Control method for electric drive system of vehicle, electric drive system and vehicle

Abstract

The control method for the electric drive system of the vehicle includes the steps of: obtaining a current heat generation power of the electric drive system based on the current operating point of the vehicle; determining a current adjustment amplitude value based on the heating power required for the vehicle and the current heat generation power; obtaining a current direct axis current value and a current quadrature axis current value of the motor at the current operating point of the vehicle based on the three-phase current values ​​and position value of the motor; and controlling the current direct axis current value to oscillate at a predetermined conversion frequency and current adjustment amplitude value to become a target direct axis current value, thereby making it possible to make the electric drive system generate heat and oscillate the current flowing through the power battery itself, and accelerating the heat generation rate of the power battery itself, so that the electric drive system of the vehicle can be applied to cold regions. An electric drive system and a vehicle are also disclosed.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This disclosure claims priority to a Chinese patent application filed on March 31, 2021, bearing application number 202110351040.0 and entitled "Control method for vehicle electric drive system, electric drive system and vehicle," the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of vehicles, and in particular to a control method for an electric drive system of a vehicle, an electric drive system, and a vehicle. [Background technology]

[0003] In new energy vehicles, when operating in cold regions or under extremely cold conditions, the charge and discharge capabilities of the vehicle power battery are limited due to the effect of low temperature, which affects the performance of the vehicle.

[0004] Therefore, the related art provides a method for improving the heating effect by utilizing the residual heat of the motor, which uses the residual heat of the motor through a battery cooler to improve the heating performance of the heat pump and perform defrosting on the external condenser, but the art cannot control the amount of heat of the residual heat of the motor, and when the environmental temperature is very low, the utilization effect of the residual heat of the motor is low.

[0005] The related art also provides a heating device and method for a vehicle and its power battery. In this technology, when the power battery needs to be heated, a three-phase AC motor is controlled to generate heat to heat the coolant flowing through the power battery, and in the heating process, the phase current of the three-phase AC motor is adjusted according to a predetermined direct axis current and a predetermined quadrature axis current, so that the output of the motor shaft cannot move the vehicle, and the output shaft of the motor only outputs a biasing force to the transmission mechanism, eliminating the meshing gap and preventing the vehicle from shaking. Although this technology can control the amount of heat generated by the electric drive system, it can only be used when the vehicle is stopped, and its application scenarios are limited. Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure relates to a direct axis current value of a motor and Horizontal axis The present invention provides a control method for a vehicle electric drive system, an electric drive system, and a vehicle, which adjusts the current value to generate heat in the electric drive system and accelerate the self-heating rate of the power battery, thereby enabling the amount of heat to be applied to thermal management of the vehicle and allowing the electric drive system of the vehicle to be used in cold climates. [Means for solving the problem]

[0007] In a first aspect, the present disclosure provides a method of controlling an electric drive system of a vehicle, the electric drive system including a motor and a motor controller, the method comprising: obtaining a motor end shaft torque and a current vehicle operating point in response to a vehicle heating demand signal; obtaining a current heat generation power of the electric drive system based on a current driving operating point of the vehicle; determining a current adjustment amplitude value based on a heating power required for a vehicle and the current heating power; acquiring three-phase current values ​​and position values ​​of the motor, and acquiring a current direct axis current value and a current quadrature axis current value of the motor at a current operating point of the vehicle based on the three-phase current values ​​and the position value; controlling a current D-axis current value to oscillate at a predetermined conversion frequency and current adjustment amplitude value to a target D-axis current value; obtaining a target quadrature-axis current value based on the target direct-axis current value and a torque at the motor shaft end; obtaining a motor drive signal based on the target direct-axis current value, the target quadrature-axis current value, and the current direct-axis current value and the current quadrature-axis current value; sending the motor drive signal to the motor controller to control operation of the motor.

[0008] The control method for the electric drive system of the vehicle according to the embodiment of the present disclosure obtains a target lateral axis current value based on the target direct axis current value and the torque at the motor shaft end, i.e., ensures that the torque at the motor shaft end of the vehicle does not change during the driving state of the vehicle, avoids discomfort caused by vehicle vibration, and controls the target direct axis current value to oscillate at a constant current adjustment amplitude value and a predetermined conversion frequency, thereby causing the electric drive system to heat up and oscillating the current flowing through the power battery itself, accelerating the heat generation rate of the power battery itself, so that the electric drive system of the vehicle can be applied to cold regions, and the heat generation of the power battery itself and the heat quantity of the electric drive system can also be applied to the thermal management of the vehicle. In addition, the control method for the electric drive system of the vehicle only requires improving the software and does not require changing the hardware architecture, which is low cost and easy to be popularized.

[0009] In a second aspect, an electric drive system according to the present disclosure includes a motor, a motor controller, a current sensor, a position sensor, and a processor, wherein the current sensor collects three-phase current values ​​of the motor, the position sensor collects position values ​​of the motor, and the processor is connected to the motor controller, the current sensor, and the position sensor, respectively, and executes the control method for the electric drive system of a vehicle described in any one of the above embodiments.

[0010] The electric drive system according to the embodiment of the present disclosure uses a general-purpose electric drive system hardware, and executes the control method of the electric drive system of any one of the above embodiments by a processor, and controls the target direct axis current value to oscillate at a constant current adjustment amplitude value and a predetermined conversion frequency, thereby generating heat in the electric drive system and oscillating the current flowing through the power battery itself, thereby accelerating the heat generation rate of the power battery itself, so that the electric drive system of the vehicle can be applied to cold regions, and the heat generated by the power battery itself and the heat quantity of the electric drive system can also be applied to the thermal management of the vehicle. Moreover, the control method of the electric drive system of the vehicle requires only improving the software and does not require changing the hardware architecture, which is low cost and easy to spread.

