JP2009161083A - Load driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load driving device for restraining vibration of a battery discharge electric current, even in a hybrid vehicle for performing an anti-lock brake system and VDC control. <P>SOLUTION: This load driving device has a power source, a load of two systems or more connected to the power source, a switching element arranged on the downstream side of a plurality of loads, a capacitor arranged between the power source and the plurality of loads, and a control means for controlling the plurality of loads by PWM by driving the switching element. The control means sets a PWM signal to respective groups in a different phase by dividing the plurality of loads into a plurality of groups. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a brake control device that obtains a braking force by hydraulic pressure control in a wheel cylinder, and in particular, a brake-by-wire control device that performs hydraulic pressure control using an electric load such as a motor or a valve regardless of a driver's stepping force. The present invention relates to a load driving circuit.

  Conventionally, in a hybrid vehicle, a smoothing capacitor is disposed in the vicinity of an inverter of a traveling motor and an inverter of a power generating motor for power supply stabilization. At that time, if both inverters are turned ON / OFF at the same time, an excessive ripple current is generated, so that the life of the capacitor is remarkably deteriorated. If the capacitor is increased in size in response to an excessive current, the overall size of the apparatus will be increased.

Therefore, in the technique described in Patent Document 1, the ripple current is reduced by shifting the timing of turning on / off the two inverters and setting the two inverters not to be turned on / off at the same time.
JP 2000-78850 A

  However, the above-described prior art simply shifts the inverter control timing of the two systems, and has a problem that the ripple current cannot be reduced when there are three or more systems of loads.

  For example, in an electronic control brake that controls the wheel cylinder pressure by appropriately controlling a plurality of hydraulic solenoid valves, in a system in which the solenoid valve to be operated for each control pattern (pressure increase, pressure reduction, hold) and the control amount are switched, It is difficult to suppress an excessive ripple current simply by shifting the control timing as in the prior art.

  The present invention has been made paying attention to the above-mentioned problem, and the object of the present invention is to reduce excessive ripple current even in a system in which an operation load and a control amount are different for each control pattern, and avoid an increase in the size of the capacitor. It is to provide a load driving device.

  In order to achieve the above object, in the present invention, a power source, at least two or more loads connected to the power source, a switching element provided upstream or downstream of the plurality of loads, the power source, and the power source A capacitor provided between the plurality of loads; and a control unit configured to perform PWM control on the plurality of loads by driving the switching element, the control unit including the plurality of loads in a plurality of groups. The phase difference is provided for the PWM signals for each group.

  Therefore, it is possible to provide a load driving device that reduces excessive ripple current and avoids an increase in the size of a capacitor even in a system in which an operation load and a control amount are different for each control pattern.

  Hereinafter, the best mode for realizing a load driving device of the present invention will be described based on an embodiment shown in the drawings.

  Example 1 will be described. FIG. 1 is a system configuration diagram according to the first embodiment, and FIG. 2 is a hydraulic circuit diagram. The brake hydraulic device is a hydraulic brake-by-wire system that increases the pressure of wheel cylinders W / C (FL to RR) of all four wheels by a pump.

  The master cylinder M / C is a so-called tandem type, and is connected to the FL and FR wheel cylinders W / C (FL, FR) by manual circuits A (FL) and A (FR).

  The master cylinder M / C is connected to the reservoir RSV, and each solenoid valve is driven by the control unit CU. The pump which is a hydraulic pressure source is provided with a normal main pump Main / P and an emergency sub pump Sub / P in parallel.

  The main pump Main / P is a bidirectional pump, and the sub pump Sub / P is a one-way pump, and is driven by the main motor Main / M and the sub motor Sub / M based on commands from the control unit CU.

  On the manual circuits A (FL) and A (FR), a shut-off valve S.I. that is a normally open solenoid valve (ON / OFF valve). OFF / V (FL, FR) is provided to communicate / block the first and second master cylinders M / C1, M / C2 and the FL, FR wheel cylinders W / C (FL, FR), respectively.

  On the manual circuit A (FL), the first master cylinder M / C and the shutoff valve S.E. A stroke simulator S / Sim is provided between OFF / V (FL). This stroke simulator S / Sim is connected to the manual circuit A (FL) via a cancel valve Can / V which is a normally closed solenoid valve (ON / OFF valve).

  FL shutoff valve When OFF / V (FL) is closed and the cancel valve Can / V is opened, the hydraulic oil in the first master cylinder M / C is transferred to the stroke simulator S / Sim as the brake pedal BP is depressed. Introduced and secured pedal stroke.

  The discharge sides of the main and sub pumps Main / P, Sub / P are connected to a pressure-increasing circuit C, and connected to each wheel cylinder W / C (FL to RR) at a connection point I (FL to RR). On the other hand, the suction side of each pump Main / P, Sub / P is connected to the decompression circuit B.

  On the pressure increasing circuit C, pressure increasing valves IN / V (FL to RR), which are normally closed solenoid valves (proportional valves), are provided. Each pump Main / P, Sub / P and each wheel cylinder W / C (FL ~ RR) communication / blocking.

  Each wheel cylinder W / C (FL to RR) is connected to the decompression circuit B at the connection point I (FL to RR). On this pressure reducing circuit B, there are a front wheel pressure reducing valve OUT / V (FL, FR) which is a normally closed electromagnetic valve (proportional valve) and a rear wheel pressure reducing valve OUT / V (RL, RR) which is a normally open electromagnetic valve. Provided to switch communication / blocking between each wheel cylinder W / C (FL to RR) and the reservoir RSV.

