JP2011160528A - Drive control circuit for electric motors - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To early and reliably detect and cope with any abnormal condition in a capacitor connected in parallel with an electric motor in a drive control circuit for the electric motor. <P>SOLUTION: The drive control circuit 40 includes a first SW element 61 connected in series with the high-side power supply connecting terminal 24b1 of a pump motor 24b to connect or disconnect a battery BAT and the pump motor 24b to or from each other, a second SW element 62 connected in series with the low-side power supply connecting terminal 24b2 of the pump motor 24b to connect or disconnect the battery BAT and the pump motor 24b to or from each other, capacitors 45b, 45c connected in parallel with a series circuit 71 comprised of the first SW element 61 and the pump motor 24b, and a potential detection circuit 44 that detects a potential of either of the high-side and low-side power supply connecting terminals of the pump motor 24b or a correlation value thereof. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drive control circuit for an electric motor.

  As a form of a drive control circuit for an electric motor, one disclosed in Patent Document 1 is known. As shown in FIG. 2 of Patent Document 1, a DC motor 2 is connected to a battery voltage UB in a drive control circuit of an electric motor, and this DC motor has a switching device S1 having an integrated diode D1. Clocked. A capacitor C1 in the form of a film capacitor is connected between the positive and negative feed lines.

Japanese Patent No. 4129118

  In the drive control circuit of the electric motor described in Patent Document 1 described above, when a short circuit failure occurs in the capacitor C1 connected in parallel to the DC motor 2, there is a possibility that a current continues to flow from the battery voltage UB.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to quickly and surely detect and deal with an abnormality in a capacitor connected in parallel to a motor in a drive control circuit of the motor. .

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 is that in the drive control circuit that drives the motor by receiving power supply from the power source, the power connection terminal on the high side of the motor is connected in series. A first switching unit that is connected and opens and closes a connection between the power source and the motor; a second switching unit that is connected in series to the power connection terminal on the low side of the motor and opens and closes the connection between the power source and the motor; A portion between the first switching unit and the power supply side portion of the power supply circuit including the power source, the first switching unit, the motor, and the second switching unit, and the motor and the second switching unit in the power supply circuit. The capacitor connected in parallel to the series circuit composed of the first switching unit and the motor, and a small number of high side and low side of the motor A detecting unit for detecting a potential or correlation values thereof of one of the power connection terminals also is that it comprises a.

  According to a second aspect of the present invention, there is provided a structural feature of the first aspect, further comprising: a reflux diode connected in parallel to the motor so that the low side of the motor is connected to the anode and the high side is connected to the cathode. It is to have.

  The structural feature of the invention according to claim 3 is that in claim 1 or claim 2, in the power supply circuit, a portion between the power source and the first switching unit, and in the power supply circuit, the electric motor and the second switching In addition, a first resistor connected in parallel with the series circuit and the capacitor is further provided between the part and the part.

  The structural feature of the invention according to claim 4 is that, in claim 1 or claim 2, the second resistor connected in parallel to the capacitor, and a parallel circuit composed of the capacitor and the second resistor are connected in series. A third switching unit that opens and closes a connection between the parallel circuit and a portion of the power supply circuit between the motor and the second switching unit; and between the motor and the second switching unit of the power supply circuit. A third resistor connected in parallel to the second switching unit between the portion and the portion of the power supply circuit between the second switching unit and the power supply; is there.

  The structural feature of the invention according to claim 5 is the fourth resistor according to claim 1 or 2, wherein the fourth resistor is connected in parallel to the capacitor, and the fourth resistor is connected in series to the fourth resistor. And a fourth switching unit that opens and closes a connection between the motor and the second switching unit in the power supply circuit, a portion between the motor and the second switching unit in the power supply circuit, and a power supply The circuit further includes a fifth resistor connected in parallel with the second switching unit between the second switching unit and the power source in the circuit.

  In the invention according to claim 1 configured as described above, each of the first and second switching units is turned off (in an open state), and the high side side and the low side side of the motor detected by the detection unit in that state are turned on. Based on the potential of at least one of the power connection terminals or the correlation value thereof, it can be determined whether or not a short circuit failure has occurred in the capacitor.

  Specifically, when a short circuit failure has occurred in the capacitor with the first and second switching units turned off, the power connection terminal on the low side of the motor is connected to the power source via the short circuit capacitor. Therefore, the potential of the power connection terminal on the low side (and the high side) of the electric motor is almost equal to the power supply voltage. On the other hand, if no short-circuit failure has occurred in the capacitor, the power connection terminal on the low side of the motor is connected to the power supply through a normal capacitor, so the power connection on the low side (and high side) of the motor The potential at the terminal is lower than when a short circuit failure has occurred.

  Therefore, when the potential of the power connection terminal on at least one of the high side and the low side of the electric motor or the correlation value thereof is higher than a predetermined threshold when the first and second switching units are turned off, the capacitor is short-circuited. It can be determined that a failure has occurred.

  In addition, when it is determined that a short-circuit failure has occurred in the capacitor, the short-circuit failure is prevented by opening the connection between the short-circuited capacitor and the power supply by turning off the second switching unit. It is possible to suppress the expansion of the resulting failure location. In this way, it is possible to detect and deal with the abnormality of the capacitor connected in parallel to the electric motor early and reliably.

  In the invention according to claim 2 configured as described above, the voltage (flyback energy) generated between the two power supply connection terminals of the motor when power feeding to the motor is stopped is absorbed by the freewheeling diode, and the first And the burden of the flyback energy to the 2nd switching part can be reduced. In particular, the invention according to claim 2 is suitable for the configuration of the invention according to claim 1, comprising a detector that detects the potential of the power connection terminal on the high side of the motor. That is, in the invention according to claim 2, when a short circuit failure of the capacitor occurs, in addition to the current path by the capacitor and the motor, a current path by the capacitor and the free wheel diode is formed. As a result, the potential of the power connection terminal on the high side of the electric motor greatly changes depending on whether or not there is a short circuit failure of the capacitor, and therefore it is possible to more accurately determine the presence or absence of a short circuit failure of the capacitor.

  In the invention according to claim 3 configured as described above, the first switching unit is turned off (open state), the second switching unit is turned on (closed state), and the second switching unit is turned on in that state. It is possible to determine whether or not an open fault has occurred in the capacitor based on the transition of the potential of the power connection terminal on at least one of the high side and low side of the electric motor from the time of turning off or the correlation value thereof. it can.

  Specifically, when no open failure has occurred in the capacitor, when the second switching unit is turned off, the power supply on the low side (and high side) of the motor is caused by the action of the capacitor connected in parallel with the power supply. The potential at the connection terminal rises slowly. On the other hand, when an open failure has occurred in the capacitor, the above-described capacitor does not work, so the potential of the power connection terminal on the low side (and high side) of the motor is not open. It rises sharply compared to.

  Therefore, for example, the elapsed time from when the second switching unit is turned off to when the potential of the power connection terminal on at least one of the high side and the low side of the motor or the correlation value thereof reaches a predetermined value is detected. When the elapsed time is shorter than the predetermined threshold time, it can be determined that an open failure has occurred in the capacitor.

  In addition, for example, the potential of the power connection terminal of at least one of the high-side side and the low-side side of the motor at the time when a predetermined time has elapsed from when the second switching unit is turned off from on or the correlation value thereof is detected. When the value is higher than a predetermined threshold, it can be determined that an open failure has occurred in the capacitor. Then, a warning that an open failure has occurred in the capacitor can be given.

