JP2008265730A - Electric brake device and method of controlling electric brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric brake device and its controlling method, which both improves motor rotational frequency in a situation requiring high responsiveness without flowing electric current which does not contribute to toque, and secures quietness in a situation which does not require high responsiveness. <P>SOLUTION: When it is determined that rapid pressure intensification is required in Step 6, that an output voltage command is higher than sine wave output possible voltage in Step 7, and that motor rotating speed is large in Step 9, a motor is driven by 180° rectangular wave drive. In other cases, the motor is driven by sine wave drive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention belongs to the technical field of an electric brake device that generates a braking force by driving a brushless motor.

In the conventional electric brake device, in order to increase the motor rotation speed without reducing the motor torque as necessary, control is performed to weaken the electromagnetic field portion of the motor that affects the motor dynamics (for example, (See Patent Document 1).
Special Table 2002-537170

  However, in the above prior art, a current that does not contribute to the motor torque is caused to flow by the sine wave drive that places importance on the motor rotation speed, which causes a decrease in motor efficiency and a problem of heat generation due to an increase in current. .

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to improve the motor rotation speed in a situation where high responsiveness is required without passing a current that does not contribute to torque, and high response. It is an object of the present invention to provide an electric brake device and a method for controlling the electric brake device that can achieve a balance between ensuring quietness in a situation where safety is not required.

  In order to achieve the above object, the present invention applies a first waveform voltage to each phase of the brushless motor when the calculated braking request is larger than the pressure increase gradient that requires a predetermined pump discharge flow rate, and performs a predetermined increase. When it is smaller than the pressure gradient, the second waveform voltage is applied.

  Therefore, in the present invention, the improvement of the motor rotation speed in a situation where high responsiveness is required without passing a current that does not contribute to torque, and the assurance of quietness in a situation where high responsiveness is not required. Both can be achieved.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for realizing an electric brake device and an electric brake device control method according to the present invention will be described below based on an embodiment shown in the drawings.

[System configuration]
FIG. 1 is a system configuration diagram of a four-wheel brake-by-wire system to which the electric brake device of Embodiment 1 is applied, and FIG. 2 is a hydraulic circuit diagram of a hydraulic control device CU.

  In the four-wheel brake-by-wire system of the first embodiment, the wheel cylinders W / C (FL to RR) of all four wheels are increased by one pump Main / P. The master cylinder M / C is a so-called tandem type, and is connected to the FL wheel wheel cylinder W / C (FL, FR) by manual circuits A (FL), A (FR).

  The master cylinder M / C is connected to the reservoir RSV, and each solenoid valve is driven by the control unit ECU. The pump which is a hydraulic pressure source is provided with a main pump Main / P for normal use and a sub pump Sub / P for emergency use 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 ECU. In the first embodiment, a gear pump is used as the main pump Main / P, and a three-phase brushless motor is used as the main motor Main / M.

  On the manual circuits A (FL) and A (FR), there are provided shut-off valves S.OFF/V (FL, FR) that are normally open solenoid valves (ON / OFF valves). Cylinder M / C, M / C2 and FL, FR wheel cylinder W / C (FL, FR) are communicated / blocked.

  A stroke simulator S / Sim is provided on the manual circuit A (FL) and between the first master cylinder M / C and the shut-off valve S.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).

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

  The discharge sides of the main and sub pumps Main / P and 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 a decompression circuit B.

  An in-valve IN / V (FL to RR), which is a normally closed solenoid valve (proportional valve), is provided on the pressure increasing circuit C. Each pump Main / P, Sub / P and each wheel cylinder W / C (FL to 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, an out valve OUT / V (FL to RR), which is a normally closed solenoid valve (proportional valve), is provided, and communication / interruption between each wheel cylinder W / C (FL to RR) and the reservoir RSV Switch.

  A check valve C / V is provided on the discharge side of each pump Main / P and Sub / P to prevent the hydraulic fluid 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.

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

  The control unit ECU receives the detected first and second master cylinder pressures Pm1, Pm2, the hydraulic pressures P (FL to RR), and the detection value of the stroke sensor S / Sen that detects the stroke of the brake pedal BP. The

  Based on these detected values, the control unit ECU calculates the target hydraulic pressure P * (FL to RR) of each wheel FL to RR, drives the hydraulic control unit CU, and controls the wheel cylinder W / C (FL to RR). Control fluid pressure.

  In addition, the control unit ECU 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). When the hydraulic pressure shows an abnormal response, an abnormal signal is output to the warning lamp WL. In addition, the wheel speed VSP is input to the control unit ECU, and it is determined whether the vehicle is running or stopped.

Next, the configuration of the control unit ECU will be described.
FIG. 3 is a diagram illustrating an internal configuration of the control unit ECU, and the control unit ECU is disposed, for example, in an engine room. The control unit ECU receives the state of the four-wheel brake-by-wire system, for example, information on the current value of the brake fluid pressure and the current value of the operation mode, via the data signal line, via the CAN communication 1.

  Thus, while monitoring the state of the four-wheel brake-by-wire system, the CPU 2 calculates an appropriate control signal corresponding to the pedal operation amount or the braking force target value obtained as a result of the vehicle behavior control process, and passes the data signal line. Then, a control signal is transmitted to the actuator control device 3 to operate the brake-by-wire system appropriately. In addition, when the system fails, control such as fail-safe is also performed.

Next, each operation mode of the four-wheel brake by wire system of the first embodiment will be described.
(Pressure increase mode)
In the normal pressure increasing mode, the cancel valve Can / V is opened, the shutoff valve S.OFF/V (FL, FR) is shut off, and the depression of the brake pedal BP by the driver is detected by the stroke sensor S / Sen. Based on this detected value, the target hydraulic pressure P * (FL to RR) of each wheel cylinder W / C (FL to RR) is calculated in the control unit CU.

  Further, the control unit ECU drives the main motor Main / M or the sub motor Sub / M by the motor M so that the discharge pressure is applied to the pressure increasing circuit C. Furthermore, each in-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) to control it. Get power.

(Decompression mode)
In the decompression mode, the control unit ECU drives each out valve OUT / V (FL to RR), and discharges hydraulic oil from each wheel cylinder W / C (FL to RR) to the reservoir RSV via the decompression circuit B.

(Retention mode)
In the holding mode, each in-valve IN / V (FL to RR) and each out-valve OUT / V (FL to RR) are closed, and each wheel cylinder W / C (FL to RR) is increased and the pressure reducing circuit C, Shut off B.

(Manual brake)
When the system fails, the normally open shut-off valve S.OFF/V (FL, FR) is opened, and each normally closed in-valve IN / V (FL to RR) and out-valve OUT / V (FL to RR) Is closed. As a result, the master cylinder M / C communicates with the FL and FR wheel cylinders (FL, FR), and a manual brake is secured.

