Motor control device and vehicle braking system

Abstract

To provide a motor control device which prevents heat generation from deviating to a specific phase at the time of lock energization of a polyphase motor.SOLUTION: Motor control devices 351 to 354 include: a torque command calculation part 40 for calculating a torque command value Trq*; a current command value calculation part 50 for calculating a current command value I*; an inverter (power converter) 55; and a stop position adjusting device 67. The stop position adjusting device 67 executes "stop position adjusting processing" of adjusting a rotation stop position within a predetermined position adjusting range, at the time of lock energization of performing energization in a state where rotation of a polyphase motor 60 is stopped, except for a case of satisfying a predetermined application exception requirement. In the stop position adjusting processing, the stop position adjusting device 67 adjusts a rotation stop position so as to reduce a current absolute value of a maximum current phase whose current absolute value becomes maximum among each phase. The torque command calculation part 40 or the current command calculation part 50 calculates the torque command value Trq* or the current command value I* reflecting the rotation stop position after adjustment.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a motor control device and a vehicle braking device. [Background technology]

[0002] Conventionally, motor control devices that control the energization of multiphase motors are known. Also known are electric brake devices for vehicles that convert the torque output by a multiphase motor into linear force using a linear motion mechanism and press it against the corresponding wheel to generate braking force.

[0003] For example, in the electric brake device disclosed in Patent Document 1, the motor control device controls the motor drive current based on the magnitude of the pressing force detected by the load sensor. The relationship between motor torque and pressing force has a hysteresis characteristic. When applying and holding a pressing force to the brake disc, this motor control device increases the motor torque along the positive efficiency line until the pressing force rises to a predetermined value greater than the target value, and then decreases the motor torque along the negative efficiency line until the pressing force decreases to the target value. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6080682 [Overview of the project] [Problems that the invention aims to solve]

[0005] According to the prior art described in Patent Document 1, the current can be reduced by generating a braking force slightly higher than the target braking force using the positive efficiency line, then reducing the current while maintaining the braking force, and finally operating with the negative efficiency line to reduce it to the target braking force. However, when the actuator of an electric brake is composed of a multiphase motor, lock current is required during the process of maintaining the braking force, which causes current to concentrate on a specific phase and leads to uneven heat generation. This problem is not limited to electric brake devices but is common to all multiphase motors that may be subject to lock current.

[0006] The object of the present invention is to provide a motor control device that prevents heat generation from being unevenly distributed to a specific phase when a multiphase motor is energized in a locked state. Another object of the present invention is to provide a vehicle braking system equipped with a plurality of motor control devices for the above purpose that control the energization of the multiphase motors constituting the electric brakes for each wheel. [Means for solving the problem]

[0007] The motor control device of the present invention comprises a torque command calculation unit (40) and a current command performance It comprises a calculation unit (50), a power converter (55), and a stop position adjuster (67). The torque command calculation unit is This is a three-phase, two-system motor with two sets of three-phase windings (601, 602) and an inter-system phase difference of 30 ± (60 × n)° (where n is an integer). The torque command value for the multiphase motor (60) is calculated. The current command calculation unit calculates the current command value to energize the multiphase motor based on the torque command value. The power converter converts the input power and supplies AC power to the multiphase motor according to the current command value.

[0008] The stop position adjuster performs a "stop position adjustment process" to adjust the rotation stop position within a predetermined position adjustment range when the multiphase motor is energized while rotation is stopped, unless the specified exemption requirements are met. The position adjustment range for the stop position adjustment process is set to within ±15° of the electrical angle.

[0009] In the stop position adjustment process, the stop position adjuster adjusts the rotational stop position so as to reduce the absolute value of the current in the maximum current phase, which is the phase with the largest absolute value of current among each phase. The torque command calculation unit or the current command calculation unit calculates a torque command value or a current command value in which the adjusted rotational stop position is reflected.

[0010] Thereby, the motor control device of the present invention can prevent heat generation from being biased to a specific phase during locked energization of the multiphase motor. Preferably, in the stop position adjustment process, the rotational stop position of the multiphase motor is adjusted to a position where the absolute value of the current in the maximum current phase is minimized within the position adjustment range.

[0011] The vehicle braking device of the present invention is mounted on a vehicle (900) having four or more wheels including left and right pairs of wheels (91 - 94) arranged in two or more rows in the front - rear direction. This vehicle braking device brakes the vehicle by a plurality of electric brakes (81 - 84) that convert the torque output by the multiphase motor (60) into linear driving force by a linear motion mechanism (85) and press the corresponding wheels to generate braking force.

[0012] The vehicle braking device includes the above - described motor control device that controls the energization of the multiphase motor in each electric brake, and coordinates the stop position adjustment processes by a plurality of motor control devices. Thereby, it is possible to prevent the occurrence of yaw and spin, and minimize the change in the actual braking force with respect to the required braking force for the entire vehicle.