[0011] In a third aspect, a vehicle according to the present disclosure includes a heating demand system, a vehicle controller, and an electric drive system as described in the above examples, wherein the vehicle controller transmits a vehicle heating demand signal when it determines that there is a heating demand in the heating demand system, and the electric drive system is connected to the vehicle controller and forms a heat conduction circuit with the heating demand system. Effect of the Invention

[0012] In a vehicle according to an embodiment of the present disclosure, a heat conduction circuit communicates with vehicle modules that may require heat, such as a power battery. When there is a demand for heat generation from the electric drive system, a vehicle controller receives a heating demand signal and uses a control method for an electric drive system of a vehicle according to any one of the above embodiments to control the quadrature axis current value and the direct axis current value to oscillate at a constant current adjustment amplitude value and a predetermined conversion frequency, and a motor controller controls the operation of the motor. In this way, even in any operating condition of the vehicle, the amount of heat generated by the electric drive system can be dynamically adjusted, and the temperature of the vehicle's power battery and other vehicle components can be quickly increased.

[0013] Additional aspects and advantages of the disclosure will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. [Brief description of the drawings]

[0014] The above and / or additional aspects and advantages of the present disclosure will become more apparent and easier to understand by describing examples with reference to the following drawings, in which:

[0015] [Figure 1] 4 is a flowchart of a control method for a vehicle electric drive system according to one embodiment of the present disclosure. [Diagram 2] FIG. 13 is a schematic diagram of a motion locus of a combination of quadrature axis current and direct axis current according to an embodiment of the present disclosure. [Diagram 3]FIG. 4 is a schematic diagram of periodic oscillation of a direct axis current value according to an embodiment of the present disclosure. [Figure 4] 6 is a flowchart of a control method for a vehicle electric drive system according to another embodiment of the present disclosure. [Diagram 5] 10 is a flowchart of a control method for a vehicle electric drive system according to yet another embodiment of the present disclosure. [Figure 6] 10 is a flowchart of a control method for a vehicle electric drive system according to yet another embodiment of the present disclosure. [Figure 7] FIG. 1 is a block diagram of an electric drive system according to one embodiment of the present disclosure. [Figure 8] FIG. 1 is a block diagram of a vehicle according to an embodiment of the present disclosure. [Figure 9] FIG. 2 is a schematic diagram of carrier frequency variation according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The embodiments of the present disclosure will be described in detail below. do. The embodiments described with reference to the drawings are illustrative. be .

[0017] Hereinafter, a control method for an electric drive system of a vehicle according to an embodiment of the present disclosure will be described with reference to FIGS.

[0018] FIG. 1 is a flowchart of a control method for a vehicle electric drive system according to one embodiment of the present disclosure.

[0019] In some embodiments of the present disclosure, an electric drive system includes a motor and a motor controller that controls the operating conditions of the motor. For example, the motor controller can control a power switching device to turn on or off based on a motor drive signal, or adjust the operating power of the motor to operate at a specific power to meet the heat regulation demands of the electric drive system.

[0020] As shown in FIG. 1, the control method for the electric drive system of the vehicle includes at least steps S1 to S8, and is specifically as follows.

[0021] At S1, motor shaft end torque and the vehicle's current driving operating point are obtained in response to a vehicle heating demand signal.

[0022] In some embodiments of the present disclosure, for example, in a cold region or in a severe cold operating condition, the charging and discharging capability of the vehicle power battery is limited due to the influence of low temperature, and the vehicle power battery needs to be heated, and the vehicle transmits a vehicle heating demand signal to the electric drive system. Also, for example, when the vehicle is driving, if there is a heating demand in other modules of the vehicle, it is determined that it is necessary to enter the heat regulation function of the electric drive system, for example, if the user determines to perform a heating operation of the air conditioning system, or the user operates to control the seat of the passenger compartment of the vehicle to be heated, the vehicle transmits a vehicle heating demand signal to the electric drive system.

[0023] The electric drive system detects the torque at the motor shaft end in response to the vehicle heating demand signal to determine a current driving operating point of the vehicle. For example, when the vehicle is driving, the torque at the motor shaft end does not change, and by detecting the torque at the motor shaft end, a current driving operating point at which the driving energy consumption of the vehicle is optimal at the torque at the motor shaft end is determined.

[0024] In S2, the current heat generating power of the electric drive system is obtained based on the current driving operating point of the vehicle.

[0025] A current operating power of the motor may be detected, and a current heat generating power of the electric drive system may be obtained based on the current operating power of the motor.

[0026] In S3, a current adjustment amplitude value is determined based on the heating power required for the vehicle and the current heating power.

[0027] Specifically, the vehicle controller can aggregate the heating demands of each heating demand system of the vehicle, such as the power battery, the passenger compartment, and its components, to determine the heating power required for the vehicle, and send the heating power required for the vehicle to the electric drive system. The heating power of the electric drive system is related to the operating current of the motor, and different heating powers can be generated by adjusting the operating current of the motor.

[0028] In some embodiments, if the current heat generation power of the electric drive system cannot meet the heating power required for the vehicle, the operating current of the motor needs to be adjusted, and the electric drive system determines a current adjustment amplitude value for adjusting the operating current of the motor based on the heating power required for the vehicle and the current heat generation power. Specifically, a power difference value between the heating power required for the vehicle and the current heat generation power is calculated, and a current adjustment amplitude value is obtained based on the power difference value. The calculation of the current heat generation power can be obtained by looking up a table, which is a relationship between the motor rotation speed, the composite current vector value, and the current heat generation power, and the composite current vector value is a composite current value of the current direct axis current value and the current quadrature axis current value, and the table can be obtained by calibration on a bench in advance. By writing the table into the motor controller, the current heat generation power can be obtained based on the current direct axis current value, the current quadrature axis current value, and the motor rotation speed, and there is no need to calculate the heat generation amount of each component individually, thereby reducing the calculation time.