FIG. 4 is a control block diagram of braking control processing in the control unit ECU.
In the friction / regenerative braking force distribution block 6, the pedal operation amount of the brake pedal BP by the driver 4, ABS (Antilock Brake System), TCS (Traction Control System), VDC (Vehicle Dynamics Control), front vehicle following control, front Distributes hydraulic pressure command during automatic brake control operation (vehicle control block 5) such as collision avoidance brake control to hydraulic pressure command to 4-wheel brake-by-wire system and braking force command to regenerative brake RB (see Fig. 1) To do.

  The hydraulic servo block 7 is a drive signal for each valve and main motor Main / M (hereinafter simply referred to as motor M) that makes the actual braking force coincide with the braking force request (hydraulic pressure command) to the hydraulic control unit CU. Is output. In the hydraulic control CU, the brake fluid pressure is generated in the wheel cylinder W / C (FL to RR) by operating according to the drive signal. A braking force is generated in the vehicle 9 by pressing the disc rotors with the brake pads so as to sandwich each disc rotor.

  Here, the friction / regenerative braking force distribution block 6 determines whether or not the hydraulic pressure command to the four-wheel brake-by-wire system is a sudden pressure increase request. If it is not a set or rapid pressure increase request, the rapid pressure increase flag is reset. The hydraulic servo block 7 performs applied voltage switching control that varies the voltage waveform applied to each phase of the motor M based on the rapid pressure increase flag and other conditions.

  FIG. 5 is a control block diagram of applied voltage switching control in the control unit ECU. The control unit ECU includes a braking request calculation unit 11, a voltage command value determination unit 12, a rotation speed detection unit 13, and a 180-degree rectangular wave. A drive unit (first waveform drive unit) 14, a sine wave drive unit (second waveform drive unit) 15, and an applied voltage switching unit 16 are included.

The braking request calculation unit 11 calculates a braking request to the four-wheel brake by wire system according to the state of the vehicle.
The voltage command value determination unit 12 determines whether or not the output voltage command value of the motor M is a sine wave voltage that can be output.
The rotation speed detector 13 detects the rotation speed of the motor M.

The 180 degree rectangular wave drive unit 14 executes a 180 degree rectangular wave drive control process for applying a 180 degree rectangular wave voltage (first waveform voltage) to each phase of the motor M based on the braking request.
The sine wave drive unit 15 applies a sine wave voltage (second waveform voltage) to each phase of the motor M based on the braking request, that is, applies a voltage so that the phase current of the motor M has a sine wave shape. A sine wave drive control process is executed.

  The applied voltage switching unit 16 switches the driving method of the motor M between the 180-degree rectangular wave driving control and the sine wave driving control based on the braking request, the output voltage command value of the motor M, and the rotation speed. When the 180 degree rectangular wave drive control is selected, the inverter 17 that controls the voltage applied to the motor M is controlled by the 180 degree rectangular wave drive unit 14, and when the sine wave drive control is selected, the inverter 17 It is controlled by the sine wave drive unit 15.

  FIG. 6 is a diagram showing a configuration of the inverter circuit 17. The inverter circuit 17 includes six FETs (field effect transistors) and six free-wheeling diodes, and supplies the battery voltage Ed to the motor M according to the output of the actuator control device 3. The motor M is provided with a magnetic pole position detector 18 that detects the magnetic pole position of the motor M.

[Applied voltage switching control process]
FIG. 7 is a flowchart showing a flow of an applied voltage switching control process executed by the control unit ECU of the first embodiment. Each step will be described below.

  In step S1, the braking request calculation unit 11 reads the battery voltage value Bd and proceeds to step S2.

  In step S2, the braking request calculation unit 11 reads the motor torque command value T * and proceeds to step S3.

  In step S3, the braking request calculation unit 11 reads the motor rotor position θe and proceeds to step S4.

  In step S4, the rotational speed detector 13 reads the actual measured value ωe of the motor rotational speed as the rotational speed of the motor M, and proceeds to step S5.

  In step S5, the braking request calculation unit 11 executes a current control voltage command value calculation process, which will be described later, and proceeds to step S6.

  In step S6, the applied voltage switching unit 16 determines whether or not it is a sudden pressure increase request based on the rapid pressure increase flag. If YES, the process proceeds to step S7. If NO, the process proceeds to step S11.

  Here, the rapid pressure increase flag indicates that the flow rate command of the wheel cylinder W / C corresponding to the motor torque command value T * read in step S2 in the braking request calculation unit 11 is less than the flow rate that can be output by sine wave voltage control. In some cases, the rapid pressure increase flag is reset (low level signal output), and when the flow rate command exceeds the flow rate that can be output by sine wave voltage control, the rapid pressure increase flag is set (high level signal output).

ただし、Tsinは正弦波駆動制御一周期、Td_sinは正弦波駆動におけるデッドタイムである。ここで、「デッドタイム」とは、インバータ回路１７を構成する上流と下流の半導体スイッチを共にオフする期間をいう。すなわち、電源電圧値から前記インバータ回路１７を動作させる場合に回路短絡を防止するために付与される時間であり、その間、電圧降下を発生する。
なお、Vsin_maxは||Vdq*||と比較するために、座標変換による絶対変換係数が含まれている。また、Tsinは正弦波駆動で印加する電圧基本周期に対して十分に短い必要がある。 In step S7, the voltage command value determination unit 12 determines whether or not the output voltage command (the magnitude of the output voltage command vector || Vdq * ||) exceeds the sine wave output possible voltage Vsin_max. If YES, the process proceeds to step S8, and if NO, the process proceeds to step S11. A method of calculating the magnitude of the output voltage command vector || Vdq * || will be described later.
The sine wave output possible voltage Vsin_max is expressed by the following equation.

However, Tsin is one cycle of sine wave drive control, and Td_sin is a dead time in sine wave drive. Here, “dead time” refers to a period during which both the upstream and downstream semiconductor switches constituting the inverter circuit 17 are turned off. That is, it is a time given to prevent a short circuit when operating the inverter circuit 17 from a power supply voltage value, during which a voltage drop occurs.
Note that Vsin_max includes an absolute conversion coefficient by coordinate conversion in order to compare with || Vdq * ||. Moreover, Tsin needs to be sufficiently short with respect to the voltage basic period applied by sine wave drive.

  In step S8, the application voltage switching unit 16 applies the application during the transition period when switching from the sine wave drive to the 180-degree rectangular wave drive from the power supply voltage value Ed and the motor torque command value T * using the map shown in FIG. The voltage switching speed ωch is calculated, and the process proceeds to step S9. In the map of FIG. 12, the applied voltage switching speed ωch is set to decrease as the power supply voltage value Ed decreases, and to decrease as the motor torque command value T * increases.

