Auxiliary heating control method for electric drive system

Abstract

The present invention discloses an auxiliary heating control method for an electric drive system, comprising: determining whether motor auxiliary heating is required, and if so, determining the vehicle operation and charging gun plug-in status, and based on this, determining whether the electric drive system meets the auxiliary heating conditions, and if so, actively performing auxiliary heating; determining whether the electric drive system meets the full-load heating conditions, and if so, performing full-load heating; adjusting the d-axis current of the motor winding according to the motor temperature and increasing the IGBT switching frequency; determining whether the full-load exit conditions are met according to the coolant temperature and the IGBT temperature, and if so, performing general heating; detecting the vehicle status and the electric drive status, and adjusting the d-axis current of the motor winding; determining whether the auxiliary heating exit conditions are met, and if so, exiting. The auxiliary heating control method for an electric drive system of the present invention comprehensively utilizes the heat of the entire vehicle, transfers the waste heat of the electric drive system to the battery through a heat pump air conditioner, and heats the battery, thereby saving component costs.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to an auxiliary heating control method for an electric drive system. Background Art

[0002] The chemical activity of new energy vehicle batteries decreases in low-temperature environments, resulting in low charge and discharge currents. This slow charging is particularly severe. Therefore, in low-temperature environments, batteries must be heated to a suitable temperature before charging or discharging.

[0003] At present, the use of PTC water heaters to heat power batteries requires the addition of an additional PTC component in the front compartment, which is not conducive to the space utilization of the front compartment. At the same time, the heating of the PTC during the operation of the vehicle requires separate energy consumption, which will affect the vehicle's range.

[0004] Therefore, there is an urgent need for an auxiliary heating control method for an electric drive system. Summary of the Invention

[0005] The purpose of the present invention is to provide an auxiliary heating control method for an electric drive system to solve the problems in the above-mentioned prior art. It can comprehensively utilize the heat of the entire vehicle, transfer the waste heat generated by the electric drive system during operation to a heat pump air conditioner, and then transfer the heat to the battery through the heat pump air conditioner, thereby heating the battery. This can save component costs, reduce heating energy consumption, and increase the vehicle's cruising range.

[0006] The present invention provides an auxiliary heating control method for an electric drive system, which includes:

[0007] Determine whether the vehicle currently requires motor-assisted heating. If so, determine the vehicle's operating status and the charging gun's plug-in status.

[0008] Based on the vehicle's operating status and the charging plug's plug-in status, the system determines whether the electric drive system meets the auxiliary heating conditions. If so, the system enters the active auxiliary heating mode.

[0009] Determine whether the electric drive system meets the full-load heating conditions. If so, enter the full-load heating state.

[0010] After entering the full-load heating state, the D-axis current of the motor winding is adjusted according to the motor temperature, and the switching frequency of the IGBT of the motor controller is increased to transfer the heat generated by the drive motor winding and the IGBT of the motor controller to the battery system through the air conditioning system;

[0011] According to the coolant temperature and IGBT temperature, it is judged whether the full-load heating state exit condition is met. If so, the full-load heating state is exited and the general auxiliary heating state is entered;

[0012] After entering the general auxiliary heating state, the vehicle status and electric drive status are detected in real time, and the D-axis current of the motor winding is adjusted to transfer the heat of the drive motor winding to the battery system through the air conditioning system;

[0013] Determine whether the auxiliary heating exit conditions are met. If so, exit the auxiliary heating state.

[0014] In the auxiliary heating control method for the electric drive system as described above, preferably, the step of determining whether the vehicle currently requires motor auxiliary heating specifically includes:

[0015] The vehicle controller determines whether the vehicle currently requires motor-assisted heating based on whether it receives an auxiliary heating command from the battery. If the vehicle controller receives an auxiliary heating command from the battery, the vehicle currently requires motor-assisted heating.