[0029] The larger the power difference value, the larger the current adjustment amplitude value becomes, and conversely, the smaller the current adjustment amplitude value becomes.

[0030] The current regulation amplitude value or the predetermined conversion frequency at different driving operating points of the vehicle may not match, and the predetermined conversion frequency or the current regulation amplitude value can be adjusted to adapt to the heating demand of the vehicle.

[0031] In S4, the three-phase current values ​​and position values ​​of the motor are acquired, and the current direct axis current value and the current quadrature axis current value of the motor at the current driving operating point of the vehicle are acquired based on the three-phase current values ​​and position values.

[0032] In some embodiments of the present disclosure, a position sensor collects motor position values, such as the real-time position and rotational speed of the motor rotor, and a current sensor collects motor three-phase current values ​​between the motor and the motor controller, where the collected three-phase current values ​​are three-phase quiescent current values.

[0033] By using a coordinate transformation method, the current direct axis current value and the current quadrature axis current value of the motor can be obtained. For example, by using coordinate transformation, the three-phase current value can be transformed into a two-phase rotating current value, and the two-phase rotating current value includes the current quadrature axis current value and the current direct axis current value.

[0034] In S5, the current D-axis current value is controlled so as to be vibrated at a predetermined conversion frequency and current adjustment amplitude value to reach the target D-axis current value.

[0035] The step of controlling the current D axis current value to oscillate with a predetermined conversion frequency and a current adjustment amplitude value to become a target D axis current value includes the steps of obtaining a first D axis current value and a second D axis current value based on the current adjustment amplitude value, and the target D axis current value taking the current D axis current value as a reference value, peaking at the first D axis current value, and bottoming out at the second D axis current value, and periodically changing according to the predetermined conversion frequency, wherein the first D axis current value is a sum value of the current D axis current value and the current adjustment amplitude value, and the second D axis current value is a difference value between the current D axis current value and the current adjustment amplitude value.

[0036] Taking a sine wave as an example, the target D-axis current value is an effective value with the current D-axis current value as the reference value, the first D-axis current value as the peak, and the second D-axis current value as the bottom. In other words, the target D-axis current value is an effective value that oscillates with the current D-axis current value as the reference value at a predetermined conversion frequency and current adjustment amplitude value.

[0037] Specifically, as shown in FIG. 2, it is a schematic diagram of the operation locus of the combination of the quadrature axis current and the direct axis current according to one embodiment of the present disclosure, the horizontal axis is the direct axis current value, the vertical axis is the quadrature axis current value, and the three curves are all constant torque curves, that is, the combination of the quadrature axis current and the direct axis current at any point on the same curve can output the same torque at the motor shaft end, and the different torque curves represent the torque at different motor shaft ends, and the closer the torque curve is to the zero point, the smaller the value is, and the farther away from the zero point, the larger the value is, that is, the torque at the motor shaft end corresponding to torque curve 1 is larger than the torque at the motor shaft end corresponding to torque curve 2, and is larger than the torque at the motor shaft end corresponding to torque curve 3. Points A, B, C, D, and E on torque curve 3 are respectively the driving operation points of the vehicle with the same torque at the motor shaft end, and curve OF represents the MTPA ( Maximum Torque Per Ampere A curve of OFPA is a maximum torque per voltage (MTPV) curve, and a curve of GH is a maximum torque per voltage (MTPV) curve. The curve combining MTPA and MTPV is obtained by performing calibration under a plurality of boundary conditions, and a detailed calibration method will not be described. In the related art, the direct axis current value is controlled and adjusted within the region surrounded by OFGH, and the adjustment range is limited.

[0038] In some embodiments of the present disclosure, the vehicle determines that it is necessary to enter the heat regulation function of the electric drive system according to the heating demand of the vehicle, and when the vehicle is operating at the operating point A, determines the D-axis current value at the operating point A as the current D-axis current value. Taking the acquired current regulation amplitude value as Δd and the predetermined conversion frequency as an example, it determines that the operating point A is located on the torque curve 3, slides left and right with the current regulation amplitude value Δd along the torque curve 3 where the operating point A is located, slides right from the operating point A to the operating point B at the top, and determines the D-axis current value of the operating point B as the first D-axis current value, slides left from the operating point A to the operating point C at the bottom, and determines the D-axis current value of the operating point C as the second D-axis current value. In FIG. 2 , the trajectory of the combination of the quasi-axis current and the direct-axis current is a trajectory A→B→A→C→A in the torque curve 3, and the target quasi-axis current value and the target direct-axis current value are periodically adjusted. With the change of the current adjustment over time, the direct-axis current value exhibits a periodic oscillation waveform, such as a sine waveform, a square waveform or other applicable waveform, and the amplitude value of the waveform is related to the current adjustment amplitude value.