Brief Description of the Drawings

[0013] [Figure 1] Configuration diagram showing a motor control device for an electric brake motor of a vehicle. [Figure 2] Schematic configuration diagram of an electric brake for each wheel. [Figure 3] (a) Schematic diagram of a pad of an electric brake, (b) Characteristic diagram of pad load and pad position. [Figure 4] Diagram showing the hysteresis characteristics between the torque of the motor and the braking force. [Figure 5] Block diagram showing a configuration example of the motor control device according to the first embodiment. [Figure 6] A diagram showing the stopping position relative to the required load in a comparative example. [Figure 7] A three-phase current waveform diagram showing an example of the lock current position in a comparative example. [Figure 8] A diagram showing the stopping position relative to the required load in this embodiment. [Figure 9] A three-phase current waveform diagram showing an example of the locked energized position in this embodiment. [Figure 10] A diagram comparing the current during locking before and after adjustment of the stopping position. [Figure 11] This figure illustrates an example of stop position adjustment processing in a three-phase motor. [Figure 12] A schematic diagram of a three-phase, two-system motor with a phase difference between systems and an electric angle of 30°. [Figure 13] This figure illustrates an example of stop position adjustment processing in a three-phase two-system motor with a phase difference between systems of 30°. [Figure 14] Flowchart for the stop position adjustment process. [Figure 15] A flowchart for determining whether an exemption condition is met. [Figure 16] A flowchart for mediating the stopping position adjustment process using a vehicle's braking system. [Figure 17] A block diagram showing an example configuration of the motor control device according to the second embodiment. [Modes for carrying out the invention]

[0014] Embodiments of the motor control device and vehicle braking device of the present invention will be described based on the drawings. The following first and second embodiments will be collectively referred to as "this embodiment." The motor control device of this embodiment controls the energization of three-phase motors mounted on a vehicle and used for the electric brakes of each wheel. The vehicle braking device includes a motor control device that controls the energization of three-phase motors as "multi-phase motors" in each electric brake, and mediates the processing described later by multiple motor control devices.

[0015] [Vehicle configuration] Referring to Figures 1 to 3(b), the configuration of the vehicle 900 and electric brakes 81-84 on which the vehicle braking system 30 of this embodiment is mounted will be described. As shown in Figure 1, the vehicle 900 is a four-wheeled vehicle having two rows of left and right pairs of wheels 91, 92, 93, and 94 in the front-rear direction. The front left and right wheels 91 and 92 are labeled "FL" and "FR," and the rear left and right wheels 93 and 94 are labeled "RL" and "RR." Multiple (four in this example) electric brakes 81, 82, 83, and 84 are provided corresponding to each wheel 91, 92, 93, and 94.

[0016] The vehicle braking system 30 includes four motor control devices 351, 352, 353, and 354 that control the energization of the three-phase motors 60 in each of the electric brakes 81, 82, 83, and 84. Hereafter, four consecutive symbols will be abbreviated as "wheels 91-94", "electric brakes 81-84", and "motor control devices 351-354". The same applies to the symbols "load torque TL1-TL4" and "motor temperature Temp1-Temp4" described later. The vehicle braking system 30 also acquires the vehicle speed V from the vehicle speed sensor 97.

[0017] The actuators of the electric brakes 81-84 are composed of a three-phase motor (indicated as "three-phase M" in the figure) 60 as a "multi-phase motor". Specifically, the three-phase motor 60 is a permanent magnet type brushless motor. In this embodiment, the configuration and operation of the three-phase motor 60 corresponding to each electric brake 81-84 are assumed to be the same, and a single reference numeral "60" is used. In the following specification, the three-phase motor 60 will be abbreviated as simply "motor 60" as appropriate.

[0018] The motor control devices 351-354 control the braking force generated by each electric brake 81-84 based on the requested braking force commanded from an external source. The requested braking force is commanded by the driver's brake operation or braking signals from the driver assistance system. As shown by the dashed double arrows, each motor control device 351-354 may communicate information with each other.

[0019] The four motor control devices 351-354 are not necessarily physically separate and may be integrated and configured on a single circuit board. Specifically, the ECU constituting the vehicle braking system 30 functions as the motor control devices 351-354. The ECU consists of a microcontroller and pre-driver, and includes a CPU, ROM, RAM, I / O (not shown), and bus lines connecting these components. The ECU performs software processing by executing a program pre-stored in a physical memory device such as ROM (i.e., a readable non-temporary tangible recording medium) using the CPU, and control through hardware processing using dedicated electronic circuits.

[0020] The motor control devices 351-354 may acquire load torques TL1-TL4 or motor temperatures Temp1-Temp4. Load torques TL1-TL4 may be estimated from the power consumption of the inverter. Motor temperatures Temp1-Temp4 are detected, for example, by a temperature sensor. Alternatively, the motor temperatures Temp1-Temp4 may be calculated by estimating the temperature rise from the Joule heating caused by energizing the three-phase motor 60 and adding it to the ambient temperature. Load torques TL1-TL4 and motor temperatures Temp1-Temp4 will be described later in the explanation of exemptions. If not used to determine the exemption requirements, the motor control device 351-354 It is not necessary to obtain the load torque TL1-TL4 or the motor temperature Temp1-Temp4.

[0021] In this embodiment, the control configuration of each electric brake 81-84 is the same. Figure 2 illustrates the control configuration of the electric brake by the motor control device 351-354, using one of the electric brakes 81-84 as an example.