  A check valve C / V is provided on the discharge side of each of the pumps Main / P and Sub / P to prevent the hydraulic oil from flowing back from the pressure increasing circuit C to the pressure reducing circuit B via the pump P. Further, the pressure increasing circuit C and the pressure reducing circuit B are connected via a relief valve Ref / V, and when the pressure in the pressure increasing circuit C becomes equal to or higher than a specified value, hydraulic oil is released to the pressure reducing circuit B.

  On the manual circuits A (FL) and A (FR), the shutoff valve S.I. Between the OFF / V (FL, FR) and the master cylinder M / C, first and second master cylinder pressure sensors MC / Sen 1 and 2 are provided, respectively, and each wheel cylinder W / C (FL to RR). Is provided with a hydraulic pressure sensor WC / Sen (FL to RR).

  In the control unit CU, the detected values of the detected first and second master cylinder pressures Pm1, Pm2, the hydraulic pressures P (FL to RR), and the stroke sensors S / Sen1, 2 for detecting the stroke of the brake pedal BP are stored. Entered.

  Based on these detected values, the control unit CU calculates the target hydraulic pressure P * (FL to RR) of each wheel FL to RR, and each motor Main / M, Sub / M and the pressure increasing valve IN / V (FL to RR). ), The pressure reducing valve OUT / V (FL to RR) is driven. Further, the shut-off valve S.D. OFF / V (FL, FR) is closed and the cancel valve Can / V is opened.

  Further, the control unit CU compares the target hydraulic pressure P * (FL to RR) and the actual hydraulic pressure P (FL to RR) of each wheel cylinder W / C (FL to RR) to When the fluid pressure shows an abnormal response, an abnormal signal is output. In addition, the wheel speed VSP is input to the control unit CU to determine whether the vehicle is running / stopped.

[Brake control]
(Normal pressure increase)
During normal pressure increase, the cancel valve Can / V is opened and the shut-off valve S.I. OFF / V (FL, FR) is shut off, and the depression of the brake pedal BP by the driver is detected by the two stroke sensors S / Sen 1 and 2, and based on this detection value, each wheel cylinder W / C ( The target hydraulic pressure P * (FL to RR) of FL to RR) is calculated.

  Further, the control unit CU drives the main motor Main / M or the sub motor Sub / M by the motor M so that the discharge pressure acts on the pressure increasing circuit C. Further, each pressure increasing valve IN / V (FL to RR) is driven according to the calculated target hydraulic pressure P * (FL to RR), and hydraulic oil is supplied to each wheel cylinder W / C (FL to RR). Get braking force.

(At reduced pressure)
At the time of depressurization, each pressure reducing valve OUT / V (FL to RR) is driven by the control unit CU, and the hydraulic oil is discharged from each wheel cylinder W / C (FL to RR) to the reservoir RSV via the pressure reducing circuit B. .

(When holding)
At the time of holding, a predetermined pressure increasing valve IN / V (FL to RR) and each pressure reducing valve OUT / V (FL to RR) are closed, and each wheel cylinder W / C (FL to RR) is pressure increasing and pressure reducing circuit. Shut off C and B.

(Manual brake)
When the system fails, etc., the normally open shut-off valve OFF / V (FL, FR) is opened, each normally closed pressure increasing valve IN / V (FL to RR) and the front pressure reducing valve OUT / V (FL, FR) are closed, and the normally opened rear wheel The pressure reducing valve OUT / V (RL, RR) is opened. As a result, the master cylinder M / C communicates with the FL and FR wheel cylinders (FL, FR), and a manual brake is secured.

[Control block diagram]
FIG. 3 is a control block diagram of the control unit CU. The control unit CU includes a first unit CU1 that controls the FR and RL wheel hydraulic pressure, and a second unit CU2 that controls the FL and RR wheel hydraulic pressure. First and second CPUs 1 and 2 are provided in the first and second units CU1 and CU2, respectively.

  The hydraulic pressure unit HU includes first and second hydraulic pressure units HU1 and HU2, and solenoid valves (pressure increase valves IN / V (FR, RL), pressure reduction valves OUT / V) for controlling the FR and RL wheel hydraulic pressures. (FR, RL)) is provided in the first hydraulic unit HU1. Solenoid valves (pressure increasing valves IN / V (FL, RR) and pressure reducing valves OUT / V (FL, RR)) for controlling the FL and RR wheel hydraulic pressures are provided in the second hydraulic pressure unit HU2.

  Further, the normal main motor Main / M and the main pump Main / P are provided in the first hydraulic unit HU1, and the emergency sub motor Sub / M and the sub pump Sub / P are provided in the second hydraulic unit HU2. .

  Wheel speed, longitudinal G, yaw rate, lateral G, first pedal stroke, first master cylinder pressure, FR, RL wheel cylinder pressure are input to the first CPU 1. The second CPU 2 receives the second pedal stroke, the second master cylinder pressure, and the FL and RR wheel cylinder pressures.

  Sensor signals other than the FL and RR wheel cylinder pressures are input to the CPUs 1 and 2 via the input circuit 3, and the FL and RR wheel cylinder pressures are input to the input circuit 3a. The input circuit 3a is an interface circuit that distributes the FL and RR wheel cylinder pressures to the first and second CPUs 1 and 2.

  Further, the first CPU 1 communicates with a steering angle sensor, an engine C / U (control unit), a meter, an ACC (auto cruise controller) radar, and a regenerative unit (regenerative brake unit) not shown in the figure via a CAN communication line CAN1. I do. Further, the first and second CPUs 1 and 2 are connected to each other via a CAN communication line CAN2 so as to be capable of bidirectional communication, and share information with each other.