[0039] Take an example, as shown in Fig. 3, which is a schematic diagram of the periodic oscillation of the direct axis current value according to an embodiment of the present disclosure, where the vertical axis is the direct axis current value, and the five dashed lines correspond to the target direct axis current values ​​at the operating points A, B, C, D, and E in Fig. 2, respectively. The sine curve 1 is the direct axis current oscillation curve M, and the predetermined conversion frequency in the direct axis oscillation curve M is f in Hz, and the current adjustment amplitude is Δd in A. The sine curve 2 is a D-axis current vibration curve N, a predetermined conversion frequency in the D-axis vibration curve N is f in Hz, a current adjustment amplitude value is Δd1 in A, the current amplitude value Δd is a difference value of the target D-axis current corresponding to operating point A to operating point B or operating point A to operating point C, and the difference value of the target D-axis current corresponding to operating point A to operating point B is equal to the difference value of the target D-axis current corresponding to operating point A to operating point C, and the current adjustment amplitude value Δd1 is a difference value of the target D-axis current corresponding to operating point A to operating point D or operating point A to operating point E, and the difference value of the target D-axis current corresponding to operating point A to operating point D is equal to the difference value of the target D-axis current corresponding to operating point A to operating point E.

[0040] In some embodiments of the present disclosure, according to the heating demand of the vehicle, it is determined that the electric drive system needs to enter the heat adjustment function, and when the vehicle is operating at the operating point A, the D-axis current value at the operating point A is determined as the current D-axis current value. Taking the acquired current adjustment amplitude value as Δd and the predetermined conversion frequency as f as an example, it is determined that the operating point A is located on the torque curve 3, and the current adjustment amplitude value Δd is slid left and right along the torque curve 3 where the operating point A is located, and the D-axis current value at the operating point B at the top is slid right from the operating point A to the operating point B at the top, and the D-axis current value at the operating point B is determined as the first D-axis current value, and the D-axis current value at the operating point C at the bottom is slid left from the operating point A to the operating point C at the bottom, and the D-axis current value at the operating point C is determined as the second D-axis current value. In Figure 2, the trajectory of the combination of the quadrature axis current and the direct axis current is the trajectory A → B → A → C → A on the torque curve 3, and in Figure 3, the target direct axis current value changes on the direct axis current vibration curve M, and the trajectory of the target direct axis current value vibration is formed along the direct axis current vibration curve M.

[0041] As shown in FIG. 2 and FIG. 3, specifically, in FIG. 2, the operation operating point moves from the operating point A to the operating point B along the torque curve 3 in a direction in which the target D-axis current value increases and the target Q-axis current value increases. Synchronously, in FIG. 3, the target D-axis current value moves from point A to point B along the D-axis current vibration curve M. At this time, the target D-axis current value increases, and the target Q-axis current value also increases correspondingly, and the operation operating point continues to move, moving from the operating point B in FIG. 2 back to the operating point A in a direction in which the target D-axis current value decreases and the target Q-axis current value decreases along the torque curve 3, and the target D-axis current value in FIG. 3 moves from point B to point A1 along the D-axis current vibration curve M. At this time, the target D-axis current value decreases, and the target Q-axis current value also decreases correspondingly, and the operation point continues to move. In FIG. 2, the target D-axis current value decreases along the torque curve 3, and the operation point moves to the operation point C in the direction in which the target Q-axis current value decreases. Synchronously, in FIG. 3, the D-axis current value moves from the A1 point to the C point along the D-axis current oscillation curve M. At this time, the target D-axis current value decreases, and the target Q-axis current value also decreases correspondingly, and the operation point continues to move. In FIG. 2, the target D-axis current value increases along the torque curve 3, and the target Q-axis current value also decreases correspondingly, and the operation point continues to move. In FIG. 2, the target D-axis current value increases, and the operation point moves back to the operation point A in the direction in which the target Q-axis current value increases. Synchronously, in FIG. 3, the target D-axis current value moves from the C point to the A2 point along the D-axis current oscillation curve M. At this time, the target D-axis current value increases, and the target Q-axis current value also increases correspondingly, and up to this point, one oscillation period of the target D-axis current value at the operation point A is completed. If the vehicle continues to operate at operating point A in FIG. 2, the above steps are executed repeatedly.

[0042] In S6, a target quadrature-axis current value is obtained based on the target direct-axis current value and the torque at the motor shaft end.

[0043] In some embodiments of the present disclosure, when the vehicle is driven under the same operating conditions, if it is determined that the torque of the motor shaft end does not change and the electric drive system needs to enter the heat regulation function, the change of the target direct axis current value needs to be adjusted, and the target quasi-axis current value also changes, and in order to ensure that the vehicle runs normally, it is necessary to obtain a target quasi-axis current value corresponding to the target direct axis current value. For example, it can be limited using a fixed algorithm, and the target quasi-axis current value can be obtained by directly calculating based on the target direct axis current value, without the need to look up and obtain a table, and the method is simple.

[0044] In S7, a motor drive signal is obtained based on the target direct axis current value, the target quadrature axis current value, and the current direct axis current value and the current quadrature axis current value. The target direct axis current value, the current direct axis current value, and the target quadrature axis current value and the current quadrature axis current value are processed through several calculations, etc., to finally obtain the motor drive signal.

[0045] In S8, a motor drive signal is sent to a motor controller to control the operation of the motor. In response to the motor drive signal, the motor controller controls the power switching device to turn on or off, thereby controlling the operation of the motor to meet the heat regulation demand of the electric drive system. The motor controller further adjusts the operating power of the motor to realize that the amount of heat generated by the electric drive system can be adjusted for use by other modules of the vehicle.

[0046] According to the control method of the electric drive system of the vehicle according to the embodiment of the present disclosure, the torque of the motor shaft end, the current operating point of the vehicle, and the three-phase current value and position value of the motor are obtained to obtain the target direct axis current value and the target lateral axis current value, and the torque of the motor shaft end of the vehicle is guaranteed not to change in the driving state of the vehicle, and the target direct axis current value is controlled to oscillate at a constant current adjustment amplitude value and a predetermined conversion frequency to accelerate the self-heating speed of the power battery, so that the electric drive system of the vehicle can be applied to cold regions, and the self-heating of the power battery and the heat amount of the electric drive system can also be applied to the thermal management of the vehicle. In addition, the control method of the electric drive system of the vehicle only requires improving the software and does not require changing the hardware architecture, which is low cost and easy to be popularized. The heat amount of the electric drive system includes the heat amount generated by the motor itself and the heat amount generated by the power switching device of the motor controller.