[0016] In the auxiliary heating control method for the electric drive system described above, preferably, if it is determined that the vehicle currently requires motor auxiliary heating, then before determining the vehicle operating state and the charging plug connection state, the auxiliary heating control method for the electric drive system further includes:

[0017] The outlet of the three-way valve that controls the flow into the radiator is closed, and the outlet connected to the motor controller is opened. The three-way valve is arranged between the first heat exchanger used for heat exchange between the electric drive system and the air-conditioning system and the radiator. The radiator is connected to the motor controller, and the motor controller is connected to the vehicle controller.

[0018] In the auxiliary heating control method for the electric drive system as described above, preferably, the determining of the vehicle operation state and the charging gun plugging state specifically includes:

[0019] The vehicle controller determines the vehicle's operating status and the charging gun's plug-in status.

[0020] In the auxiliary heating control method for the electric drive system as described above, preferably, judging whether the electric drive system meets the auxiliary heating conditions based on the vehicle operating state and the charging plug plug state specifically includes:

[0021] If the vehicle is in operation, the drive motor and motor controller remain in their current states without adjustment, and the waste heat of the current drive motor is directly transferred to the battery system through the first heat exchanger, the air conditioning system, and the second heat exchanger. The first heat exchanger is used to exchange heat between the electric drive system and the air conditioning system, and the second heat exchanger is used to exchange heat between the battery system and the air conditioning system.

[0022] If the charging gun is plugged in and in charging state, the vehicle controller sends an auxiliary heating command to the motor controller, entering the active auxiliary heating mode of the electric drive system.

[0023] In the auxiliary heating control method for the electric drive system as described above, preferably, the step of determining whether the electric drive system meets the full-load heating condition specifically includes:

[0024] The motor controller obtains current vehicle status information, wherein the vehicle status information includes a gear signal or an electronic parking status;

[0025] The motor controller determines whether the motor state of the drive motor meets the full-load heating condition, wherein the motor state includes motor temperature, motor speed or motor torque;

[0026] If the motor state of the drive motor meets the full-load heating condition, the electric drive system is controlled to perform full-load heating.

[0027] In the auxiliary heating control method for the electric drive system as described above, preferably, after entering the full-load heating state, adjusting the d-axis current of the motor winding according to the motor temperature and increasing the switching frequency of the IGBT of the motor controller specifically include:

[0028] The d-axis current of the motor winding rises to a current range near the first preset d-axis current threshold, and the d-axis current of the motor winding is adjusted according to the motor temperature to stabilize the motor temperature within a temperature range near the first motor temperature threshold; at the same time, the switching frequency of the IGBT is increased from the first frequency threshold to the second frequency threshold, the first frequency threshold is 9.5k-10.5k, and the second frequency threshold is 14.5k-15.5k.

[0029] In the auxiliary heating control method for the electric drive system as described above, preferably, the step of determining whether a full-load heating state exit condition is satisfied based on the coolant temperature and the IGBT temperature, and if so, exiting the full-load heating state and entering the general auxiliary heating state, specifically includes:

[0030] When the switching frequency of the IGBT of the motor controller is in the frequency increasing state, if the coolant temperature is greater than the coolant temperature threshold or the temperature of the IGBT is greater than the first IGBT temperature threshold, the switching frequency of the IGBT is reduced to the first frequency threshold, and the full-load heating state is exited and the general auxiliary heating state is entered.

[0031] In the auxiliary heating control method for the electric drive system as described above, preferably, after entering the general auxiliary heating state, the real-time detection of the vehicle state and the electric drive state and the adjustment of the d-axis current of the motor winding specifically include:

[0032] The d-axis current channel and the q-axis current channel of the motor winding of the motor controller are turned on, and while ensuring that the q-axis current is zero and no torque is generated, the d-axis current is gradually increased: when the d-axis current is less than a first preset d-axis current threshold, the current increase / decrease gradient is a first step length; when the d-axis current is greater than the first preset d-axis current threshold, the current increase / decrease gradient is a second step length, wherein the first step length is greater than the second step length, and the d-axis current channel and the q-axis current channel are perpendicular to each other;

[0033] If it is detected that the motor temperature is greater than a second motor temperature threshold, the motor temperature is lowered by reducing the current value and reaching a temperature equilibrium state within a temperature range near the second motor temperature threshold, wherein the second motor temperature threshold is lower than the first motor temperature threshold.