  The invention according to claim 4 configured as described above has the same effect as the invention according to claim 3. That is, when the first and second switching units are turned off (open state) and the third switching unit is turned on (closed state), if a short-circuit failure occurs in the capacitor, Since the power connection terminal on the low side is connected to the power supply through the capacitor and the third switching unit in which the short circuit has failed, the potential of the power connection terminal on the low side (and the high side) of the motor is almost equal to the power supply voltage. Become. On the other hand, when a short circuit failure has not occurred in the capacitor, the power connection terminal on the low side of the motor is connected to the power source via the second resistor and the third switching unit. The potential of the power connection terminal on the side side is lower than the voltage drop of the second resistor as compared with the case where a short circuit failure has occurred.

  Therefore, the potential of the power connection terminal of at least one of the high-side side and the low-side side of the motor or the correlation value thereof in a state where the first and second switching units are turned off and the third switching unit is turned on is greater than a predetermined threshold value. If it is higher, it can be determined that a short circuit fault has occurred in the capacitor. Further, when it is determined that a short-circuit failure has occurred in the capacitor, turning off the second switching unit or / and the third switching unit can suppress the expansion of the failure location due to the short-circuit failure. it can.

  Further, when no open failure has occurred in the capacitor, when the second switching unit is turned off from on with the first and third switching units turned off (or the second switching unit is turned on from off). At the same time, the potential of the power connection terminal on the low side (and the high side) of the motor gradually rises (or falls) due to the action of the capacitor connected in parallel with the power source. On the other hand, when an open failure has occurred in the capacitor, the above-described capacitor does not work, so the potential of the power connection terminal on the low side (and high side) of the motor is not open. It rises sharply (or falls) compared to.

  Therefore, based on the change in the potential of the power connection terminal of at least one of the high-side side and the low-side side of the motor or the correlation value thereof from the time when the second switching unit is turned off from on (or when it is turned on from off). It can be determined that an open failure has occurred in the capacitor.

  Furthermore, the invention according to claim 4 has the effect of being able to suppress electrolytic corrosion in the electric motor, in addition to the same effect as the invention according to claim 3. That is, when the motor is not driven, that is, when the first and second switching units are turned off, the power connection terminal on the low side (and the high side) of the motor when the third switching unit is turned off. Is determined by the resistor, the off-resistance of the third switching unit, and the divided voltage of the third resistor, and the potential can be almost 0V. Therefore, the electric corrosion (migration) in an electric motor can be suppressed by suppressing the voltage applied at the time of the non-drive of an electric motor comparatively low.

  The invention according to claim 5 configured as described above has the same effect as the invention according to claim 4. That is, when the first, second and fourth switching units are turned off (opened) and the capacitor has a short circuit fault, the power connection terminal on the low side of the motor has a short circuit fault. Therefore, the potential of the power connection terminal on the low side (and the high side) of the electric motor is almost equal to the power supply voltage. On the other hand, if no short-circuit failure has occurred in the capacitor, the power connection terminal on the low side of the motor is connected to the power supply through a normal capacitor, so the power connection on the low side (and high side) of the motor The potential at the terminal is lower than when a short circuit failure has occurred.

  Therefore, when the potential of the power connection terminal of at least one of the high side and the low side of the electric motor in the state where the first, second and fourth switching units are turned off or the correlation value thereof is higher than a predetermined threshold value, It can be determined that a short fault has occurred in the capacitor. In addition, when it is determined that a short-circuit failure has occurred in the capacitor, it is possible to suppress the expansion of the failure location due to the short-circuit failure by turning off the second switching unit.

  Further, when an open failure has not occurred in the capacitor, when the first switching unit is turned off and the second switching unit is turned off from the on state with the fourth switching unit turned on (or the second switching unit is turned on) When turned on from off), the potential of the power connection terminal on the low side (and the high side) of the motor gradually rises (or falls) due to the action of the capacitor connected in parallel with the power source. On the other hand, when an open failure has occurred in the capacitor, the above-described capacitor does not work, so the potential of the power connection terminal on the low side (and high side) of the motor is not open. It rises sharply (or falls) compared to.

  Therefore, based on the change in the potential of the power connection terminal of at least one of the high-side side and the low-side side of the motor or the correlation value thereof from the time when the second switching unit is turned off from on (or when it is turned on from off). It can be determined that an open failure has occurred in the capacitor.

  Further, when the electric motor is not driven, that is, when the first and second switching units are turned off, the power connection terminal on the low side (and the high side) of the electric motor when the fourth switching unit is turned off. Is determined by the divided voltage of the fourth resistor, the off-resistance of the fourth switching unit, and the fifth resistor, and the potential can be almost 0V. Therefore, the electric corrosion (migration) in an electric motor can be suppressed by suppressing the voltage applied at the time of the non-drive of an electric motor comparatively low.

1 is a schematic view showing a first embodiment of a hydraulic brake device to which a drive control circuit for an electric motor according to the present invention is applied. It is a schematic diagram which shows the drive control circuit of the electric motor by this invention. It is an example of a flowchart of a control program executed by the brake ECU shown in FIG. It is a schematic diagram which shows the drive control circuit of the electric motor of 2nd Embodiment by this invention. It is an example of the flowchart of the control program performed by brake ECU in 2nd Embodiment. It is a time chart which shows determination of the open failure of a capacitor among control performed in a 2nd embodiment. It is an example of the flowchart of the control program which concerns on the modification performed by brake ECU in 2nd Embodiment. It is a schematic diagram which shows the drive control circuit of the motor of 3rd Embodiment by this invention. It is an example of the flowchart of the control program performed in brake ECU in 3rd Embodiment. It is a schematic diagram which shows the drive control circuit of the motor of 4th Embodiment by this invention. It is an example of the flowchart of the control program performed in brake ECU in 4th Embodiment.

1) First Embodiment Hereinafter, a first embodiment in which a drive control circuit for an electric motor according to the present invention is applied to a hydraulic brake device will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a hydraulic brake device, and FIG. 2 is a diagram showing a drive control circuit of an electric motor.

  The hydraulic brake device is for braking the vehicle. As shown in FIG. 1, each of the wheel cylinders WCfl, WCfr, WCrl, WCrr, a brake pedal 11 as a brake operation member, and a vacuum brake booster 12 , A master cylinder 13, a reservoir tank 14, a brake actuator 15 that is an automatic hydraulic pressure generator, and a brake ECU 16.

  Each wheel cylinder WCfl, WCfr, WCrl, WCrr regulates rotation of each wheel Wfl, Wfr, Wrl, Wrr, and is provided in each caliper CLfl, CLfr, CLrl, CLrr. When at least one of the basic hydraulic pressure and the control hydraulic pressure is supplied to each wheel cylinder WCfl, WCfr, WCrl, WCrr, each piston (not shown) of each wheel cylinder WCfl, WCfr, WCrl, WCrr is a friction member. A pair of brake pads (not shown) are pressed to restrict the rotation of the disc rotors DRfl, DRfr, DRrl, DRrr, which are rotating members that rotate integrally with the wheels Wfl, Wfr, Wrl, Wrr from both sides. It has become. In this embodiment, the disc type brake is adopted, but a drum type brake may be adopted.

  The vacuum braking booster 12 is a booster that boosts (increases) the brake operating force generated by the depression of the brake pedal 11 by applying the intake negative pressure of the engine to the diaphragm.

  The master cylinder 13 is a device that converts the operating force of the brake pedal 11 by the driver to form a base hydraulic pressure, and can generate friction braking force on the wheels Wfl, Wfr, Wrl, Wrr by the base hydraulic pressure. In the present embodiment, the master cylinder 13 converts the brake operation force boosted by the vacuum brake booster 12 into a basic hydraulic pressure and supplies it to the wheel cylinders WCfl, WCfr, WCrl, WCrr.