  In step S9, the applied voltage switching unit 16 determines whether or not the motor rotation speed ωe is higher than the applied voltage switching speed (predetermined rotation speed) ωch. That is, it is determined whether the speed is such that a sufficient voltage margin for controlling the current applied to the torque by the induced electromotive voltage cannot be secured. If YES, the process proceeds to step S10, and if NO, the process proceeds to step S11. The motor rotation speed can be obtained by various methods other than actual measurement.

  In step S10, the applied voltage switching unit 16 connects the 180 degree rectangular wave driving unit 14 to the inverter 17, and the 180 degree rectangular wave driving unit 14 applies a 180 degree rectangular wave voltage to each phase of the motor M. The 180-degree rectangular wave drive control process is executed, and this control is terminated. Details of the 180-degree rectangular wave drive control process will be described later.

  In step S11, the applied voltage switching unit 16 connects the sine wave drive unit 15 to the inverter 17, and the sine wave drive unit 15 applies a voltage so that the phase current of the motor M is sinusoidal. Control processing is executed and this control is terminated. Details of the sine wave drive control process will be described later.

[Current control voltage command value calculation processing]
FIG. 8 is a flowchart showing the flow of the current control voltage command value calculation process in step S5, and each step will be described below.

  In step S51, a current command calculation process described later is executed, and the process proceeds to step S52.

  In step S52, a coordinate conversion process for converting the coordinates (u, v, w) of the three-phase alternating current into the coordinates (q, d) of the biaxial direct current is executed, and the process proceeds to step S53. Details of the coordinate conversion process will be described later.

  In step S53, a current PI control process for determining a control amount by PI control from the deviation amount of the actual current with respect to the command current is executed, and this control is terminated. Details of the current PI control process will be described later.

(Current command calculation processing)
FIG. 9 is a flowchart showing the flow of the current command calculation process in step S51, and each step will be described below.

In step S511, the command torque current Iq * is calculated from the motor torque command value T * obtained by the hydraulic servo processing unit 8 by the following formula, and the process proceeds to step S512. Specifically, the vector-converted torque current and the output motor torque are in a proportional relationship when used in a region where the magnetic saturation of the stator core does not occur, so Gq in the equation is a constant specific to the motor. Become.
Iq * ＝ T * × Gq
Here, if the sign of the command torque current Iq * is positive, torque is output in the CW direction, and if it is negative, torque is output in the CCW direction. In the first embodiment, when the torque command value T * on the pressurization side is positive, it is considered to rotate in the positive (CW) direction. However, for the convenience of the rotation direction of the pump, an example where the sign does not match the motor torque command value T * is also considered. It is done. In such a case, the sign is inverted with a constant Gq.

  In step S512, the command excitation current Id * is set, and this control is terminated. Generally, it is often set to zero, and Id * = 0 is also set in the first embodiment.

(Coordinate conversion process)
FIG. 10 is a flowchart showing the flow of the coordinate conversion process in step S52, and each step will be described below.

  In step S521, a signal is received from the magnetic pole position detector 18 that detects the magnetic pole position of the motor M, the electrical angle (motor rotor position) θe set in the CW direction with respect to the u phase is calculated, and the process proceeds to step S522. . That is, since the coordinate conversion is performed in accordance with the position of the magnetic field, a process for detecting the magnetic pole position is required. In the first embodiment, the magnetic pole position detector 18 whose position signal is the electrical angle θe is used.

  In step S522, the magnitude (Iu, Iv, Iw) of the actual current flowing in each phase of the motor M shown in FIG. 7 is read from the current sensor, and the process proceeds to step S523.

In step S523, coordinate conversion is performed on the current value read in step S522, and the process proceeds to step S524. Specifically, a three-phase alternating current (Iu, Iv, Iw) is converted into a two-phase alternating current (Iα, Iβ) using the following equation.

In step S524, the biaxial direct current (actual torque current Iq, actual excitation current Id) is calculated from the two-phase alternating current (Iα, Iβ) obtained in step S523 and the electrical angle θe obtained in step S521 using the following equations. ) To finish this control.

(Current PI control processing)
FIG. 11 is a flowchart showing the flow of the current PI control process in step S53, and each step will be described below.

In step S531, a torque current deviation amount Δiq that is a deviation between the command torque current Iq * calculated in step S511 and the actual torque current Iq calculated in step S524 is obtained, and the process proceeds to step S532.
Δiq ＝ Iq * −Iq

In step S532, a control amount (command torque voltage Vq *) output by PI control from the torque current deviation amount Δiq is calculated using the following equation, and the process proceeds to step S533.
Vq * ＝ Kpq × Δiq + Kiq × Σ (Δiq)
Here, Kpq is a proportional control gain, Kiq is an integral control gain, and Σ (Δiq) is a time integral value of the torque current deviation amount Δiq. By this processing, the command value is converted from current to voltage.

In step S533, the excitation current deviation amount Δid is calculated by the same processing as in step S531, and the process proceeds to step S534.
Δid = Id * −Id

In step S534, a command excitation voltage Vd * is calculated using the following equation by the same process as in step S532, and the process proceeds to step S535.
Vd * ＝ Kpd × Δid + Kid × Σ (Δid)
Here, kpd is a proportional control gain, Kid is an integral control gain, and Σ (Δid) is a time integral value of the excitation current deviation amount Δid.

In step S535, the magnitude of the voltage command vector || Vdq * || is obtained from Vd * and Vq * using the following expression, and this control is terminated.

[180 degree rectangular wave drive control processing]
FIG. 13 is a flowchart showing the flow of the 180-degree rectangular wave drive control process in step S10, and each step will be described below.

In step S1001, a voltage command (Vd * _s, Vq * _s) that satisfies the motor current command (Id *, Iq *) is obtained according to the following formula, and its phase angle (tan ^-1 (Vd * _s, Vq * _s)) and the motor rotor position θe, the voltage command phase θ_V * is calculated, and the process proceeds to step S1002.
Vd * _s ＝ -ωeLqIq *
Vq * _s ＝ ωe (LdId * + Φ)
However, ωe is an electrical angular velocity [rad / sec], Ld and Lq are axial inductance values [H], and Φ is a permanent magnet interlinkage magnetic flux number [Wb].

In step S1002, a voltage switching phase for determining the output voltage pattern is obtained, and the process proceeds to step S1002. First, the dead time Td_sq to be given to suppress the torque fluctuation due to the applied voltage switching is obtained from the motor rotation speed ωe and the motor torque command value T * by the map shown in FIG. In the map of FIG. 14, the dead time Td_sq is set so as to decrease as the motor rotation speed ωe increases, and to decrease as the motor torque command value T * increases.
The dead time Td_sq may be obtained by calculation from the relationship between the magnitude of the voltage command and the battery voltage.

The voltage switching phase is obtained from Td_sq and the rectangular wave drive control period Tsq according to the following equation.

