Electric suspension device and electric motor control device

Abstract

To provide an electric suspension apparatus capable of responding appropriately to a vibration or the like that is applied to the vehicle.SOLUTION: An electric suspension apparatus 11 includes: a return prevention circuit 190 which is configured to operate in one of operation modes including a return prevention mode of preventing a current from flowing from power storage 172 toward a power supply 180 and a return allowance mode of allowing a current to flow from the power storage 172 toward the power supply 180; and a discharge controller 124 which is configured to determine whether or not an electric motor 31 is in regenerative operation, and in response to determining that the electric motor is in regenerative operation, set the operation mode of the return prevention circuit 190 to the return prevention mode, or otherwise in response to determining that the electric motor is not in regenerative operation, set the operation mode of the return prevention circuit 190 to the return allowance mode.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electric suspension device and an electric motor control device. [Background technology]

[0002] In recent years, efforts to provide access to sustainable transportation systems that take into consideration vulnerable users such as the elderly and children have been gaining momentum. To achieve this, the applicant is focusing on research and development to further improve the safety and convenience of transportation through developments related to vehicle behavior stability, such as improving the performance of electric suspension devices.

[0003] Regarding the power source for driving an electric suspension system, Patent Document 1 below describes selecting either a capacitor or a battery based on vehicle state variables. That is, Patent Document 1 determines whether the vibration occurring is high-frequency or low-frequency based on the steering state and vibration amplitude. When emphasis is placed on ride comfort and high-frequency vibration is to be suppressed, a capacitor is selected as the power source, and when emphasis is placed on attitude control and low-frequency vibration is to be suppressed, a battery is selected as the power source. Furthermore, Patent Document 2 below describes a device that commands a driving force to an electric suspension system in accordance with vehicle speed, yaw rate, stroke position, etc. It is possible to employ the same control methods as those publicly known in Patent Documents 1 and 2, and in this respect, the contents of these documents are incorporated herein. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-118714 [Patent Document 2] Japanese Patent Application Publication No. 2020-172228 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to ensure vehicle behavioral stability, it is important to ensure that the electric suspension system responds appropriately to vibrations and other factors applied to the vehicle. However, conventional electric suspension systems have the problem of not always being able to respond appropriately to vibrations and other factors applied to the vehicle. The present invention has been made in view of the above circumstances, and has as its object to provide an electric suspension device and an electric motor control device that can appropriately respond to vibrations and the like applied to a vehicle. [Means for solving the problem]

[0006] In order to achieve the above object, an electric suspension device of the present invention includes an electromagnetic actuator provided between a body and a wheel of a vehicle and including an electric motor; an information acquisition unit that acquires information on a stroke speed of the electromagnetic actuator; a driving force calculation unit that outputs a driving force command value for the electric motor based on the stroke speed; a drive control unit that performs drive control of the electric motor based on the driving force command value; and a power supply unit that outputs a first voltage to the drive control unit, wherein the drive control unit includes a power storage unit that can be charged by the power supply unit; a drive circuit that modulates a second voltage that is a terminal voltage of the power storage unit based on the driving force command value and applies the second voltage to the electric motor; a return prevention circuit that operates in either an anti-return mode that prevents a current from flowing from the power storage unit to the power supply unit or a return allowance mode that allows a current from the power storage unit to flow from the power supply unit; and a discharge control unit that determines whether the electric motor is in a regenerative operation, and if the determination result is positive, sets the operation mode of the return prevention circuit to the return allowance mode, The discharge control unit sets the return prevention circuit to a return permission mode when the second voltage exceeds a predetermined threshold voltage even when the electric motor is in a regenerative operation. It is characterized by: [Effects of the Invention]

[0007] According to the present invention, it is possible to make an electric suspension system respond appropriately, thereby improving the performance of the electric suspension system and contributing to further improving traffic safety and convenience. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram of an electric suspension device according to a first embodiment. [Figure 2] FIG. 2 is a partial cross-sectional view of an electromagnetic actuator that constitutes a part of the electric suspension device. [Figure 3] FIG. 2 is a diagram showing the internal and peripheral configuration of an ECU provided in an electric suspension device. [Figure 4] FIG. 2 is a block diagram showing the configuration of a drive control unit. [Figure 5] 5 is a flowchart showing an example of a discharge processing routine executed by a capacitor discharge control unit. [Figure 6] FIG. 10 is a diagram showing the relationship between the maximum motor current and the motor rotation speed during regenerative operation. [Figure 7] FIG. 10 is a diagram showing the relationship between a capacitor voltage, an actually measured current, and a target current. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] Overall Configuration of First Embodiment The electric suspension device according to the first embodiment will be described in detail below with reference to the drawings as appropriate. In the drawings shown below, components having common functions are denoted by common reference numerals, and the size and shape of components may be exaggerated or distorted for ease of explanation.

