Electric motor control method and electric motor control system

Abstract

To provide an electric motor control method and an electric motor control system that can suppress the temperature change of the smoothing capacitor while maintaining the electric motor in the desired operating state.SOLUTION: In an electric motor control method for controlling the operation of a generator and an electric motor, which is executed in an electric motor control system having a generator, a capacitive element that temporarily stores the generated power output by the generator, and an electric motor driven by the generated power, when the temperature of the capacitive element is above a predetermined threshold value, the temperature suppression control is executed to suppress a rise in temperature of the capacitive element by reducing the current of the generator.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Patent Document 1 proposes an electric motor control system that detects the temperature of a smoothing capacitor provided on the input side of an inverter that drives an electric motor, and adjusts the control gain of feedback control of the inverter based on the detected temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-354763 A Summary of the Invention [Problem to be solved by the invention]

[0004] The motor control system of Patent Document 1 aims to achieve stable feedback control by adjusting the control gain according to the temperature of the smoothing capacitor. However, the motor control system of Patent Document 1 does not suppress the temperature change (particularly the temperature rise) of the smoothing capacitor itself. Therefore, depending on the mode of the temperature rise of the smoothing capacitor, the range of change in the control gain may become large, which may impair the control stability of the operation of the motor.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a motor control method and a motor control system that are capable of suppressing temperature changes in a smoothing capacitor while maintaining the motor in a desired operating state. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a motor control method that is executed in a motor control system including a generator, a capacitive element that temporarily stores the generated power output by the generator, and a motor driven by the generated power, and that controls the operation of the generator and the motor.

[0007] When the temperature of the capacitance element is equal to or higher than a predetermined threshold, a temperature suppression control is executed to suppress an increase in the temperature of the capacitance element by reducing a current of the generator. Electric motor control method.

[0008] In this motor control method, when the temperature of the capacitance element is equal to or higher than a predetermined threshold value, a temperature suppression control is executed to suppress an increase in the temperature of the capacitance element by reducing the current of the generator. The motor control system further includes a first motor that functions as a motor, and a second motor different from the first motor. The temperature suppression control includes a first suppression process that reduces the current of the generator while maintaining the generated power, a suppression region determination process that determines whether the state of the motor control system is in a temperature suppression region where a certain degree of effect of suppressing the increase in the temperature of the capacitive element can be obtained, and a second suppression process that reduces the output of the first motor and increases the output of the second motor while maintaining the sum of the output of the first motor and the output of the second motor when it is determined that the state of the motor control system is in the temperature suppression region. In particular, in the suppression region determination process, when a combined change in loss, which is a change in loss of the capacitive element caused by a change in the output of the first motor and a change in loss of the capacitive element caused by a change in the combined output of the generator and the first motor, is in a decreasing direction, it is determined that the state of the motor control system is in the temperature suppression region. Effect of the Invention

[0009] According to the present invention, it is possible to suppress temperature changes in a smoothing capacitor while maintaining the motor in a desired operating state. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an electric motor control system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart illustrating the temperature suppression control. [Diagram 3] FIG. 3 is a map showing the relationship between the operating points of the engine and the generator and the generated current. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings.

[0012] 1 is a diagram illustrating the configuration of an electric motor control system 100 in which an electric motor control method according to the present embodiment is executed. It is assumed that the electric motor control system 100 according to the present embodiment is mounted on an electric vehicle or a hybrid vehicle, particularly a 4WD hybrid vehicle (hereinafter simply referred to as a "vehicle").

[0013] The motor control system 100 includes a drive motor 10 (particularly, a front motor 10fr and a rear motor 10rr), a battery 12, an inverter 14 (particularly, a front inverter 14fr and a rear inverter 14rr), a generator 16 as a power generator, an engine 18 as a drive device, and a controller 20.

[0014] The drive motor 10 is made up of a front motor 10fr provided at the front of the vehicle (on the front wheel side) for driving the front wheels, and a rear motor 10rr provided at the rear (on the rear wheel side) for driving the rear wheels.

