Motor control device and motor control method

Abstract

The invention provides a motor control device and a motor control method which can further limit the power of a drive circuit with good precision. A motor control device controls a motor by supplying a drive signal generated by a drive circuit on the basis of a rotation command value to the motor, the motor control device including: a voltage detection unit that detects a voltage of the drive signal as a load voltage; a current detection unit that detects the current of the drive signal as a load current; and a power limiting unit that detects the load power of the drive circuit on the basis of the load voltage and the load current, and performs power limitation by lowering the rotation command value when the load power exceeds a predetermined upper limit value.

Description

Technical Field

[0001] The invention relates to a motor control device and a motor control method. Background Art

[0002] A fan motor control method and a fan motor control device are disclosed in the following patent document 1. In the background technology, when a fan motor (brushless DC motor) is driven by an inverter main circuit, the load of the inverter main circuit is detected, and when the detected load is greater than a specified load, the command rotation number output from the motor control unit to the inverter main circuit is reduced, and when the detected load is less than the specified load, the command rotation number is increased.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2001-286179 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] In the background art, when an overload is detected, thermal protection of the inverter main circuit is performed by reducing the command rotation speed, and load detection is performed based on the motor current supplied from the inverter main circuit (drive circuit) to the fan motor (controlled object).

[0008] That is, in the background art, the load cannot be accurately detected in a state where the voltage applied to the control object, that is, the motor voltage, is variable. Therefore, the background art has a problem that the power of the drive circuit cannot be limited accurately.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a motor control device and a motor control method capable of limiting the power of a drive circuit with further high accuracy.

[0010] [Technical means to solve the problem]

[0011] In order to achieve the above-mentioned purpose, in the present invention, as a first solution of a motor control device, the following means is adopted: a motor control device controls the motor by supplying a drive signal generated by a drive circuit based on a rotation command value to the motor, the motor control device comprising: a voltage detection unit, which detects the voltage of the drive signal as a load voltage; a current detection unit, which detects the current of the drive signal as a load current; and a power limiting unit, which detects the load power of the drive circuit based on the load voltage and the load current, and reduces the rotation command value when the load power exceeds a specified upper limit value, thereby implementing power limitation.

[0012] In the present invention, as a second solution means of the motor control device, in the first solution means, the electric power limiter increases the rotation command value when the load electric power is lower than a predetermined lower limit value.

[0013] In the present invention, as a third solution for the motor control device, the following means is adopted: in the first solution, the power limiting unit releases the power limitation when the load power is lower than a specified release value, a higher-level command rotation number lower than the current command rotation number is specified, and the load power is lower than the release value.

[0014] In the present invention, as a fourth solution means of the motor control device, there is adopted the following means: in any one of the first to third solutions means, the voltage detection unit detects a power supply voltage supplied to the drive circuit as the load voltage.

[0015] In the present invention, as a solution to the motor control method, the following means are adopted: a motor control method, which controls the motor by supplying a drive signal generated by a drive circuit based on a rotation command value to the motor, the motor control method comprising: a load power detection process, which detects the load power of the drive circuit based on the load voltage and load current of the drive circuit; and a rotation command value correction process, which reduces the rotation command value when the load power exceeds a specified upper limit value, thereby implementing power limitation.

[0016] [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a motor control device and a motor control method capable of limiting the power of a drive circuit with further high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a block diagram showing the configuration of a motor control device A according to one embodiment of the present invention.

[0019] Figure 2This is a flowchart showing a motor control method according to one embodiment of the present invention.

[0020] Figure 3 (a) and Figure 3 (b) is a timing chart showing a motor control method according to an embodiment of the present invention.

[0021] [Explanation of Symbols]

[0022] A: Motor control device

[0023] B: Battery

[0024] F: Fuse

[0025] M: Motor

[0026] J: Host control unit (ECU)

[0027] 1: Microcomputer

[0028] 1a: Control instruction generation unit

[0029] 1b: Power Limitation Unit

[0030] 2: Motor control IC

[0031] 2a: Voltage detection unit

[0032] 2b: Current detection unit

[0033] 2c: Control signal generation unit

[0034] 3: Motor drive circuit

[0035] 4: Power circuit

[0036] 5: Low voltage power supply circuit DETAILED DESCRIPTION

[0037] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0038] like Figure 1 As shown, the motor control device A of the present embodiment includes a microcomputer 1, a motor control integrated circuit (IC) 2, a motor drive circuit 3, a power supply circuit 4, and a low-voltage power supply circuit 5 as functional components.

