A method and device for controlling heating of a motor, and a vehicle

Abstract

The application provides a motor efficiency reduction heating control method and device and a vehicle. The optimal balance between efficiency and noise is achieved by shortening the noise deterioration interval and combining real-time feedback adjustment. The method comprises the following steps: in response to the motor efficiency reduction heating function being turned on, determining the motor efficiency reduction heating target speed under the current driving working condition; before the target speed of the motor changes to the efficiency reduction heating target speed, reading a set of noise reduction parameters matched with the current driving working condition from the pre-stored control parameter set and preloading; making the current target speed of the motor change to the efficiency reduction heating target speed according to a preset rule; during the current target speed changing process and the running stage after reaching the efficiency reduction heating target speed, collecting the running state feedback signal of the motor in real time and constructing an evaluation function; taking the noise reduction parameters as optimization variables, and taking the minimum value of the evaluation function as the optimization target, the specific value of the noise reduction parameters is adjusted in real time within the preset parameter constraint range of the noise reduction parameters.

Description

Technical Field

[0001] This application relates to the field of motor control, specifically to a method, device, and vehicle for controlling the degraded heating of a motor. Background Technology

[0002] As the range reduction problem of electric vehicles in low-temperature environments becomes increasingly prominent, the inefficient heating technology that utilizes the heat recovery of the electric drive system itself is gradually becoming one of the mainstream thermal management methods. This technology artificially increases the copper and iron losses of the motor by introducing abnormal excitation currents into the motor control (such as increasing the negative value of Id, injecting harmonics, and deepening field weakening), thereby achieving heating of the motor body, inverter, or battery system.

[0003] However, existing de-efficiency heating control strategies have the following prominent problems:

[0004] Insufficient noise control: In a specific motor speed range (such as near the resonant frequency), harmonic current or pulsating torque can easily excite mechanical structure resonance, producing high-frequency howling or vibration noise, which seriously affects NVH performance.

[0005] Efficiency and noise are difficult to balance: to heat up quickly, power loss needs to be increased, but strong excitation is more likely to cause noise; if noise is suppressed too much, heating efficiency will decrease and cannot meet the thermal management requirements in low-temperature cold start scenarios.

[0006] Lack of dynamic adaptability: Traditional solutions rely on bench calibration and do not take into account changes in actual driving conditions (such as vehicle speed fluctuations and load disturbances), resulting in unstable control performance; No closed-loop feedback mechanism: Most solutions are open-loop control and cannot be adjusted according to real-time noise or temperature response, which poses a risk of overheating or sudden NVH changes. Summary of the Invention

[0007] This application provides a method, device, and vehicle for controlling the degraded heating of an electric motor, which achieves an optimal balance between efficiency and noise by shortening the noise degradation range and combining real-time feedback adjustment.

[0008] The technical solution of this application is as follows:

[0009] In a first aspect, this application provides a method for controlling the degraded heating of an electric motor, comprising:

[0010] In response to the activation of the motor's degraded heating function, the target speed for degraded heating of the motor under the current driving conditions is determined;

[0011] Before the target speed of the motor changes to the target speed of the de-efficiency heating, the initial value of the noise reduction parameter that matches the current driving condition is read from the pre-stored control parameter set and preloaded;

[0012] The current target speed of the motor is adjusted to change towards the target speed of the degraded heating according to a preset rule;

[0013] During the current target speed change process and the operation phase after reaching the target speed for degraded heating, the operating status feedback signal of the motor is collected in real time and an evaluation function is constructed.

[0014] The value of the noise reduction parameter is used as the optimization variable, and the minimum value of the evaluation function is taken as the optimization objective. The specific value of the noise reduction parameter is adjusted in real time within the preset parameter constraint range of the noise reduction parameter.

[0015] The evaluation function includes at least heating power-related terms and noise-related terms, and the weight of each related term is dynamically allocated according to the current driving conditions.

[0016] By preloading noise reduction parameters before the target speed begins to change, the control gap problem caused by parameter loading delay in traditional solutions is solved. Since the noise reduction parameters are in place the moment the degraded heating function is activated, the motor is in an optimized noise control state from the first moment of acceleration, avoiding transient noise spikes caused by parameter lag.

[0017] By adjusting the target rotation speed according to a preset pattern towards the de-efficiency heating target speed, the duration of noise transmission through the noise-sensitive zone is significantly shortened while maintaining heating efficiency. Although the instantaneous noise amplitude may increase slightly, based on the characteristics of human hearing, a very short-term noise surge is subjectively perceived as far weaker than a longer-lasting moderate noise. This strategy of sacrificing short-term noise for overall comfort achieves substantial optimization of the subjective perception of noise.