[0034] In the auxiliary heating control method for the electric drive system as described above, preferably, the auxiliary heating exit condition includes: the motor controller monitors that the motor temperature is greater than a third motor temperature threshold or the IGBT temperature is greater than a second IGBT temperature threshold, wherein the third motor temperature threshold is greater than the second motor temperature threshold and less than the first motor temperature threshold, and the second IGBT temperature threshold is greater than the first IGBT temperature threshold; or the motor controller monitors that the motor state is abnormal; or the vehicle controller monitors that the vehicle state is abnormal;

[0035] The auxiliary heating control method of the electric drive system further includes:

[0036] After exiting the auxiliary heating state, after the motor temperature and IGBT temperature drop, if the motor temperature is less than the fourth motor temperature threshold and the IGBT temperature is less than the third IGBT temperature threshold, the auxiliary heating mode is re-entered, wherein the fourth motor temperature threshold is less than the second motor temperature threshold, and the third IGBT temperature threshold is less than the first IGBT temperature threshold.

[0037] The present invention provides an auxiliary heating control method for an electric drive system. In a full-load heating state, the heat of the drive motor winding and the heat generated by the switching of the IGBT of the motor controller are both transferred to the battery system through the air-conditioning system. In a general auxiliary heating state, the heat of the drive motor winding is transferred to the battery system through the air-conditioning system. The heat generated by the electric drive system can be transported to the battery system through the air-conditioning system to increase the temperature of the battery, thereby comprehensively utilizing the heat of the entire vehicle. The waste heat of the electric drive system during operation is transferred to the heat pump air-conditioning, and then the heat is transferred to the battery through the heat pump air-conditioning, thereby achieving battery heating and eliminating the need for PTC. Or replacing a PTC with a smaller power can save component costs, which is beneficial to reducing costs, while reducing heating energy consumption, increasing the vehicle's cruising range, and solving the problem of large heat loss in the process of transferring electric drive heat to the battery through the cooling circuit; in the full-load auxiliary heating state, the auxiliary heating power of the electric drive system can be increased by adjusting the switching frequency of the IGBT, and the problem of low heating power of a single motor under low-temperature charging can be optimized; in the general auxiliary heating state, the current increase and decrease steps are divided into different ranges to prevent vehicle shaking caused by auxiliary heating, which can solve the shaking problem of the entire vehicle that is prone to occur when the electric drive system enters and exits the heating mode in the charging state. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0039] Figure 1 A flowchart of an embodiment of an auxiliary heating control method for an electric drive system provided by the present invention;

[0040] Figure 2 A schematic diagram of the working principle of an embodiment of the auxiliary heating control method for an electric drive system provided by the present invention. DETAILED DESCRIPTION

[0041] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure, its application, or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions, and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0042] The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are simply used to distinguish different parts. Terms such as "include" or "comprising" mean that the elements preceding the term include the elements listed after the term, and do not exclude the possibility of also including other elements. Terms such as "upper," "lower," and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be an intervening component between the specific component and the first component or the second component. When a specific component is described as being connected to another component, the specific component may be directly connected to the other component without an intervening component, or may not be directly connected to the other component but have an intervening component.

[0044] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0045] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0046] The current mainstream battery heating technology uses PTC heating, which heats the coolant and, in turn, the battery by increasing the temperature of the PTC resistor wire. This requires adding an additional PTC component to the front compartment, which is not conducive to space utilization. Furthermore, PTC heating requires separate energy consumption during vehicle operation, which affects the vehicle's range. Another battery heating technology is to directly transfer the waste heat from the drive motor to the battery. This involves connecting the motor and battery cooling water circuits in series, and heating the battery through the coolant motor. In this solution, because the motor and drive battery are located relatively far apart, more than half of the heat generated by the motor is lost in the heat transfer circuit, resulting in low heat transfer efficiency.