  The reservoir tank 14 stores brake fluid and replenishes the master cylinder 13 with the brake fluid.

  The brake actuator 15 is provided between the master cylinder 13 and each wheel cylinder WCfl, WCfr, WCrl, WCrr, and automatically generates a control hydraulic pressure regardless of whether the brake pedal 11 is operated or not. It is a device that can be applied to WCfr, WCrl, WCrr and generate friction braking force on the corresponding wheels Wfl, Wfr, Wrl, Wrr.

  The configuration of the brake actuator 15 will be described in detail with reference to FIG. The brake actuator 15 is composed of a plurality of systems that are hydraulic circuits that operate independently. Specifically, the brake actuator 15 has a first system 15a and a second system 15b that are X pipes. The first system 15a communicates the first hydraulic chamber 13a of the master cylinder 13 with the left rear wheel Wrl and the wheel cylinders WCrl and WCfr of the right front wheel Wfr to control the braking force of the left rear wheel Wrl and the right front wheel Wfr. It is a system concerning. The second system 15b communicates the second hydraulic chamber 13b of the master cylinder 13 with the left front wheel Wfl and the wheel cylinders WCfl and WCrr of the right rear wheel Wrr, respectively, and controls the braking force of the left front wheel Wfl and the right rear wheel Wrr. It is a system concerning.

  The first system 15 a includes a differential pressure control valve 21, a left rear wheel hydraulic pressure control unit 22, a right front wheel hydraulic pressure control unit 23, and a first pressure reduction unit 24.

  The differential pressure control valve 21 is a normally open linear solenoid valve (normally disposed between the master cylinder 13 and the upstream portion of the left rear wheel hydraulic pressure control unit 22 and the upstream portion of the right front wheel hydraulic pressure control unit 23. Open linear solenoid valve). The differential pressure control valve 21 is controlled to be switched between a communication state (non-differential pressure state) and a differential pressure state by the brake ECU 16. Although the differential pressure control valve 21 is not energized and is in a normal communication state, the hydraulic pressure on the wheel cylinders WCrl, WCfr side is changed to the hydraulic pressure on the master cylinder 13 side by energizing to the differential pressure state (closed side). The pressure can be kept higher than the predetermined control differential pressure. This control differential pressure is regulated by the brake ECU 16 in accordance with the control current. As a result, a control hydraulic pressure corresponding to the control differential pressure is formed on the premise of pressurization by the pump 24a.

  The left rear wheel hydraulic pressure control unit 22 can control the hydraulic pressure supplied to the wheel cylinder WCrl, and is a two-port two-position switching type normally open electromagnetic on-off valve 22a and a two-port two-position switching type. And a pressure reducing valve 22b which is a normally closed electromagnetic on-off valve. The pressure increasing valve 22a is interposed between the differential pressure control valve 21 and the wheel cylinder WCrl, and can communicate or block the differential pressure control valve 21 and the wheel cylinder WCrl in accordance with a command from the brake ECU 16. . The pressure reducing valve 22b is interposed between the wheel cylinder WCrl and the pressure regulating reservoir 24c, and can communicate or block the wheel cylinder WCrl and the pressure regulating reservoir 24c in accordance with a command from the brake ECU 16. As a result, the hydraulic pressure in the wheel cylinder WCrl can be increased, held and reduced.

  The right front wheel hydraulic pressure control unit 23 can control the hydraulic pressure supplied to the wheel cylinder WCfr, and includes a pressure increasing valve 23 a and a pressure reducing valve 23 b as with the left rear wheel hydraulic pressure control unit 22. The pressure increasing valve 23a and the pressure reducing valve 23b are controlled by a command from the brake ECU 16, so that the hydraulic pressure in the wheel cylinder WCfr can be increased, held, and reduced.

  The first pressure reducing unit 24 includes a pump 24a, a pump motor 24b, and a pressure regulating reservoir 24c. The pump 24a pumps up the brake fluid in the pressure regulating reservoir 24c and supplies the brake fluid between the differential pressure control valve 21 and the pressure increasing valves 22a and 23a. The pump 24a is driven by a pump motor 24b that is driven in accordance with a command from the brake ECU 16. The pump motor 24b is an electric motor that is driven by power supply from a power source (battery BAT) as will be described later.

  The pressure regulating reservoir 24c is a device that temporarily accumulates brake fluid extracted from the wheel cylinders WCrl and WCfr via the pressure reducing valves 22b and 23b. Further, the pressure regulating reservoir 24c communicates with the master cylinder 13, and when the brake fluid in the pressure regulating reservoir 24c is equal to or less than a predetermined amount, the brake fluid is supplied from the master cylinder 13 while the predetermined amount. In the case of more, the supply of brake fluid from the master cylinder 13 is stopped.

  Thereby, when a differential pressure state is formed by the differential pressure control valve 21 and the pump 24a is driven (for example, in the case of side slip prevention control, traction control, etc.), the brake fluid supplied from the master cylinder 13 is discharged. The pressure can be supplied to the upstream side of the pressure increasing valves 22a and 23a via the pressure regulating reservoir 24c.

  The second system 15 b includes a differential pressure control valve 31, a left front wheel hydraulic pressure control unit 32, a right rear wheel hydraulic pressure control unit 33, and a second pressure reducing unit 34.

  The differential pressure control valve 31 is a normally open linear solenoid valve interposed between the master cylinder 13 and the upstream part of the left front wheel hydraulic pressure control unit 32 and the upstream part of the right rear wheel hydraulic pressure control unit 33. . In the same manner as the differential pressure control valve 21, the differential pressure control valve 31 is a pressure that is higher by the brake ECU 16 than the hydraulic pressure on the master cylinder 13 side by the hydraulic pressure on the wheel cylinders WCfl, WCrr side by a predetermined control differential pressure. Can be retained.

  The left front wheel hydraulic pressure control unit 32 and the right rear wheel hydraulic pressure control unit 33 can control the hydraulic pressure supplied to the wheel cylinders WCfl and WCrr, respectively. The pressure increase valve 32a and the pressure reduction valve 32b, and the pressure increase valve 33a and the pressure reduction valve 33b are comprised. The pressure-increasing valve 32a and the pressure-reducing valve 32b, and the pressure-increasing valve 33a and the pressure-reducing valve 33b are respectively controlled by commands from the brake ECU 16, so that the hydraulic pressure in the wheel cylinder WCfl and the wheel cylinder WCrr can be increased, held, and reduced, respectively. It has become.

  Similar to the first decompression unit 24, the second decompression unit 34 includes a pump 34a, a pump motor 24b (shared with the first decompression unit 24), and a pressure regulating reservoir 34c. The pump 34a pumps up brake fluid in a pressure regulating reservoir 34c similar to the pressure regulating reservoir 24c, and supplies the brake fluid between the differential pressure control valve 31 and the pressure increasing valves 32a, 33a. The pump 34a is driven by a pump motor 24b that is driven in accordance with a command from the brake ECU 16.

  In the brake actuator 15 configured in this way, all the solenoid valves are de-energized during normal braking, and the brake hydraulic pressure corresponding to the operating force of the brake pedal 11, that is, the basic hydraulic pressure is set to the wheel cylinder WC. Each can be supplied to **. In addition, ** is a subscript corresponding to each ring and is any one of fl, fr, rl, and rr, and indicates left front, right front, left rear, and right rear. The same applies to the following description and drawings.