この状態でのデッドタイムTd_sqは、矩形波駆動制御周期Tsqの中で、マイコンの内部タイマを使ってTd_sq期間だけHi/Lo両側スイッチをOFFにすることで与えられる。この切り替え位相とデッドタイムTd_sqとの関係は、図１５、図１６に示される。図１５は矩形波駆動処理において、デッドタイムTd_sqが制御周期よりも長い場合にFETのON/OFF状態を切り替える位相を示す図であり、図１６は矩形波駆動処理において、デッドタイムTd_sqが制御周期よりも短い場合に、FETのON/OFFを切り替える位相を示す図である。 However, when Td_sq ≦ Tsq is satisfied, the following equation is used.

The dead time Td_sq in this state is given by turning off the Hi / Lo both-side switch for the Td_sq period using the internal timer of the microcomputer in the rectangular wave drive control period Tsq. The relationship between this switching phase and dead time Td_sq is shown in FIGS. FIG. 15 is a diagram showing a phase for switching the ON / OFF state of the FET when the dead time Td_sq is longer than the control period in the rectangular wave driving process, and FIG. 16 is a diagram showing the dead time Td_sq being the control period in the rectangular wave driving process. It is a figure which shows the phase which switches ON / OFF of FET when it is shorter than this.

  In step S1003, ON / OFF of each phase FET is selected according to FIG. 17 from the voltage switching phase (θh_s, θh_e, θl_s, θl_e) and voltage command phase θ_V * obtained in step S1002, and the process proceeds to step S1004.

  In step S1004, the state of the microcomputer port connected to the actuator control device 3 is changed in order to drive the FET according to the selection in step S1003.

  The rectangular wave drive control process is thus completed, and the inverter circuit 17 outputs to the motor M. However, the means for changing the output voltage pattern according to the voltage switching phases (θh_s, θh_e, θl_s, θl_e) needs to have Tsq sufficiently fast with respect to the electrical angular period. In addition to the means for achieving the switching of the output pattern in the voltage switching phase by confirming the voltage command phase θ_V * at a high speed as described above, the voltage switching timing is predicted and predicted from the motor rotation speed. It is also possible to use means for fixing the output voltage during the period from the time point to the voltage switching phase.

[Sine wave drive control processing]
FIG. 18 is a flowchart showing the flow of the sine wave drive control process in step S11, and each step will be described below.

  In step S1101, Vd * and Vq * obtained in step S105 are read, and the process proceeds to step S1102.

In step S1102, in order to drive the motor M with the command value set in the two-axis DC coordinate system (q, d), the motor M is returned to the three-phase AC coordinate system (u, v, w) and the following equation is used. The two-axis DC voltage command (Vq *, Vd *) is converted into a two-phase AC voltage command (Vα *, Vβ *), and the process proceeds to step S1103.

In step S1103, the two-phase AC voltage command (Vα *, Vβ *) and the motor rotor position θe are converted into a three-phase AC voltage command (Vu *, Vv *, Vw *) using the following formula, The process proceeds to S1104.

In step S1104, the center of the three-phase AC voltage command (Vu *, Vv *, Vw *) is offset to Ed / 2 (V) using the following equation, and the process proceeds to step S1105. This is a three-phase AC voltage command (Vu *, Vv *, Vw *) is a sine wave that is output in the ± direction around the center of 0 (V), but the voltage that can actually be output is 0 to Ed (V). Because there is.

  In step S1105, control processing is performed based on the truth table of FIG. 19 so that the voltage command values (Vu_buf *, Vv_buf *, Vw_buf *) set in step S1104 fall within the output voltage range. The process proceeds to S1106.

In step S1106, in order to perform PWM output to each phase, a duty (Du, Dv, Dw) corresponding to the voltage command value (Vu *, Vv *, Vw *) is calculated using the following formula, The process proceeds to S1107.

In step S1107, the ON / OFF time (THon_u, THOff_u, TLon_u, TLoff_u, THon_v, THOff_v, TLon_v, TLoff_v, THon_w) of each FET is calculated from the Duty (Du, Dv, Dw) obtained in step S1106 using the following formula: , THOff_w, TLon_w, TLoff_w), and proceeds to step S1108.

  That is, in the sine wave drive control process, the PWM signal is output to the actuator control device 3 using the timer function of the microcomputer. There is one FET in the inverter circuit 17 (FIG. 6) for each phase on the Hi side and the Lo side, and a microcomputer in the control unit ECU is used to turn each FET on and off in a time corresponding to the duty. This is because it is necessary to control the output port.

In step S1108, the microcomputer timer is set to the ON / OFF time obtained in step S1107. When the ON / OFF time of each FET is set in the timer function, the microcomputer controls the level of the output port connected to the gate of the FET through the actuator control device 3 that performs signal amplification according to the set timing.
The sine wave drive control process is thus completed, and the inverter circuit 17 outputs to the motor M.

Next, the operation will be described.
(Applied voltage switching action)
FIG. 20 is a time chart showing the applied voltage switching process when a rapid pressure increase is required. Note that the command value is indicated by a thin solid line in the case where only the wavy line and the sine wave drive are not switched, and the thick solid line in the first embodiment.

In the interval from time t0 to t1, the output voltage command rises in response to the rise of the motor torque command value T *, and the motor M accelerates.
At time t1, since the flow rate command of the wheel cylinder W / C exceeds the flow rate that can be output by the sine wave drive control, the rapid pressure increase flag is set. At this time, in the flowchart of FIG. 7, the flow of steps S1 → step S2 → step S3 → step S4 → step S5 → step S6 → step S7 → step S11 is repeated, and the motor M is driven by sinusoidal driving. .

  At time t2, the motor rotational speed ωe exceeds the applied voltage switching speed ωch, and the output voltage command (the magnitude of the output voltage command vector || Vdq * ||) exceeds the sine wave output possible voltage Vsin_max. In this flowchart, the flow proceeds from step S1 → step S2 → step S3 → step S4 → step S5 → step S6 → step S7 → step S8 → step S9 → step S10, from sine wave drive control to 180 degree rectangular wave drive control It becomes a transition period to switch to.

  Here, since the applied voltage switching speed ωch in the transition period is set to a smaller value as the motor torque command value T * is larger, the voltage command || Vdq * || usually exceeds the sine wave output possible voltage Vsin_max. Before that, the motor rotation speed ωe exceeds the applied voltage switching speed ωch. Accordingly, it is possible to continuously drive up to the maximum output without reducing the motor torque by the rectangular wave driving.

  At time point t3, 180-degree rectangular wave drive control is started, and during the period from time point t3 to t4, each phase of the motor M is controlled by 180-degree rectangular wave drive. FIG. 21 is a diagram showing a phase voltage waveform and its fundamental wave when the driving method is switched from sine wave driving to 180 degree rectangular wave driving, and after switching from sine wave driving to 180 degree rectangular wave driving, It can be seen that the voltage fundamental wave is output exceeding the battery voltage Ed. That is, with 180-degree rectangular wave driving, the voltage that can be used for motor driving increases, so that a larger output can be obtained compared to sine wave driving.