[0022] Each electric brake 81-84 includes a motor 60, a linear motion mechanism 85, and a caliper 86. The motor 60 is, for example, a permanent magnet type three-phase brushless motor, and outputs torque by a drive current supplied from the braking force control unit 400. The linear motion mechanism 85 is an actuator that converts the output rotation of the motor 60 into linear motion while reducing its speed. The rotation angle θ of the motor 60 and the stroke X of the linear motion mechanism 85 are proportional. In this way, each electric brake 81-84 converts the torque output by the motor 60 into linear force by the linear motion mechanism 85 and presses it against the corresponding wheel 91-94 to generate braking force.

[0023] The output torque of the motor 60 acts on the pads 87 of the caliper 86 via the linear motion mechanism 85. As the pads 87 move and press against the discs 88 of each wheel 91-94, braking force is generated by friction. The braking force is released when the pads 87 move away from the discs 88.

[0024] Referring to Figures 3(a) and (b), the characteristics of the pad 87 of the electric brake 81-81 shown in section IIIa of Figure 2 will be supplemented. As shown in Figure 3(a), the pad 87 has spring-like characteristics, and the pressing force Fd by the linear motion mechanism 85 and the reaction force Fr corresponding to the amount of strain act in opposite directions. As shown in Figure 3(b), the pad position X based on the stroke of the linear motion mechanism 85 and the pad load F are approximately proportional. If the pad position changes by ΔX due to a change in the rotation angle Δθ of the motor 60, the pad load changes by ΔF. Note that in Figures 3(b) and 8, the symbol "ΔF" indicates the change in load. This has a different meaning from the "ΔF" used in Figure 5, which indicates the load deviation between the load command value and the actual load in load control.

[0025] Returning to Figure 2, the motor control devices 351-354 include a torque command calculation unit 40, a current command calculation unit 50, and an inverter 55. The torque command calculation unit 40 calculates the torque command value Trq of the motor 60 based on the requested braking force commanded from the outside. * The current command calculation unit 50 calculates the current command value I to energize the motor 60 based on the torque command value. * Perform the calculation.

[0026] The inverter 55 converts the DC power from the input battery 15 into AC power, and sets the current command value I * AC power corresponding to this is supplied to the motor 60. The configuration of current feedback from the current command calculation unit 50 to the inverter 55, and the stop position adjuster specific to this embodiment will be described later with reference to Figure 5.

[0027] The electric brakes 81-84 also include at least one of an angle sensor 72 or a stroke sensor 73. The angle sensor 72 detects the actual angle θ, which is the actual rotation angle of the motor 60. In this embodiment, the actual angle θ is defined as the motor electrical angle. The stroke sensor 73 detects the actual stroke X, which is the actual stroke of the linear motion mechanism 85. The stroke sensor 73 may also detect a change in the position of the moving part of the linear motion mechanism 85, or it may detect a change in the position of the pad 87.

[0028] The angle sensor 72 and the stroke sensor 73 are collectively referred to as the "position sensor." The position sensors 72 and 73 are composed of, for example, Hall elements or magnetoresistive elements, and can detect position with relatively high accuracy. The actual angle θ and actual stroke X are collectively referred to as the "actual position." The actual positions θ and X detected by the position sensors 72 and 73 are input to the torque command calculation unit 40. In this embodiment, a configuration mainly consisting of the angle sensor 72 is assumed, and in the following description only the symbols for "position sensor 72" and "actual position θ" will be used. A configuration consisting of the stroke sensor 73 will be described in other embodiments.

[0029] In the first embodiment, the electric brakes 81-84 are further equipped with load sensors 71. The load sensors 71 detect the actual load F, which is the braking load actually pressed against the wheels 91-94. The actual load F detected by the load sensors 71 is input to the torque command calculation unit 40. In the second embodiment, the electric brakes 81-84 are not equipped with load sensors 71 in the first place, or the actual load F detected by the load sensors 71 is not used in the calculations of the torque command calculation unit 40.

[0030] Next, referring to Figure 4, the relationship between motor torque and braking force in this configuration of electric brake will be explained. The braking force correlates with the brake pad load. Hereinafter, "torque" simply refers to the torque output by the motor 60, and "load" simply refers to the pressing load by the pad 87. Figure 4 corresponds to Figure 10 of Patent Document 1 (Japanese Patent No. 6080682).

[0031] The relationship between the torque of motor 60 and the braking force generated in electric brakes 81-84 exhibits hysteresis characteristics. When the torque increases, the braking force increases along the positive efficiency curve. When the torque decreases from the turning point Tconv, where it begins to decrease, to the holding critical value Tcr, the braking force is maintained constant. When the torque decreases from the holding critical value Tcr, the braking force decreases along the negative efficiency curve. Here, the torque correlates with the drive current of motor 60.

[0032] In the prior art described in Patent Document 1, the magnitude of the load detected by the load sensor is the "target value F". * The motor torque is increased until it reaches a value greater than a predetermined offset value dF. After that, the magnitude of the load detected by the load sensor reaches the target value F. * The motor drive current is controlled to reduce the motor torque until a certain point is reached. The load F is maintained during the process of reducing the motor torque. This allows for a reduction in the current while maintaining the braking force.