[0047] In some embodiments of the present disclosure, obtaining the current heat generating power of the electric drive system based on the current driving operating status of the vehicle can be done by looking up a table to obtain the current heat generating power based on the vector change amount of the composite current of the motor at different rotation speeds of the current vehicle, and the table is obtained by pre-calibrating on the bench based on the electric drive system, thereby reducing the calculation time required for the actual control process.

[0048] In some embodiments of the present disclosure, the motor is a three-phase permanent magnet synchronous motor, for example, in which the target direct axis current value and the target quadrature axis current value satisfy the formula (1-1). For other types of motors, a torque formula corresponding to the motor can be set.

[0049] Here, T e is the torque at the motor shaft end, in Nm, and N P is the number of pole pairs of the motor rotor, and L d is the direct-axis inductance value, the unit is uH, and L q is the inductance value on the horizontal axis, the unit is uH, and i dis the target direct axis current value, the unit is A, and φ f is the flux linkage value, with the unit being Vs, and i q is the target quadrature axis current value, in A. T e =1.5N P [(L d -L q )i d +φ f ]i q Formula (1-1)

[0050] In some embodiments of the present disclosure, in the process of providing heat regulation demand to an electric drive system, a target direct-axis current value i d Vibration control is performed on the target direct-axis current value i d When changes occur, the target quadrature current value i q In order to ensure that the vehicle runs normally, the target direct-axis current value i d The target quadrature current value i q It is necessary to obtain the target quadrature axis current value i by using the algorithm of equation (1-1). q When the vehicle is driven under the same operating conditions, the torque T e If it is determined that the electric drive system needs to enter the heat regulation function without changing the target direct-axis current value i d Based on the target quadrature axis current value i q can be directly calculated, and the quadrature axis current and the direct axis current are both controlled to oscillate at a constant predetermined conversion frequency f and a current adjustment amplitude value Δd, thereby ensuring the normal running of the vehicle.

[0051] In some embodiments of the present disclosure, as shown in FIG. 4, which is a flowchart of a control method for an electric drive system of a vehicle according to another embodiment of the present disclosure, the control method for an electric drive system of a vehicle further includes step S9 and step S10, and is specifically as follows:

[0052] In S9 it is determined that the heating power required for the vehicle has changed.

[0053] For example, after the vehicle has been driving for a certain period of time, the temperature of the vehicle power battery needs to be adjusted; when the heating power required by the vehicle changes, the heat adjustment function of the electric drive system needs to be adaptively adjusted; or when the heating demand of other modules of the vehicle changes, the heat adjustment function of the electric drive system needs to be adjusted to adapt to the heating power required by the vehicle; for example, when a user decides to perform heating operation of the air conditioning system, or when the user operates to control the seats in the vehicle passenger compartment to be heated, the vehicle sends a corresponding vehicle heating demand signal to the electric drive system.

[0054] In S10, the current adjustment amplitude value is adjusted or the predetermined conversion frequency is adjusted based on the heating power required for the vehicle after the change.

[0055] In the embodiment of the present disclosure, when it is determined that the heating power required for the vehicle has changed, the current adjustment amplitude value Δd is determined based on the heating power required for the vehicle and the current heat generation power, and the current adjustment amplitude value Δd or the predetermined conversion frequency f is adjusted to realize the heating power demand of the vehicle. For example, when the heat generation regulation demand of the electric drive system increases, the current adjustment amplitude value Δd needs to be increased. When the heat generation regulation demand of the electric drive system decreases, the current adjustment amplitude value Δd needs to be decreased.

[0056] As shown in Figure 2 and Figure 3, take the vehicle running at the operating point A as an example, when the heat demand of the electric drive system increases, the current adjustment amplitude value Δd needs to be adjusted to be increased, and the combination of the target quasi-axis current and the target direct-axis current is adjusted accordingly. For example, by pre-calibration or real-time calculation by a related algorithm, the adjusted predetermined conversion frequency is determined as f, the unit is Hz, and the adjusted current adjustment amplitude value is determined as Δd1, the unit is A. In Figure 2, the combination of the quasi-axis current and the direct-axis current is the trajectory A→D→A→E→A on the torque curve 3. In Figure 3, the target direct-axis current value is switched from the direct-axis current vibration curve M to the direct-axis current vibration curve N, and the target direct-axis current value vibration trajectory is formed along the direct-axis current vibration curve N. The current adjustment amplitude value Δd1 is a difference value of the target D axis current corresponding to operating point A to operating point D or from operating point A1 to operating point E, and the difference value of the target D axis current corresponding to operating point A to operating point D is the same as the difference value of the target D axis current corresponding to operating point A1 to operating point E.