  As is clear from the time chart of FIG. 20, in the case of “no switching”, the motor rotation speed reaches a peak at the output possible upper limit value of the sine wave drive, so that the wheel cylinder hydraulic pressure cannot follow the command value, There is a control delay.

  On the other hand, in the first embodiment, by switching the driving method from sine wave driving to 180 degree rectangular wave driving, the motor M can be accelerated after time t3 to increase the flow rate of the wheel cylinder, and the wheel cylinder hydraulic pressure can be increased. It is possible to follow the command value.

  At time t4, since the sudden pressure increase flag is reset, the 180-degree rectangular wave drive control is switched to the sine wave drive control. In other words, in situations where high responsiveness is required, motor rotation speed can be increased by 180-degree rectangular wave drive, and in situations where high responsiveness is not required, sine wave drive can be used to achieve quietness. Can be secured.

[Dead time adjustment]
FIG. 22 shows an FET drive signal when the sine wave drive is switched to the 180-degree rectangular wave drive. Here, for the sake of convenience, it is drawn so that one cycle of the rectangular wave drive control corresponds to two cycles of PWM at the time of sine wave drive. Normally, to improve quietness, the PWM frequency when driving a sine wave is set to a very high frequency in order to remove noise generated in synchronization with that frequency from the human audible range and controllability. Therefore, one cycle of the rectangular wave drive control (one cycle of electrical angle) and the sine wave PWM cycle that is in synchronization are larger than those shown in FIG.

  It can be seen from FIG. 22 that the dead time Td_sq included in the voltage waveform increases during sine wave drive control. Although this dead time Td_sq is indispensable for protecting the inverter circuit 17, since the inverter circuit 17 cannot supply power during the dead time period, the increase in the included dead time Td_sq causes the inverter circuit 17 to move to the motor. The power that can be supplied to M decreases.

  On the other hand, in the 180-degree rectangular wave drive, Td_sq is included only twice for one period of electrical angle regardless of the rotation speed. Therefore, it can be seen that the rate at which the power supply voltage can be used increases. A high voltage utilization rate is effective in improving the maximum output of the motor M. In addition, in the applied voltage switching period, the dead time Td_sq in the 180-degree rectangular wave drive is made variable (the dead time Td_sq is gradually increased), so that during the transition from the sine wave drive to the complete 180-degree rectangular wave drive. Torque is controlled to enable smooth switching of applied voltage. However, in addition to the means for making the dead time Td_sq variable, this can also be achieved by controlling the motor torque by making the voltage command phase θ_V * variable, and using these means together. .

[Application to automatic brake control]
As described above, in the electric brake device according to the first embodiment, when a predetermined condition is satisfied when a sudden pressure increase is requested, the control method of the motor M that drives the pump P is switched from sine wave driving to 180 degree rectangular wave driving. Therefore, high braking force responsiveness can be obtained during automatic brake control operations such as ABS, TCS, VDC, forward vehicle following control, forward collision avoidance brake control, and the like.
In the following, explanation will be made taking TCS operation and VDC operation as examples.

(When TCS is activated)
FIG. 23 is a time chart showing the applied voltage switching action during TCS operation, in which Example 1 is shown by a thick solid line, and the case without switching is shown by a thin solid line. In the first embodiment, when the acceleration slip is generated, the wheel cylinder hydraulic pressure increase response is higher than in the case where there is no switching. Therefore, the increase in wheel speed can be suppressed earlier, and the acceleration slip can be suppressed to be small. it can.

(When VDC operates)
FIG. 24 is a time chart showing the applied voltage switching action during VDC operation, in which Example 1 is shown by a thick solid line, and the case without switching is shown by a thin solid line. In Example 1, when the vehicle is oversteered and the VDC is activated, compared to the case without switching, the pressure increase response of the wheel cylinder hydraulic pressure is high, so the oversteer tendency can be suppressed earlier, The followability to the target yaw rate can be improved.

[Effect of Example 1]
The effects of Example 1 are listed below.
In the electric brake device of the first embodiment, when the braking request is a sudden pressure increase request greater than the pressure increase gradient that requires a predetermined pump discharge flow rate, a 180-degree rectangular wave voltage that is the first waveform voltage is applied to each phase of the motor M. When there is no request for sudden pressure increase, a sine wave voltage that is the second waveform voltage is applied.

  Thereby, compared with the case where the motor M is driven only by the sine wave drive, the motor output at the time of the rapid pressure increase request can be improved, so that the braking force can be raised at a higher speed. Further, compared with the case where the control of the first embodiment is not applied, the same output characteristics can be obtained even when a small brushless motor is used, so that the electric brake device can be made compact.

Furthermore, when driving with rectangular waves, the number of FET ON / OFF times can be reduced compared to sine wave driving, and energy that does not contribute to motor output is not given to improve output. , Energy efficiency can be improved.
On the other hand, when there is no sudden pressure increase request, driving the motor M by sine wave driving suppresses the pulsation of the motor torque, and high silence can be obtained.

  In the electric brake device of the first embodiment, when the output voltage command (the magnitude of the output voltage command vector || Vdq * ||) exceeds the sine wave output possible voltage Vsin_max, the sine wave drive is changed to the 180-degree rectangular wave drive. And switch. That is, when the motor torque corresponding to the output voltage request of the motor M cannot be secured by the sine wave drive, the required motor torque can be secured by increasing the motor output by the 180-degree rectangular wave drive. On the other hand, when the output voltage requirement of the motor M is low, high controllability and high silence can be obtained by driving the motor M by sinusoidal drive.

  In the electric brake device according to the first embodiment, when the motor rotation speed ωe is higher than the applied voltage switching speed ωch, the sine wave drive is switched to the 180-degree rectangular wave drive. That is, when the rotational speed (rotational speed ωe) of the motor M is small, when switching from the sine wave drive to the 180-degree rectangular wave drive, an excessive current flows through the motor M and excessive pulsation occurs in the motor torque. In addition, the inverter circuit 17 may be damaged due to overcurrent flowing through the inverter circuit 17.

  Therefore, in the first embodiment, a rapid pressure increase is required while avoiding excessive torque pulsation by switching from sine wave drive to 180-degree rectangular wave drive only when the motor speed increases to some extent. It is possible to achieve both high responsiveness in a situation and high silence in a situation where rapid pressure increase is not required.

  In the electric brake device according to the first embodiment, when switching from sine wave drive to 180 degree rectangular wave drive, the period (dead time Td_sq) in which both the upstream and downstream semiconductor switches constituting the inverter circuit 17 are turned off is adjusted, and PWM is performed. The carrier cycle, which is the signal carrier repetition cycle, is lengthened.