[0018] The real-time adjustment mechanism, which aims to minimize the value of the evaluation function, ensures that the noise reduction parameter value always follows the changes in motor status: when heating efficiency is insufficient, the optimization direction automatically tilts towards increasing power; when noise exceeds the standard, the optimization direction automatically tilts towards suppressing noise. This dynamic adaptive capability can solve the problem of unstable performance of traditional open-loop control under fluctuating operating conditions.

[0019] In some possible embodiments, the conditions under which the degraded heating function is activated include:

[0020] The ambient temperature where the vehicle is located is lower than the first preset temperature threshold.

[0021] The vehicle's power battery temperature is below the second preset temperature threshold;

[0022] The vehicle's power battery SOC is higher than the preset charge threshold.

[0023] The vehicle's air conditioning system requested heating, but the actual output power of the PTC heater could not meet the heating needs of the passenger compartment.

[0024] The current speed of the motor is within the preset motor speed range and the current output torque of the motor is within the preset motor torque range.

[0025] For example, if the first and second preset temperature thresholds are 0°C, low temperature is the root cause of reduced range and increased heating demand. At this time, battery activity decreases and PTC heating efficiency decreases. Simply relying on PTC may not be able to quickly raise the cabin temperature, and an additional heat source is required.

[0026] When the SOC of the power battery is higher than the preset charge threshold, it means that the battery SOC is sufficient. Since heating will increase energy consumption due to degradation, it is necessary to ensure that the battery has enough charge to support it and avoid over-discharge of the battery due to heating, which will affect the normal driving of the vehicle or subsequent power output.

[0027] The fact that the air conditioner requests heating and the PTC power is insufficient is a necessary judgment to start the degraded heating system. It indicates that the user has a clear heating demand, but the existing heating method (PTC) is no longer able to meet it, and it is necessary to introduce the heat generated by the motor as a supplement.

[0028] When the current speed of the motor is within the preset motor speed range and the current output torque of the motor is within the preset motor torque range, the operating conditions of the motor are limited to a safe range for starting, ensuring that the vehicle's power performance is not disturbed.

[0029] In summary, these conditions together ensure that degraded heating starts only when truly needed, with sufficient power, and under safe conditions for the motor, thus achieving a synergistic balance between thermal management and power control.

[0030] In some possible embodiments, the current driving conditions include cold start conditions, urban low-speed conditions, and high-speed driving conditions, and the weight allocation strategies corresponding to each condition are as follows:

[0031] Under cold start conditions, the weight of the heating power-related item is higher than the weight of the noise-related item;

[0032] Under low-speed urban conditions, the weight of the heating power-related term is equal to the weight of the noise-related term;

[0033] Under high-speed driving conditions, the weight of the noise-related item is higher than the weight of the heating power-related item.

[0034] During cold start conditions, since the vehicle has just started, the ambient temperature is low and the passenger compartment needs to be heated up quickly. The optimization direction at this time prioritizes meeting the target heating power. By giving a higher weight to heating power-related items than noise-related items, a certain degree of noise increase is allowed in exchange for rapid heating, ensuring that the thermal comfort of the passenger compartment is prioritized in low-temperature environments.

[0035] In urban low-speed conditions, the vehicle speed is low and the environmental noise is relatively complex, and users have a certain tolerance for noise. By setting the weight of the heating power-related items to be equal to the weight of the noise-related items, noise control is taken into account while ensuring basic heating, avoiding insufficient heating due to excessive pursuit of quietness, and adapting to the characteristics of frequent starts and stops and vehicle speed fluctuations in urban conditions.

[0036] Under high-speed driving conditions, where vehicle speed is high and wind and tire noise are already present, users are sensitive to abnormal electromagnetic noise. By setting the weight of noise-related items higher than that of heating power-related items, electromagnetic noise is suppressed first, allowing for a slight decrease in heating efficiency in exchange for quiet comfort, thus avoiding motor noise interfering with the driving experience at high speeds.

[0037] In some possible embodiments, the noise reduction parameters include harmonic injection amplitude and dead-zone compensation gain;

[0038] The harmonic injection amplitude is the amplitude of the 5th harmonic component and the amplitude of the 7th harmonic component injected into the theoretical output current of the motor determined based on the target speed of the degraded heating.

[0039] The preset constraint range of the harmonic injection amplitude is 5% to 10% of the theoretical output current of the motor determined based on the target speed of the degraded heating.