[0039] The motor control device A is a vehicle control device mounted on a vehicle and operates based on battery power supplied from a battery B also mounted on the vehicle. As shown in the figure, the battery power as the output power of the battery B is supplied to the motor control device A via a fuse F.

[0040] The motor control device A is a vehicle-mounted motor control device that controls the motor M under the control of a higher-level control device J (electronic control unit (ECU)) mounted on the vehicle. The higher-level control device J controls the motor control device A, which is a component of the vehicle, together with other components by outputting a higher-level control command value to the motor control device A. The higher-level control command value is, for example, a higher-level command rotation number R0 indicating a rotation target value of the motor M.

[0041] As shown in the figure, the microcomputer 1 includes a control command generation unit 1a and a power limiter 1b as functional components. The microcomputer 1 includes a storage unit, a calculation unit, and an input / output unit as hardware components.

[0042] The microcomputer 1 generates an instruction rotation number Ra (rotation instruction value) corresponding to the upper instruction rotation number R0 (upper control instruction value) received by the input and output part from the upper control device J (ECU) by using the operation part to execute the motor control program pre-stored in the storage part, and outputs the instruction rotation number Ra to the motor control IC2 via the input and output part.

[0043] The control command generating unit 1a is a functional component that assumes the main function of the microcomputer 1, that is, the function of generating the command rotation number Ra (rotation command value). That is, the control command generating unit 1a takes the upper command rotation number R0 as the main input signal, generates the command rotation number Ra corresponding to the upper command rotation number R0, and outputs it to the motor control IC 2.

[0044] In addition, when a power limiting signal is input from the power limiting unit 1b, the control command generating unit 1a corrects the command rotation number Ra according to the content of the power limiting signal (power limiting content). The power limiting content includes: a) reducing the load power of the motor drive circuit 3 by reducing the command rotation number Ra, b) increasing the load power of the motor drive circuit 3 by increasing the command rotation number Ra, c) maintaining the load power of the motor drive circuit 3 at the current value by maintaining the command rotation number Ra at the current value, etc.

[0045] The power limiting unit 1b is a functional component that assumes a secondary function of the microcomputer 1, that is, a function of limiting power consumption in the motor drive circuit 3, relative to the control command generating unit 1a. That is, the power limiting unit 1b reduces or increases the rotation command value of the control command generating unit 1a based on the load voltage and load current of the motor drive circuit 3 input from the motor drive circuit 3 via the motor control IC 2.

[0046] As will be described in detail later, the power limiting unit 1b calculates the load power Wa of the motor drive circuit 3 as the drive load based on the load voltage and load current of the motor drive circuit 3. The power limiting unit 1b generates the power limit signal by comparing the load power Wa (drive load) with power limit thresholds such as the upper limit value WH, the release value WK, and the lower limit value WL.

[0047] In addition, the power limiting unit 1b outputs the power limiting signal to the control command generating unit 1a to correct the command rotation number Ra. By correcting the command rotation number Ra based on the power limiting signal, the load power of the motor drive circuit 3 functioning as a power conversion circuit changes as a result. That is, this power limiting unit 1b is the main body of the power limiting control of the motor drive circuit 3 executed by the microcomputer 1 as a secondary function.

[0048] As shown in the figure, the motor control IC 2 includes a voltage detection unit 2a, a current detection unit 2b, and a control signal generation unit 2c as functional components. The motor control IC 2 is an integrated circuit (IC) including a plurality of input terminals and a plurality of output terminals as hardware components.

[0049] In this motor control IC 2, the input end of the voltage detection unit 2a is connected to the power supply terminal of the motor drive circuit 3, and the power supply voltage of the motor drive circuit 3 is detected as the load voltage when generating the drive signal. The voltage detection unit 2a outputs this load voltage (power supply voltage) to the power limiting unit 1b of the microcomputer 1.

[0050] A pair of input terminals of the current detection unit 2b are respectively connected to both ends of a shunt resistor provided in the motor drive circuit 3. That is, one input terminal of the current detection unit 2b is connected to one end of the shunt resistor, and the other input terminal is connected to the other end of the shunt resistor.