  The first CPU 1 is a main CPU that calculates the hydraulic pressure command value for the front wheels of the four wheels. The first CPU 1 calculates the hydraulic pressure command value for each wheel in the normal brake based on the input information, and ABS (anti-lock brake control) or VDC (vehicle attitude). Control).

  In addition, the first CPU 1 drives the main motor Main / M to supply hydraulic pressure to the four wheels, and sets the FR and RL wheel solenoid valves IN / V (FR, RL) and OUT / V (FR, RL). Drive to control FR and RL wheel hydraulic pressure. Further, during normal operation, a valve opening command is output to the cancel valve Can / V of the stroke simulator S / Sim.

  The second CPU 2 is for backup of the first CPU 1, and monitors the first CPU 1 to determine whether it is normal. When the first CPU 1 is normal, the solenoid valves IN / V (FL, RR) and OUT / V (FL, RR) of the FL and RR wheels are driven to control the FL and RR wheel hydraulic pressures. If the second CPU 1 is abnormal, the sub motor Sub / M is driven to supply hydraulic pressure to the four wheels.

  The first and second CPUs 1 and 2 are separate power sources. The first CPU 1 receives power from the first power source B1 and the second CPU 2 receives power from the second power source B2. Each CPU 1, 2 outputs a command to each solenoid valve and motor via the output circuit 4.

[Details of the first CPU]
FIG. 4 is a control configuration of the first CPU 1 and a circuit configuration diagram of the output circuit 4. Each solenoid valve in the first hydraulic unit HU1 is indicated by a solenoid. Further, the description of the cancel valve Can / V, the main motor Main / M, and their circuit configurations is omitted.

  The first CPU 1 includes a control hydraulic pressure calculation unit 11 and a load drive control unit 100. This load drive control unit 100 is provided in the first CPU 1 in the same number as the load (each electromagnetic valve, motor, etc. to be controlled), and each load drive control unit 100 passes through the output circuit 4 for one load. Outputs a command.

  Each load drive control unit 100 and the output circuit 4 use the power supply B1 as a power supply, and a capacitor 300 is provided between the output circuit 4 and the power supply B1. The capacitor 300 reduces noise due to current vibration when the solenoid of each solenoid valve that is a load is switched between energization and non-energization.

  Note that each solenoid valve IN / V (FR, RL), OUT / V (FR, RL), and S.P. Since the control of OFF / V (FR) is the same, only the control of the FR wheel pressure reducing valve OUT / V (FR) will be described below.

(Control hydraulic pressure calculator)
The control hydraulic pressure calculation unit 11 calculates the control amount of the FR wheel pressure reducing valve OUT / V (FR) based on the FR, RL wheel wheel cylinder pressure, the first master cylinder pressure, and the first stroke sensor value, and the output circuit 4 The control amount is output to

(Load drive control unit)
The load drive control unit 100 sets the current of each solenoid valve based on the control amount calculated by the control hydraulic pressure calculation unit 11, and includes a command current calculation unit 110, a DUTY setting unit 120, a control frequency setting unit 130, A phase difference setting unit 140, a phase difference determination unit 150, and a fail safe determination unit 160 are included.

  The command current calculation unit 110 calculates a command current to be supplied to the FR wheel pressure reducing valve OUT / V (FR) based on the calculated control amount, and outputs the command current to the DUTY setting unit 120 and the phase difference determination unit 150.

  The DUTY setting unit 120 calculates the PWM duty based on the command current and the current value of the FR wheel pressure reducing valve OUT / V (FR), and outputs the PWM duty to the phase difference setting unit 140.

  The control frequency setting unit 130 sets the PWM duty frequency based on the current phase difference (detected by the phase difference determination unit 150) and outputs the PWM duty frequency to the DUTY setting unit 120.

  The phase difference setting unit 140 changes the PWM duty phase difference with respect to the FR wheel pressure reducing valve OUT / V (FR) based on the phase difference change request from the phase difference determination unit 150, and drives the switching element 43 in the output circuit 4. Output a signal. The phase difference may be changed by the DUTY setting unit 120 or the control frequency setting unit 130.

  The phase difference determination unit 150 cooperates with the phase difference determination unit 150 in the other load drive control unit 100, compares the phase of the FR wheel pressure reducing valve OUT / V (FR) with respect to the phase of another load, and compares the phase of the FR wheel pressure reducing valve OUT. It is determined whether or not the phase of / V (FR) needs to be changed. The determination result is output to DUTY setting unit 120, control frequency setting unit 130, and phase difference setting unit 140.

  The fail safe determination unit 160 performs a failure determination based on the detection results of the current detection unit 41 and the disconnection detection unit 42 provided in the output circuit 4, and executes fail safe processing.

(Output circuit)
The output circuit 4 includes a current detection unit 41, a disconnection detection unit 42, a switching element 43, and a flywheel diode 44.

  The current detection unit 41 detects a current value flowing through the FR wheel pressure reducing valve solenoid SOL-OUT (FR), and outputs the detected value to the fail safe determination unit 160.

  The disconnection detection unit 42 detects disconnection downstream of the FR wheel pressure reducing valve solenoid SOL-OUT (FR). If the solenoid downstream voltage is equivalent to the power supply B1, it is judged as normal, and if it is equivalent to the ground (grounding) voltage, it is judged as a disconnection, and the judgment result is outputted to the fail safe judgment unit 160.

  The switching element 43 is provided downstream of the FR wheel pressure reducing valve solenoid SOL-OUT (FR), and performs switching of the solenoid current through the drive signal from the phase difference setting unit 140 in the first CPU 1.