[0040] The dead-time compensation gain is the gain coefficient used to compensate for voltage distortion caused by the dead time of the inverter.

[0041] The preset constraint range for the dead zone compensation gain is 10% to 20% of the nominal compensation value.

[0042] The harmonic injection amplitude is set to 5%~10% of the theoretical output current of the motor. The lower limit of 5% ensures effective cancellation of electromagnetic noise of the motor body, and the upper limit of 10% avoids overcompensation that may cause new noise and excessive current stress. The dead zone compensation gain is set to 10%~20% of the nominal compensation value. The lower limit of 10% compensates for insufficient compensation caused by non-ideal hardware characteristics, and the upper limit of 20% prevents overcompensation that may cause system oscillation. The two parameter ranges are obtained through bench calibration, providing an optimization space that balances compensation effectiveness, system safety and control stability for real-time adjustment.

[0043] In some possible embodiments, the step of adjusting the specific value of the noise reduction parameter in real time within the preset parameter constraints of the noise reduction parameter, with the noise reduction parameter as an adjustable variable and the evaluation function as the objective, includes:

[0044] Based on the current parameter value of the noise reduction parameter, parameter search is performed in the increasing and decreasing directions with a preset iteration step size, resulting in four search directions: increasing harmonic injection amplitude, decreasing harmonic injection amplitude, increasing dead zone compensation gain, and decreasing dead zone compensation gain.

[0045] Calculate the current parameter value and the evaluation function value corresponding to each of the search directions;

[0046] Compare the evaluation function values ​​corresponding to each search direction with the current parameter value. If the evaluation function value of at least one search direction is less than the evaluation function value of the current parameter value, then select the search direction that minimizes the evaluation function value as the parameter adjustment direction, and update the values ​​of the harmonic current injection amplitude and / or the dead time compensation gain with the preset iteration step size.

[0047] If the evaluation function value corresponding to all search directions is greater than or equal to the evaluation function value corresponding to the current parameter value, then the values ​​of the harmonic current injection amplitude and the dead time compensation gain remain unchanged.

[0048] Repeat the above search and comparison process until the evaluation function value converges to a local optimum or reaches the preset maximum number of iterations.

[0049] By searching and comparing evaluation function values ​​in four directions based on the current parameter values, the method can autonomously perceive the comprehensive impact of parameter changes on heating efficiency and noise levels, and continuously iterate and adjust in the direction of decreasing evaluation function values, thereby converging to the local optimal parameter combination under the current operating conditions. When the motor state changes and causes the evaluation function value to rise again, the method can restart the optimization process, so that the noise reduction parameters always follow the dynamic operating conditions and remain optimal in real time. At the same time, by keeping the parameters unchanged near the optimal point, the method avoids invalid oscillations caused by measurement disturbances, and achieves the synergistic effect of autonomous optimization, dynamic tracking and steady-state maintenance.

[0050] In some possible embodiments, during the real-time adjustment of the harmonic current injection amplitude and the dead time compensation gain, if a certain search direction causes the harmonic current injection amplitude to exceed the preset value range of the harmonic injection amplitude and / or the dead time compensation gain to exceed the preset value range of the dead time compensation gain, then the search direction is discarded, and only the evaluation function values ​​within the effective search directions are calculated and compared.

[0051] If the current value of the harmonic current injection amplitude is located at the upper or lower limit of the preset range of the harmonic injection amplitude, and / or the current value of the dead time compensation gain is located at the upper or lower limit of the preset range of the dead time compensation gain, if the search direction that exceeds the corresponding preset range is discarded and all valid search directions cause the evaluation function value to increase, then the current values ​​of the harmonic current injection amplitude and the dead time compensation gain are determined to be local optimal values ​​under the constraint condition, and parameter adjustment is stopped.

[0052] When the operating state of the motor changes and the value of the evaluation function rises again, the optimization process aimed at minimizing the value of the evaluation function is restarted, and parameter optimization continues under the new operating state of the motor.

[0053] A boundary constraint handling mechanism is introduced during the real-time adjustment of noise reduction parameters: when the search direction exceeds the preset range of 5%~10% of the harmonic injection amplitude or 10%~20% of the dead zone compensation gain, it is discarded, and optimization is only allowed within the effective range; when the parameter is already at the boundary and all directions within the boundary cause the evaluation function value to increase, the current value is determined to be the local optimum under the constraint and the adjustment is stopped; when the change in the running state causes the evaluation function value to rise again, the optimization process is automatically restarted to ensure that the parameter always dynamically converges to the real-time optimum value within the safe boundary.