[0015] The front motor 10fr is configured as a three-phase AC motor. The front motor 10fr applies driving force to the front wheels by receiving power from the battery 12. The front motor 10fr also converts regenerative driving force obtained from the front wheels while the vehicle is running into AC power.

[0016] Meanwhile, the rear motor 10rr is configured as a three-phase AC motor. The rear motor 10rr applies driving force to the rear wheels by receiving power from the battery 12. The rear motor 10rr also converts regenerative driving force obtained from the rear wheels while the vehicle is running into AC power.

[0017] The battery 12 is an on-board DC power supply composed of a lithium ion secondary battery or the like. The battery 12 is charged with power generated by a generator 16, and is configured to be able to supply power to the drive motor 10 or receive regenerative power from the drive motor 10.

[0018] The inverter 14 adjusts the input and output power of each of the elements: the drive motor 10, the battery 12, and the generator 16. In particular, the inverter 14 is made up of a front inverter 14fr and a rear inverter 14rr.

[0019] The front inverter 14fr has a smoothing capacitor 30 as a capacitance element that temporarily stores the generated power output by the generator 16, a front motor power converter 32 that adjusts the power supplied from the battery 12 to the front motor 10fr (i.e., the output of the front motor 10fr), and a generator power converter 34 that adjusts the power supplied from the generator 16 to the battery 12 (i.e., the generated power). The front motor power converter 32 and the generator power converter 34 are connected in parallel to the smoothing capacitor 30.

[0020] The smoothing capacitor 30 functions as a common capacitance element for the front motor power converter 32 and the generator power converter 34. The smoothing capacitor 30 also has a temperature sensor (hereinafter, “capacitor temperature T c A temperature sensor 36 is provided to detect a temperature (also referred to as a temperature sensor).

[0021] The front motor power converter 32 is mainly composed of a switching circuit made up of semiconductor elements such as IGBTs, and a switching control device (not shown) for driving the switching circuit. Note that this switching control device controls the output torque command value (hereinafter, "front motor torque T fr_m In particular, the front motor power converter 32 generates a PWM signal for driving (switching) the switching circuit based on the front motor torque T fr_m In the following description, for the sake of convenience, a current equivalent to the DC power from the battery 12 is referred to as a "front motor DC current I dc_fmThe three-phase AC current equivalent to the three-phase AC power supplied to the front motor 10fr is called the "front motor current I ac_fm In particular, the front motor power converter 32 is configured to convert the actual output torque of the front motor 10fr into the front motor torque T fr_m The front motor current I ac_fm Operate.

[0022] The generator power converter 34 is mainly composed of a switching circuit made up of semiconductor elements such as IGBTs, and a switching control device (not shown) for driving the switching circuit. The switching control device controls the rotation speed command value (hereinafter referred to as the "generator rotation speed N fr_g In particular, the generator power converter 34 generates a PWM signal for driving (switching) the switching circuit based on the generator rotation speed N fr_g In the following, for the sake of convenience, the current equivalent to this DC generated power is referred to as the "generated current I dc_fg The current equivalent to the three-phase AC power output by the generator 16 is referred to as the generator current I ac_fg " It is called.

[0023] In particular, the generator power converter 34 controls the generator rotation speed N based on a predetermined rotation speed control logic using the actual rotation speed N of the generator 16 detected by a sensor (not shown) as feedback. fr_g From the above, the appropriate output torque of the generator 16 (hereinafter referred to as the "generator torque T fr_g More specifically, the generator power converter 34 calculates the generator torque T fr_g Calculate the following.

[0024]

number

[0025] The generator power converter 34 converts the actual output torque of the generator 16 into the calculated generator torque T fr_g The generator current I ac_fg Adjust.

[0026] For the sake of convenience, in the following description, the total power supplied from the battery 12 to the front inverter 14fr, that is, the DC power from the battery 12 to the front motor power converter 32 (front motor DC current I dc_fm The power obtained by combining the power generated by the generator 16 and the power generated by the generator 16 is also referred to simply as the "composite power." The DC current equivalent to this composite power is also referred to as the "composite current I dc_f " is also called.