[0051] Such a current detection unit 2b detects the current supplied to the motor drive circuit 3 via the motor M, that is, the drive current flowing in the motor drive circuit 3 and the motor M based on the drive signal generated by the motor drive circuit 3 in the motor M, as the load current of the motor drive circuit 3. The current detection unit 2b outputs the load current of the motor drive circuit 3 to the power limiting unit 1b of the microcomputer 1.

[0052] The control signal generating unit 2c is a functional component that performs the main function of the motor control IC 2, namely, the function of generating a drive control signal. The control signal generating unit 2c generates a drive control signal based on the rotation command value input from the control command generating unit 1a of the microcomputer 1 and the waveform of the drive signal input from the motor drive circuit 3. The control signal generating unit 2c outputs the drive control signal to the motor drive circuit 3.

[0053] The motor drive circuit 3 is a drive signal generating circuit that generates a drive signal supplied to the motor M based on a drive control signal input from the motor control IC 2. The motor drive circuit 3 is a power conversion circuit that converts the power supply power (DC power) supplied from the power supply circuit 4 into a drive signal (AC power) based on the drive control signal.

[0054] Such a motor drive circuit 3 is typically a three-phase inverter circuit. That is, the motor drive circuit 3 includes a U-phase switching leg, a V-phase switching leg, and a W-phase switching leg connected in parallel with the power supply circuit 4. The U-phase switching leg, the V-phase switching leg, and the W-phase switching leg include a switching transistor for an upper arm and a switching transistor for a lower arm, respectively.

[0055] That is, the U-phase switch bridge arm, the V-phase switch bridge arm and the W-phase switch bridge arm are switch circuits formed by connecting the upper arm switch transistor and the lower arm switch transistor in series. In addition, the motor drive circuit 3 includes a shunt resistor connected in series with the U-phase switch bridge arm, the V-phase switch bridge arm and the W-phase switch bridge arm.

[0056] In addition, when the motor drive circuit 3 is configured as a three-phase inverter circuit, the drive control signal is typically a pulse width modulation (PWM) signal. That is, it is a pulse signal for the control signal generating unit 2c of the motor control IC 2 to turn on / off the three upper arm switching transistors and the three lower arm switching transistors in the U-phase switching bridge arm, the V-phase switching bridge arm, and the W-phase switching bridge arm.

[0057] In the power circuit 4, the input end is connected to the other end of the fuse F, and the battery power supplied from the battery B via the fuse F is transformed. In the power circuit 4, the output end is connected to the power terminal of the motor control IC 2 and the input terminal of the motor drive circuit 3, and the power supply power after the battery power is transformed is supplied to the motor control IC 2 and the motor drive circuit 3.

[0058] The input end of the low-voltage power supply circuit 5 is connected to the output end of the power supply circuit 4, and the power supply power input from the power supply circuit 4 is low-voltage converted to a voltage that meets the specifications of the microcomputer 1. The output end of the low-voltage power supply circuit 5 is connected to the power supply terminal of the microcomputer 1, and the low-voltage power after the power supply power is low-voltage is supplied to the microcomputer 1.

[0059] Next, refer to Figure 2 as well as Figure 3 (a) and Figure 3(b) describes in detail the main part operation of the motor control device A of this embodiment, that is, the motor control method of this embodiment.

[0060] In addition, before explaining the main part operation of the motor control device A, the main operation of the motor control device A is explained. In the motor control device A, the upper command rotation number R0 (upper control command value) corresponding to the state of the vehicle is sequentially input from the upper control device J. In the motor control device A, the control command generation unit 1a of the microcomputer 1 generates the command rotation number Ra (rotation command value) corresponding to the upper command rotation number R0 and outputs it to the control signal generation unit 2c of the motor control IC 2.

[0061] Then, the control signal generating unit 2c of the motor control IC 2 generates a drive control signal based on the command rotation number Ra input from the control command generating unit 1a, and outputs the drive control signal to the motor drive circuit 3. Then, the motor drive circuit 3 generates a drive signal based on the drive control signal input from the control signal generating unit 2c, and supplies the drive signal to the motor M. As a result, the motor M rotates at a rotation number corresponding to the upper command rotation number R0 input from the upper control device J to the motor control device A.

[0062] In the main operation of such motor control device A, when the motor drive circuit 3 falls into an overload state due to generating a drive signal based on the upper command rotation number R0, there is a concern that it may be damaged by abnormal heat, or may fail to generate a drive signal depending on the situation.