  The flywheel diode 44 circulates the induced energy when the FR wheel pressure reducing valve solenoid SOL-OUT (FR) flows, and is provided in parallel with the solenoid SOL-OUT (FR) and the current detection unit 41.

[Flow phase control]
When current is passed through a plurality of solenoid valves in the same phase, the discharge current of the capacitor 300 that covers the transient power supply immediately after the start of the conduction is equivalent to the total current of the plurality of solenoid valves. For this reason, it is necessary to select a capacitor corresponding to the current corresponding to the total current. As a result, the capacitor 300 is increased in size and the size of the apparatus is increased.

  In addition, when performing anti-lock brake system (ABS) control or vehicle attitude control (VDC), energization and non-energization of each solenoid valve is appropriately switched according to a pattern (control pattern) corresponding to the control. In addition, since the energization amount varies depending on the solenoid valve, the discharge current of the capacitor 300 cannot be suppressed by simply shifting the phase as in the prior art.

  Therefore, in this application, the phase which flows through a solenoid valve according to the control amount of each solenoid valve is shifted, the discharge current of the capacitor 300 is suppressed, the optimum capacitor is selected, and the grouping is performed. At that time, the solenoid valves in each group are energized in the same phase, and a phase difference is provided for each group.

  Thereby, capacitor discharge is performed only at the ON timing dispersed for each group of solenoid valves, and the discharge current of the capacitor 300 is suppressed. Further, the grouping of the solenoid valves is calculated by the CPU 1 or CPU 2 and is performed based on the target control current value set for each solenoid valve, so that the current distribution between the groups is optimized and the discharge current is reliably suppressed. .

  Furthermore, in the first embodiment, the rising (falling) of another load is shifted in accordance with the rising (falling) timing of an electromagnetic valve (for example, FR wheel shut-off valve) that is a reference for setting the phase difference. As a result, the phase difference set in the PWM signal of the other solenoid valve can be made variable, and the phase difference is set reliably.

  Further, the phase difference setting start condition is limited to a condition in which the discharge current of the capacitor 300 becomes excessive, and the discharge current is effectively suppressed. In the first embodiment, the phase difference setting start condition is set depending on whether or not the sum of the target control currents for a plurality of solenoid valves exceeds the target control current (threshold value) of the solenoid valves.

[Outline of flow phase control]
FIG. 6 is an outline of a change in current when the present application phase control (during pressure reduction) is performed. FIG. 5 shows a comparative example in which phase control is not performed. 5 and 6, it is assumed that one PWM pulse energization cycle is completed at a phase of 0 ° to 360 °.

  For illustration purposes, the FR wheel shut-off valve S.I. Only OFF / V (FR) and pressure reducing valve OUT / (FR) are shown, and will be described simply as a shutoff valve and pressure reducing valve. Other solenoid valves are omitted for simplification.

(Phase 0 °)
In the comparative example, a command to rise at the same timing (phase 0 °) is output without setting a phase difference between the currents of the shutoff valve and the pressure reducing valve.
Therefore, although the electric charge of the capacitor 300 is suddenly discharged and reaches the current a, the discharge current tends to decrease as the current of the power source B1 increases.

On the other hand, in the present application, the shut-off valve and the pressure reducing valve are in separate groups, and energization is performed with a phase difference of 180 ° from each other. In the phase range of 0 ° to 180 °, only the shutoff valve is ON and the pressure reducing valve is OFF.
Therefore, the discharge current of the capacitor 300 is less than half that of the comparative example.

(Phase 60 °)
In the present application, charging of the capacitor 300 is started at a phase of 60 °. This is because the capacitor 300 of the present application was less discharged.

(Phase 180 °)
In the comparative example, both the shutoff valve and the pressure reducing valve are turned off, and charging of the capacitor 300 is started.
On the other hand, in the present application, the shutoff valve is turned off and the pressure reducing valve is turned on, and the operation is the same as in the case of the phase 0 °.

(Phase 180 ° ~ 360 °)
It is the same as the phase 0 ° to 180 ° only by reversing the operation of the shutoff valve and the pressure reducing valve.

  As described above, the discharge current of the capacitor 300 can be suppressed by grouping a plurality of solenoid valves and energizing them with a phase difference therebetween. 5 and 6 show the case where two electromagnetic valves are divided into two groups, but even when three or more electromagnetic valves are divided into two or more groups, a phase difference is provided between them. Similarly, the capacitor discharge current can be suppressed.

[Flow phase control processing]
(Main flow)
FIG. 7 is a main flow of solenoid valve flow control executed in the first CPU 1.

  In step S100, the first and second master cylinder pressures and the first and second pedal strokes are detected, and the process proceeds to step S101.

  In step S101, it is determined whether there is a brake request based on the first and second master cylinder pressures and the first and second pedal strokes. If YES, the process proceeds to step S102, and if NO, the process proceeds to step S103.

  In step S102, the control hydraulic pressure (hydraulic pressure target value) P1 of each wheel cylinder W / C (FL to RR) is calculated, and the process proceeds to step S104.

  In step S103, it is determined that there is no brake request, control for all the solenoid valves is stopped, and the process returns to step S100.

  In step S104, the current hydraulic pressure P2 of each wheel cylinder W / C (FL to RR) is read, and the process proceeds to step S105.

  In step S105, the control hydraulic pressure P1 is compared with the current hydraulic pressure P2, and if P1> P2, the process proceeds to step S106 as pressure increase control, and if P1 <P2, the process proceeds to step S122 as pressure reduction control. If P1 = P2, the process proceeds to step S114 as holding control.