[0027] On the other hand, the rear inverter 14rr has a smoothing capacitor 40 as a power storage element arranged on the input side of the battery 12, and a rear motor power converter 42 that adjusts the power supplied from the battery 12 to the rear motor 10rr (i.e., the output of the rear motor 10rr).

[0028] The rear motor power converter 42 is configured with a switching circuit made up of multiple semiconductor elements such as IGBTs, and a switching control device (not shown) for driving the switching circuit. Note that this switching control device controls the output torque command value (hereinafter referred to as "rear motor torque T rr_m In particular, the rear motor power converter 42 generates a PWM signal for driving (switching) the switching circuit based on the rear motor torque T rr_m The DC power from the battery 12 is adjusted so that three-phase AC power based on the above is supplied to the rear motor 10rr. For ease of explanation, the current equivalent to this DC power will be referred to as the "rear motor DC current I dc_rm The three-phase AC current equivalent to the three-phase AC power supplied to the rear motor 10rr is called the rear motor current I ac_rm In particular, the rear motor power converter 42 is configured to convert the actual output torque of the rear motor 10rr into the rear motor torque T rr_m The rear motor current I ac_rm Operate.

[0029] The controller 20 controls the operations of the front motor 10fr, the rear motor 10rr, the generator 16, and the engine 18 via the front inverter 14fr and the rear inverter 14rr, based on various input information.

[0030] The generator 16 is a generator that receives the driving force of the engine 18 to generate electric power for driving the front motor 10fr and the rear motor 10rr, and supplies the generated electric power to the battery 12. The generator 16 may be configured to receive electric power from the battery 12 depending on the situation, and perform a powering operation to drive the engine 18. This makes it possible to use the generator 16 to perform cranking (motoring), for example, when starting the engine 18.

[0031] The engine 18 is connected to the generator 16 via mechanical elements such as gears (not shown), and transmits power for generating electricity to the generator 16. In other words, the engine 18 is used as a drive source for generating electricity using the generator 16. In particular, the engine 18 is driven by an engine torque T eng It operates at an operating point according to.

[0032] The controller 20 is composed of a computer equipped with a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface), and is programmed to execute each process described below. In particular, when the motor control system 100 of this embodiment is mounted on a vehicle, the functions of the controller 20 can be realized by any on-board computer such as a vehicle controller (VCM: Vehicle Control Module) and a motor controller, and / or a computer installed outside the vehicle. The controller 20 may be realized by a single piece of computer hardware, or may be realized by distributing various processes among multiple pieces of computer hardware.

[0033] The controller 20 operates the front inverter 14fr, the rear inverter 14rr, the generator 16, and the engine 18 based on various input information.

[0034] In particular, the controller 20 distributes the total output required by the electric motor control system 100 (for example, the total driving force required for the vehicle according to the accelerator pedal operation amount) to the front motor 10fr and the rear motor 10rr according to a predetermined distribution ratio κ. More specifically, the controller 20 calculates the above-mentioned front motor torque T fr_m and rear motor torque T rr_m Then, the controller 20 determines the determined front motor torque T fr_m and rear motor torque T rr_mare output to the front inverter 14fr (particularly the front motor power converter 32) and the rear inverter 14rr (the rear motor power converter 42), respectively.

[0035] The controller 20 also calculates the required power generation (engine torque T eng ), and the capacitor temperature T c Based on the generator 16 operating point (generator speed N fr_g In particular, the controller 20 of the present embodiment determines the capacitor temperature T c Under the given conditions, the generator rotation speed N fr_g The basic generator speed N fr_g0 and the capacitor temperature T c The corrected rotation speed command value N is determined from the viewpoint of suppressing the increase of fr_g1 Set it to either

[0036] Furthermore, the controller 20 calculates the required power generation and the condenser temperature T c Based on this, the operating point of the engine 18 (engine torque T eng In particular, the controller 20 of the present embodiment determines the capacitor temperature T c Under the given conditions, the engine torque T eng The basic engine torque T eng0 and the capacitor temperature T c The corrected engine torque T is determined from the viewpoint of suppressing the increase of eng1 Then, the controller 20 sets the obtained engine torque T eng In response to this, the controller 16 operates peripheral actuators (such as a throttle valve) of the engine 18 to control the operation of the engine 18.