[0047] like Figure 1 and Figure 2 As shown, the auxiliary heating control method for the electric drive system provided in this embodiment includes the following steps during actual execution:

[0048] Step S1: Determine whether the vehicle currently requires motor-assisted heating. If so, determine the vehicle's operating status and the charging gun's plug-in status.

[0049] Specifically, the vehicle controller determines whether the vehicle currently requires motor-assisted heating based on whether it receives an auxiliary heating command from the battery. If so, the vehicle currently requires motor-assisted heating. The vehicle controller then determines the vehicle's operating status and the status of the charging plug.

[0050] In some embodiments of the present invention, if it is determined that the vehicle currently requires motor auxiliary heating, then before determining the vehicle operating state and the charging plug connection state, the auxiliary heating control method of the electric drive system further includes:

[0051] Step S1', control the outlet of the three-way valve flowing into the radiator to be closed, and open the outlet connected to the motor controller, wherein the three-way valve is arranged between the first heat exchanger used for heat exchange between the electric drive system and the air-conditioning system and the radiator, the radiator is connected to the motor controller, and the motor controller is connected to the vehicle controller.

[0052] Step S2: Determine whether the electric drive system meets the auxiliary heating conditions based on the vehicle's operating status and the charging gun's plug-in status. If so, enter the active auxiliary heating mode of the electric drive system.

[0053] In one embodiment of the auxiliary heating control method for an electric drive system of the present invention, step S2 may specifically include:

[0054] Step S21: If the vehicle is in operation, the drive motor and the motor controller remain in their current state without adjustment, and Figure 2 As shown, the waste heat of the current drive motor is directly transferred to the battery system through the first heat exchanger, the air-conditioning system and the second heat exchanger in sequence. The first heat exchanger is used to exchange heat between the electric drive system and the air-conditioning system, and the second heat exchanger is used to exchange heat between the battery system and the air-conditioning system.

[0055] Step S22: If the charging gun is in the charging state, the vehicle controller sends an auxiliary heating instruction to the motor controller to enter the active auxiliary heating mode of the electric drive system.

[0056] Step S3: Determine whether the electric drive system meets the full-load heating condition. If so, enter the full-load heating state.

[0057] In one embodiment of the auxiliary heating control method for an electric drive system of the present invention, step S3 may specifically include:

[0058] Step S31 : The motor controller obtains current vehicle status information, where the vehicle status information includes a gear signal or an electronic parking status.

[0059] Step S32: The motor controller determines whether the motor state of the drive motor meets the full-load heating condition, where the motor state includes the motor temperature, the motor speed, or the motor torque.

[0060] It should be noted that the present invention does not specifically limit the types of vehicle status information and motor status information.

[0061] Step S33: If the motor state of the drive motor meets the full-load heating condition, control the electric drive system to perform full-load heating.

[0062] By judging the vehicle state and determining whether to control the electric drive system to perform full-load heating, the safety of full-load auxiliary heating can be improved.

[0063] Step S4: After entering the full-load heating state, adjust the d-axis current of the motor winding according to the motor temperature, and increase the switching frequency of the IGBT of the motor controller to transfer the heat of the drive motor winding and the heat generated by the on-off of the IGBT of the motor controller to the battery system through the air-conditioning system.

[0064] Specifically, the d-axis current of the motor winding rises to a current range near a first preset d-axis current threshold, and the d-axis current of the motor winding is adjusted according to the motor temperature to stabilize the motor temperature within a temperature range near the first motor temperature threshold. Simultaneously, the switching frequency of the IGBT is increased from a first frequency threshold to a second frequency threshold. The first frequency threshold is 9.5k-10.5k (e.g., 10k), and the second frequency threshold is 14.5k-15.5k (e.g., 15k). It should be noted that the present invention does not specifically limit the values ​​of the first and second frequency thresholds.

[0065] Step S5: Determine whether the full-load heating state exit condition is met based on the coolant temperature and the IGBT temperature. If so, exit the full-load heating state and enter the general auxiliary heating state.