[0054] In some possible embodiments, the pre-stored set of control parameters is a noise optimization MAP table obtained through bench calibration, which stores the target speed for reduced heating and the initial values ​​of noise reduction parameters under different driving conditions.

[0055] By pre-constructing a noise optimization MAP table through bench calibration, the target speed for reduced heating under different operating conditions is associated with and stored with the initial values ​​of noise reduction parameters. This allows the system to quickly read and preload the matching initial parameters based on the current operating conditions when the function is activated. This mechanism solves the cold start problem of online optimization, ensuring a better noise suppression effect from the start of control, while providing a reliable initial benchmark for subsequent real-time adjustments, avoiding problems such as long optimization time or getting trapped in local suboptimal conditions due to improper initial parameters.

[0056] In some possible embodiments, the current target speed of the motor changes toward the degraded heating target speed according to a preset gradient, the gradient being configured to shorten the duration of the noise degradation range while ensuring heating efficiency.

[0057] By setting a preset gradient, the target rotational speed changes towards the degraded heating target value at a controlled rate, significantly reducing the duration of passing through the noise-sensitive region while ensuring heating efficiency. Compared to a slow-rise strategy, although the instantaneous noise amplitude may increase slightly, according to the characteristics of human hearing, a very short-term noise surge is subjectively far weaker than a long-lasting high noise, thus optimizing the overall driving experience. Compared to a step-change strategy, gradient rise avoids the system shock and severe noise caused by instantaneous jumps in current commands, providing a smooth transition process for the pre-loaded noise reduction parameters to take effect, achieving a synergistic balance between heating speed and noise suppression.

[0058] Secondly, this application also provides a heating control device for reducing the efficiency of an electric motor, comprising:

[0059] The target speed determination module is used to determine the target speed of the motor under the current driving conditions in response to the activation of the motor's de-efficiency heating function.

[0060] The noise reduction parameter preloading module is used to read a set of initial values ​​of noise reduction parameters that match the current driving conditions from the pre-stored control parameter set and preload them before the target speed of the motor changes to the target speed of the de-efficiency heating.

[0061] The speed change module is used to change the current target speed of the motor to the target speed of the degraded heating according to a preset rule;

[0062] The evaluation function construction module is used to collect the motor's operating status feedback signal in real time and construct the evaluation function during the current target speed change process and after reaching the degraded heating target speed.

[0063] An optimization module is used to adjust the specific value of the noise reduction parameter in real time within the preset parameter constraint range of the noise reduction parameter, with the value of the noise reduction parameter as an adjustable variable and the evaluation function as the target.

[0064] The evaluation function includes at least heating power-related terms and noise-related terms, and the weight of each related term is dynamically allocated according to the current driving conditions.

[0065] Thirdly, this application also provides a vehicle including the aforementioned degraded heating control device for the electric motor. Attached Figure Description

[0066] Figure 1 This is a flowchart illustrating the method for controlling the degraded heating of a motor in an embodiment of this application.

[0067] Figure 2 This is a schematic diagram of the arrangement S104 in the embodiment of this application;

[0068] Figure 3 This is a structural block diagram of the motor de-efficiency heating control device in the embodiments of this application. Detailed Implementation

[0069] Reference Figure 1 This application provides a method for controlling the degraded heating of an electric motor, including:

[0070] S101, in response to the activation of the motor's degraded heating function, determine the target speed for degraded heating of the motor under the current driving conditions;

[0071] S102, before the target speed of the motor changes to the target speed of the de-efficiency heating, read the initial value of the noise reduction parameter that matches the current driving condition from the pre-stored control parameter set and preload it;

[0072] S103 causes the motor's current target speed to change towards the de-efficiency heating target speed according to a preset rule;

[0073] S104: During the current target speed change process and the operation phase after reaching the target speed for de-efficiency heating, the operating status feedback signal of the motor is collected in real time to construct an evaluation function;

[0074] S105, with the value of the noise reduction parameter as the optimization variable and the minimum value of the evaluation function as the optimization objective, adjusts the specific value of the noise reduction parameter in real time within the preset parameter constraint range of the noise reduction parameter.

[0075] The evaluation function includes at least heating power-related terms and noise-related terms, and the weights of each related term are dynamically allocated according to the current driving conditions.

[0076] In this embodiment, the degraded heating function refers to the function of artificially increasing copper and iron losses in the motor by controlling it to operate in a low-efficiency condition when the power of the PTC heater cannot meet the heating needs of the passenger compartment in a low-temperature vehicle environment. This utilizes the heat generated by the motor's own losses to supplement the heating of the passenger compartment. The technical essence of this degraded heating function is to intentionally convert electrical energy into thermal energy rather than mechanical energy to achieve auxiliary heating of the passenger compartment.