[0037] In the present embodiment, the controller 20 detects the capacitor temperature T c The capacitor temperature T cIn the motor control system 100 of the present embodiment, the capacitor temperature T c is the front motor DC current I dc_fm , generator current I ac_fg , or the combined power (combined current I dc_f ) changes depending on the magnitude of the capacitor temperature T c When the generator current I ac_fg ) to reduce the capacitor temperature T c The temperature suppression control is described in detail below.

[0038] FIG. 2 is a flowchart illustrating the temperature suppression control. The controller 20 repeatedly executes each process shown in the flowchart of FIG. 2 at a predetermined calculation cycle. fr_g and engine torque T eng are the normal basic generator speeds N fr_g0 and basic engine torque T eng0 It is assumed that the setting is

[0039] As shown in the figure, in step S101, the controller 20 detects the capacitor temperature T c Here, the controller 20 determines whether the capacitor temperature T c is less than the reference value α, the generator rotation speed N fr_g and engine torque T eng and the basic generator speed N fr_g0 and basic engine torque T eng0 The routine ends while maintaining the capacitor temperature T c is equal to or greater than the reference value α, the process proceeds to step S102 and subsequent steps.

[0040] In step S102, the controller 20 executes the first suppression process. fr_g The basic generator speed N fr_g0 to corrected rotation speed command value N fr_g1 , engine torque T eng The basic engine torque T eng0 Corrected engine torque T eng1 Change to respectively.

[0041] FIG. 3 shows the operating points of the engine 18 and the generator 16 and the generator current I ac_fg In the figure, "g0" indicates the operating point before the change (hereinafter also referred to as "basic operating point g0"). Also, "g1" indicates the operating point after the change (hereinafter also referred to as "corrected operating point g1"). Furthermore, "C1" indicates the output of the engine 18 (=engine torque T eng ×Engine RPM N eng ) is constant (hereinafter, also referred to as the "engine output line C1"). Also, "C2" represents the output of the generator 16 (=generator torque T fr_g × Generator RPM N fr_g ) is constant (hereinafter, also referred to as the "generator output line C2"). Furthermore, "C3" represents the generator current I ac_fg (hereinafter, also referred to as "equal output current line C3").

[0042] As shown, in this embodiment, the controller 20 keeps the output of the generator 16 constant (along the generator output line C2) while increasing the generator rotation speed N fr_g The basic generator speed N fr_g0 to corrected rotation speed command value N fr_g1 Accordingly, the generator torque T fr_g The magnitude (absolute value) of decreases, and the generator current I ac_fgTherefore, in the process in which the operating point of the generator 16 transitions from the basic operating point g0 to the corrective operating point g1, the amount of heat generated by the smoothing capacitor 30 is reduced compared to when the basic operating point g0 is maintained, and the capacitor temperature T c It is possible to suppress the increase in

[0043] Furthermore, in this embodiment, the correction operation point g1 is set to the generator current I ac_fg More specifically, the controller 20 adjusts the operating point to a value where the output of the generator 16 and the generator rotation speed N fr_g , and the generator current I ac_fg The generator speed N obtained by applying the output value of the generator 16 at the base operating point g0 to the map showing the relationship between fr_g and the generator current I ac_fg From the above relationship, the generator current I ac_fg The generator speed N when takes the minimum value fr_g This is determined as the correction operation point g1. c In more detail, the effect of suppressing the increase in the generator torque T fr_g Despite the relatively small magnitude of the generator current I ac_fg Even in situations where the capacitor temperature T c It is possible to suppress the increase in

[0044] As described above, in the process in which the operating point transitions from the basic operating point g0 to the corrective operating point g1, the generator current I ac_fg Although the output of the generator 16 decreases, the output of the generator 16 is maintained constant. dc_fg ) is maintained, and the combined power in the front inverter 14fr can also be maintained. That is, the power supplied to the front motor 10fr (front motor DC current I dc_fm ,Front motor current Iac_fm ) to maintain its operation at the desired state, while the capacitor temperature T c It is possible to suppress the increase in

[0045] Returning to FIG. 2, the controller 20 judges whether the transition of the operating point to the corrected operating point g1 has been completed. Specifically, the controller 20 determines whether the generator rotation speed N fr_g and the actual rotation speed N is equal to or smaller than a predetermined difference threshold value β, the controller 20 determines that the transition to the correction operation point g1 is completed. That is, the controller 20 determines that the transition to the correction operation point g1 is completed when the following formula (2) is satisfied.