  Further, when the pump motor 24b, that is, the pumps 24a and 34a is driven and the differential pressure control valves 21 and 31 are excited, the brake hydraulic pressure obtained by adding the control hydraulic pressure to the basic hydraulic pressure from the master cylinder 13 is set to the wheel cylinder WC **. Can be supplied to each.

  Further, the brake actuator 15 can individually adjust the hydraulic pressure of the wheel cylinder WC ** by controlling the pressure increasing valves 22a, 23a, 32a, 33a and the pressure reducing valves 22b, 23b, 32b, 33b. . Thereby, according to instructions from the brake ECU 16, for example, well-known anti-skid control, front / rear braking force distribution control, side slip prevention control that is ESC (Electronic Stability Control) (specifically, understeer suppression control, oversteer suppression control), Traction control, inter-vehicle distance control, etc. can be achieved.

  In addition, the hydraulic brake device includes wheel speed sensors Sfl, Sfr, Srl, Srr. Wheel speed sensors Sfl, Sfr, Srl, Srr are provided in the vicinity of each wheel Wfl, Wfr, Wrl, Wrr, and brake a pulse signal having a frequency according to the rotation of each wheel Wfl, Wfr, Wrl, Wrr. It is output to the ECU 16.

  The hydraulic brake device includes a stop switch 17 that is turned on when the brake pedal 11 is depressed and turned off when the depression is released. An on / off signal of the stop switch 17 is input to the brake ECU 16.

  The brake ECU 16 includes a drive control circuit 40 that receives power supplied from a battery BAT that is a power source and controls driving of a pump motor 24b that is an electric motor. As shown in FIG. 2, the drive control circuit 40 includes a microprocessor 41, a motor control unit 42, a motor drive circuit 43, and a potential detection circuit 44.

  The motor control unit 42 receives a control command signal (driving request) from the microprocessor 41 and controls on / off of a driving current (driving voltage) supplied to the pump motor 24b to be controlled in accordance with the control command signal ( (Duty control). Specifically, the motor control unit 42 sends an on / off signal (which may be a PWM signal having a predetermined duty ratio) according to a drive request from the microprocessor 41 to the motor drive circuit 43 (first and second SW elements 61 and 62). ) To control energization / non-energization of the pump motor 24b.

  The motor drive circuit 43 is a circuit that rotates and stops the pump motor 24b. The motor drive circuit 43 is connected in series between a battery BAT (for example, + 12V) that is a DC power supply and the pump motor 24b, and switches the power supply / stop to the pump motor 24b to switch between the first SW element 61 and the second SW element 62. It has.

  The first SW element 61 includes a first SW part 61a and a first diode part (first parasitic diode) 61b. The first SW element 61 is configured by, for example, a MOSFET (MOS field effect transistor).

  The first SW unit 61a is a first switching unit that is connected in series to the high-side power connection terminal 24b1 of the pump motor 24b and opens and closes the connection between the battery BAT and the pump motor 24b. The drain (input terminal) of the first SW unit 61a is connected to the positive electrode of a battery BAT (for example, + 12V), which is a DC power supply, via a coil 45a. The source (output end) of the first SW unit 61a is connected to one terminal 24b1 (high-side power connection terminal) of the pump motor 24b and to the cathode of the freewheeling diode 46.

  The cathode of the first diode part 61b is connected to the drain of the first SW part 61a, and the anode is connected to the source of the first SW part 61a.

  The second SW element 62 includes a second SW part 62a and a second diode part (second parasitic diode) 62b. Similarly to the first SW element 61, the second SW element 62 is configured by, for example, a MOSFET.

  The second SW unit 62a is a second switching unit that is connected in series to the low-side power connection terminal 24b2 of the pump motor 24b and opens and closes the connection between the battery BAT and the pump motor 24b. The drain (input end) of the second SW section 62a is connected to the other terminal 24b2 (low-side power connection terminal) of the pump motor 24b and to the anode of the freewheeling diode 46. The source (output terminal) of the second SW unit 62a is connected to the negative electrode of the battery BAT which is a DC power source.

  The cathode of the second diode part 62b is connected to the drain of the second SW part 62a, and the anode is connected to the source of the second SW part 62a.

  The gates (signal input terminals) of the first SW unit 61a and the second SW unit 62a are connected to the output ports 42a and 42b of the motor control unit 42, respectively. When the on signal is supplied from the motor control unit 42, the first and second SW elements 61 and 62 are turned on, and when the off signal is supplied, the first and second SW elements 61 and 62 are turned off.

  In the present embodiment, when the pump motor 24b is driven, the second SW element 62 is turned on and the first SW element 61 is PWM-controlled. In addition, when the first SW element 61 is on-failed, the second SW element 62 functions as a fail safe that stops power supply to the pump motor 24b.

  The motor drive circuit 43 includes a low pass filter circuit 45. The low-pass filter circuit 45 includes a coil 45a connected in series between the first SW element 61 and the battery BAT, a first capacitor 45b on the battery BAT side of the coil 45a, and a first capacitor 45b on the first SW element 61 side of the coil 45a. 2 capacitors 45c.

  The first capacitor 45b includes a power supply circuit 73 including the battery BAT, the first SW element 61, the pump motor 24b, and the second SW element 62, and a portion between the first SW element 61 and the portion on the battery BAT side. A capacitor connected in parallel to the series circuit 71 including the first SW element 61 and the pump motor 24b between the circuit 73 and the portion between the pump motor 24b and the second SW element 62. . Specifically, one end of the first capacitor 45b is connected to a portion between the coil 45a and the battery BAT (positive electrode), and the other end is connected to a portion between the pump motor 24b and the second SW element 62. Yes.

  Similarly to the first capacitor 45b, the second capacitor 45c is a capacitor connected in parallel to the series circuit 71. Specifically, one end of the second capacitor 45c is connected to a portion between the coil 45a and the first SW element 61, and the other end is connected to a portion between the pump motor 24b and the second SW element 62. .

  The first and second capacitors 45b and 45c are desirably capacitors having a small ESR (equivalent series resistance), and are preferably ceramic capacitors, for example.

  The first and second capacitors 45b and 45c have a function of turning on the duty-controlled pump motor 24b in a short time. The second capacitor 45c has the function of smoothing the input (rectangular wave) from the battery BAT and outputting it to the pump motor 24b in cooperation with the coil 45a. Further, the first capacitor 45b has a function of smoothing (low-pass filtering) the noise generated in the drive control circuit 40 in cooperation with the coil 45a and outputting it to the battery BAT side.

  Further, the motor drive circuit 43 includes a reflux diode 46 connected in parallel with the pump motor 24b. That is, the cathode of the reflux diode 46 is connected to the terminal 24b1 of the pump motor 24b, and the anode is connected to the terminal 24b2 of the pump motor 24b. Therefore, the voltage (flyback energy) generated between the both terminals of the pump motor 24b when the power supply to the pump motor 24b is stopped is absorbed by the freewheeling diode 46 and is sent to the first and second SW elements 61 and 62. The burden of flyback energy is reduced. Further, when a short circuit failure occurs in the capacitors 45b and 45c, in addition to the current path by the capacitors 45b and 45c and the pump motor 24b, a current path by the capacitors 45b and 45c and the free wheel diode 46 is formed. As a result, the potential of the power connection terminal 24b1 on the high side of the pump motor 24b changes greatly depending on whether or not the capacitors 45b and 45c are short-circuited. Can be determined.