  As a result, the torque during the transition from the sine wave drive with a short cycle to the 180-degree rectangular wave drive with a long cycle can be controlled, so that torque fluctuation at the time of control switching can be suppressed. Furthermore, by gradually increasing the carrier cycle, the sine wave drive can be smoothly shifted to the 180-degree rectangular wave drive, and the torque fluctuation can be further suppressed and a good operational feeling can be obtained.

  In the control method for the electric brake device according to the first embodiment, the sine wave voltage is applied to each phase of the motor M before the 180-degree rectangular wave voltage is applied. As a result, high quietness, which is the characteristic of sine wave drive, is obtained in the initial driving stage of the motor M, and thereafter, high response, characteristics of the 180 degree rectangular wave drive, improvement of voltage utilization, and high motor M characteristics. Rotation is obtained. In addition, a small brushless motor can be used, and the electric brake device can be made compact.

  In the control method for the electric brake device according to the first embodiment, the braking request according to the state of the vehicle exceeds a predetermined pump discharge amount, and the output voltage command of the motor M (the magnitude of the output voltage command vector || Vdq * | |) Exceeds the sine wave output possible voltage Vsin_max, and after the rotation speed ωe of the motor M becomes higher than the applied voltage switching speed ωch, the 180-degree rectangular wave voltage is applied.

  Thereby, when the rotational speed of the motor M is low and the voltage required for the motor M is a voltage that can be output by sine wave drive, pulsation of the motor torque can be suppressed by sine wave drive. On the other hand, when a rapid pressure increase is requested, when the rotational speed of the motor M is high and the voltage required for the motor M exceeds the voltage that can be output by sine wave driving, high response is ensured by 180 degree rectangular wave driving be able to. Therefore, both silence and responsiveness can be achieved.

  In the control method of the electric brake device according to the first embodiment, when switching from sine wave drive to 180 degree rectangular wave drive, the period (dead time Td_sq) in which both the upstream and downstream semiconductor switches constituting the inverter circuit 17 are turned off is adjusted. Then, the carrier cycle that is the carrier repetition cycle of the PWM signal is lengthened.

  As a result, the torque during the transition from the sine wave drive with a short cycle to the 180-degree rectangular wave drive with a long cycle can be controlled, so that torque fluctuation at the time of control switching can be suppressed. Furthermore, by gradually increasing the carrier cycle, the sine wave drive can be smoothly shifted to the 180-degree rectangular wave drive, and the torque fluctuation can be further suppressed and a good operational feeling can be obtained.

[Brake-specific effects]
In the control of pump motors, brake applications that are used frequently at relatively low speeds have many functions that require normal convenience, such as normal brakes and automatic tracking systems for the preceding vehicle (preceding vehicle), and require quietness. Is done.
When the rectangular wave drive is used in the above situation, the so-called goo noise (low frequency noise generated from the undercarriage due to braking at the time of creep in AT cars, etc.) is caused by the periodic contact between the rotor and the pad due to the pulsation of the hydraulic pressure. Sound), giving passengers discomfort.

On the other hand, in the control of pump motors, brake applications that are used at a relatively high rotation frequency have many functions that are used in emergency such as ABS, VDC, and collision avoidance brake, and responsiveness is required rather than quietness. In addition, in the above functions, there are many cases where the calculation load of the CPU is high, such as processing of the wheel speed signal, and there is a possibility that calculation will be limited when using sine wave drive with higher calculation load than rectangular wave drive in the above situation There is.
In the first embodiment, by switching between sinusoidal wave driving and rectangular wave driving according to the above situation, it is possible to realize both quietness and high functionality as a brake system.

  The second embodiment is different from the first embodiment only in the hydraulic circuit configuration of the hydraulic control device CU. In the first embodiment, an open hydraulic circuit is used as the hydraulic circuit of the hydraulic control device CU, whereas in the second embodiment, a closed hydraulic circuit is used.

  Here, the open hydraulic circuit is a hydraulic circuit that can return the brake fluid supplied to the wheel cylinder directly to the reservoir without going through the master cylinder. On the other hand, the closed hydraulic circuit is a hydraulic circuit that returns brake fluid supplied to the wheel cylinder to the reservoir via the master cylinder.

FIG. 25 is a hydraulic circuit diagram of the hydraulic control device CU of the second embodiment. The brake circuit is divided into two independent systems, that is, P system and S system, and has brake circuits 10P and 20S corresponding to each system. ing. Brake circuit 10P is connected to wheel cylinder W / C (FL) on the left front wheel and wheel cylinder W / C (RR) on the right rear wheel, and brake circuit 20S is connected to wheel cylinder W / C (FR) on the right front wheel and left It is connected to the wheel cylinder W / C (RL) on the rear wheel, and has a so-called X piping structure. The brake circuit does not have to be X piping.
The brake pedal BP transmits the driver's stepping operation to the master cylinder M / C via a booster and an input rod (not shown).

  The master cylinder M / C is a tandem type as in the first embodiment, and two hydraulic chambers are separated in the cylinder by two master cylinder pistons arranged in front and rear. Each of the two hydraulic chambers receives supply of brake fluid from the reservoir RSV. One hydraulic chamber is connected to the brake circuit 10P, and the other hydraulic chamber is connected to the brake circuit 20S.

  When the brake pedal BP is depressed, the master cylinder M / C generates hydraulic pressure in the two hydraulic pressure chambers according to the depression amount of the brake pedal BP. The master cylinder pressure is supplied to the brake circuits 10P and 10S, respectively.

  A known cup-shaped seal member is provided on the outer periphery of each master cylinder piston. During the piston stroke, the communication between each hydraulic chamber and the reservoir RSV is blocked by this seal member, so that each liquid Pressurization in the pressure chamber is possible.

  At this time, the brake fluid is not supplied from the reservoir RSV to the brake circuits 10P and 10S, and the brake fluid is supplied to the brake circuits 10P and 10S only from the hydraulic pressure chamber of the master cylinder M / C.

  On the other hand, when the brake pedal BP is returned, each master cylinder piston is returned by the force of the return spring (provided in the hydraulic pressure chamber). At this time, the fluid pressure chamber of the master cylinder M / C and the reservoir RSV communicate with each other due to the structure of the seal member. As a result, the brake fluid of the reservoir RSV can be supplied again to the hydraulic chamber of the master cylinder M / C.

  On the way from the master cylinder M / C side (hereinafter referred to as upstream) of the brake circuit 10P to the wheel cylinder W / C side (hereinafter referred to as downstream), a gate pressure reducing valve GV-OUT ( P) is provided. An oil passage 10j is connected to the brake circuit 10P in parallel with the gate pressure reducing valve VG-OUT (P).

  On the oil passage 10j, a check valve 10p for preventing the flow of brake fluid from the downstream side to the upstream side is provided. Hereinafter, the brake circuit 10P on the upstream side of the gate pressure reducing valve GV-OUT (P) is referred to as a brake circuit 10n, and the brake circuit 10P on the downstream side of the gate pressure reducing valve GV-OUT (P) is referred to as a brake circuit 10k.