[0033] However, when the actuator of an electric brake is composed of a multiphase motor, "lock energization," which is required when the motor rotation is stopped and energized, is necessary during the process of maintaining braking force. This causes current to concentrate on a specific phase, resulting in uneven heat generation. As a result, it can lead to failure of inverter elements or motor windings, or necessitate the use of heat-resistant components. Therefore, the motor control device 351-354 of this embodiment aims to prevent uneven heat generation in a specific phase when the three-phase motor 60 is energized in lock mode during the braking force maintenance operation of the electric brake 81-84.

[0034] Next, the detailed configuration for each embodiment will be described. The motor control devices of the first and second embodiments differ only in the control configuration of the part that switches between executing and not executing the stop position adjustment process, and the operational effects are the same. Regarding the signs of the torque command calculation units that include the switching part between executing and not executing the stop position adjustment process, the torque command calculation unit of the first embodiment is assigned the sign "401", and the torque command calculation unit of the second embodiment is assigned the sign "402" for distinction.

[0035] (First Embodiment) Referring to FIGS. 5 to 16, the first embodiment will be described. In the first embodiment, when the stop position adjustment process is executed, position control is performed to make the actual position θ follow the position command value θ * , and when the stop position adjustment process is not executed, load control is performed to make the actual load F follow the load command value F * . Load control is executed during the process in which the braking force increases along the positive efficiency line and the process in which it decreases along the negative efficiency line. In the process of reducing the torque while maintaining the braking force, the stop position adjustment process is executed by position control as necessary. Note that by setting the adjustment amount of the stop position adjustment process to zero, the execution of the stop position adjustment process may be substantially terminated.

[0036] FIG. 5 shows a block diagram of the motor control device of the first embodiment. It includes each motor control device 351 - 354, and the sign of the motor control device is denoted as "35". The torque command calculation unit 401 includes a load command calculation unit 41, a load deviation calculator 42, a load controller 43, a position deviation calculator 45, a position controller 46, and a switch 48.

[0037] The load command calculation unit 41 calculates a load command value F * based on the required braking force. The load deviation calculator 42 calculates a load deviation ΔF (= F * - F) between the actual load F detected by the load sensor 71 and the load command value F * . The load controller 43 calculates a torque command value Trq * (f) so as to bring the load deviation ΔF closer to zero, that is, to bring the actual load F closer to the load command value F * .

[0038] The position deviation calculator 45 uses the actual position θ detected by the position sensor 72 and the position command value θ output by the stop position adjuster 67. * The positional deviation Δθ(=θ) * The position controller 46 calculates the position deviation Δθ to zero, i.e., the actual position θ to the position command value θ. * Torque command value Trq * Calculate (θ).

[0039] The switch 48, in accordance with the switching signal from the stop position adjuster 67, outputs the torque command value Trq from the torque command calculation unit 401. * Trq * (f) or Trq * Switching (θ). In the configuration example shown in Figure 5, a switch 48 is provided on the output side of each controller 43, 46, but the configuration is not limited to this, and the switching function may be implemented to mask the operation of either the load controller 43 or the position controller 46, for example.

[0040] Furthermore, the motor control device 35 has a current indicator performance In addition to the calculation unit 50 and the inverter (labeled "INV" in the figure) 55, it also includes a current feedback control unit 53, a lock energization determination unit 69, and a stop position adjuster 67, which are omitted in Figure 2.

[0041] current finger performance The calculation unit 50 calculates the current command value I * Specifically, the dq axis current command value Id by vector control * , IQ * The current feedback control unit 53 calculates the current and outputs it to the current feedback control unit 53. The current feedback control unit 53 acquires the three-phase currents Iu, Iv, and Iw detected by the current sensor 57, and the motor electrical angle, i.e., the actual position θ, detected by the position sensor 72, and converts the three-phase currents Iu, Iv, and Iw into dq-axis currents Id and Iq. The current feedback control unit 53 converts the dq-axis currents Id and Iq into current command values ​​Id * , IQ * The voltage command value is calculated to follow the signal, and a switching signal is generated using PWM control or the like and output to the inverter 55.

[0042] The lock energization determination unit 69 determines whether the motor 60 is in a "locked energized" state, where it is energized while the rotation of the motor 60 has stopped, based on the fluctuation range and time derivative of the actual position θ. When it determines that the motor is in a locked energized state, it outputs a lock energization signal to the stop position adjuster 67. Note that "stopped" rotation includes, for example, an ultra-low rotation state of a few rpm.

[0043] The stop position adjuster 67 obtains the load torque TL1-TL4 and motor temperature Temp1-Temp4 from the corresponding electric brakes 81-84 and determines whether the exemption requirements described later are met. Unless the exemption requirements are met, the stop position adjuster 67 performs a "stop position adjustment process" to adjust the rotation stop position within a predetermined position adjustment range when the lock is energized. In the following specification, "stop position" means the rotation stop position.