(Pressure increase control)
In step S106, the FR wheel shut-off valve S.I. Control amounts of OFF / V (FR), FR, RL wheel increase, pressure reducing valves IN / V (FR, RL), OUT / V (FR, RL) are calculated, and the process proceeds to step S107.

  In step S107, based on the calculated control amount, the solenoid SOL-S. Command currents for OFF (FR), SOL-IN (FR, RL), and SOL-OUT (FR, RL) are calculated, and the process proceeds to step S108.

  In step S108, the solenoid SOL-S. OFF (FR), SOL-IN (FR, RL), and SOL-OUT (FR, RL) are divided into a plurality of groups, and a phase difference is set in the command current between one group and the other group, step S109. Migrate to

  In steps S109 to 113, each solenoid valve solenoid is driven based on the set phase difference and command current to increase the pressure, and the process returns to step S100.

(Holding control)
In steps S114 to S121, holding control is executed instead of the pressure increase control in steps S106 to S113, and the process returns to step S100.

(Decompression control)
In steps S122 to S129, pressure reduction control is executed instead of the pressure increase control in steps S106 to S113, and the process returns to step S100.

(Phase difference setting flow)
FIG. 8 is a phase difference setting flow. This corresponds to steps S106 to S108, S114 to S116, and S122 to S124 in FIG.

  In S106, S114, and S122, each solenoid valve control amount is calculated, and the process proceeds to Steps S107, S115, and S123.

In steps S107, S115, and S123, the solenoid command current of each solenoid valve is calculated based on the calculated control amount, and the process proceeds to steps S108, S116, and S123.
FR wheel shut-off valve solenoid command current = is1
FR wheel booster valve solenoid command current = is2
FR wheel pressure reducing valve solenoid command current = is3
RL wheel booster valve solenoid command current = is4
RL wheel pressure reducing valve solenoid command current = is5
And

(Phase difference setting target load judgment flow)
Steps S108, S116, and S123 (phase difference setting target load determination) include a plurality of steps S200 to S214. Hereinafter, each step will be described.

In step S200, the sum isA of each solenoid valve command current is calculated, and the process proceeds to step S201.
In addition,
isA = is1 + is2 + is3 + is4 + is5
It is.

In step S201, a plurality of solenoid valves S.P. OFF / V (FR), IN / V (FR, RL), and OUT / V (FR, RL) are divided into a plurality of groups, and the process proceeds to step S202.
The grouping may be three or more. The number of groups is represented by CNT. In the first embodiment, CNT = 2.

In step S202, the target average current isAV is calculated for each of a plurality of groups, and the process proceeds to step S203. The target average current isAV is calculated by the following formula.
Target average current isAV = isA / CNT
Therefore, the target average current isAV of the first embodiment isAV = isA / 2.

  In step S203, the command current isX (X = 1, 2, 3, 4, 5) of each solenoid valve is arranged in ascending order in the order of high current, and the process proceeds to step S204.

In step S204, the difference C1 between the highest average current value isA1 among the target average current isAV and the command current isX of each solenoid valve is calculated, and the process proceeds to step S205.
C1 = isAV-isA1

In step S205, it is determined whether or not the difference C1 is positive (C1 ≧ 0A). If YES, the process proceeds to step S206, and if NO, the process proceeds to step S213.
If NO, the current value is of the highest solenoid valve is greater than or equal to the A1 target average current isAV, and only this solenoid valve is included in one group.

In step S206, since the highest current value isA1 of the solenoid valve does not reach the target average current isAV, the highest current value isA1 and the lowest current value isA5 among the target average current isAV and the command current isX of each solenoid valve. And the difference C2 of the sum is calculated and the process proceeds to step S207.
C2 = isAV− (isA1 + isA5)

In step S207, it is determined whether or not the difference C2 is positive (C2 ≧ 0A). If YES, the process proceeds to step S208, and if NO, the process proceeds to step S212.
If NO, the sum of the current values isA1 and isA5 is equal to or greater than the target average current isAV, and the solenoid valves having the current values isA1 and isA5 are grouped into one group.

In step S208, since the sum of the highest solenoid valve current value isA1 and the lowest solenoid valve current value isA5 does not reach the target average current isAV, the highest current value isA1 among the command currents isX of each solenoid valve, In addition to isA5, a sum with the fourth highest current value isA4 is calculated, a difference C3 from the target average current isAV is calculated, and the process proceeds to step S209.
C3 = isAV− (isA1 ++ isA4 + isA5)

In step S209, it is determined whether or not the difference C3 is positive (C3 ≧ 0A). If YES, the process proceeds to step S210, and if NO, the process proceeds to step S211.
If NO, the sum of the current values isA1, 4, 5 is equal to or greater than the target average current isAV, and the solenoid valves having the current values isA1, 4, 5 are grouped into one group.

  In step S210, since the sum of the current values isA1, 4, 5 does not reach the target average current isAV, in addition to the solenoid valves having the current values isA1, 4, 5, the solenoid valve having the third highest current value isA3 is set. One grouping is performed, and only the remaining solenoid valves having the current value isA2 are grouped into the other group, and the process proceeds to step S214.

  In step S211, the solenoid valves having current values isA1, 4, and 5 are grouped into one phase group 1, and the remaining solenoid valves having current values isA2 and 3 are grouped in another group to be phase group 2 and the process proceeds to step S214.

  In step S212, the solenoid valves with current values isA1,5 are grouped into one phase group 1 and the remaining solenoid valves with current values isA2,3,4 are grouped into another phase group 2 and the process proceeds to step S214.