[0057] Specifically, in FIG. 2, the operation operating point moves from operating point A along torque curve 3 in a direction in which the target D axis current value increases and the target quasi-axis current value increases to operating point D. Synchronously, in FIG. 3, the target D axis current value moves from point A to point D along D axis current vibration curve N. At this time, the target D axis current value increases and the target quasi-axis current value also increases correspondingly, and the operation operating point continues to move, moving from operating point D in FIG. 2 back to operating point A along torque curve 3 in a direction in which the target D axis current value decreases and the target quasi-axis current value decreases, and the target D axis current value in FIG. 3 moves from point D to point A1 along D axis current vibration curve N. At this time, the target D-axis current value decreases, and the target Q-axis current value also decreases correspondingly, and the operation point continues to move. In FIG. 2, the target D-axis current value decreases along the torque curve 3, and the operation point moves to the operation point E in the direction in which the target Q-axis current value decreases. Synchronously, in FIG. 3, the D-axis current value moves from the A1 point to the E point along the D-axis current oscillation curve N. At this time, the target D-axis current value decreases, and the target Q-axis current value also decreases correspondingly, and the operation point continues to move. In FIG. 2, the target D-axis current value increases along the torque curve 3, and the target Q-axis current value also decreases correspondingly, and the operation point continues to move. In FIG. 2, the target D-axis current value increases, and the operation point moves back to the operation point A in the direction in which the target Q-axis current value increases. Synchronously, in FIG. 3, the target D-axis current value moves from the E point to the A2 point along the D-axis current oscillation curve N. At this time, the target D-axis current value increases, and the target Q-axis current value also increases correspondingly, and up to this point, one oscillation period of the target D-axis current value at the operation point A is completed. If the vehicle continues to operate at operating point A in FIG. 2, the above steps are executed repeatedly.

[0058] In some embodiments of the present disclosure, as shown in Figure 5, which is a flowchart of a control method for an electric drive system of a vehicle according to another embodiment of the present disclosure. In the above step S4, the step of obtaining a current direct axis current value and a current quadrature axis current value of the motor at a current driving operating point of the vehicle based on three-phase current values ​​and position values ​​may include steps S41 and S42, and is specifically as follows:

[0059] In S41, the three-phase current values ​​are converted into two-phase quiescent current values ​​by Clark transformation.

[0060] The Clark transformation is a coordinate transformation method for converting three-phase static variables into two-phase static variables, and the Clark transformation can convert three-phase current values ​​into two-phase static current values.

[0061] In S42, the two-phase stationary current values ​​are transformed into two-phase rotating current values ​​by Park transformation, where the two-phase rotating current values ​​include a current quadrature axis current value and a current direct axis current value.

[0062] The Park transformation is a coordinate transformation method for converting two-phase stationary variables into two-phase rotating variables. Through the Park transformation, two-phase stationary current values ​​can be converted into two-phase rotating current values, which include a present quadrature axis current value and a present direct axis current value.

[0063] In some embodiments of the present disclosure, as shown in Fig. 6, a flowchart of a control method for a vehicle electric drive system according to still another embodiment of the present disclosure. In the above step S7, the step of acquiring a motor drive signal based on the target direct axis current value, the target quasi-axis current value, and the current direct axis current value and the current quasi-axis current value may include steps S71 to S75, and is specifically as follows:

[0064] In S71, a difference between a target direct axis current value and a current direct axis current value is calculated to obtain a direct axis current difference value, and a difference between a target quadrature axis current value and a current quadrature axis current value is calculated to obtain a quadrature axis current difference value.

[0065] In some embodiments of the present disclosure, when the target direct axis current value and the target quasi-axis current value change with a constant current adjustment amplitude value or a predetermined conversion frequency, the output target direct axis current value and target quasi-axis current value are the changed values, and the time interval for collecting the target direct axis current value and the target quasi-axis current value is set as necessary, thereby ensuring efficient operation of the system, dynamically adjusting the heat generation amount of the electric drive system, and ensuring that the temperature of the vehicle power battery and other vehicle components is quickly heated.

[0066] In S72, a direct axis voltage value and a quadrature axis voltage value are obtained by performing a current closed-loop adjustment based on the direct axis current difference value and the quadrature axis current difference value.

[0067] When performing closed-loop current adjustment for the direct axis current difference and the quadrature axis current difference, the direct axis voltage value and the quadrature axis voltage value can be obtained by performing adjustment using a proportional integral controller (PI) and feedforward decoupling.

[0068] In S73, the direct axis voltage value and the quadrature axis voltage value are converted into two-phase static voltage values ​​by TPark conversion.

[0069] The TPark (inverse Park) transformation is a coordinate transformation method for converting two-phase rotating variables into two-phase stationary variables, and the TPark transformation can convert two-phase rotating voltage values ​​into two-phase stationary voltage values.

[0070] In S74, the bus voltage value of the electric drive system is obtained, and the torque at the motor shaft end, the current driving operating point of the vehicle, the three-phase current values ​​and position values ​​of the motor are obtained, and when calculating these data, the motor controller can synchronously collect the bus voltage value of the electric control DC terminal of the system.

[0071] In S75, a motor drive signal is obtained by performing pulse width modulation based on the bus voltage value and the two-phase quiescent voltage value.

[0072] In an embodiment of the present disclosure, the bus voltage value and the two-phase quiescent voltage value are transmitted to a module having a pulse width modulation function for processing to obtain a motor driving signal and send it to a motor controller. The motor driving signal may be a switching signal, and the operation of the motor can be controlled by controlling a power switching device to be turned on or off to adjust the heat generation of the electric drive system and provide thermal energy to other components of the vehicle to meet the heat generation adjustment demand of the electric drive system.

[0073] In some embodiments, the motor controller includes a power switching device, and a carrier frequency of the power switching device varies within a predetermined range when the target direct axis current value is greater than the limit value.

[0074] The inventors have found that when the direct current is greater than the limit value, the magnetic force between the stator and rotor is strong and the carrier frequency does not change, and the motor operates at a carrier frequency of f N 9, it can be seen that the power switching device is turned on or off based on the motor drive signal, the time from the previous on to the next on of the power switching device is one period, the above carrier frequency is the reciprocal of the period, and the predetermined range is from 90% of the current carrier frequency to 110% of the current carrier frequency. % The carrier frequency control policy is used to effectively distribute the harmonic voltages over a wider frequency spectrum, reduce the motor vibration and noise, and optimize the NVH performance of the vehicle.