[0044] The motor control device 35 of this embodiment is applied to a system in which the load acting on the load changes depending on the rotational stop position of the motor 60 when the lock energization is applied. Next, referring to Figures 6 to 10, the technical significance of the stop position adjustment process will be explained in comparison with a comparative example in which the stop position adjustment process is not performed when the lock energization is applied.

[0045] Figures 6 and 7 show examples of the stopping position and the lock-on position for the required load in the comparative example. In the comparative example, the stopping position is uniquely determined when the required load, which is the target value of the load acting on the load, is determined, and it is possible to stop at a position where the current is concentrated in a particular phase. The phase in which the absolute value of the current is maximum is defined as the "maximum current phase". In the example in Figure 7, the absolute value of the V-phase current Iv is maximum at the lock-on position, and the V-phase corresponds to the maximum current phase.

[0046] Figures 8 and 9 show examples of the stop position and the lock energized position for the required load in this embodiment. In the stop position adjustment process, the rotation stop position of the motor 60 is adjusted to a range corresponding to the allowable range of variation of the required load. In Figure 8, the load change due to position adjustment is represented as ΔF. The direction of position adjustment is defined, for example, as positive when the load increases and negative when the load decreases. Figure 8 shows that the adjustment of position θ and the adjustment of load F are correlated with each other. In the example in Figure 9, the stop position is adjusted from the position before adjustment to a position where the signs of the V-phase current Iv and the U-phase current Iu are opposite and their absolute values ​​are equal.

[0047] Figure 10 shows the phase currents when the lock is energized. In the comparative example, the pre-adjustment state persists, and heat generation is unevenly distributed in the elements of the inverter 55 and the windings of the motor 60, which are the phases with the maximum current. In contrast, in the stop position adjustment process of this embodiment, the stop position is adjusted to reduce the absolute value of the current of the V phase, which is the phase with the maximum current. The torque command calculation unit 401 calculates the torque command value Trq, which reflects the adjusted rotation stop position. * Perform the calculation.

[0048] Next, an example of the stop position adjustment process will be described with reference to Figures 11 to 13. Figure 11 shows an example of a typical three-phase motor, that is, a single three-phase motor system. In a three-phase motor, the absolute value of the current amplitude of one of the phases is maximum at every 60° electrical angle, and at the intermediate 60° electrical angles, the absolute values ​​of the current amplitudes of two phases become equal. This position is the target position θtgt where the absolute value of the current of the maximum current phase is minimum.

[0049] The adjustment amount from the position where the absolute value of the current amplitude of the maximum current phase is maximum to the target position θtgt is ±30° of electrical angle. Therefore, the position adjustment range from any stopping position is set within ±30° of electrical angle. Here, in order to minimize the load change ΔF associated with the adjustment of the stopping position, it is preferable to set the adjustment amount to the minimum. For this reason, it is preferable to adjust in the direction toward the target position θtgt closest to the stopping position before adjustment.

[0050] Next, we will explain an example of a three-phase two-system motor. As shown in Figure 12, the three-phase two-system motor is a double-winding motor having two sets of three-phase windings 601 and 602. In this example, the phase difference between the first and second systems is set to an electrical angle of 30°. That is, the three-phase windings 601 of the first system and the three-phase windings 602 of the second system are arranged on a common stator with an electrical angle offset of 30° from each other. Here, considering the inversion of the two systems and the symmetry of the three phases, the equivalent phase difference between systems in Figure 12 can be expressed as an electrical angle of 30 ± (60 × n)° (where n is an integer).

[0051] Figure 13 shows an example of stop position adjustment processing for a three-phase two-system motor with an electrical angle phase difference of 30° between systems. In the figure, Iu1, Iv1, and Iw1 represent the three-phase currents of the first system, and Iu2, Iv2, and Iw2 represent the three-phase currents of the second system. At every 30° electrical angle, the absolute value of the current amplitude of one of the phases is maximized, and at the intermediate 30° electrical angles, the absolute values ​​of the current amplitudes of two phases become equal. This position is the target position θtgt where the absolute value of the current of the maximum current phase is minimized. Therefore, the phase adjustment range from any stop position is set to within ±15° of the electrical angle.

[0052] For example, the stop position adjuster 67 may store the relationship between the actual position θ before adjustment and the target position θtgt as a map, or, in the case of a three-phase motor, it may adjust the position so that the remainder when the actual position θ is divided by 60° is a specific value. Alternatively, instead of directly adjusting the position, the stop position adjuster 67 may store a map of the load corresponding to the target position θtgt and adjust the position so that the actual load F falls within an appropriate range.

[0053] Thus, in the stop position adjustment process, it is preferable that the rotation stop position of the motor 60 is adjusted to the target position θtgt where the absolute value of the current of the maximum current phase is minimized. However, the position adjustment range, which is limited based on the allowable range of fluctuations in the required load, may be smaller than the electrical angle of ±30° for a three-phase motor or the electrical angle of ±15° for a three-phase two-system motor with an electrical angle of 30° between systems. In that case, the rotation stop position of the motor 60 is adjusted to the position where the absolute value of the current of the maximum current phase is minimized within the position adjustment range, that is, the position closest to the target position θtgt within the position adjustment range.