  In step S213, only the solenoid valves having the current value isA1 are grouped into one phase group 1 and the remaining solenoid valves having the current values isA2, 3, 4, and 5 are grouped into the other group and the phase group 2 is transferred to step S214. .

  In step S214, with respect to the solenoid valve current corresponding to the phase group 1, a phase difference is set to the current flowing through the solenoid valve corresponding to the phase group 2, and the control is terminated.

[Phase change setting control over time: Normal braking]
FIG. 9 is a time chart of phase difference setting control during normal braking.

(Time t1)
At time t1, the driver's braking request is not generated, and all the solenoid valves are in a non-energized state.

(Time t2)
Pressure increase control is started at time t2, and the hydraulic pressure command value increases. Accordingly, the FR wheel shut-off valve S.I. OFF-V (FR) is closed, the pressure increasing valve IN / V (FR, RL) is opened, and the pressure reducing valve OUT / V (FR, RL) is closed.
The shut-off valve S.I. Since OFF / V (FR) and the pressure increasing valve IN / V (FR, RL) are all normally closed, they are opened by PWM drive. On the other hand, since the pressure reducing valve OUT / V (FR, RL) is normally closed on the FR side and normally opened on the RL side, only the RL side is energized with PWM, and the FR side is in an uncontrolled state.
During the pressure increase control, all the solenoid valves other than the FR wheel pressure reducing valve OUT / V (FR) are driven. OFF / V (FR) and booster valve IN / V (FR) are allocated to the same group, and the remaining RL wheel booster valve IN / V (RL) and pressure-reducing valve OUT / V (RL) are allocated to the same group. Thus, a 180 ° phase difference is provided and energization is performed. This suppresses the current fluctuation of the capacitor 300.

(Time t3)
At time t3, the pressure increase control is finished, and the holding control is started. Since all the solenoid valves are closed during the holding control, the normally open FR wheel shut-off valve S.I. Only OFF / V (FR) and RL wheel pressure reducing valve OUT / V (RL) are closed by PWM energization.
At the time of holding control, the two solenoid valves S.P. Since only OFF / V (FR) and OUT / V (RL) are driven, each solenoid valve is driven into another group with a phase difference.

(Time t4)
At time t4, the holding control ends, and the pressure reduction control is started. The normally closed FR wheel pressure reducing valve OUT / V (FR) is opened by PWM drive, and the normally open RL wheel pressure reducing valve OUT / V (RL) is de-energized. Also, the normally open shut-off valve S.I. OFF / V (FR) is also energized and closed.
When the pressure is reduced, the two solenoid valves S.P. Since only OFF / V (FR) and OUT / V (FR) are driven, each solenoid valve is divided into different groups and driven with a phase difference as in the holding control.

(Time t5)
At time t5, the driver's braking request is stopped, and all solenoid valves are deenergized.

[Change over time in phase difference setting control: during VDC control]
FIG. 10 is a time chart of phase difference setting control during VDC control. Note that VDC control is performed only for the FR wheel and not for the RL wheel.

(Time t6)
At time t6, the driver's braking request is not generated, and all the solenoid valves are in a non-energized state.

(Time t7)
At time t7, pressure increase of the FR wheel is started by VDC control, and the normally closed FR wheel shut-off valve S.P. OFF / V (FR) is closed and the normally closed FR wheel booster valve IN / V (FR) is opened.
When the VDC pressure is increased, the two solenoid valves S.P. Since only OFF / V (FR) and IN / V (FR) are driven, each solenoid valve is driven into another group with a phase difference.

(Time t8)
At time t8, the VDC pressure increase control ends, and the holding control is started. Since both the FR wheel pressure increasing valve and the pressure reducing valves IN / V (FR) and OUT / V (FR) are normally closed, energization is not performed and the normally open shut-off valve S.R. Only OFF / V (FR) is closed by PWM control.
When holding VDC, one solenoid valve S.P. Since only OFF / V (FR) is driven, no grouping is performed.

(Time t9)
At time t9, the VDC holding control ends, and the pressure reduction control is started. The normally closed FR wheel pressure reducing valve OUT / V (FR) is opened by the PWM drive, and the normally open shut-off valve S.I. OFF / V (FR) is also energized and closed.
When the VDC is reduced, the two solenoid valves S.P. Since only OFF / V (FR) and OUT / V (FR) are driven, each solenoid valve is divided into another group and driven with a phase difference as in the case of VDC pressure increase.

(Time t10)
At time t10, the driver's braking request is stopped, and all the solenoid valves are deenergized.

[Effect of Example 1]
(1) Between the power sources B1 and B2, two or more loads connected to the power sources B1 and B2, the switching element 43 provided on the downstream side of the plurality of loads, and between the power sources B1 and B2 and the plurality of loads A capacitor 300 provided and first and second CPUs 1 and 2 that perform PWM control of a plurality of loads by driving the switching element 43 are provided. The first and second CPUs 1 and 2 each include a plurality of loads in a plurality of groups. The PWM signal for each group is set to a different phase.

  As a result, even in an anti-lock brake system or a hybrid vehicle that performs VDC control, it is possible to provide a load driving device that suppresses vibration of the battery discharge current.

  (2) The plurality of loads are three or more. Even in the system that supplies current to the load, the same effect as the above (1) can be obtained.

  (3) The first and second CPUs 1 and 2 determine which load among a plurality of loads is allocated to which group based on a predetermined distribution condition. By appropriately grouping the loads according to the conditions, current oscillation can be effectively suppressed.