[0066] In the case of low-temperature charging (the initial stage of electric drive auxiliary heating, i.e., the full-load heating state), the heat generated by the electric drive auxiliary heating is composed of the heat of the motor windings under the auxiliary heating condition and the heat generated by the switching of the IGBT of the motor controller. In the case of high-temperature charging (the later stage of electric drive auxiliary heating, i.e., the general auxiliary heating state), the heat generated by the electric drive auxiliary heating is composed of the heat of the motor windings under the auxiliary heating condition. Specifically, when the switching frequency of the IGBT of the motor controller is in the frequency-up state, if the coolant temperature is greater than the coolant temperature threshold or the temperature of the IGBT is greater than the first IGBT temperature threshold, the switching frequency of the IGBT is reduced to the first frequency threshold (e.g., 10k), and the full-load heating state is exited, and the general auxiliary heating state is entered.

[0067] Step S6: After entering the general auxiliary heating state, the vehicle state and electric drive state are detected in real time, and the d-axis current of the motor winding is adjusted to transfer the heat of the drive motor winding to the battery system through the air conditioning system.

[0068] In one embodiment of the auxiliary heating control method for an electric drive system of the present invention, step S6 may specifically include:

[0069] Step S61: Open the d-axis current channel and the q-axis current channel of the motor winding of the motor controller, and ensure that the q-axis current (i q ) is 0 and no torque is generated, gradually increase the d-axis current (i d ):D-axis current (i d )<first preset d-axis current threshold value (for example, 150A), the current increase / decrease gradient is the first step length (for example, 5A); under the condition that the d-axis current (i d )>under a first preset d-axis current threshold (for example, 150A), the current increase / decrease gradient is a second step length (for example, 5A), wherein the first step length is greater than the second step length, and the d-axis current channel and the q-axis current channel are perpendicular.

[0070] After entering the auxiliary heating state, by dividing the current increase and decrease step size into different ranges, vehicle shaking caused by auxiliary heating can be prevented. It should be noted that the present invention does not specifically limit the values ​​of the first preset d-axis current threshold, the first step size, and the second step size.

[0071] Step S62: If it is detected that the motor temperature is greater than a second motor temperature threshold (for example, 110°C), the motor temperature is lowered by reducing the current value, and a temperature equilibrium state is reached within a temperature range near the second motor temperature threshold, wherein the second motor temperature threshold is less than the first motor temperature threshold.

[0072] Considering that the motor temperature will increase as the auxiliary heating is turned on for a longer time, if the motor temperature is detected to be greater than 110°C, the motor temperature is lowered by reducing the current value and reaching a temperature equilibrium state near the second motor temperature threshold.

[0073] Step S7: determine whether the auxiliary heating exit condition is met, and if so, exit the auxiliary heating state.

[0074] Among them, the auxiliary heating exit conditions include: the motor controller monitors that the motor temperature is greater than the third motor temperature threshold (for example, 120°C) or the IGBT temperature is greater than the second IGBT temperature threshold (for example, 60°C), wherein the third motor temperature threshold is greater than the second motor temperature threshold and less than the first motor temperature threshold, and the second IGBT temperature threshold is greater than the first IGBT temperature threshold; or the motor controller monitors that the motor state is abnormal (for example, unexpected torque, etc.); or the vehicle controller monitors that the vehicle state is abnormal (for example, shaking, etc.). When any of the above auxiliary heating exit conditions is met, the auxiliary heating mode should be exited immediately.

[0075] Furthermore, in some embodiments of the present invention, the auxiliary heating control method of the electric drive system further includes:

[0076] Step S8, after exiting the auxiliary heating state, after the motor temperature and IGBT temperature drop, if the motor temperature is less than the fourth motor temperature threshold value (for example, 70°C), and the IGBT temperature is less than the third IGBT temperature threshold value (for example, 40°C), then re-enter the auxiliary heating mode, wherein the fourth motor temperature threshold value is less than the second motor temperature threshold value, and the third IGBT temperature threshold value is less than the first IGBT temperature threshold value.