  The potential detection circuit 44 is a detection unit that detects the potential of the power supply connection terminal 24b1 on the high side of the pump motor 24b, and includes a comparator 44a and a reference voltage circuit 44b. The comparator 44a inputs an input voltage to be compared from the first input port 44a1, and also inputs a reference voltage from the second input port 44a2, determines the magnitude of the input voltage with respect to the reference voltage, and outputs the determination result to the output port. 44a3 to the microprocessor 41.

  The first input port 44a1 is connected to the power supply connection terminal 24b1 on the high side of the pump motor 24b. Thereby, the potential (voltage) of the power connection terminal 24b1 on the high side of the pump motor 24b can be detected by the potential detection circuit 44. Note that the potential of the power supply connection terminal 24b2 on the low side may be detected instead of the potential of the power connection terminal 24b1 on the high side of the pump motor 24b, or the correlation value thereof may be detected. Good.

  The reference voltage circuit 44b is composed of two resistors 44b1 and 44b2 connected in series between the power supply V and the ground. A portion between the two resistors 44b1 and 44b2 is connected to the second input port 44a2. The reference voltage is set to a value obtained by dividing the voltage of the power supply V by the two resistors 44b1 and 44b2. In this embodiment, the detection unit is configured by the potential detection circuit 44 that outputs the determination result of whether or not the detection voltage is larger than the reference voltage to the microprocessor 41. However, the detection voltage is directly detected and detected. You may make it comprise with the electric potential detection circuit 44 which outputs a value to the microprocessor 41. FIG.

  The portion between the high-side power connection terminal 24b1 of the pump motor 24b and the first input port 44a1 of the comparator 44a, and the portion between the battery BAT (negative electrode) and the source of the second SW unit 62a. A resistor 47 is connected between them. The resistor 47 is for fixing the voltage level of the potential detection circuit 44a1 to the ground level when both the first SW unit 61a and the second SW unit 62a are turned off.

  Next, the initial check of the brake ECU 16 configured as described above will be described with reference to the flowchart shown in FIG. When the initial check ends normally, the brake ECU 16 starts executing the control program for the hydraulic brake device. In the initial check, it is confirmed whether there is an abnormality in each of the valves 21, 22a, 22b, 23a, 23b, 31, 32a, 32b, 33a, 33b, the pump motor 24b, the first and second SW units 61a, 62a, Here, the presence or absence of failure of the capacitors 45b and 45c will be described in detail.

  When an ignition switch (not shown) is turned on, the brake ECU 16 starts an initial check related to the capacitors 45b and 45c in the initial check. In step 102, the brake ECU 16 turns off the first SW element 61 and turns off the second SW element 62.

  In step 104, the brake ECU 16 detects the potential of the connection terminal 24b1 on the high side of the pump motor 24b by the potential detection circuit 44, and determines whether or not the detected value is equal to or greater than a determination value. In the present embodiment, the brake ECU 16 determines from the determination result from the comparator 44a. In the present embodiment, when the battery BAT is 12V, the determination value is set to 3V.

  Hereinafter, the first and second SW elements 61 and 62 are turned off (opened), respectively, and at least one of the high side and the low side of the pump motor 24b detected by the potential detection circuit 44 in this state The reason why it is possible to determine whether or not a short failure has occurred in the capacitors 45b and 45c based on the potential of the power supply connection terminal or the correlation value thereof will be described.

  In the state where the first and second SW elements 61 and 62 are turned off, if a short circuit failure has occurred in either of the capacitors 45b and 45c, the power connection terminal 24b2 on the low side of the pump motor 24b has a short circuit failure. Is connected to the battery BAT via the capacitor 45b (and / or 45c), the potentials of the power connection terminals 24b1 and 24b2 on the low side (and high side) of the pump motor 24b are the power supply voltage (of the battery BAT Approximately equal to the potential of the positive electrode). On the other hand, if no short-circuit failure has occurred in either of the capacitors 45b and 45c, the power connection terminal 24b2 on the low side of the pump motor 24b is connected to the battery BAT via a normal capacitor. The electric potentials of the power connection terminals 24b1 and 24b2 on the low side (and high side) of the motor 24b are lower than those in the case where a short circuit failure has occurred. Specifically, the potential is substantially 0 V, which is equal to the potential of the negative electrode of the battery BAT.

  Therefore, the potential of at least one of the power connection terminals on the high side and the low side of the pump motor 24b in a state where the first and second SW elements 61 and 62 are turned off or the correlation value thereof is a determination value (predetermined threshold value). Higher than that, it can be determined that a short circuit failure has occurred in the capacitors 45b and 45c.

  When a short circuit failure has occurred in either one of the capacitors 45b and 45c, the potential detected by the potential detection circuit 44 is equal to or higher than the determination value, so the brake ECU 16 determines “YES” in step 104, It is determined that one of the capacitors 45b, 45c is a short circuit failure (step 106). On the other hand, if no short circuit failure has occurred in either of the capacitors 45b and 45c, the potential detected by the potential detection circuit 44 is less than the determination value, so the brake ECU 16 determines “NO” in step 104. Then, it is determined that neither of the capacitors 45b and 45c is a short circuit failure (step 108).

  As is apparent from the above description, according to the first embodiment, the first and second SW elements 61 and 62 are turned off (opened), respectively, and in this state, the potential detection circuit 44 (detection unit) Based on the detected potential of at least one of the power connection terminals 24b1 and 24b2 on the high side and the low side of the pump motor 24b or the correlation value thereof, a short circuit failure has occurred in either of the capacitors 45c and 45b. It can be determined whether or not.

  When it is determined that a short circuit failure has occurred in either one of the capacitors 45c and 45b, the second SW element 62 is turned off, so that one of the capacitors 45c and 45b in the short circuit failure and the battery BAT (power source) ) Is opened, it is possible to suppress the expansion of the failure location due to the short circuit failure. In this way, it is possible to detect and deal with the abnormality of the capacitors 45b and 45c connected in parallel to the pump motor 24b early and reliably.

  Furthermore, since ceramic capacitors have lower ESR (equivalent series resistance) than aluminum electrolytic capacitors, replacement of aluminum electrolytic capacitors with ceramic capacitors can be expected to reduce EMI emission noise. However, since there are many short faults as the failure mode of the ceramic capacitor, there is a concern about the expansion of the failure location due to the short failure, and replacement with the ceramic capacitor is not progressing.

  According to the first embodiment, it is possible to determine that a short circuit failure has occurred in the capacitors 45b and 45c, and to suppress the expansion of the failure location due to the short circuit failure. Can be replaced. Thereby, EMI emission noise can be reduced.

  Further, the filter effect by the capacitor becomes higher as the capacitor is provided closer to the noise generation source. Capacitors 45b and 45c are provided between the part on the battery BAT side with respect to the first SW element 61 and the part of the pump motor 24b with respect to the second SW element 62, that is, the pump motor 24b and the first SW which are noise sources. By providing the capacitors 45b and 45c near the element 61, the capacitor 45b is provided between the part on the battery BAT (positive electrode) side of the first SW element 61 and the part of the battery BAT (negative electrode) side of the second SW element 62. , 45c, the filter effect by the capacitors 45b, 45c can be enhanced.