[0063] The main part of the operation of the motor control device A is based on the power limiting unit 1b of the microcomputer 1 and the voltage detection unit 2a and current detection unit 2b of the motor control IC 2. The load power (driving load) of the motor drive circuit 3 is detected based on the load voltage detected by the voltage detection unit 2a and the load current detected by the current detection unit 2b, and the command rotation number Ra is corrected to at least reduce it based on the comparison result between the load power (driving load) and the specified control threshold.

[0064] In this main part action, such as Figure 2 As shown, the power limiting unit 1b of the microcomputer 1 first detects the load power Wa (driving load) based on the load voltage input from the voltage detection unit 2a and the load current input from the current detection unit 2b (step S1). That is, the power limiting unit 1b calculates the load power Wa of the motor drive circuit 3 by multiplying the load voltage and the load current. In addition, the step S1 is equivalent to the load power detection process in the present invention.

[0065] Then, the power limiting unit 1b determines whether the motor drive circuit 3 is already in a power limiting state (step S2). The power limiting unit 1b includes, for example, a storage area for storing a plurality of control variables (flags) indicating past power limiting states, and determines whether the current state is power limiting by referring to a control variable (first flag) indicating implementation / non-implementation of power limiting among the plurality of control variables stored in the storage area.

[0066] Furthermore, when the result of the judgment in step S2 is "Yes", that is, when the power is limited, the power limiting unit 1b judges whether the upper command rotation number R0 is different from the command rotation number Ra (step S3). When the result of the judgment in step S3 is "Yes", the power limiting unit 1b judges whether the upper command rotation number R0 is greater than the command rotation number Rb during the power limitation (step S4).

[0067] Furthermore, when the result of the judgment in step S4 is "Yes", the power limiting unit 1b judges whether the load power Wa is greater than the upper limit value WH in the power limiting threshold value (step S5). Then, when the result of the judgment in step S5 is "Yes", the power limiting unit 1b outputs a power limiting signal indicating the rotation reduction process to the control command generating unit 1a (step S6). Step S6 is equivalent to the rotation command value correction process in the present invention.

[0068] The rotation reduction processing is a processing to overcome the upper command rotation number R0 and correct the command rotation number Rb in the power limitation to a rotation number lower than the upper command rotation number R0. That is, when the power limitation using the power limitation unit 1b is not implemented, the control instruction generation unit 1a generates a command rotation number Ra equal to the command rotation number R0, but when the power limitation signal indicating the rotation reduction processing is input from the power limitation unit 1b, the command rotation number Rb in the power limitation is corrected to a corrected command rotation number Rc indicating a rotation number lower than the upper command rotation number R0.

[0069] As a result, the control signal generating unit 2c of the motor control IC 2 generates a correction drive control signal based on the correction command rotation number Rc and outputs it to the motor drive circuit 3. Furthermore, the motor drive circuit 3 generates a correction drive signal based on the correction drive control signal and supplies it to the motor M. Since the correction drive signal reduces the rotation number of the motor M, the load power of the motor drive circuit 3 is reduced, and the rotation number of the motor M is reduced.

[0070] When the rotation reduction process is completed, the power limiting unit 1b stores the implementation state of the power limitation on the motor drive circuit 3 in the storage area (step S7). That is, the power limiting unit 1b stores in the storage area the state that the power limitation of the motor drive circuit 3 is being implemented and the state that the motor drive circuit 3 is controlled based on the corrected command rotation number Rc.

[0071] In addition, when the judgment result of step S5 is "No", the power limiting unit 1b judges whether the load power Wa is less than the lower limit value WL in the power limit threshold value (step S8). Then, when the judgment result of step S8 is "Yes", the power limiting unit 1b outputs a power limit signal indicating the rotation increase process to the control command generating unit 1a (step S9). Step S9 is equivalent to the rotation command value correction process in the present invention.

[0072] The rotation increase process is a process of correcting the command rotation number Rb in the power limit to a rotation number higher than the current value. That is, when the load power Wa is less than the lower limit value WL, when the power limit signal indicating the rotation increase process is input from the power limiter 1b, the control command generator 1a corrects the command rotation number Rb in the power limit to a corrected command rotation number Rd indicating a rotation number higher than the current value.