[0077] The auxiliary heating control method of the electric drive system provided by the embodiment of the present invention, in the full-load heating state, the heat of the drive motor winding and the heat generated by the switching of the IGBT of the motor controller are both transferred to the battery system through the air-conditioning system. In the general auxiliary heating state, the heat of the drive motor winding is transferred to the battery system through the air-conditioning system. The heat generated by the electric drive system can be transported to the battery system through the air-conditioning system to increase the temperature of the battery, and the heat of the entire vehicle is comprehensively utilized. The waste heat during the operation of the electric drive system is transferred to the heat pump air conditioner, and then the heat is transferred to the battery through the heat pump air conditioner, thereby achieving battery heating, and the PT can be eliminated. C or replacing a PTC with a smaller power can save component costs, which is beneficial to reducing costs, while reducing heating energy consumption, increasing the vehicle's cruising range, and solving the problem of large heat loss in the process of transferring electric drive heat to the battery through the cooling circuit; in the full-load auxiliary heating state, the auxiliary heating power of the electric drive system can be increased by adjusting the switching frequency of the IGBT, and the problem of low heating power of a single motor under low-temperature charging can be optimized; in the general auxiliary heating state, the current increase and decrease steps are divided into different ranges to prevent vehicle shaking caused by auxiliary heating, which can solve the problem of vehicle shaking that is prone to occur when the electric drive system enters and exits the heating mode in the charging state.

[0078] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0079] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. An auxiliary heating control method for an electric drive system, characterized in that: include: Determine whether the vehicle currently requires motor-assisted heating. If so, determine the vehicle's operating status and the charging gun's plug-in status. Based on the vehicle's operating status and the charging plug's plug-in status, the system determines whether the electric drive system meets the auxiliary heating conditions. If so, the system enters the active auxiliary heating mode. Determine whether the electric drive system meets the full-load heating conditions. If so, enter the full-load heating state. After entering the full-load heating state, the D-axis current of the motor winding is adjusted according to the motor temperature, and the switching frequency of the IGBT of the motor controller is increased to transfer the heat generated by the drive motor winding and the IGBT of the motor controller to the battery system through the air conditioning system; According to the coolant temperature and IGBT temperature, it is judged whether the full-load heating state exit condition is met. If so, the full-load heating state is exited and the general auxiliary heating state is entered; After entering the general auxiliary heating state, the vehicle status and electric drive status are detected in real time, and the D-axis current of the motor winding is adjusted to transfer the heat of the drive motor winding to the battery system through the air conditioning system; Determine whether the auxiliary heating exit condition is met. If so, exit the auxiliary heating state. After entering the full-load heating state, the d-axis current of the motor winding is adjusted according to the motor temperature, and the switching frequency of the IGBT of the motor controller is increased, which specifically includes: The d-axis current of the motor winding rises to a current range near the first preset d-axis current threshold, and the d-axis current of the motor winding is adjusted according to the motor temperature to stabilize the motor temperature within a temperature range near the first motor temperature threshold; at the same time, the switching frequency of the IGBT is increased from the first frequency threshold to the second frequency threshold, the first frequency threshold is 9.5k-10.5k, and the second frequency threshold is 14.5k-15.5k.

2. The auxiliary heating control method of the electric drive system according to claim 1, characterized in that: The determining whether the vehicle currently requires motor-assisted heating specifically includes: The vehicle controller determines whether the vehicle currently requires motor-assisted heating based on whether it receives an auxiliary heating command from the battery. If the vehicle controller receives an auxiliary heating command from the battery, the vehicle currently requires motor-assisted heating.

3. The auxiliary heating control method of the electric drive system according to claim 1, characterized in that: If it is determined that the vehicle currently requires motor auxiliary heating, then before determining the vehicle operating state and the charging plug connection state, the auxiliary heating control method of the electric drive system further includes: The outlet of the three-way valve that controls the flow into the radiator is closed, and the outlet connected to the motor controller is opened. The three-way valve is arranged between the first heat exchanger used for heat exchange between the electric drive system and the air-conditioning system and the radiator. The radiator is connected to the motor controller, and the motor controller is connected to the vehicle controller.