[0075] FIG. 7 is a block diagram of an electric drive system according to one embodiment of the present disclosure.

[0076] In some embodiments of the present disclosure, as shown in FIG. 7, an electric drive system 10 includes a motor 1, a motor controller 2, a current sensor 3, a position sensor 4, and a processor 5.

[0077] When the motor 1 operates, it can provide thermal energy to the vehicle's power battery and other components, and the motor controller 2 can control the operating state of the motor 1 based on the motor drive signal, for example, the motor controller 2 can control the operation of the motor by controlling a power switching device to turn on or off. The current sensor 3 is provided between the motor 1 and the motor controller 2, and can collect three-phase current values ​​of the motor 1. The position sensor 4 collects the position value of the motor 1, and the position value may include the real-time position and rotation speed of the rotor of the motor, etc.

[0078] The processor 5 is connected to the motor controller 2, the current sensor 3 and the position sensor 4, and executes the control method for the electric drive system of a vehicle according to any one of the above embodiments.

[0079] The electric drive system 10 according to the embodiment of the present disclosure uses general-purpose electric drive system hardware and executes the control method for the vehicle electric drive system according to any one of the above embodiments with the processor 5, and can accelerate the heat generation rate of the power battery itself, so that the vehicle electric drive system can be applied to cold regions, and the amount of heat generated by the power battery itself can also be applied to the thermal management of the vehicle. In addition, the control method for the vehicle electric drive system requires only software improvement without the need to change the hardware architecture, which is low cost and easy to disseminate.

[0080] FIG. 8 is a block diagram of a vehicle according to one embodiment of the present disclosure.

[0081] In some embodiments of the present disclosure, as shown in FIG. 8, a vehicle 01 includes a heating demand system 20, a vehicle controller 30, and an electric drive system 10 according to any one of the above embodiments.

[0082] When the vehicle controller 30 determines that there is a heating demand in the heating demand system 20, it transmits a heating demand signal of the vehicle. The heating demand system may include various modules or components in the vehicle, such as a power battery in a new energy vehicle, a passenger compartment and an air conditioning system of the vehicle, etc. A temperature sensor can collect the current environmental temperature and / or the temperature of a module or component in the heating demand system 20, and transmit the heating demand signal when it determines that the module or component needs to be heated. Alternatively, a user transmits the heating demand signal by operating a human-machine interaction device such as a display screen, a button, etc.

[0083] The electric drive system 10 is connected to a vehicle controller 30, and the electric drive system 10 and the heating demand system 20 form a heat conduction circuit. The heat generated by the electric drive system 10 is provided to other modules of the vehicle or the vehicle power battery as needed or simultaneously through the heat conduction circuit. The structure of the heat conduction circuit is not limited here, and the specific heat conduction flow direction can be determined according to the actual situation of each module of the vehicle.

[0084] According to the vehicle 01 according to the embodiment of the present disclosure, the heat conduction circuit communicates the modules of the vehicle 01 that may require heat, such as the power battery, and when a heat generation demand is issued to the electric drive system 10, the vehicle controller 30 receives the heating demand signal and controls the quadrature axis current value and the direct axis current value to oscillate at a constant current adjustment amplitude value and a predetermined conversion frequency by using the control method of the electric drive system of the vehicle according to any one of the above embodiments, and the motor controller 2 controls the operation of the motor 1. In this way, the amount of heat generated by the electric drive system 10 is dynamically adjusted even in any operating condition of the vehicle 01, and the vehicle 01 The temperature of the power battery and other vehicle components can be increased quickly.

[0085] In some embodiments of the present disclosure, the heating demand system 20 includes a power battery. For example, when a new energy vehicle needs to heat the vehicle 01 and the power battery in a cold or severe cold operating condition, the vehicle 01 can be configured to adjust the heat of the electric drive system 10. function By using the control method for an electric drive system of a vehicle in any one of the above embodiments, the heat generation of the electric drive system 10 can be controlled, and the heat can be transferred to the power battery via the thermal conduction circuit, improving the heat generation rate of the power battery itself, without affecting the torque output at the end of the motor shaft, and preventing low temperatures from affecting the charge and discharge ability of the power battery, which in turn affects the performance of the vehicle.

[0086] In some embodiments of the present disclosure, the heating demand system 20 includes a passenger compartment and an air conditioning system of the vehicle. For example, when a user needs to heat the seats in the passenger compartment of the vehicle or when the user needs to heat the vehicle using the air conditioning system, the vehicle 01 may request the electric drive system 10 to adjust the heat. function By using the control method for a vehicle electric drive system according to any one of the above embodiments, the heat generation of the electric drive system 10 can be controlled, and under the premise of meeting the normal driving of the vehicle, the amount of heat generated by the electric drive system 10 can be dynamically adjusted, and the temperature of the vehicle heating demand system 20 can be quickly increased through the heat conduction circuit to meet the user's needs.

[0087] The remaining configuration and operation of vehicle 01 according to the embodiment of the present application is known to those skilled in the art and will not be described in detail herein.

[0088] In the description herein, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "examples," "particular examples," or "some examples" mean that the specific feature, configuration, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In the description herein, exemplary references to the above terms do not necessarily refer to the same embodiment or example.