[0073] As a result, the control signal generating unit 2c of the motor control IC 2 generates a correction drive control signal based on the correction command rotation number Rd and outputs it to the motor drive circuit 3. Furthermore, the motor drive circuit 3 generates a correction drive signal based on the correction drive control signal and supplies it to the motor M. The correction drive signal increases the rotation number of the motor M, so the load power of the motor drive circuit 3 increases, and the rotation number of the motor M increases.

[0074] When the rotation increase process is completed, the power limiting unit 1b stores the implementation state of the power limitation on the motor drive circuit 3 in the storage area (step S10). That is, the power limiting unit 1b stores in the storage area the state that the power limitation of the motor drive circuit 3 is being implemented and the state that the motor drive circuit 3 is controlled based on the corrected command rotation number Rd.

[0075] In addition, when the result of the judgment of step S8 is "No", the power limiting unit 1b outputs a power limiting signal indicating the rotation maintenance process to the control command generating unit 1a (step S11). The rotation maintenance process is a process of maintaining the command rotation number Rb in the power limitation at the current value. That is, when the power limiting signal indicating the rotation maintenance process is input from the power limiting unit 1b, the control command generating unit 1a maintains the command rotation number Rb in the power limitation at the current value.

[0076] As a result, the control signal generating unit 2c generates a drive control signal based on the command rotation number Rb in the power limitation and outputs it to the motor drive circuit 3. Furthermore, the motor drive circuit 3 generates a drive signal based on the drive control signal and supplies it to the motor M. As a result, the load power of the motor drive circuit 3 is maintained at the current value, and the rotation number of the motor M is maintained at the current value.

[0077] When the rotation maintaining process is completed, the power limiting unit 1b stores the implementation state of the power limitation on the motor drive circuit 3 in the storage area (step S12). That is, the power limiting unit 1b stores in the storage area the state that the power limitation of the motor drive circuit 3 is being implemented and the state that the motor drive circuit 3 is controlled based on the command rotation number Rb.

[0078] In addition, when the judgment result of step S4 is "No", that is, when the upper command rotation number R0 is less than the command rotation number Rb in the power limitation, the power limiting unit 1b performs the substitution process of the upper command rotation number R0 into the command rotation number Rb (step S13). As a result, the control signal generating unit 2c generates a drive control signal based on the command rotation number Rb in the power limitation (=the upper command rotation number R0) and outputs it to the motor driving circuit 3.

[0079] The motor drive circuit 3 generates a drive signal based on the drive control signal and supplies it to the motor M. As a result, the load power of the motor drive circuit 3 is set based on the upper command speed R0, and the speed of the motor M is set based on the upper command speed R0.

[0080] Then, the power limiting unit 1b stores the implementation state of the power limitation on the motor drive circuit 3 in the storage area (step S14). That is, the power limiting unit 1b stores in the storage area the state that the power limitation on the motor drive circuit 3 is being implemented and the state that the motor drive circuit 3 is controlled based on the upper command rotation number R0.

[0081] Furthermore, when the judgment result of step S3 is "No", that is, when the upper command rotation number R0 is equal to the command rotation number Rb in the power limitation, the power limiting unit 1b judges whether the load power Wa is greater than the release value WK in the power limitation threshold (step S15). Then, when the judgment result of step S15 is "Yes", the power limiting unit 1b outputs the power limitation signal indicating the rotation reduction process to the control instruction generating unit 1a (step S16). Step S16 is equivalent to the rotation command value correction process in the present invention.

[0082] The rotation reduction process is the same as step S6. As a result of the rotation reduction process, the command rotation number Rb in the power limit is corrected to the corrected command rotation number Rc, so the control signal generating unit 2c of the motor control IC 2 generates a corrected drive control signal based on the corrected command rotation number Rc and outputs it to the motor drive circuit 3.

[0083] Then, the motor drive circuit 3 generates a correction drive signal based on the correction drive control signal and supplies the correction drive signal to the motor M. Since the correction drive signal reduces the rotation speed of the motor M, the load power of the motor drive circuit 3 is reduced, and the rotation speed of the motor M is reduced.

[0084] When the rotation reduction process of step S16 is completed, the power limiting unit 1b stores the implementation state of the power limitation on the motor drive circuit 3 in the storage area (step S17). That is, the power limiting unit 1b stores in the storage area the state that the power limitation of the motor drive circuit 3 is being implemented and the state that the motor drive circuit 3 is controlled based on the corrected command rotation number Rc.