  The brake circuit 10k branches to the brake circuits 10a and 10b. The brake circuits 10a and 10b are connected to the wheel cylinders W / C (FL, RR), respectively. On the brake circuits 10a and 10b, booster valves IN / V (FL, RR), which are normally open proportional solenoid valves, are provided, respectively.

  An oil passage 10l is connected to the brake circuit 10a in parallel with the pressure increasing valve IN / V (FL). A check valve 10q for preventing the flow of brake fluid from the upstream side to the downstream side is provided on the oil passage 10l. Similarly, a check valve 10r for preventing the flow of brake fluid from the upstream side to the downstream side is provided on the oil passage 10m connected in parallel with the pressure increasing valve IN / V (RR).

  Return circuits 10c and 10d are connected to the brake circuits 10a and 10b on the downstream side of the pressure increasing valve IN / V (FL, RR), respectively. The return circuits 10c and 10d are each provided with a pressure reducing valve OUT / V (FL) which is a normally closed on / off solenoid valve. The return circuits 10c and 10d merge to form a return circuit 10e. The return circuit 10e is connected to the reservoir 10t.

  On the other hand, a suction circuit 10g is connected to the brake circuit 10n on the upstream side of the gate pressure reducing valve GV-OUT (P). On the suction circuit 10g, there is provided a gate pressure increasing valve GV-IN (P) which is a normally closed on / off solenoid valve for switching communication / shutoff of the suction circuit 10g. The suction circuit 10g merges with the return circuit 10f from the reservoir 10t to form a suction circuit 10h.

  The hydraulic control unit CU is provided with a pump P for sucking and discharging brake fluid as a hydraulic pressure source other than the master cylinder M / C. The pump P is a gear pump that is operated by a motor M, and includes a first pump P1 (P system) and a second pump P2 (S system).

  The suction side of the first pump P1 is connected to the suction circuit 10h. The discharge side of the first pump P1 is connected to the discharge circuit 10i, and is connected to the brake circuit 10k via the discharge circuit 10i.

  A check valve 10s is provided on the return circuit 10f to prevent the flow of brake fluid from the suction circuit 10g (gate pressure increasing valve GV-IN (P)) toward the reservoir 10t.

A check valve 10u is provided on the discharge circuit 10i, and the first pump P1 (discharge) is supplied from the brake circuit 10k (gate pressure reducing valve GV-OUT (P)) or the brake circuits 10a, 10b (wheel cylinder W / C). Brake fluid flow toward the side) is prevented.
The hydraulic circuit on the brake circuit 20S side is also configured in the same manner as the brake circuit 10P.

  The hydraulic control unit CU of the second embodiment can execute the following boost control during normal braking, and can execute automatic brake control such as TCS, ABS, VDC, etc., as in the first embodiment.

  At the time of automatic brake control, taking the brake circuit 10P side as an example, the gate pressure reducing valve GV-OUT (P) is closed while the gate pressure increasing valve GV-IN (P) is opened. At the same time, the pump P is operated to supply brake fluid from the master cylinder M / C to the brake circuits 10a and 10b via the suction circuits 10g and 10h and the discharge circuit 10i.

  Further, the gate pressure reducing valve GV-OUT (P) or the pressure increasing valve IN / V (FL, RR) is controlled so as to generate the wheel cylinder target hydraulic pressure corresponding to the braking force required for vehicle behavior stabilization. The same applies to the brake circuit 20S side.

  In addition, during ABS operation, taking the wheel FL as an example, the pressure reducing valve OUT / V (FL) connected to the wheel cylinder W / C is opened and the pressure increasing valve IN / V (FL) is closed, The pressure is reduced by discharging the brake fluid of the wheel cylinder W / C to the reservoir 10t. When the wheel FL recovers from the locking tendency, the pressure reducing valve OUT / V (FL) is closed to maintain the wheel cylinder pressure.

  Further, the pump P is operated and the pressure increasing valve IN / V (FL) is opened to increase the pressure appropriately. The pump P serves to return the brake fluid that has escaped to the reservoir 10t during decompression to the brake circuit 10k.

  Even in the electric brake device including the hydraulic control device CU that employs the closed hydraulic circuit having the above-described configuration, by applying the applied voltage switching control shown in the first embodiment, the same effects as those in the first embodiment can be obtained. it can.

[Other embodiments]
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 scope of the invention is not deviated. Design changes and the like are included in the present invention.

  For example, in the embodiment, as a switching condition from the sine wave drive to the 180 degree rectangular wave drive, the presence / absence of a sudden pressure increase request (step S6), the relationship between the output voltage command and the sine wave output possible voltage (step S7), Although the three conditions of the motor rotation speed (step S9) are set, the switching condition may be any one or two of the above three conditions.

  In the first embodiment, an example in which the actual measured value ωe of the rotational speed is used as the rotational speed of the motor M has been described. However, the rotational speed may be calculated from the required rotational speed value of the motor M.

1 is a system configuration diagram of a four-wheel brake-by-wire system to which an electric brake device according to a first embodiment is applied. 1 is a hydraulic circuit diagram of a hydraulic control device CU according to Embodiment 1. FIG. It is a figure which shows the internal structure of control unit ECU. It is a control block diagram of a braking control process in the control unit ECU. It is a control block diagram of applied voltage switching control in the control unit ECU. It is a figure which shows the structure of the inverter circuit 17 which controls the voltage applied to the main motor Main / M. 3 is a flowchart showing a flow of a drive means switching control process executed by the control unit ECU of the first embodiment. It is a flowchart which shows the flow of the current control voltage command value calculation process of step S5. It is a flowchart which shows the flow of the electric current command calculation process of step S51. It is a flowchart which shows the flow of the coordinate transformation process of step S52. It is a flowchart which shows the flow of the current PI control process of step S53. It is a map which calculates | requires the speed used as the switching threshold value at the time of switching a drive means. It is a flowchart which shows the flow of a 180 degree | times rectangular wave drive control process of step S10. It is a map which calculates | requires dead time. In the rectangular wave driving process, it is a diagram illustrating a phase for switching the ON / OFF state of the FET when the dead time Td_sq is longer than the control period. In the rectangular wave driving process, it is a diagram showing a phase for switching ON / OFF of the FET when the dead time Td_sq is shorter than the control cycle. 14 is a table showing the state switching phase shown in FIGS. It is a flowchart which shows the flow of the sine wave drive control process of step S11. It is a truth table which shows the limit process of a voltage command by a sine wave drive control process. It is a time chart which shows the drive means switching process when sudden pressure increase is requested | required. It is a figure which shows the phase voltage waveform at the time of switching a drive system from sine wave drive to 180 degree | times rectangular wave drive, and its fundamental wave. It is a figure which shows the FET drive signal at the time of switching from sine wave drive to 180 degree | times rectangular wave drive. It is a time chart which shows the applied voltage switching effect | action at the time of TCS operation | movement. It is a time chart which shows the applied voltage switching effect | action at the time of VDC operation | movement. FIG. 5 is a hydraulic circuit diagram of a hydraulic control device CU according to a second embodiment.