[0077] In step S101, the conditions for activating the degraded heating function include:

[0078] The ambient temperature where the vehicle is located is lower than the first preset temperature threshold.

[0079] The vehicle's power battery temperature is below the second preset temperature threshold;

[0080] The vehicle's power battery SOC is higher than the preset charge threshold.

[0081] The vehicle's air conditioning system requested heating, but the actual output power of the PTC heater could not meet the heating needs of the passenger compartment.

[0082] And the current speed of the motor is within the preset motor speed range and the current output torque of the motor is within the preset motor torque range.

[0083] For example, if the first and second preset temperature thresholds are 0°C, low temperature is the root cause of reduced range and increased heating demand. At this time, battery activity decreases and PTC heating efficiency decreases. Simply relying on PTC may not be able to quickly raise the cabin temperature, and an additional heat source is required.

[0084] When the SOC of the power battery is higher than the preset charge threshold, it means that the battery SOC is sufficient. Since heating will increase energy consumption due to degradation, it is necessary to ensure that the battery has enough charge to support it and avoid over-discharge of the battery due to heating, which will affect the normal driving of the vehicle or subsequent power output.

[0085] The fact that the air conditioner requests heating and the PTC power is insufficient is a necessary indicator to activate the degraded heating system. This means that the user has a clear heating need, but the existing heating method (PTC electric heater) is no longer sufficient, and it is necessary to introduce a motor to generate heat as a supplement.

[0086] When the current speed of the motor is within the preset motor speed range and the current output torque of the motor is within the preset motor torque range, the operating conditions of the motor are limited to a safe range during startup, ensuring that the vehicle's power performance is not disturbed.

[0087] In summary, these conditions together ensure that degraded heating starts only when truly needed, with sufficient power, and under safe conditions for the motor, thus achieving a synergistic balance between thermal management and power control.

[0088] In step S102, the pre-stored control parameter set is a noise optimization MAP table obtained through bench calibration. The noise optimization MAP table stores the target speed of the de-efficiency heating and the initial values ​​of the noise reduction parameters under different driving conditions.

[0089] The noise optimization MAP table refers to a multi-dimensional data table that is pre-built and stored in the motor controller through bench calibration. Its input dimension is the driving condition identifier, and its output dimensions include the target speed for degraded heating, the initial value of harmonic injection amplitude, and the initial value of dead zone compensation gain under different driving conditions.

[0090] The noise optimization MAP table is obtained through bench calibration: different driving conditions are simulated on the bench, and grid scanning is performed on the target speed, harmonic injection amplitude, and dead zone compensation gain. The heating power and noise level under each combination of noise reduction parameters are measured, and the parameter combination that makes the evaluation function value optimal is selected and stored in the noise optimization MAP table.

[0091] During the control process, when the degraded heating function is activated, the corresponding target speed and initial value of noise reduction parameters are read from the table according to the current driving conditions and preloaded to ensure that the function has a better noise suppression effect at the moment of activation. At the same time, it provides a reliable initial benchmark for subsequent real-time adjustments, avoiding slow convergence or getting stuck in local suboptimal problems caused by starting optimization from random points.

[0092] By pre-constructing a noise optimization MAP table through bench calibration, the target speed for reduced heating under different operating conditions is associated with and stored with the initial values ​​of noise reduction parameters. This allows the system to quickly read and preload the matching initial parameters based on the current operating conditions when the function is activated. This mechanism solves the cold start problem of online optimization, ensuring a better noise suppression effect from the start of control, while providing a reliable initial benchmark for subsequent real-time adjustments, avoiding problems such as long optimization time or getting trapped in local suboptimal conditions due to improper initial parameters.

[0093] In step S102, the noise reduction parameters include harmonic injection amplitude and dead zone compensation gain;

[0094] The harmonic injection amplitude is the amplitude of the 5th harmonic component and the amplitude of the 7th harmonic component injected into the theoretical output current of the motor, which is determined based on the target speed of the degraded heating.

[0095] The preset constraint range for the harmonic injection amplitude is 5% to 10% of the theoretical output current of the motor, which is determined based on the target speed for degraded heating.

[0096] Dead-time compensation gain is the gain coefficient used to compensate for voltage distortion caused by the dead time of the inverter.

[0097] The preset constraint range for dead zone compensation gain is 10% to 20% of the nominal compensation value.