[0010] FIG. 1 is a diagram showing the overall configuration of an electric suspension device 11 according to the first embodiment. As shown in Fig. 1, an electric suspension device 11 according to this embodiment includes a plurality of electromagnetic actuators 13, one for each wheel of a vehicle 10, and an ECU (Electronic Control Unit: electronic control device, electric motor control device) 15. The electromagnetic actuators 13 are also equipped with an electric motor (not shown). Between the plurality of electromagnetic actuators 13 and the ECU 15 are arranged power supply lines 14 (see solid lines in Fig. 1) for supplying drive control power from the ECU 15 to the plurality of electromagnetic actuators 13, and signal lines 16 (see dashed lines in Fig. 1) for transmitting an electrical angle signal of the electric motor from the plurality of electromagnetic actuators 13 to the ECU 15.

[0011] In this embodiment, a total of four electromagnetic actuators 13 are provided, one for each wheel including the front wheels (left front wheel and right front wheel) and rear wheels (left rear wheel and right rear wheel) of the vehicle 10. The electromagnetic actuators 13 provided for each wheel are driven and controlled independently of one another in accordance with the extension and contraction movement of each wheel. In this embodiment, each of the multiple electromagnetic actuators 13 has a common configuration unless otherwise specified. Therefore, the configuration of one electromagnetic actuator 13 will be described instead of the description of the multiple electromagnetic actuators 13.

[0012] FIG. 2 is a partial cross-sectional view of the electromagnetic actuator 13 that constitutes a part of the electric suspension device 11. As shown in FIG. 2, the electromagnetic actuator 13 includes a base housing 17, an outer tube 19, a ball bearing 21, a ball screw shaft 23, a plurality of balls 25, a nut 27, an inner tube 29, and an electric motor 31. The electric motor 31 is, for example, a permanent magnet type synchronous motor having a rotor with a permanent magnet and a stator with U-phase, V-phase, and W-phase windings.

[0013] The base housing 17 supports the base end side of the ball screw shaft 23 via a ball bearing 21 so as to be rotatable about its axis. The outer tube 19 is provided in the base housing 17 and accommodates a ball screw mechanism 18 including the ball screw shaft 23, a plurality of balls 25, and a nut 27. The plurality of balls 25 roll along the thread groove of the ball screw shaft 23. The nut 27 engages with the ball screw shaft 23 via the plurality of balls 25 and converts the rotational motion of the ball screw shaft 23 into linear motion. The inner tube 29 connected to the nut 27 is displaced along the axial direction of the outer tube 19 integrally with the nut 27.

[0014] 2, the electromagnetic actuator 13 is equipped with an electric motor 31, a pair of pulleys 33, and a belt member 35 to transmit the rotational driving force to the ball screw shaft 23. The electric motor 31 is provided in the base housing 17 so as to be parallel to the outer tube 19. A pulley 33 is attached to each of the motor shaft 31a of the electric motor 31 and the ball screw shaft 23. A belt member 35 for transmitting the rotational driving force of the electric motor 31 to the ball screw shaft 23 is suspended between the pair of pulleys 33.

[0015] The electric motor 31 is provided with a resolver 37 that detects a rotation angle signal of the electric motor 31. The resolver 37 detects the electrical angle θe of the motor, and makes it possible to calculate the position of the ball screw mechanism 18 relative to the outer tube 19, i.e., the stroke position, based on the electrical angle θe. The electrical angle θe of the motor is sent to the ECU 15 via a signal line 16. The rotational drive of the electric motor 31 is controlled in accordance with drive control power that the ECU 15 supplies to each of the multiple electromagnetic actuators 13 via a power supply line 14.