Explanation of symbols

ECU control unit
M motor (brushless motor)
P pump
W / C wheel cylinder 11 Braking request calculation unit 12 Voltage command value determination unit 13 Rotational speed detection unit 14 180 degree rectangular wave drive unit (first waveform drive unit)
15 Sine wave drive unit (second waveform drive unit)
16 Applied voltage switching unit 17 Inverter circuit

Claims (23)

A brushless motor that drives a pump that generates a braking force by increasing the pressure of a wheel cylinder provided on the wheel;
An inverter circuit for driving the brushless motor;
A control unit for sending a drive signal to the inverter circuit;
With
The control unit is
A braking request calculation unit that calculates a braking request according to the state of the vehicle;
A first waveform driver for applying a first waveform voltage to each phase of the brushless motor;
A second waveform driver for applying a second waveform voltage to each phase of the brushless motor;
An applied voltage switching unit that switches a voltage to be applied according to the calculated braking request;
Have
The applied voltage switching unit applies a first waveform voltage to each phase of the brushless motor when the calculated braking request is greater than a pressure increase gradient that requires a predetermined pump discharge flow rate, and the predetermined pressure increase An electric brake device characterized by applying a second waveform voltage when the gradient is smaller than the gradient. In the electric brake device according to claim 1,
The electric brake device according to claim 1, wherein the first waveform is a 180-degree rectangular wave, and the second waveform is a sine wave. In the electric brake device according to claim 1,
The applied voltage switching unit elongates a PWM carrier cycle for driving the inverter circuit when switching the applied voltage. The electric brake device according to claim 3,
The electric brake device according to claim 1, wherein the applied voltage switching unit gradually lengthens the PWM carrier cycle when the applied voltage is switched. The electric brake device according to claim 4,
The control unit has a voltage command value determination unit that determines whether or not the output voltage command value of the brushless motor can be output as a sine wave voltage,
The applied voltage switching unit switches an applied voltage when an output voltage command value exceeds a voltage that can be output as a sine wave voltage. The electric brake device according to claim 5,
The control unit includes a rotation speed detection unit that detects a rotation speed of the brushless motor;
The applied voltage switching unit switches the applied voltage when the detected rotation speed becomes faster than a predetermined rotation speed. The electric brake device according to claim 4,
The control unit includes a rotation speed detection unit that detects a rotation speed of the brushless motor;
The applied voltage switching unit switches the applied voltage when the detected rotation speed becomes faster than a predetermined rotation speed. A brushless motor as an actuator for generating braking force on the vehicle;
An inverter circuit for driving the brushless motor;
A control unit for sending a drive signal to the inverter circuit;
With
The control unit is
A 180 degree rectangular wave driving unit that applies a 180 degree rectangular wave voltage to each phase of the brushless motor;
A second waveform driver for applying a second waveform voltage;
An applied voltage switching unit that applies a second waveform voltage before applying a 180-degree rectangular wave voltage to each phase of the brushless motor;
An electric brake device comprising: The electric brake device according to claim 8,
The electric brake device, wherein the second waveform voltage is a sine wave. The electric brake device according to claim 9,
The actuator has a pump that generates a braking force by increasing the pressure of a wheel cylinder provided on a wheel,
The control unit has a braking request calculation unit that calculates a braking request according to the state of the vehicle,
The applied voltage switching unit switches the applied voltage when the calculated braking request is more than a predetermined pump discharge flow rate. The electric brake device according to claim 10,
The control unit has a voltage command value determination unit that determines whether or not the output voltage command value of the brushless motor can be output as a sine wave voltage,
The applied voltage switching unit switches an applied voltage when an output voltage command value exceeds a voltage that can be output as a sine wave voltage. The electric brake device according to claim 11,
The control unit includes a rotation speed detection unit that detects a rotation speed of the brushless motor;
The applied voltage switching unit switches the applied voltage when the detected rotation speed becomes faster than a predetermined rotation speed. The electric brake device according to claim 12,
The applied voltage switching unit elongates a PWM carrier cycle for driving the inverter circuit when switching the applied voltage. The electric brake device according to claim 13,
The electric brake device according to claim 1, wherein the applied voltage switching unit gradually lengthens the PWM carrier cycle when the applied voltage is switched. The electric brake device according to claim 9,
The control unit is
A braking request calculation unit that calculates a braking request according to the state of the vehicle;
A voltage command value determination unit for determining whether or not the output voltage command value of the brushless motor can be output as a sine wave voltage;
Have
The applied voltage switching unit switches the applied voltage when the calculated requested braking is greater than the requested pump discharge flow rate and the output voltage command value exceeds the output possible voltage of the sine wave voltage. . The electric brake device according to claim 15,
A rotation speed detector for detecting the rotation speed of the brushless motor;
The applied voltage switching unit switches the applied voltage when the detected rotation speed becomes faster than a predetermined rotation speed. The electric brake device according to claim 9,
A rotation speed detector for detecting the rotation speed of the brushless motor;
The applied voltage switching unit switches the applied voltage when the detected rotation speed becomes faster than a predetermined rotation speed. The electric brake device according to claim 9,
The applied voltage switching unit elongates a PWM carrier cycle for driving the inverter circuit when switching the applied voltage. The electric brake device according to claim 18,
The electric brake device according to claim 1, wherein the applied voltage switching unit gradually lengthens the PWM carrier cycle when the applied voltage is switched. In the control method of the electric brake device for controlling the applied voltage of the brushless motor that drives the pump that generates the braking force by increasing the pressure of the wheel cylinder provided on the wheel according to the required braking force,
A method for controlling an electric brake device, comprising applying a sine wave voltage before applying a rectangular wave voltage to each phase of the brushless motor. In the control method of the electric brake device according to claim 20,
The method for controlling an electric brake device, wherein the rectangular wave voltage is a 180-degree rectangular wave voltage. In the control method of the electric brake equipment according to claim 21,
The braking request according to the state of the vehicle exceeds a predetermined pump discharge flow rate, the output voltage command value of the brushless motor exceeds the output voltage of a sine wave voltage, and the rotation speed of the brushless motor is a predetermined rotation A control method for an electric brake device, wherein a 180-degree rectangular wave voltage is applied after the speed is increased. In the control method of the electric brake device according to claim 22,
A method for controlling an electric brake device characterized by gradually increasing a PWM carrier cycle for driving an inverter circuit for driving the brushless motor when switching a sine wave voltage to a rectangular wave voltage.

Images