[0098] The harmonic injection amplitude is set to 5%~10% of the theoretical output current of the motor. The lower limit of 5% ensures effective cancellation of electromagnetic noise of the motor body, and the upper limit of 10% avoids overcompensation that may cause new noise and excessive current stress. The dead zone compensation gain is set to 10%~20% of the nominal compensation value. The lower limit of 10% compensates for insufficient compensation caused by non-ideal hardware characteristics, and the upper limit of 20% prevents overcompensation that may cause system oscillation. The two parameter ranges are obtained through bench calibration, providing an optimization space that balances compensation effectiveness, system safety and control stability for real-time adjustment.

[0099] In step S102, the current driving condition includes cold start condition, urban low-speed condition, and high-speed driving condition. The identification of the current driving condition is achieved through real-time collection and comprehensive judgment of vehicle operating status parameters. In this embodiment, the cold start condition refers to the stage when the vehicle is first started in a low-temperature environment (ambient temperature below a preset threshold, battery temperature below a preset threshold) or when it is driven for the first time after being parked for a long time. The urban low-speed condition refers to the stage where the vehicle is driving on urban roads at a speed below a preset threshold (e.g., 30 km / h), accompanied by frequent starts and stops and fluctuations in motor torque. The high-speed driving condition refers to the stage where the vehicle is driving on highways or urban expressways at a speed above a preset threshold (e.g., 80 km / h) and operating continuously and stably.

[0100] The weight allocation strategies for each working condition are as follows:

[0101] Under cold start conditions, the weight of heating power-related items is higher than that of noise-related items;

[0102] Under low-speed urban conditions, the weight of heating power-related terms is equal to the weight of noise-related terms;

[0103] Under high-speed driving conditions, the weight of noise-related items is higher than that of heating power-related items.

[0104] In the cold start condition, since the vehicle has just started, the ambient temperature is low and the passenger compartment needs to be heated up quickly. The optimization direction at this time is to prioritize the target heat generation power. By giving a higher weight to the heating power related items than the noise related items, a certain degree of noise increase is allowed in exchange for rapid heating, ensuring that the thermal comfort of the passenger compartment is guaranteed in the low temperature environment.

[0105] In urban low-speed conditions, the vehicle speed is low and the environmental noise is relatively complex, and users have a certain tolerance for noise. By setting the weight of the heating power-related items to be equal to the weight of the noise-related items, noise control is taken into account while ensuring basic heating, avoiding insufficient heating due to excessive pursuit of quietness, and adapting to the characteristics of frequent starts and stops and vehicle speed fluctuations in urban conditions.

[0106] Under high-speed driving conditions, where vehicle speed is high and wind and tire noise are already present, users are sensitive to abnormal electromagnetic noise. By setting the weight of noise-related items higher than that of heating power-related items, electromagnetic noise is suppressed first, allowing for a slight decrease in heating efficiency in exchange for quiet comfort, thus avoiding motor noise interfering with the driving experience at high speeds.

[0107] In step S103, in some possible embodiments, the current target speed of the motor changes towards the degraded heating target speed according to a preset gradient. The gradient is configured to shorten the duration of the noise degradation range while ensuring heating efficiency. That is, after the degraded heating function is activated, the current target speed of the motor does not jump directly to the final target value, but gradually increases according to the preset gradient until the degraded heating target speed is reached.

[0108] The gradient refers to the change in the target speed of a motor per unit time, and is usually expressed as:

[0109] The gradient rise rate = (target speed for degraded heating - gradient rise time for initial target speed) / (target speed for degraded heating - initial target speed), which determines how quickly the target speed rises from the initial value to the final set value. It can be seen that selecting the gradient rise rate is a process of finding the optimal balance between heating speed, noise duration, transient noise amplitude, and system stability: the lower limit of the gradient is determined by the heating efficiency requirement, the upper limit of the gradient is determined by the system stability boundary, and the optimization is guided by the human ear's insensitivity to short-term noise. Bench tests are used to verify the comprehensive effect under different gradients, and finally, a gradient value that can improve overall subjective comfort by sacrificing extremely short transient noise while ensuring heating efficiency is selected. Actual verification shows that a gradient rise rate of 60,000 rpm, compared to 20,000 rpm, can reduce motor noise by approximately 10 dB within 5 seconds after entering degraded heating.