[0046]

number

[0047] Then, when the controller 20 determines that the transition to the correction operation point g1 is completed, the process proceeds to step S104.

[0048] In step S104, the controller 20 executes a suppression region determination process for determining whether or not the state of the motor control system 100 is in the temperature suppression region. Specifically, the controller 20 executes this determination using the logic described below.

[0049] First, after the transition to the correction operation point g1 is completed, the controller 20 adjusts the total output of the motor control system 100, i.e., the total driving force of the vehicle (front motor torque T fr_m and rear motor torque T rr_m By changing the distribution ratio κ while maintaining the front motor torque T fr_m Decrease by ΔT (>0) and reduce the rear motor torque T rr_m is increased by ΔT, where ΔT is the desired front motor current I ac_fm The value is set to a suitable value from the viewpoint of minimizing the discomfort felt by the vehicle occupants while realizing a reduction in the noise generated by the vehicle. Then, the controller 20 determines whether or not the condition of the following formula (3) is satisfied.

[0050]

number

[0051] Here, the first equation of equation (3) is the front motor torque T fr_m When the front motor current I ac_fm The condition where the capacitor temperature T c On the other hand, the second equation of (3) expresses the condition under which the front motor torque T fr_m and rear motor torque T rr_m When increasing the front motor current I ac_fm (Front motor DC current I dc_fm The decrease in loss of the smoothing capacitor 30 due to the change in _ loss(I ac_fm )) is the combined power (combined current I dc_f The increase in loss of the smoothing capacitor 30 due to the change in + loss(I dc_f )) is specified, i.e. in some cases the front motor current I ac_fm (Front motor DC current I dc_fm ) is reduced, the resultant current I dc_f As the capacitor temperature T c Therefore, in the second equation of (3), the effect of suppressing the rise in the capacitor temperature T c The conditions regarding the state of the motor control system 100 that can suppress the increase in the load are defined.

[0052] In addition, the front motor current I ac_fm and losses _ loss(I ac_fm ) can be calculated by using a map that is determined in advance for the torque and rotation speed of the front motor 10fr. dc_fThe change in the composite power is calculated from the rotation speed and torque of the front motor 10fr and the rotation speed and torque of the generator 16, and can be calculated using the battery voltage. dc_f Loss of + loss(I dc_f ) can be calculated by using a predetermined map for these parameters.

[0053] If the controller 20 determines that the condition of the formula (3) is satisfied, the process proceeds to step S105, and if the condition is not satisfied, the controller 20 ends this routine.

[0054] In step S105, the second suppression process is executed. Specifically, the controller 20 suppresses the front motor torque T fr_m At the same time, the rear motor torque T rr_m By increasing the capacitor temperature T c In particular, in this process, as in step S104, the front motor torque T fr_m The reduction in the rear motor torque T rr_m It is preferable to determine the amount of increase in the vehicle speed (the increase in the vehicle speed) so as to minimize the discomfort felt by the vehicle occupants.

[0055] According to the first suppression process (step S102) of the temperature suppression control described above, the generator current I ac_fg This reduces the capacitor temperature T without changing the combined power of the front inverter 14fr. c In addition, according to the suppression region determination process (step S104) and the second suppression process (step S105), the front motor current I ac_fm The increase or decrease in loss due to the change in and the combined power of the front inverter 14fr (combined current I dc_f In a scene (temperature suppression region) where a certain degree of temperature suppression effect can be obtained depending on the increase or decrease in loss due to the change in the front motor current Iac_fm Therefore, the output performance of the motor control system 100 (driving performance when installed in a vehicle) is ensured while the capacitor temperature T c Therefore, the increase in the temperature can be more effectively suppressed.