[0016] 2, the present embodiment employs a layout in which the motor shaft 31a of the electric motor 31 and the ball screw shaft 23 are arranged substantially parallel to each other and connected to each other, thereby reducing the axial dimension of the electromagnetic actuator 13. However, a layout in which the motor shaft 31a of the electric motor 31 and the ball screw shaft 23 are arranged coaxially to each other and connected to each other may also be employed.

[0017] 2, the electromagnetic actuator 13 according to this embodiment has a connecting portion 39 provided at the lower end of the base housing 17. This connecting portion 39 is connected and fixed to an unsprung member (such as a lower arm or knuckle on the wheel side) (not shown). Meanwhile, an upper end 29a of the inner tube 29 is connected and fixed to a sprung member (such as a strut tower on the vehicle body side) (not shown). In short, the electromagnetic actuator 13 is arranged alongside a spring member (not shown) provided between the vehicle body and the wheel of the vehicle 10.

[0018] The electromagnetic actuator 13 configured as above operates as follows. That is, for example, consider a case where a thrust force associated with upward vibration is input to the coupling part 39 from the wheel side of the vehicle 10. In this case, the inner tube 29 and the nut 27 attempt to descend together with the outer tube 19 to which the thrust force associated with the upward vibration has been applied. In response to this, the ball screw shaft 23 attempts to rotate in a direction that follows the downward movement of the nut 27. At this time, the electric motor 31 generates a rotational drive force in a direction that prevents the nut 27 from descending. This rotational drive force of the electric motor 31 is transmitted to the ball screw shaft 23 via the belt member 35. In this way, by applying a reaction force (damping force) to the ball screw shaft 23 against the propulsive force associated with the upward vibration, the vibration that is about to be transmitted from the wheel side to the vehicle body side is damped.

[0019] FIG. 3 is a diagram showing the configuration of the inside and peripheral parts of the ECU 15 provided in the electric suspension device 11 of this embodiment. The ECU 15 includes a microcomputer that performs various types of calculations. The ECU 15 has a drive control function that controls the drive of each of the electromagnetic actuators 13 based on the motor electrical angle θe detected by the resolver 37, thereby generating a drive force related to vibration damping of the vehicle body.

[0020] 3, the ECU 15 includes an information acquisition unit 42, a characteristic information storage unit 44, a filter processing unit 45, a driving force calculation unit 47, and a driving control unit 100. A battery 180 (power supply unit) supplies power to the ECU 15.

[0021] The information acquisition unit 42 acquires the stroke position based on the motor electrical angle θe detected by the resolver 37, and acquires information on the stroke speed SV by differentiating the stroke position with respect to time. As shown in Fig. 3, the information acquisition unit 42 also acquires information on the vehicle speed detected by the vehicle speed sensor 40 and the yaw rate detected by the yaw rate sensor 41. The information on the stroke speed SV, vehicle speed, and yaw rate acquired by the information acquisition unit 42 is sent to the characteristic information storage unit 44 and the filter processing unit 45, respectively.

[0022] The filter processing unit 45 may be configured with an analog circuit or a digital circuit (digital filter). The filter processing unit 45 may be configured with software or hardware. Furthermore, the filter processing unit 45 may be configured with a combination of software and hardware.

[0023] The driving force calculation unit 47 receives the filtered stroke speed signal, calculates a target damping force, and calculates a driving force command value F* for achieving the target damping force. The driving force command value F* is a target value for the driving force generated by the electric motor 31, and is supplied to the drive control unit 100. Note that the details of the information acquisition unit 42, characteristic information storage unit 44, filter processing unit 45, and driving force calculation unit 47 may be those described in, for example, Patent Document 2.

[0024] <Configuration of drive control unit 100> FIG. 4 is a block diagram showing the configuration of the drive control unit 100. 4, the drive control unit 100 includes a calculation unit 110 (drive circuit) and a power control unit 150. The calculation unit 110 includes a torque command value generation unit 111, a q-axis current command value generation unit 112, a feedback control unit 114, a current calculation unit 115, a voltage command value generation unit 116, a signal conversion unit 118, a capacitor voltage measurement unit 122, and a capacitor discharge control unit 124 (discharge control unit).

[0025] The power control unit 150 also includes a drive circuit 152 (drive circuit), a bridge circuit 160 (drive circuit), a capacitor 172 (power storage unit), and a return prevention circuit 190. The return prevention circuit 190 includes a diode 194, a switching element 196, and a diode 198.