  (4) The predetermined distribution condition is a target current value for each of a plurality of loads. By setting the phase difference by grouping the loads based on the target current value, current oscillation can be reliably suppressed.

  (9) The first and second CPUs 1 and 2 change the phase difference set in the PWM signals for a plurality of groups by shifting the rising or falling timing of the current with respect to the load.

  It is possible to rise and fall other loads in accordance with the rise and fall timing of the load, which is the reference for setting the phase difference, and the phase difference can be set reliably.

  (11) The first and second CPUs 1 and 2 set the phase difference when a predetermined start condition is satisfied. By setting the start condition in advance so that the phase difference is set under conditions where current vibration is likely to occur, current vibration can be effectively suppressed.

  (12) The predetermined start condition for setting the phase difference is whether or not the sum of the target current values for a plurality of loads exceeds a threshold value.

  As the total sum of the target current values increases, the battery discharge current also increases and current oscillation is likely to occur. Therefore, current oscillation can be reliably suppressed by providing a threshold value for the sum of the target current values as a starting condition for setting the phase difference.

  (14) Power source B1, B2, wheel cylinder W / C (FL to RR), main pump Main / P driven by power sources B1 and B to increase the pressure of wheel cylinder W / C (FL to RR), and foil Solenoid valve connected to cylinder W / C (FL to RR) OFF / V (FL, FR), IN / V (FL to RR), OUT / V (FL to RR), and the wheel cylinder W / C (FL to RR) A load driving circuit of a brake control device including a control unit CU for controlling pressure, and the load is each solenoid valve.

Thereby, even if it exists in the solenoid valve drive circuit of a brake-by-wire vehicle, the effect of said (1)-(13) can be acquired.
In particular, when anti-lock brake system (ABS) control or vehicle attitude control (VDC) is performed in a hybrid vehicle, the energization and de-energization of the solenoid valve is switched randomly, and the energization amount varies depending on the solenoid valve. In the case of a drive circuit, current oscillation can be more effectively suppressed.

  Example 2 will be described. The basic configuration is the same as that of the first embodiment. In the first embodiment, the solenoid valves are grouped based on the target current value of each solenoid valve, but in the second embodiment, the grouping is performed based on the PWM pulse width of each solenoid valve.

  FIG. 11 is a phase difference setting flow in the second embodiment. This corresponds to FIG. 8 of the first embodiment. In steps S303 to S308, the target average current isAV in steps S204 to S209 in FIG. 8 is changed to the power supply current approximate value ib.

  Steps S106, S114, and S122, and steps S107, S115, and S123 are the same as those in FIG.

In step S300, the PWM pulse width (conductivity = DUTY) of each solenoid valve is calculated based on the calculated control amount, and the process proceeds to step S301.
FR wheel cutoff valve solenoid flow rate = DUTY1
FR wheel booster valve solenoid flow rate = DUTY2
FR wheel pressure reducing valve solenoid flow rate = DUTY3
RL wheel booster valve solenoid flow rate = DUTY4
RL wheel pressure reducing valve solenoid flow rate = DUTY5
And

In step S301, an approximate value ib of the power supply current is calculated based on the command current isX and the duty ratio DUTYX (X = 1, 2, 3, 4, 5) of each solenoid valve, and the process proceeds to step S302.
ib = is1, DUTY1 + is2, DUTY2 + is3, DUTY3 + is4, DUTY4 + is5, DUTY5
It is.

  In step S302, the command current isX (X = 1, 2, 3, 4, 5) of each solenoid valve is arranged in ascending order in the order of high current, and the process proceeds to step S303.

In step S303, a difference C1 between the power supply current approximate value ib and the highest current value isA1 among the command currents isX of each solenoid valve is calculated, and the process proceeds to step S304.
C1 = ib-isA1

In step S304, it is determined whether or not the difference C1 is positive (C1 ≧ 0A). If YES, the process proceeds to step S305, and if NO, the process proceeds to step S312.
If NO, the highest current value is of the solenoid valve is a value equal to or greater than the A1 power supply current approximate value ib, and only this solenoid valve is included in one group.

In step S305, since the highest solenoid valve current value isA1 does not reach the power supply current approximate value ib, the highest current value isA1 and the lowest current among the power supply current approximate value ib and the command current isX of each solenoid valve. The difference C2 of the sum with the value isA5 is calculated, and the process proceeds to step S306.
C2 = ib− (isA1 + isA5)

In step S306, it is determined whether or not the difference C2 is positive (C2 ≧ 0A). If YES, the process proceeds to step S307, and if NO, the process proceeds to step S311.
If NO, the sum of the current values isA1 and isA5 is equal to or greater than the power supply current approximate value ib, and the solenoid valves having the current values isA1 and isA5 are grouped into one group.

In step S307, since the sum of the highest solenoid valve current value isA1 and the lowest solenoid valve current value isA5 does not reach the power supply current approximate value ib, the highest current value isA1 among the command currents isX of each solenoid valve. In addition to isA5, the sum of the current value isA4, which is the fourth highest, is calculated, the difference C3 from the power supply current approximate value ib is calculated, and the process proceeds to step S308.
C3 = ib− (isA1 ++ isA4 + isA5)

In step S308, it is determined whether or not the difference C3 is positive (C3 ≧ 0A). If YES, the process proceeds to step S309, and if NO, the process proceeds to step S310.
If NO, the sum of the current values isA1, 4, 5 is equal to or greater than the power supply current approximate value ib, and the solenoid valves having the current values isA1, 4, 5 are grouped.