2) Second Embodiment Next, a second embodiment will be described with reference to FIGS. In the second embodiment, as shown in FIG. 4, the portion between the battery BAT and the first SW element 61 in the power supply circuit 73 and the pump motor 24 b and the second SW element in the power supply circuit 73. And a resistor 48 connected in parallel to the series circuit 71 (consisting of the first SW element 61 and the pump motor 24b) and the capacitors 45b and 45c. This is different from the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  Furthermore, the initial check of the brake ECU 16 configured as described above will be described with reference to the flowchart shown in FIG. The brake ECU 16 determines an open failure after determining whether there is a short circuit failure of the capacitor shown in the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The brake ECU 16 can determine a short circuit failure as in the first embodiment even when the resistor 48 is provided. If one of the capacitors 45b and 45c is short-circuited, the potential of the power connection terminals 24b1 and 24b2 on the low side (and the high side) of the pump motor 24b becomes substantially equal to the power supply voltage (the potential of the positive electrode of the battery BAT). It is.

  If the brake ECU 16 determines that the capacitors 45b and 45c are not short-circuited ("NO" in step 104), the brake ECU 16 determines whether or not the capacitors 45b and 45c are open-circuited. Specifically, the brake ECU 16 turns on the second SW element 62 while turning off the first SW element 61 at time t1 shown in FIG. 6 (step 204). When the second SW element 62 is turned on, the current from the battery BAT flows through the resistor 48 and the second SW section 62a of the second SW element 62. Therefore, at this time, the potential of the power connection terminal 24b2 on the low side of the pump motor 24b (that is, the potential of the power connection terminal 24b1 on the high side) is lower than the voltage of the positive electrode of the battery BAT by the voltage drop of the resistor 48. Voltage.

  After that, when the potential of the power connection terminal 24b2 on the low side of the pump motor 24b is stabilized at a voltage that is lower than the voltage drop (when the predetermined time T1 elapses from the time when the second SW element 62 is turned on) (time t2) The brake ECU 16 turns off the second SW element 62 again (step 206) and starts counting the elapsed time T3 (step 208). The elapsed time T3 is from the time point when the second SW element 62 is turned off to the time point (time t2) until the time point when the potential of the power connection terminal 24b1 on the high side of the pump motor 24b becomes equal to or higher than the determination value (time t3). Is the elapsed time. The brake ECU 16 sets the flag Fa to 1 (step 210). The flag Fa indicates whether or not an open failure of the capacitor has been determined. 1 indicates that an open failure is being determined, and 0 indicates that an open failure has not been determined. By setting the flag Fa to 1, it is possible to omit the determination of the short-circuit failure and the start of counting the elapsed time T3.

  Then, the brake ECU 16 has elapsed time T3 from the time when the second SW element 62 is turned off to the time (time t2) until the time when the potential of the power connection terminal 24b1 on the high side of the pump motor 24b becomes equal to or higher than the determination value. Is derived.

  Specifically, the brake ECU 16 is the power supply connection terminal 24b1 on the high side of the pump motor 24b that is detected by the potential detection circuit 44 after the time point when the second SW element 62 is turned off (time t2). Is less than the determination value, the determinations of “YES” and “NO” are repeatedly executed in steps 202 and 212, respectively, and the elapsed time T3 is continuously counted. On the other hand, the brake ECU 16 detects the potential of the power connection terminal 24b1 on the high side of the pump motor 24b detected by the potential detection circuit 44 after the time when the second SW element 62 is turned off (time t2). If it is equal to or greater than the determination value, “YES” is determined in steps 202 and 212, respectively, and the counting of the elapsed time T3 is terminated (step 214). Note that the determination value in step 212 is set to 3 V, for example. In the second embodiment, the resistor 48, the freewheeling diode 46, and the resistor 47 are connected in series to the battery BAT, and the current continues to flow. However, the current value can be changed by changing the resistance value of the resistor 47. Is kept small.

  In this way, the brake ECU 16 has elapsed from the time when the second SW element 62 is turned off to the time (time t2) until the time when the potential of the power connection terminal 24b1 on the high side of the pump motor 24b becomes equal to or higher than the determination value. The time T3 is derived.

  In step 216, the brake ECU 16 determines whether or not the derived elapsed time T3 is equal to or shorter than the predetermined time T2. In the present embodiment, the predetermined time T2 is set based on the resistor 48 and the capacitor 45b, and is set to 0.1 seconds, for example.

  Hereinafter, the first SW element 61 is turned off (open state), the second SW element 62 is turned on (closed state), and the high side of the pump motor 24b from the time when the second SW element 62 is turned off from on in this state. The reason why it is possible to determine whether or not an open failure has occurred in the capacitors 45b and 45c based on the potential of at least one of the power supply connection terminals on the low side and the low side or the transition of the correlation value thereof will be described.

  When no open failure has occurred in either of the capacitors 45b and 45c, the pump motor is driven by the action of the capacitors 45b and 45c connected in parallel to the battery BAT when the second SW element 62 is turned off. The potential of the low-side (and high-side) power supply connection terminal 24b2 (and 24b1) of 24b rises gently. On the other hand, when an open failure has occurred in the capacitors 45b and 45c, it is the same as the absence of the capacitor, and there is no effect of the above-described capacitor. Therefore, the power supply on the low side (and high side) of the pump motor 24b The potential of the connection terminal 24b2 (and 24b1) rises sharply compared to the case where no open failure has occurred.

  Therefore, the potential of at least one of the power connection terminals on the high side and the low side of the pump motor 24b from the time when the second SW element 62 is turned off (time t2) or the correlation value thereof is a predetermined value (determination value). Elapsed time T3 until reaching the value is derived, and when the elapsed time T3 is shorter than a predetermined threshold time (predetermined time), it can be determined that an open failure has occurred in the capacitors 45b and 45c.

  If an open failure has occurred in either of the capacitors 45b and 45c, the derived elapsed time T3 is equal to or shorter than the predetermined time, so the brake ECU 16 determines “YES” in step 216, and the capacitors 45b, 45c It is determined that any of 45c is an open failure (step 218). On the other hand, if no open failure has occurred in either of the capacitors 45b and 45c, the derived elapsed time T3 is longer than the predetermined time, so the brake ECU 16 determines “NO” in step 216, and the capacitor It is determined that neither 45b nor 45c is an open failure (step 222). In any case, the brake ECU 16 resets the flag Fa to 0 after determination (steps 220 and 224).

  As is apparent from the above description, according to the second embodiment, the first SW element 61 is turned off (open state), the second SW element 62 is turned on (closed state), and the second SW element is in that state. Based on the transition of the potential of the power connection terminal on at least one of the high side and the low side of the pump motor 24b from the time when 62 is turned off or the correlation value thereof, the capacitor 45b, 45c is opened. It can be determined whether or not a failure has occurred.

  Further, when it is determined that an open failure has occurred in any of the capacitors 45c and 45b, a warning to that effect can be given.

  Further, the brake ECU 16 and the brake actuator 15 are an integral structure, and this integral structure has a connector 16a. Wires from the battery BAT, wires from other ECUs, and the like are attached and detached via this connector 16a. Connected as possible. Therefore, when replacing the brake ECU 16, it is necessary to remove these wires from the connector 16a.

  According to the second embodiment, when the battery BAT is removed from the brake ECU 16, the charge stored in the capacitors 45 b and 45 c is discharged by the resistor 48. That is, the resistor 48 can be used as a discharge resistor. Therefore, even if it contacts the connection terminal 16a1 of the connector 16a, there is no electric shock.

  Further, by turning off the second SW element 62 when the ignition switch is turned off, it is possible to prevent a current (dark current) from flowing through the resistor 48. Therefore, an increase in dark current when the ignition switch is turned off can be suppressed as a whole.

  In the second embodiment, a capacitor open failure may be performed as follows. That is, at least one of the power connection terminals 24b1 on the high side and the low side of the pump motor 24b when the predetermined time T2 has elapsed (time t3) from the time when the second SW element 62 is turned off (time t2). 24b2 or its correlation value may be detected, and if the value is higher than a predetermined threshold value, it may be determined that an open failure has occurred in the capacitors 45b and 45c.