[0085] In addition, when the judgment result of step S15 is "No", that is, when the load power Wa is less than the release value WK, the power limiting unit 1b outputs a power limiting signal indicating the end of the power limitation on the motor drive circuit 3 to the control command generating unit 1a (step S18). As a result, the motor drive circuit 3 generates a drive signal based on the upper command rotation number R0 and supplies it to the motor M. In addition, the motor M rotates at the rotation number based on the upper command rotation number R0.

[0086] Then, when the processing of step S18 is completed, the power limiting unit 1b stores the implementation state of the power limitation on the motor drive circuit 3 in the storage area (step S19). That is, the power limiting unit 1b stores the state that the power limitation on the motor drive circuit 3 is completed and the state that the motor drive circuit 3 is controlled based on the upper command rotation number R0 in the storage area.

[0087] Furthermore, when the result of the judgment in step S2 is "No", that is, when the motor drive circuit 3 is not in power limitation, the power limiting unit 1b judges whether the load power Wa is greater than the upper limit value WH (step S20). And, when the result of the judgment in step S20 is "Yes", the power limiting unit 1b sets the command rotation number Rb when the power limitation starts to a predetermined value (step S21).

[0088] Then, the power limiting unit 1b starts to limit the power of the motor drive circuit 3 by outputting a power limiting signal indicating the command rotation number Rb to the control command generating unit 1a (step S22). Then, the control command generating unit 1a outputs the command rotation number Rb to the control signal generating unit 2c of the motor control IC 2. The control signal generating unit 2c generates a drive control signal based on the command rotation number Rb and outputs it to the motor drive circuit 3.

[0089] As a result, the motor drive circuit 3 generates a drive signal based on the drive control signal corresponding to the command rotation number Rb and supplies it to the motor M. That is, the motor drive circuit 3 is in a state where the load power is limited by the command rotation number Rb. Then, the motor M rotates at the rotation number based on the drive signal corresponding to the command rotation number Rb.

[0090] When the power restriction start process of step S22 is completed, the power restriction unit 1b saves the implementation state of the power restriction on the motor drive circuit 3 in the storage area (step S23). That is, the power restriction unit 1b stores the situation that the power restriction of the motor drive circuit 3 is being implemented and the situation that the motor drive circuit 3 is controlled based on the command rotation number Rb in the storage area. In addition, when the judgment result of step S20 is "No", the power restriction unit 1b ends the overall process as shown in the figure.

[0091] Figure 3 (a) and Figure 3 (b) is a timing diagram based on this motor control method. In the timing diagram, the waveform in the uppermost section represents the time series change of the load power Wa. In addition, the second waveform from the top represents the time series change of the upper command rotation number R0, and the third waveform from the top represents the time series change of the command rotation number R. Furthermore, the waveform in the lowermost section represents the implementation (ON) / non-implementation (OFF) of the power limitation of the motor drive circuit 3.

[0092] like Figure 3 As shown in the timing chart of (a), when the load power Wa exceeds the upper limit value WH, the power limitation is implemented (ON), thereby reducing the command speed R. Due to the reduction in the command speed R, the load power Wa decreases and becomes lower than the upper limit value WH.

[0093] Furthermore, the power restriction is released when a higher-level command rotation number R0 lower than the current command rotation number R is specified by the upper-level control device J and the load power Wa is lower than the release value WK. That is, when the above two conditions are met, the power restriction is switched from implementation (ON) to non-implementation (OFF). In addition, the power restriction is released after the command rotation number R is updated to the higher-level command rotation number R0.

[0094] Here, even if the load power Wa decreases and falls below the upper limit WH due to the decrease in the command rotation number R, the power restriction does not switch quickly from being implemented (ON) to not being implemented (OFF). That is, when the power restriction starts to be implemented (ON), the power restriction continues to be implemented (ON) even if the load power Wa falls below the upper limit WH.

[0095] Furthermore, the implementation (ON) of the power limitation is switched to not implemented (OFF) when the upper control device J specifies a higher-level command speed R0 lower than the current command speed R, except when the load power Wa is lower than the release value WK.

[0096] In addition, if Figure 3 As shown in the timing chart of (b), when the power limitation is implemented (ON), when the load power Wa is lower than the lower limit WL, the command speed Ra (rotation command value) is increased until the load power Wa reaches a value exceeding the lower limit WL.