[0026] Here, the bridge circuit 160 includes six bridge-connected switching elements 162, six diodes 164 connected in anti-parallel to the switching elements 162, and a current sensor 166. In the illustrated example, the above-mentioned switching elements 162, 196 are IGBTs (Insulated Gate Bipolar Transistors). Current sensor 166 detects three-phase AC currents iu, iv, iw flowing through U-phase, V-phase, and W-phase windings of electric motor 31.

[0027] The battery 180 described above outputs a predetermined battery voltage Vb (first voltage). In the power control unit 150, the terminal voltage of the capacitor 172 is referred to as the capacitor voltage Vc (second voltage). When the capacitor voltage Vc becomes lower than the battery voltage Vb, a charging current flows from the battery 180 to the capacitor 172 via the diode 194, and the capacitor voltage Vc becomes substantially equal to the battery voltage Vb. When the capacitor voltage Vc becomes higher than the battery voltage Vb and the switching element 196 is turned on, a discharging current flows from the capacitor 172 to the battery 180, and the capacitor voltage Vc becomes substantially equal to the battery voltage Vb.

[0028] Furthermore, when the capacitor voltage Vc is higher than the battery voltage Vb and the switching element 196 is in the OFF state, no discharge current flows from the capacitor 172 to the battery 180. Therefore, when the electric motor 31 is in regenerative operation, the capacitor voltage Vc remains higher than the battery voltage Vb. When the drive circuit 152 receives voltage command values ​​vu*, vv*, and vw* (details will be described later) for the U, V, and W phases of the electric motor 31 from the calculation unit 110, the drive circuit 152 PWM-modulates these voltage command values. The capacitor voltage Vc is also supplied to the drive circuit 152. As a result, even for the same voltage command value, the drive circuit 152 sets a lower duty ratio of the PWM-modulated wave as the capacitor voltage Vc becomes higher.

[0029] The generated PWM modulated wave is then applied to the gate terminal of each switching element 162, switching the on / off state of each switching element 162. As a result, the bridge circuit 160 applies three-phase AC voltages vu, vv, and vw to the U-phase, V-phase, and W-phase windings (reference numbers omitted) of the electric motor 31.

[0030] Next, inside the calculation unit 110, the signal conversion unit 118 receives the motor electrical angle θe from the resolver 37, and outputs the stroke position and the mechanical angle θm based on the electrical angle θe. Here, the electrical angle θe is equal to the result of multiplying the mechanical angle θm by N / 2 (where N is the number of poles of the electric motor 31). The signal conversion unit 118 also obtains the mechanical angle frequency ωm and the electrical angle frequency ωe by differentiating the mechanical angle θm and the electrical angle θe with respect to time, and supplies the obtained information to each unit within the drive control unit 100.

[0031] The torque command value generating unit 111 outputs a torque command value T* based on the driving force command value F* and the system gear ratio of the electromagnetic actuator. The system gear ratio is determined by the specifications of the ball screw mechanism 18, the belt member 35, and the pulley 33. Here, assuming a rotational coordinate system rotating at an electrical angular frequency ωe, the direction of the main magnetic flux of the rotor of the electric motor 31 is defined as the d-axis, and the axis perpendicular to the d-axis is defined as the q-axis. When the torque constant of the electric motor 31 is defined as Kq, the q-axis current command value generating unit 112 outputs a q-axis current command value Iq* such that Iq*=T* / Kq.

[0032] The current calculation unit 115 performs coordinate conversion of the AC currents iu, iv, and iw detected by the current sensor 166 based on the electrical angle θe received by the signal conversion unit 118, and outputs the results as a d-axis current measurement value Id and a q-axis current measurement value Iq.

[0033] The feedback control unit 114 performs a current feedback calculation based on the q-axis current command value Iq* and the q-axis current actual measurement value Iq, and outputs a q-axis voltage command value Vq*. The feedback control unit 114 also performs a current feedback calculation based on the d-axis current command value Id* (which is, for example, "0") and the d-axis current actual measurement value Id, and outputs a d-axis voltage command value Vd*. Here, as a specific example of the current feedback calculation, it is preferable to adopt PI control using a proportional gain Kp and an integral gain Ki.