[0054] Furthermore, for example, the current command calculation unit 50 calculates the dq axis current command value Id in the dq axis coordinates. * , IQ * Regarding the current phase, the current command value Id will be adjusted according to the time so that current is not supplied at the same current phase for longer than a predetermined time. * , IQ * A phase adjustment process may be performed to change the phase. This phase adjustment process may be used in combination with the stop position adjustment process of this embodiment. This is particularly effective when position adjustment to the target position θtgt is not possible due to limitations in the position adjustment range.

[0055] Referring to the flowchart in Figure 14, the stop position adjustment process by the stop position adjuster 67 will be explained. In the following flowchart, the symbol "S" represents a step. In S10, the stop position adjuster 67 determines whether or not the lock energization is active based on the presence or absence of a lock energization signal input. If the answer in S10 is YES, in S20 the stop position adjuster 67 determines whether the exemption requirements are met. For specific examples of the exemption requirements, refer to Figure 15.

[0056] If NO is selected in S20, the stop position adjuster 67 performs the stop position adjustment process within the phase adjustment range in S30. If NO is selected in S10, or YES in S20, the stop position adjuster 67 stops the execution of the stop position adjustment process in S25. For example, the switch 48 may switch from position control to load control, or the stop position adjuster 67 may set the adjustment amount to zero and perform position control.

[0057] (exempted from application) In this embodiment, the stop position adjuster 67 does not always perform the stop position adjustment process, and in situations where heat generation in a specific phase does not become a problem even when the lock is energized, it is not necessary to perform the stop position adjustment process. Na Therefore, if the specified exemption requirements are met, the stop position adjuster 67 does not perform the stop position adjustment process.

[0058] The flowchart in Figure 15 shows an example of determining whether the exemption requirements are met. In this example, the three requirements are judged sequentially in S21 to S23. If at least one of S21 to S23 is judged as YES, then in S24 it is determined that the exemption requirements are met.

[0059] The motor control devices 351-354 acquire the load torques TL1-TL4 or motor temperatures Temp1-Temp4 of each motor 60. In S21, it is determined whether the load torques TL1-TL4 of the motor 60 are below a predetermined torque threshold. In the low-load region, the current flowing when the motor is locked is small, so heat generation is not a problem.

[0060] In S22, it is determined whether the fluctuation of the load torque TL1-TL4 of the motor 60 is greater than a predetermined torque fluctuation threshold. If the result in S22 is YES, the motor 60 rotates, and therefore the locked energized state does not occur. In S23, it is determined whether the temperature Temp1-Temp4 of the motor 60 is below a predetermined temperature threshold. Even if the locked energized state occurs, if there is sufficient margin above the allowable upper temperature limit, it is not necessary to perform the stop position adjustment process.

[0061] Thus, if locking does not occur in the first place, or if heat generation in a specific phase does not pose a problem even when locking is performed, the stop position adjuster 67 does not perform the stop position adjustment process. This avoids the unnecessary occurrence of load changes ΔF due to position adjustment.

[0062] (Mediation of stop position adjustment process) When the motor control devices 351-354 individually adjust the stopping position for each electric brake 81-84, there is a possibility that the combination of position adjustment directions for each motor control device 351-354 may be inappropriate from the standpoint of balancing the braking force of the entire vehicle. Therefore, the vehicle braking system 30 mediates the stopping position adjustment process of each motor control device 351-354. Each motor control device 351-354 may communicate information with each other as shown in Figure 1, or a separate mediation unit may be provided to manage each motor control device 351-354.

[0063] Referring to the flowchart in Figure 16, the mediation of the stopping position adjustment process will be explained. In S27, it is determined whether the vehicle speed V is equal to or greater than the vehicle speed threshold as an exemption requirement for the entire vehicle. If the answer in S27 is YES, in S28 each motor control device 351-354 stops executing the stopping position adjustment process.

[0064] If the answer in S27 is NO, then in S30, it is determined whether each motor control device 351-354 has determined whether it is appropriate to perform the stop position adjustment process. If the answer in S30 is YES, then in S31, each motor control device 351-354 tentatively determines the direction of the position adjustment. At this stage, the stop position adjustment process is not yet performed.

[0065] The vehicle braking system 30 mediates the stopping position adjustment processes of each motor control device 351-354 at the following points. At the first mediation point, the vehicle braking system 30 mediates the stopping position adjustment processes for each pair of left and right wheels so that the direction of increase or decrease in braking force generated by the stopping position adjustment processes of the multiple motor control devices 351-354 is consistent. This suppresses yaw and spinning of the vehicle 900 while suppressing uneven heat generation when the wheels are locked.

[0066] At the second arbitration point, the vehicle braking system 30 arbitrates the stopping position adjustment processes for multiple wheels so that the directions of increase or decrease in braking force resulting from the stopping position adjustment processes of multiple motor control devices 351-354 cancel each other out. This minimizes the change in actual braking force relative to the required braking force for the entire vehicle.

[0067] When trying to achieve compatibility with the first arbitration point, the left and right pairs of wheels are excluded from the "multiple wheels" subject to arbitration. In other words, for multiple wheels arranged in the front-to-rear direction, arbitration is performed so that the directions of increase and decrease in braking force cancel each other out. On the other hand, if yaw or spin is acceptable and compatibility with the first arbitration point is not required, the left and right pairs of wheels may be included in the "multiple wheels" subject to arbitration so that the directions of increase and decrease in braking force cancel each other out.