[0056] According to the motor control method of the present embodiment described above, the following advantageous effects are achieved.

[0057] According to this embodiment, the generator 16 as a power generator and the generated power (generated current I dc_fg The present invention provides a motor control method that is executed by a motor control system 100 having a smoothing capacitor 30 as a capacitive element that temporarily stores electric power, and a front motor 10fr as an electric motor driven by the generated electric power, and controls the operation of a generator 16 and the front motor 10fr.

[0058] In this motor control method, the temperature of the smoothing capacitor 30 (capacitor temperature T c ) is equal to or greater than a predetermined threshold value (reference value α), the generator current I ac_fg By decreasing the capacitor temperature T c The temperature suppression control (particularly, the first suppression process and / or the second suppression process) is executed to suppress an increase in the temperature.

[0059] As a result, the generator current I ac_fg The heat generation of the smoothing capacitor 30 can be suppressed by reducing the capacitor temperature T c The increase in is suppressed.

[0060] In particular, in this embodiment, the temperature suppression control is performed by controlling the generator current I ac_fg The first suppression process (step S102) reduces

[0061] As a result, the capacitor temperature T c A specific control logic is implemented to suppress the increase in

[0062] The electric motor control system 100 of the present embodiment further includes a front motor 10fr as a first electric motor, and a rear motor 10rr as a second electric motor different from the front motor 10fr. The temperature suppression control is performed by controlling the output of the front motor 10fr (front motor torque T fr_m ) and rear motor 10rr output (rear motor torque T rr_m ) while maintaining the sum of the front motor torque T fr_m (Front motor current I ac_fm ) to reduce the rear motor torque T rr_m (Especially the rear motor current I ac_rm ) is increased (step S105).

[0063] As a result, the total output of the motor control system 100 (total driving force of the vehicle) is maintained while the capacitor temperature T c A more specific control logic that can suppress the increase in is realized.

[0064] In particular, the temperature suppression control of the present embodiment is performed when the state of the motor control system 100 is the capacitor temperature T c a temperature suppression region determination process (step S104) for determining whether the motor control system 100 is in a temperature suppression region (equation (3)) in which the rise suppression effect of the front motor torque T fr_m and rear motor torque T rr_m While maintaining the sum of fr_m (Especially the front motor current I ac_fm ) to reduce the rear motor torque T rr_m (Especially the rear motor current I ac_rm and a second suppression process (step S105) of increasing the

[0065] In the suppression region determination process, the front motor torque T fr_m (Front motor current I ac_fm ) and the combined output (combined current I dc_f When the change in loss in the smoothing capacitor 30 due to the change in the loss in the smoothing capacitor 30 caused by the change in the ... due to the change in the loss in the smoothing capacitor 30 caused by the change in the loss in the smoothing capacitor 30 due to the change in the loss in the smoothing capacitor 30 due to

[0066] This results in a front motor current I ac_fm The increase or decrease in loss due to the change in and the combined power of the front inverter 14fr (combined current I dc_f A control logic is realized for executing the second suppression process in a more effective scene by taking into account the balance between the increase and decrease in loss due to the change in the transmission loss (Frequency).

[0067] The motor control system 100 of this embodiment includes a generator power converter 34 that adjusts the generated power of the generator 16, and a front motor power converter 32 that serves as a motor power converter connected in parallel with the generator power converter 34 to the smoothing capacitor 30 and adjusts the output of the front motor 10fr.

[0068] This causes the generator current I ac_fg By decreasing the capacitor temperature T c Thus, a system configuration is realized for more reliably suppressing an increase in temperature.

[0069] Furthermore, in this embodiment, there is provided an electric motor control system 100 suitable for carrying out the above-described electric motor control method.

[0070] The electric motor control system 100 includes a generator 16 as a generator and a generated electric power (generated current I dc_fgThe vehicle includes a smoothing capacitor 30 as a capacitance element that temporarily stores the generated power, a front motor 10fr as an electric motor driven by the generated power, and a controller 20 as a control device that controls the generator 16 and the drive motor 10.