[0034] The voltage command value generating unit 116 performs coordinate transformation on the d-axis voltage command value Vd* and the q-axis voltage command value Vq* based on the electrical angle θe, and outputs the result as voltage command values ​​vu*, vv*, vw* to the drive circuit 152. However, the voltage command value generating unit 116 limits the maximum value of the voltage command values ​​vu*, vv*, vw* to the capacitor voltage Vc. With the above-described configuration of the calculation unit 110, in this embodiment, it is possible to control the d-axis and q-axis current actual measurement values ​​Id, Iq to follow the d-axis and q-axis current command values ​​Id*, Iq*.

[0035] Depending on the operating point of the electric motor 31, such as when the electric motor 31 is rotating at high speed, the voltage command value generator 116 may set the voltage command values ​​vu*, vv*, and vw* to the capacitor voltage Vc, which is their maximum value. In this case, a situation may arise in which the d-axis and q-axis current measurement values ​​Id and Iq cannot follow the d-axis and q-axis current command values ​​Id* and Iq*. In other words, the electric motor 31 is driven in a state in which there is a certain degree of deviation between the d-axis and q-axis current command values ​​Id* and Iq* and the d-axis and q-axis current measurement values ​​Id and Iq.

[0036] At an operating point where a deviation occurs between the d-axis and q-axis current command values ​​Id* and Iq* and the d-axis and q-axis current measurement values ​​Id and Iq, the higher the capacitor voltage Vc, the wider the usable range of the q-axis voltage command value Vq*, and as a result, the better the current tracking. For example, even if the capacitor voltage Vc is low in the initial state and the current tracking is insufficient, the current tracking can be improved if the capacitor 172 can store regenerative power and increase the capacitor voltage Vc.

[0037] The capacitor voltage measurement unit 122 measures the capacitor voltage Vc, which is the terminal voltage of the capacitor 172. When the capacitor voltage Vc exceeds a predetermined threshold voltage Vcth while the electric motor 31 is in regenerative operation, the capacitor discharge control unit 124 sets the gate voltage Vg of the switching element 196 to a predetermined on-voltage Von.

[0038] As a result, the switching element 196 is turned on, and the capacitor 172 is discharged, causing the capacitor voltage Vc to approach the battery voltage Vb. Here, the threshold voltage Vcth should be set to a value higher than the battery voltage Vb and lower than the withstand voltage of the capacitor 172. For example, the threshold voltage Vcth should be set to about 0.9 times the withstand voltage of the capacitor 172.

[0039] In addition, when the electric motor 31 is in regenerative operation and the capacitor voltage Vc is less than the threshold voltage Vcth, or when the electric motor 31 is in powering operation, the capacitor discharge control unit 124 sets the gate voltage Vg of the switching element 196 to a predetermined off voltage Voff.

[0040] This turns the switching element 196 into the OFF state. When the switching element 196 turns into the OFF state during regenerative operation, the capacitor 172 is charged with power regenerated from the electric motor 31, and the capacitor voltage Vc gradually increases. Then, the higher the capacitor voltage Vc, the easier it becomes to make the AC voltages vu, vv, and vw follow the voltage command values ​​vu*, vv*, and vw* in the bridge circuit 160.

[0041] <Operation of the First Embodiment> Next, the operation of this embodiment will be described. 5 is a flowchart showing an example of a discharge processing routine executed by the capacitor discharge control unit 124 (see FIG. 4). This routine is executed at a predetermined control period. 5, when the process proceeds to step S10, the capacitor discharge control unit 124 determines whether the electric motor 31 is in regenerative operation. For example, it may detect whether the motor torque generated by the electric motor 31 is positive or negative and whether the motor rotation direction is positive or negative, and determine "Yes" (in regenerative operation) if the signs of the two do not match, or "No" (in power running) if the signs of the two match.

[0042] If the determination here is "Yes," the process proceeds to step S12, where the capacitor discharge control unit 124 determines whether the capacitor 172 is in an overvoltage state. For example, it may be determined that the capacitor 172 is in an overvoltage state when the capacitor voltage Vc exceeds a threshold voltage Vcth (for example, 0.9 times the withstand voltage of the capacitor 172). If the determination in step S12 is "Yes," the process proceeds to step S16, where the capacitor discharge control unit 124 sets the gate voltage Vg to the on-voltage Von. This turns the switching element 196 on, discharges the capacitor 172, and supplies the discharged current to the battery 180. As a result, the capacitor voltage Vc gradually decreases thereafter.