[0068] Specifically, in S40, the vehicle braking system 30 evaluates the provisionally determined position adjustment direction. For the first arbitration point, it is evaluated whether the position adjustment directions of the motor control devices 351 and 352 corresponding to the left front wheel 91 and the right front wheel 92 coincide, or whether the position adjustment directions of the motor control devices 353 and 354 corresponding to the left rear wheel 93 and the right rear wheel 94 coincide. For the second arbitration point, for example, it is evaluated whether the position adjustment directions of the motor control devices 351 and 353 corresponding to the left front wheel 91 and the left rear wheel 93 cancel each other out, or whether the position adjustment directions of the motor control devices 352 and 354 corresponding to the right front wheel 92 and the right rear wheel 94 cancel each other out.

[0069] In S41, it is determined whether these mediation conditions are met. If the answer in S41 is NO, then in S42, the position adjustment direction of some of the motor control devices is changed. Details such as which motor control device's provisionally determined position adjustment direction takes priority may be determined as appropriate. S If the answer to 41 is YES, or if the position adjustment direction is changed in S42, then in S43, each motor control device 351-354 performs a stop position adjustment process.

[0070] Thus, the vehicle braking system 30 includes a plurality of motor control devices 351-354 that control the energization of the motor 60 in each electric brake, and mediates the stopping position adjustment process performed by the plurality of motor control devices 351-354. This makes it possible to prevent the occurrence of yaw and spin, and to minimize the change in actual braking force relative to the required braking force for the entire vehicle.

[0071] (Second Embodiment) Figure 17 shows a block diagram of the motor control device of the second embodiment. Components that are substantially the same as those of the first embodiment shown in Figure 5 are denoted by the same reference numerals and their descriptions are omitted. The torque command calculation unit 402 of the second embodiment performs position control based on the actual position θ detected by the position sensor 72 throughout the entire process of increasing, holding, and decreasing the braking force. The torque command calculation unit 402 includes a position command calculation unit 44, a position deviation calculator 45, a position controller 46, and a switch 68. The position command calculation unit 44 calculates the basic position command value θ based on the requested braking force. * Perform the operation on 0.

[0072] Similar to the first embodiment, the motor control device 35 includes a lock energization determination unit 69 and a stop position adjuster 67. When the stop position adjuster 67 determines to perform a "stop position adjustment process", it adjusts the position command value θ * The system calculates 'a' and outputs a switching signal to the switch 68. The switch 68 receives the basic position command value θ calculated by the position command calculation unit 44. * 0, and the adjusted position command value θ calculated by the stop position adjuster 67. * 'a' is entered.

[0073] When the stop position adjustment process is not performed, the switch 68 defaults to the basic position command value θ. * When 0 is selected and the stop position adjustment process is executed, the adjusted position command value θ * The switch can be switched to select a. The position command value θ selected by the switch 68. * This is input to the position deviation calculator 45. The position deviation calculator 45 and the position controller 46 have the same configuration as shown in Figure 5, so their explanation is omitted.

[0074] In the motor control device of the second embodiment, the specific configuration and effects of the stop position adjustment process are the same as in the first embodiment, and it is possible to prevent heat generation from being unevenly distributed to a specific phase when the motor 60 is locked and energized.

[0075] (Other embodiments) (a) The vehicle on which the vehicle braking device of the present invention is installed is not limited to a four-wheeled vehicle having two rows of left and right pairs of wheels in the longitudinal direction of the vehicle, but may also be a six-wheeled or more vehicle having three or more rows of wheels in the longitudinal direction of the vehicle. For example, in a six-wheeled vehicle where there is a need to suppress yaw or spin, it is preferable to match the direction of increase or decrease of braking force for the left and right pairs of wheels in the middle row, in addition to the front and rear wheels, when mediating the stopping position adjustment process by the vehicle braking device 30.

[0076] (b) In the motor control device 35 of the first and second embodiments, in the stop position adjustment process, the torque command calculation units 401 and 402 calculate the torque command value Trq which reflects the adjusted rotation stop position. * The current command calculation unit 50 calculates the current command value I that reflects the adjusted rotation stop position. * You may perform the calculation.

[0077] (c) In the above embodiment, it is assumed that the angle sensor 72 of the motor 60 is mainly used as the position sensor, but the stroke sensor 73 of the linear motion mechanism 85 may also be used as the position sensor. In that case, the position controller 46 will adjust the position deviation ΔX to be as close to zero as possible, that is, the actual position X to the position command value X * The torque command value is calculated to approximate this value. The position adjustment range for the stop position adjustment process is set in the same way as in the above embodiment, based on the rotation angle converted from the stroke.

[0078] The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit.

[0079] The motor control device according to claim 1, wherein the multiphase motor is a three-phase motor, and the position adjustment range of the stop position adjustment process is set to within ±30° of electrical angle, and the inventions of the multiphase motor are a three-phase two-system motor having two sets of three-phase winding sets (601, 602) and an inter-system phase difference of 30 ± (60 × n)° (n is an integer) of electrical angle, and the position adjustment range of the stop position adjustment process is set to within ±15° of electrical angle, may be referenced by claim 1 or 2 if the description requirements are permissible.