  Steps S309 to S313 are the same as steps S210 to S214 in FIG.

[Effect of Example 2]
(6) The distribution conditions for grouping the solenoid valves are the target current value for each of the plurality of loads and the PWM pulse width for each load. Thereby, current oscillation can be more effectively suppressed.
(Other examples)

  The best mode for carrying out the present invention has been described based on the embodiments. However, the specific configuration of the present invention is not limited to the embodiments, and the design does not depart from the gist of the invention. Any changes and the like are included in the present invention.

  (5) The solenoid valves may be grouped according to the control pattern of the load drive circuit system (vehicle control state such as ABS, VDC). Appropriate grouping according to the system control state can be performed, and current oscillation suppression by phase difference setting can be appropriately performed.

  (7) A load belonging to one group among a plurality of groups may be a specific load set in advance, and the PWM signal may be set to a different phase only for this specific load.

  For example, FR wheel shut-off valve S.I. Only the OFF / V (FR) is made into one group. If setting the phase difference of other solenoid valves based on the current phase of OFF / V (FR), the load group for setting the phase difference is fixed and does not need to be changed. Can be suppressed.

  (8) The phase difference set in the PWM signal for a plurality of groups is a fixed value. For example, FR wheel shut-off valve S.I. OFF / V (FR) is used as a phase reference, and other solenoid valves are uniformly used as the FR wheel shut-off valve S.I. If energization is performed by shifting 180 ° with respect to OFF / V (FR), the control can be simplified.

  (10) Moreover, you may set a phase difference according to the number of several groups. For example, in the case of two groups, the load of one group can be used as a reference for setting the phase difference, and the phase of the other group may be shifted by 180 °. The current oscillation cannot be reduced effectively.

  Therefore, by setting the phase difference according to the number of load groups, for example, by providing a group having a phase difference of 120 ° from a reference group of phase differences and a group having a group having a phase difference of 240 °, Even when the number is three or more, current oscillation can be effectively suppressed.

(13) The phase difference may be set according to the control pattern of the load drive circuit system (vehicle control state such as ABS, VDC). Thereby, the phase difference can be set at a timing according to the system control state.

It is a system configuration figure of a brake control device to which a load drive device is applied. It is a hydraulic circuit diagram of a brake control device. It is a control block diagram of the control unit CU. 2 is a control configuration of a first CPU 1 and a circuit configuration diagram of an output circuit 4. FIG. It is the outline of the electric current change of the comparative example which does not perform phase control. It is the outline of the electric current change at the time of performing flow phase control (at the time of pressure reduction). It is a main flow of solenoid valve flow control executed in the first CPU1. 4 is a phase difference setting flow in the first embodiment. It is a time chart of phase difference setting control at the time of normal braking. It is a time chart of phase difference setting control at the time of VDC control. It is a phase difference setting flow in Example 2.

Explanation of symbols

1, 2 1st, 2nd CPU (control means)
43 Switching element 300 Capacitor IN / V (FL to RR) Booster valve (multiple loads)
OUT / V (FL to RR) Pressure reducing valve (multiple loads)
Main / M main motor (multiple loads)
S. OFF / V (FL, FR) Shut-off valve (multiple loads)

Claims (14)

Power supply,
At least two or more loads connected to the power source;
Switching elements provided on the upstream side or the downstream side of the plurality of loads;
A capacitor provided between the power source and the plurality of loads;
Control means for PWM controlling the plurality of loads by driving the switching element,
The control means divides the plurality of loads into a plurality of groups, and provides a phase difference with respect to the PWM signal for each group. The load driving device according to claim 1,
The plurality of loads are three or more systems. The load driving device according to claim 1 or 2,
The control unit determines which load among the plurality of loads is distributed to which group based on a predetermined distribution condition. The load driving device according to claim 3,
The predetermined distribution condition is a target current value of each of the plurality of loads. The load driving device according to claim 3,
The load distribution apparatus, wherein the predetermined distribution condition is a system control pattern. The load driving device according to claim 3,
The predetermined distribution condition is a target current value for each of the plurality of loads and a PWM pulse width for each of the loads. In the load drive device according to any one of claims 1 to 6,
The control means sets a load belonging to one group among the plurality of groups as a specific load set in advance, and sets the PWM signal in a different phase only for the specific load. Load drive device. In the load drive device according to any one of claims 1 to 7,
The load driving apparatus characterized in that the control means sets a phase difference set in the PWM signals for the plurality of groups as a fixed value. In the load drive device according to any one of claims 1 to 8,
The load driving device characterized in that the control means makes the phase difference set in the PWM signals for the plurality of groups variable by shifting the rising or falling timing of the current to the load. The load driving device according to any one of claims 1 to 9,
The load driving apparatus, wherein the control unit sets the phase difference according to the number of the plurality of groups. The load driving device according to any one of claims 1 to 10,
The load driving device characterized in that the control means sets the phase difference when a predetermined start condition is satisfied. The load driving device according to claim 11,
The predetermined drive condition is whether or not a sum of target current values for the plurality of loads exceeds a threshold value. The load driving device according to claim 11,
The load driving apparatus, wherein the predetermined start condition is a system control pattern. The load driving device according to any one of claims 1 to 13,
Power supply,
A wheel cylinder,
A hydraulic pressure source driven by the power source to increase the pressure of the wheel cylinder;
A solenoid valve connected to the wheel cylinder;
A load drive circuit of a brake control device comprising: a control unit that controls the wheel cylinder pressure by driving the hydraulic pressure source and the solenoid valve;
The brake control device, wherein the load is the solenoid valve.

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