[0043] Furthermore, if the determination in step S10 or S12 is "No" (the electric motor 31 is in powering operation or regenerative operation and is not in an overvoltage state), the process proceeds to step S20. In step S20, the capacitor discharge control unit 124 sets the gate voltage Vg to the off voltage Voff. This sets the switching element 196 to the off state. Then, if the electric motor 31 is in regenerative operation, the capacitor 172 is charged by the power regenerated by the electric motor 31, and the capacitor voltage Vc gradually increases.

[0044] When the electric motor 31 is in regenerative operation, power is continuously supplied from the electric motor 31 to the capacitor 172. Therefore, the discharge or non-discharge state of the capacitor 172 is switched in units of a control cycle in which the discharge processing routine (FIG. 5) is executed. Therefore, during regenerative operation, the capacitor voltage Vc fluctuates slightly but is maintained near the threshold voltage Vcth.

[0045] 6 is a diagram showing the relationship between the maximum motor current and the motor rotation speed during regenerative operation. Note that the "motor current" can be considered to be, for example, the measured q-axis current value Iq (see FIG. 4). In Figure 6, the vertical axis represents the current value, and the horizontal axis represents the rotational speed. Current characteristics I2 and I4 respectively represent the characteristics of the maximum current value (effective value) of the motor current that can be supplied to the electric motor 31 versus the rotational speed of the electric motor 31 in this embodiment and the comparative example. Here, the comparative example excludes the diode 194, switching element 196, and diode 198 (see Figure 4), and the capacitor voltage Vc is always approximately equal to the battery voltage Vb. As shown in the figure, current characteristic I2 of this embodiment allows a larger current to be supplied to the electric motor 31 during regenerative operation compared to current characteristic I4 of the comparative example.

[0046] FIG. 7 is a diagram showing the relationship between the capacitor voltage Vc, the measured current, and the target current. In Fig. 7, the vertical axis represents current or voltage, and the horizontal axis represents time. The measured current is, for example, the above-mentioned measured q-axis current value Iq, and the target current is the q-axis current command value Iq*. The target current characteristic I12 is the characteristic of the target value of the motor current, and the measured current characteristic I14 is the characteristic of the measured value of the motor current. During the period from time t0 to t2, the capacitor voltage Vc is close to the battery voltage Vb. Then, after time t2, the capacitor voltage Vc gradually increases and reaches a value close to the threshold voltage Vcth.

[0047] The target current characteristic I12 has peaks around times t2, t4, and t6. Around time t2, the capacitor voltage Vc is relatively low, so the measured current characteristic I14 does not follow the target current characteristic I12. On the other hand, around times t4 and t6, the capacitor voltage Vc is near the threshold voltage Vcth, which is relatively high, so it can be seen that the measured current characteristic I14 follows the target current characteristic I12 sufficiently.

[0048] [Effects of the embodiment] As described above, according to the embodiment, the electric suspension device 11 includes: a power storage unit (172) that can be charged by a power supply unit (180); a drive circuit (110, 152, 160) that modulates the second voltage (Vc), which is the terminal voltage of the power storage unit (172), based on the driving force command value (F*), and applies the modulated second voltage to the electric motor 31; a return prevention circuit 190 that operates in either an anti-return mode that prevents current from flowing from the power storage unit (172) to the power supply unit (180) or a return allowance mode that allows current to flow from the power storage unit (172) to the power supply unit (180); and a discharge control unit (124) that determines whether the electric motor 31 is in regenerative operation, and sets the operation mode of the return prevention circuit 190 to the anti-return mode if the determination result is positive, or sets the operation mode of the return prevention circuit 190 to the return allowance mode if the determination result is negative.

[0049] As a result, according to this embodiment, the electric suspension device 11 can be made to respond appropriately. For example, when the electric motor 31 is in regenerative operation, the power storage unit (172) can be charged with regenerative power, and the second voltage (Vc) can be increased. This improves current response to input from the road surface during regeneration during regenerative operation, thereby improving ride comfort.

[0050] Furthermore, it is more preferable that the power storage unit (172) is a capacitor built into the drive control unit 100. By employing a capacitor, it is possible to improve the charge / discharge response compared to when a battery or the like is employed.

[0051] Furthermore, it is more preferable that the discharge control unit (124) sets the return prevention circuit 190 to the return permission mode when the second voltage (Vc) exceeds a predetermined threshold voltage Vcth even when the electric motor 31 is in regenerative operation. This prevents the second voltage (Vc) from becoming an overvoltage.