[0110] By setting a preset gradient, the target rotational speed changes towards the degraded heating target value at a controlled rate, significantly reducing the duration of passing through the noise-sensitive region while ensuring heating efficiency. Compared to a slow-rise strategy, although the instantaneous noise amplitude may increase slightly, according to the characteristics of human hearing, a very short-term noise surge is subjectively far weaker than a long-lasting high noise, thus optimizing the overall driving experience. Compared to a step-change strategy, gradient rise avoids the system shock and severe noise caused by instantaneous jumps in current commands, providing a smooth transition process for the pre-loaded noise reduction parameters to take effect, achieving a synergistic balance between heating speed and noise suppression.

[0111] In step S103, the evaluation function J is specifically expressed as:

[0112] ;

[0113] in The actual heat generation power of the motor is calculated from the motor loss model or the bus power difference. The noise intensity collected by the microphone sensor inside the vehicle or the microphone sensor located on the motor body, in dBA. This is a pre-calibrated reference noise threshold; , These are the weights of the heating power-related terms and the noise-related terms, respectively, satisfying... Adjust dynamically based on current driving conditions.

[0114] Among them, the target heating power .

[0115] Reference Figure 2 In this embodiment of the application, step S104, which involves adjusting the specific value of the noise reduction parameter in real time within the preset parameter constraint range of the noise reduction parameter, with the noise reduction parameter as an adjustable variable and the evaluation function as the optimality objective, includes:

[0116] S1041, based on the current parameter value of the noise reduction parameter, perform parameter search in the increasing and decreasing directions with a preset iteration step size respectively, to obtain four search directions: increasing harmonic injection amplitude, decreasing harmonic injection amplitude, increasing dead zone compensation gain and decreasing dead zone compensation gain;

[0117] S1042, calculate the current parameter value and the evaluation function value corresponding to each search direction respectively;

[0118] S1043, compare the evaluation function values ​​corresponding to each search direction and the current parameter value. If the evaluation function value of at least one search direction is less than the evaluation function value of the current parameter value, select the search direction that minimizes the evaluation function value as the parameter adjustment direction, and update the values ​​of harmonic current injection amplitude and / or dead time compensation gain with a preset iteration step size.

[0119] S1044, If the evaluation function value corresponding to all search directions is greater than or equal to the evaluation function value corresponding to the current parameter value, then keep the values ​​of harmonic current injection amplitude and dead time compensation gain unchanged.

[0120] S1045, repeat the above search and comparison process until the evaluation function value converges to a local optimum or reaches the preset maximum number of iterations.

[0121] In S1041, the current parameter values ​​of the noise reduction parameters include two dimensions: harmonic injection amplitude h_current and dead zone compensation gain g_current. These two values ​​may be the initial values ​​of the preloaded noise reduction parameters or the values ​​after the previous round of adjustment. The reference point is denoted as (h_current, g_current).

[0122] The iteration step size corresponding to the harmonic injection amplitude h_current and the dead zone compensation gain g_current is denoted as Δh and Δg, respectively. Δh and Δg are pre-calibrated adjustment amplitudes, for example, Δh=0.2% and Δg=1%.

[0123] Using the current parameter value (h_current, g_current) as a reference, four search points are generated by searching in both positive and negative directions of the two dimensions: the search point corresponding to the direction of increasing harmonic injection amplitude (h_current+Δh, g_current), the search point corresponding to the direction of decreasing harmonic injection amplitude (h_current-Δh, g_current), the search point corresponding to the direction of increasing dead-zone compensation gain (h_current, g_current+Δg), and the search point corresponding to the direction of decreasing dead-zone compensation gain (h_current, g_current-Δg). These four search points cover the four possible adjustment directions in the two dimensions of the parameter space.

[0124] Calculate the evaluation function value J for the current point (h_current, g_current) and the four sets of search points respectively:

[0125] J_current=J(h_current,g_current);

[0126] J_h+=J(h+Δh,g_current);

[0127] J_h-=J(h-Δh,g_current);

[0128] J_g+=J(h_current,g_current+Δg);

[0129] J_g-=J(h_current,g_current-Δg).

[0130] Compare J_current with the evaluation function values ​​corresponding to each of the four search points:

[0131] If the J value at at least one search point is less than J_current, it means the current point is not optimal and needs adjustment. From all search directions that decrease the J value, the direction with the smallest J value should be selected as the adjustment direction. For example, if J_h+ is the smallest and less than J_current, then the direction that increases harmonics should be selected.

[0132] Based on the decision result, update the parameters with a preset step size:

[0133] If the direction of harmonic increase is chosen: h_new = hcurrent + Δh, gcurrent remains unchanged;

[0134] If the direction of decreasing gain is chosen: g_new = gcurrent - Δg, hcurrent remains unchanged;

[0135] If multiple directions cause the value of the evaluation function J to decrease, only the direction with the smallest value of the evaluation function J should be selected, and the two parameters should not be adjusted at the same time (to avoid over-adjustment).