4. The auxiliary heating control method of the electric drive system according to claim 3, characterized in that: The determination of the vehicle operation status and the charging gun insertion status specifically includes: The vehicle controller determines the vehicle's operating status and the charging gun's plug-in status.

5. The auxiliary heating control method of the electric drive system according to claim 4, characterized in that: The step of determining whether the electric drive system meets the auxiliary heating conditions based on the vehicle operation status and the charging gun insertion status specifically includes: If the vehicle is in operation, the drive motor and motor controller remain in their current states without adjustment, and the waste heat of the current drive motor is directly transferred to the battery system through the first heat exchanger, the air conditioning system, and the second heat exchanger. The first heat exchanger is used to exchange heat between the electric drive system and the air conditioning system, and the second heat exchanger is used to exchange heat between the battery system and the air conditioning system. If the charging gun is plugged in and in charging state, the vehicle controller sends an auxiliary heating command to the motor controller, entering the active auxiliary heating mode of the electric drive system.

6. The auxiliary heating control method of the electric drive system according to claim 1, characterized in that: The determining whether the electric drive system meets the full-load heating condition specifically includes: The motor controller obtains current vehicle status information, wherein the vehicle status information includes a gear signal or an electronic parking status; The motor controller determines whether the motor state of the drive motor meets the full-load heating condition, wherein the motor state includes motor temperature, motor speed or motor torque; If the motor state of the drive motor meets the full-load heating condition, the electric drive system is controlled to perform full-load heating.

7. The auxiliary heating control method of the electric drive system according to claim 1, characterized in that: The determination of whether the full-load heating state exit condition is met based on the coolant temperature and the IGBT temperature, and if so, exiting the full-load heating state and entering the general auxiliary heating state, specifically includes: When the switching frequency of the IGBT of the motor controller is in the frequency increasing state, if the coolant temperature is greater than the coolant temperature threshold or the temperature of the IGBT is greater than the first IGBT temperature threshold, the switching frequency of the IGBT is reduced to the first frequency threshold, and the full-load heating state is exited and the general auxiliary heating state is entered.

8. The auxiliary heating control method of the electric drive system according to claim 7, characterized in that: After entering the general auxiliary heating state, the real-time detection of the vehicle state and the electric drive state and the adjustment of the d-axis current of the motor winding specifically include: The d-axis current channel and the q-axis current channel of the motor winding of the motor controller are turned on, and while ensuring that the q-axis current is zero and no torque is generated, the d-axis current is gradually increased: when the d-axis current is less than a first preset d-axis current threshold, the current increase / decrease gradient is a first step length; when the d-axis current is greater than the first preset d-axis current threshold, the current increase / decrease gradient is a second step length, wherein the first step length is greater than the second step length, and the d-axis current channel and the q-axis current channel are perpendicular to each other; If it is detected that the motor temperature is greater than a second motor temperature threshold, the motor temperature is lowered by reducing the current value and reaching a temperature equilibrium state within a temperature range near the second motor temperature threshold, wherein the second motor temperature threshold is lower than the first motor temperature threshold.

9. The auxiliary heating control method of the electric drive system according to claim 8, characterized in that: The auxiliary heating exit condition includes: the motor controller detects that the motor temperature is greater than a third motor temperature threshold or the IGBT temperature is greater than a second IGBT temperature threshold, wherein the third motor temperature threshold is greater than the second motor temperature threshold and less than the first motor temperature threshold, and the second IGBT temperature threshold is greater than the first IGBT temperature threshold; or the motor controller detects that the motor state is abnormal; or the vehicle controller detects that the vehicle state is abnormal; The auxiliary heating control method of the electric drive system further includes: After exiting the auxiliary heating state, after the motor temperature and IGBT temperature drop, if the motor temperature is less than the fourth motor temperature threshold and the IGBT temperature is less than the third IGBT temperature threshold, the auxiliary heating mode is re-entered, wherein the fourth motor temperature threshold is less than the second motor temperature threshold, and the third IGBT temperature threshold is less than the first IGBT temperature threshold.

Images