[0080] The invention described in claim 1, "a motor control device applicable to a system in which the load acting on a load changes according to the rotation stop position of the multiphase motor when the lock is energized, wherein in the stop position adjustment process, the rotation stop position of the multiphase motor is adjusted to a range corresponding to the allowable range of variation of the required load, which is a target value of the load acting on the load," may be referenced by any one of claims from claim 1 to the immediately preceding claim, provided that the description requirements are permitted.

[0081] The invention of "a motor control device according to claim 1, wherein the stop position adjuster stops executing the stop position adjustment process when at least one of the above exclusion requirements is met," may be referenced by any one of the claims from claim 1 to the immediately preceding claim, if the description requirements are permissible.

[0082] The invention of "a vehicle braking device according to claim 7, wherein, as an exclusion requirement, when the vehicle speed is equal to or greater than the vehicle speed threshold, the stop position adjusters of the plurality of motor control devices cease the execution of the stop position adjustment process," may be referenced from any one of the claims from claim 7 to the immediately preceding claim if the description requirements are permissible.

[0083] The motor control device and method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the motor control device and method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the motor control device and method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of Symbols]

[0084] 30. Vehicle braking systems, 35 (351-354) ... Motor control device, 40. Torque command calculation unit, 50...Current command calculation section, 55...Inverter (power converter), 60... Multiphase motor, 67...stop position adjuster, 81-84...Electric brakes, 85...Linear drive mechanism, 900...vehicles, 91-94...wheels.

Claims

1. A torque command calculation unit (40) that calculates the torque command value of a multiphase motor (60) which is a three-phase two-system motor having two sets of three-phase winding sets (601, 602) and an inter-system phase difference of electrical angle 30 ± (60 × n)° (where n is an integer), A current command calculation unit (50) calculates a current command value to energize the multiphase motor based on the torque command value, A power converter (55) that converts the input power and supplies AC power corresponding to the current command value to the multiphase motor, Except when the specified exemption requirements are met, a stop position adjuster (67) performs a stop position adjustment process to adjust the rotation stop position within a predetermined position adjustment range when the multiphase motor is energized while rotation is stopped, Equipped with, The position adjustment range of the aforementioned stop position adjustment process is set to within ±15° of the electrical angle. In the aforementioned stop position adjustment process, the stop position adjuster adjusts the rotation stop position so as to reduce the absolute value of the current of the maximum current phase, which has the highest absolute value of current among the phases. The torque command calculation unit or the current command calculation unit is a motor control device that calculates the torque command value or the current command value that reflects the adjusted rotation stop position.

2. In the aforementioned stop position adjustment process, The motor control device according to claim 1, wherein the rotation stop position of the multiphase motor is adjusted to a position in which the absolute value of the current of the maximum current phase is minimized within the position adjustment range.

3. The aforementioned multiphase motor is a three-phase motor, The motor control device according to claim 1, wherein the position adjustment range of the stop position adjustment process is set to within ±30° of the electrical angle.

4. This system is applied to a system in which the load acting on the load changes depending on the rotation stop position of the multiphase motor when the lock is energized. In the aforementioned stop position adjustment process, The motor control device according to claim 1, wherein the rotation stop position of the multiphase motor is adjusted to a range corresponding to the allowable range of fluctuation of the required load, which is the target value of the load acting on the load.

5. The aforementioned exemption requirements include, The load torque of the multiphase motor is less than a predetermined torque threshold. The load torque fluctuation of the multiphase motor is greater than a predetermined torque fluctuation threshold. The temperature of the multiphase motor is below a predetermined temperature threshold. When at least one of the following requirements is met, The motor control device according to claim 1, wherein the stop position adjuster cancels the execution of the stop position adjustment process.

6. A vehicle braking system mounted on a vehicle (900) with four or more wheels, including two or more pairs of left and right wheels (91-94) in the front-rear direction, wherein the vehicle is braked by multiple electric brakes (81-84) that convert torque output by a multiphase motor (60) into direct force by a linear motion mechanism (85) and press against the corresponding wheels to generate braking force, Each of the electric brakes is equipped with a motor control device (351-354) according to any one of claims 1 to 5, which controls the energization of the multiphase motor. A vehicle braking device that mediates the stop position adjustment processes of multiple motor control devices.

7. The vehicle braking device according to claim 6, wherein the stopping position adjustment process is mediated so that the direction of increase or decrease in braking force generated by the stopping position adjustment process of a plurality of motor control devices is the same for each pair of left and right wheels.

8. The vehicle braking device according to claim 6, wherein the stopping position adjustment process is mediated for multiple wheels such that the direction of increase or decrease in braking force generated by the stopping position adjustment process of multiple motor control devices cancels each other out.

9. As an exclusion requirement, the vehicle braking device according to claim 6, wherein when the vehicle speed is equal to or greater than the vehicle speed threshold, the stop position adjusters of the plurality of motor control devices cease the execution of the stop position adjustment process.

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