[0089] Although embodiments of the present disclosure have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and objectives of the present disclosure, and that the scope of the present disclosure is limited by the claims and their equivalents. [Explanation of symbols]

[0090] 01 Vehicle 20 Heating Demand System 30 Vehicle Controller 10 Electric Drive System 1 Motor 2 Motor Controller 3 Current Sensor 4 Position Sensor 5 Processors

Claims

1. 1. A method for controlling an electric drive system of a vehicle, the electric drive system including a motor and a motor controller, obtaining a motor end shaft torque and a current vehicle operating point in response to a vehicle heating demand signal; obtaining a current heat generation power of the electric drive system based on a current driving operating point of the vehicle; determining a current adjustment amplitude value based on a heating power required for the vehicle and the current heating power; acquiring three-phase current values ​​and position values ​​of the motor, and acquiring a current direct axis current value and a current quadrature axis current value of the motor at a current operating point of the vehicle based on the three-phase current values ​​and the position value; controlling the present D-axis current value to oscillate at a predetermined conversion frequency and the current adjustment amplitude value to a target D-axis current value; obtaining a target quadrature-axis current value based on the target direct-axis current value and a torque at the motor shaft end; obtaining a motor drive signal based on the target direct-axis current value, the target quadrature-axis current value, and the current direct-axis current value and the current quadrature-axis current value; sending the motor drive signal to the motor controller to control operation of the motor; Including, the motor controller includes a power switching device; When the target direct axis current value is greater than a limit value, the carrier frequency of the power switching device randomly varies within a predetermined range. A method for controlling an electric drive system of a vehicle.

2. controlling the current D-axis current value to oscillate at a predetermined conversion frequency and the current adjustment amplitude value to a target D-axis current value, obtaining a first D-axis current value and a second D-axis current value based on the current adjustment amplitude value, and the target D-axis current value is periodically changed according to a predetermined conversion frequency, with a current D-axis current as a reference value, the first D-axis current value as a peak, and the second D-axis current value as a bottom; the first D-axis current value is a sum of the present D-axis current value and the current adjustment amplitude value; The second D-axis current value is a difference value between the current D-axis current value and the current adjustment amplitude value.

2. The method of claim 1, wherein the control system is an electric drive system for a vehicle.

3. Determining a current adjustment amplitude value based on the heating power required for the vehicle and the current heating power, calculating a power difference value between a heating power required for the vehicle and the current heating power; obtaining the current adjustment amplitude value based on the power difference value, and the current adjustment amplitude value increases as the power difference value increases; Characterized in that it comprises 3. A method for controlling an electric drive system of a vehicle according to claim 1 or 2.

4. The target direct-axis current value and the target quadrature-axis current value satisfy the following formula: T ｅ =1.5N Ｐ [(L ｄ -L ｑ )i ｄ +φ ｆ ]i ｑ Here, T ｅ is the torque at the motor shaft end, N Ｐ is the number of pole pairs of the motor rotor, and L ｄ is the direct-axis inductance value, and L ｑ is the inductance value on the horizontal axis, and i ｄ is the target direct axis current value, and φ ｆ is the flux linkage value, i ｑ is a target quadrature axis current value, A method for controlling an electric drive system of a vehicle according to any one of claims 1 to 3.

5. determining that a heating power requirement for the vehicle has changed; adjusting the current regulation amplitude value or adjusting the predetermined conversion frequency based on the changed heating power required for the vehicle; Further comprising: A method for controlling an electric drive system of a vehicle according to any one of claims 1 to 4.

6. The step of obtaining a current direct axis current value and a current quadrature axis current value of the motor at a current operating point of the vehicle based on the three-phase current values ​​and the position value includes: converting the three-phase current values ​​to two-phase quiescent current values ​​by a Clark transformation; converting the two-phase stationary current values ​​to two-phase rotating current values ​​by a Park transformation; Including, The two-phase rotating current value includes the current quadrature axis current value and the current direct axis current value. A method for controlling an electric drive system of a vehicle according to any one of claims 1 to 5.

7. The step of obtaining a motor drive signal based on the target direct-axis current value, the target quadrature-axis current value, and the current direct-axis current value and the current quadrature-axis current value includes: calculating a difference between the target direct-axis current value and the current direct-axis current value to obtain a direct-axis current difference value, and calculating a difference between the target quadrature-axis current value and the current quadrature-axis current value to obtain a quadrature-axis current difference value; performing current closed-loop regulation based on the direct-axis current difference value and the quadrature-axis current difference value to obtain a direct-axis voltage value and a quadrature-axis voltage value; converting the direct axis voltage value and the quadrature axis voltage value into two-phase static voltage values ​​by a TPark transformation; obtaining a bus voltage value of the electric drive system; deriving the motor drive signal by performing pulse width modulation based on the bus voltage value and the two-phase quiescent voltage value; Characterized in that it comprises A method for controlling an electric drive system of a vehicle according to any one of claims 1 to 6.

8. A motor, a motor controller, a current sensor, a position sensor, and a processor. Including, The current sensor collects three-phase current values ​​of the motor; The position sensor collects position values ​​of the motor; The processor is connected to the motor controller, the current sensor, and the position sensor, and executes the control method for a vehicle electric drive system according to any one of claims 1 to 7. Electric drive system.

9. A heating demand system, a vehicle controller, and an electric drive system as claimed in claim 8, the vehicle controller transmitting a vehicle heating demand signal when the vehicle controller determines that there is a heating demand in the heating demand system; The electric drive system is connected to the vehicle controller and forms a heat transfer circuit with the heating demand system. vehicle.

10. The heating demand system includes a power battery.

10. The vehicle of claim 9.

11. The heating demand system includes a passenger compartment and an air conditioning system of a vehicle. A vehicle as claimed in claim 9 or 10.

Images