  Specifically, the brake ECU 16 determines a capacitor failure according to the flowchart shown in FIG. The process of step 302 is performed instead of the process of step 212 in the flowchart shown in FIG. 5, and the process of step 304 is performed instead of the process of step 216. In step 302, as in step 216 described above, it is determined whether the counted elapsed time T3 is equal to or shorter than the predetermined time T2. In step 304, as in step 212 described above, it is determined whether or not the potential of the power connection terminal 24b1 on the high side of the pump motor 24b is equal to or higher than a determination value.

  In the second embodiment, at least one of the power connection terminals on the high side and the low side of the pump motor 24b at the time when the predetermined time T2 has elapsed from the time when the second SW element 62 is turned on. The potentials 24b1 and 24b2 or their correlation values may be detected, and when the value is lower than a predetermined threshold value, it may be determined that an open failure has occurred in the capacitors 45b and 45c.

3) Third Embodiment Next, a third embodiment will be described with reference to FIGS. As shown in FIG. 8, the third embodiment is connected in series to a parallel circuit 72 including capacitors 45b and 45c and a resistor 48 (second resistor), and the parallel circuit 72 and a power supply circuit 73 are connected. A third SW element 63 for opening and closing a connection between the pump motor 24b and the second SW element 62, a part of the power supply circuit 73 between the pump motor 24b and the second SW element 62, A resistor 49 (third resistor) connected in parallel to the second SW element 62 between the portion of the power supply circuit 73 between the second SW element 62 and the battery BAT is further provided. This is different from the second embodiment. The same components as those of the second embodiment are denoted by the same reference numerals and the description thereof is omitted.

Similar to the first SW element 61, the third SW element 63 includes a third SW part 63a and a third diode part (third parasitic diode) 63b. The drain (input end) of the third SW section 63a is connected to capacitors 45b and 45c and a resistor 48, and the source (output end) is connected to the power connection terminal 24b2 (low side power connection terminal) of the pump motor 24b. And connected to the drain of the second SW section 62a. The cathode of the third diode part 63b is connected to the drain of the third SW part 63a, and the anode is connected to the source of the third SW part 63a. The gate (signal input terminal) of the third SW unit 63 a is connected to the output port 42 c of the motor control unit 42.
One end of the resistor 49 is connected to the drain of the second SW unit 62a, and the other end is connected to the source.

  Furthermore, an initial check of the brake ECU 16 configured as described above will be described with reference to a flowchart shown in FIG. The brake ECU 16 determines an open failure after determining whether there is a short circuit failure of the capacitor shown in the first embodiment. The same components as those in the flowchart shown in FIG.

  Specifically, the brake ECU 16 determines a capacitor failure according to the flowchart shown in FIG. The process of step 402 is performed instead of the process of step 102 in the flowchart shown in FIG. 5, and the process of step 404 is performed instead of the process of step 204. In step 402, the first and second SW elements 61 and 62 are turned off and the third SW element 63 is turned on. In step 404, with the first SW element 61 turned off, the third SW element 63 is turned off and the second SW element 62 is turned on.

  According to the third embodiment, when the first and second SW elements 61 and 62 are turned off (open state) and the third SW element 63 is turned on (closed state), the capacitors 45b and 45c are short-circuited. When a failure has occurred, the power connection terminal 24b2 on the low side of the pump motor 24b is connected to the battery BAT via the capacitors 45b and 45c and the third SW element 63 that are short-circuited. The potential of the power connection terminal 24b2 (and 24b1) on the low side (and high side) of the motor 24b is substantially equal to the power supply voltage. On the other hand, when no short circuit failure has occurred in the capacitors 45b and 45c, the power connection terminal 24b2 on the low side of the pump motor 24b is connected to the battery BAT via the resistor 48 (second resistor) and the third SW element 63. Therefore, the potential of the power connection terminal 24b2 on the low side (and the high side) of the pump motor 24b is lower than the voltage of the resistor 48 (second resistor) compared to the case where a short circuit failure has occurred. Minutes lower.

  Therefore, the power connection terminals 24b1, at least one of the high side and the low side of the pump motor 24b in a state where the first and second SW elements 61, 62 are turned off and the third SW element 63 is turned on (step 402). When the potential of 24b2 or the correlation value thereof is higher than the determination value (predetermined threshold) (determined as “YES” in step 104), it is determined that a short circuit failure has occurred in either of the capacitors 45b and 45c. be able to. In addition, when it is determined that a short circuit failure has occurred in the capacitors 45b and 45c, turning off the second SW element 62 and / or the third SW element 63 suppresses expansion of the failure location due to the short circuit failure. can do.

  Further, when no open failure has occurred in the capacitors 45b and 45c, when the second SW element 62 is turned off from the on-state with the first and third SW elements 61 and 63 turned off (or the second element 62). When the switch is turned on from off), the potential of the power connection terminal 24b2 (and 24b1) on the low side (and high side) of the pump motor 24b rises slowly due to the action of the capacitor connected in parallel to the battery BAT. (Or descend). On the other hand, when an open failure has occurred in the capacitors 45b and 45c, since the above-described capacitor does not function, the potentials of the power connection terminals 24b1 and 24b2 on the low side (and high side) of the pump motor 24b are As compared with the case where no open failure has occurred, it rises sharply (or falls).

  Therefore, the potential of the power connection terminals 24b1 and 24b2 on at least one of the high side and the low side of the pump motor 24b from the time when the second SW element 62 is turned off from on (or when the second SW element 62 is turned on from off) or the correlation thereof. Based on the change in value, it can be determined that an open failure has occurred in the capacitors 45b and 45c.

  Further, when the pump motor 24b is not driven (for example, when the ignition switch is turned off), that is, when the first and second SW elements 61 and 62 are respectively turned off, The potentials of the low-side (and high-side) power supply connection terminals 24b2 and 24b1 of the motor 24b are the resistor 48 (second resistor), the off-resistance of the third SW element 63, and the resistor 49 (third resistor). ) And its potential can be almost 0V. Therefore, electrolytic corrosion (migration) in the pump motor 24b can be suppressed by suppressing the voltage applied when the pump motor 24b is not driven relatively low.

4) Fourth Embodiment Next, a fourth embodiment will be described with reference to FIGS. In the fourth embodiment, as shown in FIG. 10, the resistor 48 (fourth resistor) is connected in series, and the resistor 48 and the pump motor 24 b in the power supply circuit 73 and the second SW element 62 are connected. A fourth SW element 64 that opens and closes a connection with the second power supply circuit 73, a part between the pump motor 24b and the second SW element 62 in the power supply circuit 73, and a second SW element 62 in the power supply circuit 73. The second embodiment is different from the second embodiment in that a resistor 49 (fifth resistor) connected in parallel to the second SW element 62 is further provided between the battery BAT and the battery BAT. . The same components as those in the third embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Similar to the first SW element 61, the fourth SW element 64 includes a fourth SW part 64a and a fourth diode part (fourth parasitic diode) 64b. The drain (input end) of the fourth SW section 64a is connected to the resistor 48, and the source (output end) is connected to the power connection terminal 24b2 (low side power connection terminal) of the pump motor 24b. It is connected to the drain of the 2SW unit 62a. The cathode of the fourth diode portion 64b is connected to the drain of the fourth SW portion 64a, and the anode is connected to the source of the fourth SW portion 64a. The gate (signal input terminal) of the fourth SW unit 64 a is connected to the output port 42 c of the motor control unit 42. That is, the resistor 48 and the fourth SW element 64 connected in series are connected in parallel to the capacitors 45b and 45c.