[0071] The controller 20 then detects the temperature of the smoothing capacitor 30 (capacitor temperature T c ) is equal to or greater than a predetermined threshold value (reference value α), the generator current I ac_fg By decreasing the capacitor temperature T c The temperature suppression control (particularly, the first suppression process and / or the second suppression process) is executed to suppress an increase in the temperature.

[0072] Although the embodiments of the present invention have been described above, the above-described embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-described embodiments.

[0073] For example, in the above embodiment, an example has been described in which the drive motor 10 is configured with a front motor 10fr that is driven together with the generator 16 by an integrated inverter 14, and a rear motor 10rr. However, the present invention is not limited to this, and the method described in the above embodiment may be applied with some modifications when only one drive motor 10 is provided to provide the total output (total driving force of the vehicle) of the electric motor control system 100 (for example, when the rear motor 10rr is omitted and a configuration is adopted in which the output is provided only by the front motor 10fr).

[0074] In the above embodiment, the description has been given on the assumption that the device in which the motor control system 100 is installed is a vehicle. However, the motor control system 100 can also be installed in something other than a vehicle to execute the control of the above embodiment. [Explanation of symbols]

[0075] 10 drive motor, 10fr front motor, 10rr rear motor, 12 battery, 14 inverter, 14fr front inverter, 14rr rear inverter, 16 generator, 18 engine, 20 controller, 30 smoothing capacitor, 32 front motor power converter, 34 generator power converter, 36 temperature sensor, 40 smoothing capacitor, 42 rear motor power converter, 100 motor control system

Claims

1. A motor control method that is executed in a motor control system including a generator, a capacitance element that temporarily stores generated power output by the generator, and a motor that is driven by the generated power, and controls operations of the generator and the motor, comprising: When the temperature of the capacitance element is equal to or higher than a predetermined threshold, a temperature suppression control is executed to suppress an increase in the temperature of the capacitance element by reducing a current of the generator; The motor control system further includes a first motor that functions as the motor, and a second motor different from the first motor, The temperature suppression control includes: a first suppression process of reducing a current of the generator while maintaining the generated power; a temperature suppression region determination process for determining whether or not the state of the motor control system is in a temperature suppression region in which a certain degree of effect of suppressing an increase in the temperature of the capacitance element can be obtained; a second suppression process of reducing the output of the first motor and increasing the output of the second motor while maintaining a sum of the output of the first motor and the output of the second motor when it is determined that the state of the motor control system is in the temperature suppression region, In the suppression region determination process, when a combined loss change of the loss change of the capacitive element caused by a change in the output of the first motor and a combined loss change of the capacitive element caused by a change in the combined output of the generator and the first motor is decreasing, the state of the motor control system is determined to be in the temperature suppression region. Electric motor control method.

2. 2. A method for controlling an electric motor according to claim 1, comprising: The motor control system includes a generator power converter that adjusts the generated power of the generator, and a motor power converter that is connected in parallel with the generator power converter with respect to the capacitance element and adjusts an output of the motor. Electric motor control method.

3. A generator, a capacitance element for temporarily storing the generated power output by the generator; an electric motor driven by the generated power; A motor control system including: a control device that controls the operation of the generator and the motor; The control device includes: When the temperature of the capacitance element is equal to or higher than a predetermined threshold, a temperature suppression control is executed to suppress an increase in the temperature of the capacitance element by reducing a current of the generator; Further comprising a first motor functioning as the electric motor and a second motor different from the first motor, The temperature suppression control includes: a first suppression process of reducing a current of the generator while maintaining the generated power; a temperature suppression region determination process for determining whether or not the state of the motor control system is in a temperature suppression region in which a certain degree of effect of suppressing an increase in the temperature of the capacitance element can be obtained; a second suppression process for reducing the output of the first motor and increasing the output of the second motor while maintaining a sum of the output of the first motor and the output of the second motor when it is determined that the state of the motor control system is in the temperature suppression region, In the suppression region determination process, when a combined loss change of the loss change of the capacitance element caused by a change in the output of the first motor and a combined loss change of the loss change of the capacitance element caused by a change in the combined output of the generator and the first motor is decreasing, the state of the motor control system is determined to be in the temperature suppression region. Motor control system.

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