[0097] The motor control device A of the present embodiment controls the motor M by supplying a drive signal generated by the motor drive circuit 3 (drive circuit) based on the command rotation number Ra (rotation command value) to the motor M, and the motor control device A includes: a voltage detection unit 2a, which detects the voltage of the drive signal as a load voltage; a current detection unit 2b, which detects the current of the drive signal as a load current; and a power limiting unit 1b, which detects the load power Wa of the motor drive circuit 3 (drive circuit) based on the load voltage and the load current, and reduces the command rotation number Ra (rotation command value) when the load power Wa exceeds a specified upper limit value WH, thereby implementing power limitation.

[0098] The motor control method of the present embodiment controls the motor M by supplying a drive signal generated by the motor drive circuit 3 (drive circuit) based on the command rotation number Ra (rotation command value) to the motor M. The motor control method comprises: a load power detection process, in which the load power Wa of the motor drive circuit 3 (drive circuit) is detected based on the load voltage and load current of the motor drive circuit 3 (drive circuit); and a rotation command value correction process, in which the command rotation number Ra (rotation command value) is reduced when the load power Wa exceeds a prescribed upper limit value WH.

[0099] According to this embodiment, a motor control device A and a motor control method can be provided, which include a voltage detection unit 2a, a current detection unit 2b and a power limiting unit 1b, and operate the command rotation number Ra (rotation command value) based on the load power Wa, thereby being able to further accurately limit the power of the motor drive circuit 3 (drive circuit).

[0100] In addition, in the motor control device A of the present embodiment, the power limiting unit 1b increases the command rotation number Ra (rotation command value) when the load power Wa is lower than the specified release value WK and lower than the lower limit value WL, thereby being able to accurately implement power limitation of the motor drive circuit 3 (drive circuit) and rotate the motor M in a state close to a state without power limitation.

[0101] In addition, the present invention is not limited to the above-described embodiment, and for example, the following modified examples are conceivable.

[0102] (1) In the above embodiment, the present invention is applied to the control of the motor M mounted on the vehicle, but the present invention is not limited thereto. The present invention can be applied to the control of motors for various purposes.

[0103] (2) In the above embodiment, when the load power Wa is lower than the predetermined release value WK and lower than the lower limit value WL, the command speed Ra (rotation command value) is increased, but the present invention is not limited to this. For example, the release value WK may not be set, and the command speed Ra (rotation command value) may be increased when the load power Wa is lower than the lower limit value WL.

[0104] (3) The rotation increase process (step S9) of increasing the command rotation number Ra (rotation command value) when the load power Wa is lower than the lower limit value WL is not essential and can be omitted as necessary.

[0105] (4) In the above embodiment, the power supply voltage supplied to the motor drive circuit 3 (drive circuit) when the motor drive circuit 3 (drive circuit) is configured as a three-phase inverter circuit is detected as the load voltage, but the present invention is not limited to this. That is, the load voltage in the present invention is not limited to the power supply voltage.

Claims

1. A motor control device for controlling a motor by supplying a drive signal generated by a drive circuit based on a rotation command value to the motor, the motor control device comprising: a voltage detection unit, detecting the voltage of the drive signal as a load voltage; a current detection unit, detecting the current of the drive signal as a load current; as well as The power limiting unit detects load power of the drive circuit based on the load voltage and the load current, and reduces the rotation command value when the load power exceeds a predetermined upper limit value, thereby implementing power limitation.

2. The motor control device according to claim 1, characterized in that: The electric power limiting unit increases the rotation command value when the load electric power is lower than a predetermined lower limit value.

3. The motor control device according to claim 1, characterized in that: The power restriction unit cancels the power restriction when the load power is lower than a predetermined cancellation value and specifies a higher command speed lower than the current command speed, and when the load power is lower than the cancellation value.

4. The motor control device according to claim 1 or 2, characterized in that: The voltage detection unit detects a power supply voltage supplied to the drive circuit as the load voltage.

5. A motor control method, comprising: supplying a drive signal generated by a drive circuit based on a rotation command value to the motor to control the motor, wherein: a load power detection step of detecting the load power of the drive circuit based on the load voltage and load current of the drive circuit; and The rotation command value correction step reduces the rotation command value when the load power exceeds a predetermined upper limit value, thereby implementing power limitation.

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