[0052] [Variations] The present invention is not limited to the above-described embodiment, and various modifications are possible. The above-described embodiment is an example for explaining the present invention in an easy-to-understand manner, and is not necessarily limited to an embodiment having all of the described configurations. Furthermore, other configurations may be added to the configurations of the above-described embodiment, and some of the configurations may be replaced with other configurations. Furthermore, the control lines and information lines shown in the figures are those considered necessary for explanation, and do not necessarily represent all control lines and information lines necessary in the product. In reality, it can be assumed that almost all configurations are interconnected. Possible modifications of the above-described embodiment include, for example, the following.

[0053] (1) The hardware of the ECU 15 in the above embodiment can be realized by a general computer. Therefore, the flowchart shown in FIG. 5 and other programs for executing the various processes described above may be stored in a storage medium or distributed via a transmission path.

[0054] (2) In the above embodiment, the processing shown in FIG. 5 and the other processing described above are described as software-based processing using a program. However, some or all of the processing may be replaced with hardware-based processing using an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), etc.

[0055] (3) The drive control unit 100 of the above embodiment may be applied not only to the electric suspension device 11 but also to an electric motor control device incorporated in other parts of a vehicle or in a device other than a vehicle. [Explanation of symbols]

[0056] 11 Electric suspension system 13 Electromagnetic Actuator 15 ECU (electric motor control unit) 31 Electric motor 42 Information Acquisition Department 47 Driving force calculation unit 100 Drive control unit 110 Calculation unit (drive circuit) 124 Capacitor discharge control unit (discharge control unit) 152 Drive circuit (drive circuit) 160 Bridge circuit (drive circuit) 172 Capacitor (power storage unit) 180 Battery (power supply) 190 Anti-return circuit SV Stroke Speed Vb Battery voltage (first voltage) Vc Capacitor voltage (second voltage) θe electrical angle θm mechanical angle Vcth threshold voltage

Claims

1. an electromagnetic actuator provided between a body and a wheel of the vehicle and including an electric motor; an information acquisition unit that acquires information about the stroke speed of the electromagnetic actuator; a driving force calculation unit that outputs a driving force command value for the electric motor based on the stroke speed; a drive control unit that controls the drive of the electric motor based on the drive force command value; a power supply unit that outputs a first voltage to the drive control unit, The drive control unit a power storage unit that can be charged by the power supply unit; a drive circuit that modulates a second voltage, which is a terminal voltage of the power storage unit, based on the drive force command value and applies the second voltage to the electric motor; a return prevention circuit that operates in either a return prevention mode that prevents current from flowing from the power storage unit to the power supply unit or a return permission mode that allows current to flow from the power storage unit to the power supply unit; a discharge control unit that determines whether the electric motor is in a regenerative operation, and sets the operation mode of the return prevention circuit to a return prevention mode if the determination result is positive, and sets the operation mode of the return prevention circuit to a return permission mode if the determination result is negative, The discharge control unit sets the return prevention circuit to a return permission mode when the second voltage exceeds a predetermined threshold voltage even when the electric motor is in a regenerative operation. An electric suspension device characterized by:

2. The power storage unit is a capacitor built into the drive control unit.

2. The electric suspension device according to claim 1.

3. a driving force calculation unit that outputs a driving force command value for the electric motor based on the electrical angle of the electric motor; a drive control unit that controls the drive of the electric motor based on the drive force command value; a power supply unit that outputs a first voltage to the drive control unit, The drive control unit a power storage unit that can be charged by the power supply unit; a drive circuit that modulates a second voltage, which is a terminal voltage of the power storage unit, based on the drive force command value and applies the second voltage to the electric motor; a return prevention circuit that operates in either a return prevention mode that prevents current from flowing from the power storage unit to the power supply unit or a return permission mode that allows current to flow from the power storage unit to the power supply unit; a discharge control unit that determines whether the electric motor is in a regenerative operation, and sets the operation mode of the return prevention circuit to a return prevention mode if the determination result is positive, and sets the operation mode of the return prevention circuit to a return permission mode if the determination result is negative, The discharge control unit sets the return prevention circuit to a return permission mode when the second voltage exceeds a predetermined threshold voltage even when the electric motor is in a regenerative operation. An electric motor control device characterized by:

Images