth switching element. A motor control device for a seat belt retractor of a vehicle. In the motor control device for a seat belt retractor for a vehicle according to claim 2,
The half-bridge circuit has a current detection information output terminal that outputs information on a current flowing through the half-bridge circuit, and the control command unit includes a current flowing through the current detection resistor and a current from the current detection information output terminal. A motor control device for a seat belt retractor for a vehicle, wherein currents flowing through the first electric motor and the second electric motor are calculated based on the information. The motor control device for a seat belt retractor for a vehicle according to claim 3,
The motor control for a vehicle seat belt retractor, wherein the first switching element, the second switching element, the third switching element, the fourth switching element, the fifth switching element, and the sixth switching element are MOSFETs. apparatus.

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