  Further, the initial check of the brake ECU 16 configured as described above will be described with reference to the flowchart shown in FIG. The brake ECU 16 determines an open failure after determining whether there is a short circuit failure of the capacitor shown in the first embodiment. The same components as those in the flowchart shown in FIG.

  Specifically, the brake ECU 16 determines the failure of the capacitor according to the flowchart shown in FIG. A process of step 502 is performed instead of the process of step 402 in the flowchart shown in FIG. 9, and a process of step 504 is performed instead of the process of step 404. In step 502, the first and second SW elements 61 and 62 are turned off and the fourth SW element 64 is turned off. In step 504, the second and fourth SW elements 62 and 64 are turned on from the off state while the first SW element 61 is kept off.

  According to the fourth embodiment, when the first, second, and fourth SW elements 61, 62, and 64 are turned off (opened), a short-circuit failure has occurred in the capacitors 45b and 45c. Since the power connection terminal 24b2 on the low side of the pump motor 24b is connected to the battery BAT via the capacitors 45b and 45c that are short-circuited, the power connection on the low side (and the high side) of the pump motor 24b The potential of the terminal 24b2 (24b1) is substantially equal to the power supply voltage. On the other hand, when no short-circuit failure has occurred in the capacitors 45b and 45c, the power connection terminal 24b2 on the low side of the pump motor 24b is connected to the battery BAT via the normal capacitors 45b and 45c. The potential of the power connection terminal 24b2 (24b1) on the low side (and high side) of the motor 24b is lower than that in the case where a short circuit failure has occurred.

  Therefore, the potential of the power connection terminal of at least one of the high side and the low side of the pump motor 24b in a state where the first, second, and fourth SW elements 61, 62, 64 are turned off or the correlation value thereof is predetermined. When it is higher than the threshold value, it can be determined that a short circuit failure has occurred in the capacitors 45b and 45c. Further, when it is determined that a short circuit failure has occurred in the capacitors 45b and 45c, by turning off the second SW element 62, it is possible to suppress the expansion of the failure location due to the short circuit failure.

  When no open failure has occurred in the capacitors 45b and 45c, when the first SW element 61 is turned off and the second SW element 62 is turned off from the on state with the fourth SW element 64 turned on (or the second SW element). When the element 62 is turned on from off), the low-side (and high-side) power connection terminal 24b2 (and 24b1) of the pump motor 24b is operated by the action of the capacitors 45b and 45c connected in parallel to the battery BAT. The potential rises slowly (or falls). On the other hand, when the open failure has occurred in the capacitors 45b and 45c, since the above-described capacitor does not work, the potential of the power connection terminal 24b2 (24b1) on the low side (and high side) of the pump motor 24b. Rises sharply (or falls) compared to when no open failure has occurred.

  Therefore, the potential of the power connection terminal of at least one of the high side and the low side of the pump motor 24b from the time when the second SW element 62 is turned off from on (or the time when the second SW element 62 is turned on) or a change in the correlation value thereof. Based on the above, it can be determined that an open failure has occurred in the capacitors 45b and 45c.

  Further, when the pump motor 24b is not driven (for example, when the ignition switch is turned off), that is, when the first and second SW elements 61 and 62 are turned off, the pump is turned off when the fourth SW element 64 is turned off. The potentials of the low-side (and high-side) power supply connection terminals 24b2 and 24b1 of the motor 24b are the resistor 48 (fourth resistor), the off-resistance of the fourth SW element 64, and the resistor 49 (fifth resistor). ) And its potential can be almost 0V. Therefore, electrolytic corrosion (migration) in the pump motor 24b can be suppressed by suppressing the voltage applied when the pump motor 24b is not driven relatively low.

  DESCRIPTION OF SYMBOLS 11 ... Brake pedal, 12 ... Vacuum brake booster, 13 ... Master cylinder, 14 ... Reservoir tank, 15 ... Brake actuator, 16 ... Brake ECU, 21, 31 ... Differential pressure control valve (linear solenoid valve), 22 ... Left rear wheel hydraulic pressure control unit, 23 ... Right front wheel hydraulic pressure control unit, 24 ... First pressure reducing unit, 32 ... Left front wheel hydraulic pressure control unit, 33 ... Right rear wheel hydraulic pressure control unit, 34 ... Second pressure reducing unit, DESCRIPTION OF SYMBOLS 41 ... Microprocessor, 42 ... Motor control part, 43 ... Motor drive circuit, 44 ... Potential detection circuit (detection part), 45 ... Low-pass filter circuit, 45b, 45c ... Capacitor, 46 ... Free-wheeling diode, 47 ... Resistor, 48 ... resistors (first resistor, second resistor, fourth resistor), 49 ... resistors (third resistor, fifth resistor), 61-64 ... first to fourth SW elements (first to fourth switches) 4th switching part), 7 ... series circuit, 72 ... parallel circuit, 73 ... power supply circuit, Wfl, Wfr, Wrl, Wrr ... wheel, Sfl, Sfr, Srl, Srr ... wheel speed sensors, WCfl, WCfr, WCrl, WCrr ... wheel cylinder.

Claims (5)

In the drive control circuit (40) that receives the power supply from the power source (BAT) and drives the electric motor (24b),
A first switching unit (61) connected in series to a power supply connection terminal (24b1) on the high side of the electric motor and opening and closing a connection between the power source and the electric motor;
A second switching unit (62) connected in series to the power connection terminal (24b2) on the low side of the electric motor to open and close the connection between the power source and the electric motor;
Of the power supply circuit (73) composed of the power source, the first switching unit, the electric motor, and the second switching unit, a portion between the first switching unit and the site on the power source side, and Capacitors (45b, 45c) connected in parallel to the series circuit (71) including the first switching unit and the motor between the motor and the portion between the second switching unit. When,
A detector (44) for detecting the potential of the power connection terminal on at least one of the high side and the low side of the electric motor or a correlation value thereof;
A drive control circuit for an electric motor.   2. The method of claim 1, further comprising a free-wheeling diode (46) connected in parallel to the motor so that the low side of the motor is connected to the anode and the high side is connected to the cathode. Electric motor drive control circuit.   In Claim 1 or Claim 2, a portion between the power supply and the first switching unit in the power supply circuit, a portion between the motor and the second switching unit in the power supply circuit, The motor drive control circuit further includes a first resistor (48) connected in parallel to the series circuit and the capacitor. In claim 1 or claim 2,
A second resistor (48) connected in parallel to the capacitor;
Connected in series to a parallel circuit (72) comprising the capacitor and the second resistor, and connecting the parallel circuit and a portion of the power supply circuit between the motor and the second switching unit. A third switching part (63) for opening and closing;
The second switching unit between a portion of the power supply circuit between the electric motor and the second switching unit and a portion of the power supply circuit between the second switching unit and the power source. A third resistor (49) connected in parallel;
A drive control circuit for an electric motor, further comprising: In claim 1 or claim 2,
A fourth resistor (48) connected in parallel to the capacitor;
A fourth switching unit (64) connected in series to the fourth resistor and opening / closing a connection between the fourth resistor and a portion of the power supply circuit between the electric motor and the second switching unit. When,
The second switching unit between a portion of the power supply circuit between the electric motor and the second switching unit and a portion of the power supply circuit between the second switching unit and the power source. A fifth resistor (49) connected in parallel;
A drive control circuit for an electric motor, further comprising:

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