[0136] The updated parameters serve as the new baseline, and the above process is repeated: four search directions are generated again at the new baseline (h_new, g_new); the value of the evaluation function J is recalculated and compared; and the process is continuously adjusted in the direction that makes the value of the evaluation function J decrease.

[0137] Iteration stops when one of the following conditions is met: the value of the evaluation function J corresponding to all search directions is greater than or equal to the value of the evaluation function J of the current point (a local optimum has been reached); or the preset maximum number of iterations is reached (to prevent infinite loops).

[0138] By searching and comparing evaluation function values ​​in four directions based on the current parameter values, the method can autonomously perceive the comprehensive impact of parameter changes on heating efficiency and noise levels, and continuously iterate and adjust in the direction of decreasing evaluation function values, thereby converging to the local optimal parameter combination under the current operating conditions. When the motor state changes and causes the evaluation function value to rise again, the method can restart the optimization process, so that the noise reduction parameters always follow the dynamic operating conditions and remain optimal in real time. At the same time, by keeping the parameters unchanged near the optimal point, invalid oscillations caused by measurement disturbances are avoided, achieving a synergistic effect of autonomous optimization, dynamic tracking and steady-state maintenance.

[0139] In some possible embodiments of this application, during the real-time adjustment of the harmonic current injection amplitude and dead time compensation gain, if a certain search direction causes the harmonic current injection amplitude to exceed the preset value range of the harmonic injection amplitude and / or the dead time compensation gain to exceed the preset value range of the dead time compensation gain, then the search direction is discarded, and only the evaluation function values ​​within the effective search direction are calculated and compared.

[0140] If the current value of the harmonic current injection amplitude is at the upper or lower limit of the preset range of the harmonic injection amplitude, and / or the current value of the dead time compensation gain is at the upper or lower limit of the preset range of the dead time compensation gain, if the search direction that exceeds the corresponding preset range is discarded and all valid search directions cause the evaluation function value to increase, then the current values ​​of the harmonic current injection amplitude and the dead time compensation gain are determined to be local optimal values ​​under the constraint conditions, and parameter adjustment is stopped.

[0141] When the operating state of the motor changes and the evaluation function value rises again, the optimization process aimed at minimizing the evaluation function value is restarted, and parameter optimization continues under the new operating state of the motor.

[0142] A boundary constraint handling mechanism is introduced during the real-time adjustment of noise reduction parameters: when the search direction exceeds the preset range of 5%~10% of the harmonic injection amplitude or 10%~20% of the dead zone compensation gain, it is discarded, and optimization is only allowed within the effective range; when the parameter is already at the boundary and all directions within the boundary cause the evaluation function value to increase, the current value is determined to be the local optimum under the constraint and the adjustment is stopped; when the change in the running state causes the evaluation function value to rise again, the optimization process is automatically restarted to ensure that the parameter always dynamically converges to the real-time optimum value within the safe boundary.

[0143] Reference Figure 3 This application embodiment also provides a motor de-efficiency heating control device consistent with the above method, including:

[0144] The target speed determination module 101 is used to determine the target speed of the motor under the current driving conditions in response to the activation of the motor's de-efficiency heating function.

[0145] The noise reduction parameter preloading module 102 is used to read a set of initial values ​​of noise reduction parameters that match the current driving conditions from the pre-stored control parameter set and preload them before the target speed of the motor changes to the target speed of the de-efficiency heating.

[0146] The speed change module 103 is used to change the current target speed of the motor towards the target speed of de-efficiency heating according to a preset law;

[0147] The evaluation function construction module 104 is used to collect the motor's operating status feedback signal in real time and construct the evaluation function during the current target speed change process and after the target speed for de-efficiency heating is reached.

[0148] The optimization module 105 is used to adjust the specific value of the noise reduction parameter in real time within the preset parameter constraint range of the noise reduction parameter, with the value of the noise reduction parameter as an adjustable variable and the evaluation function as the optimality as the goal.

[0149] The evaluation function includes at least heating power-related terms and noise-related terms, and the weights of each related term are dynamically allocated according to the current driving conditions.

[0150] Thirdly, embodiments of this application also provide a vehicle including the aforementioned motor de-efficiency heating control device.

[0151] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A method for controlling the degraded heating performance of an electric motor, characterized in that, include: In response to the activation of the motor's degraded heating function, the target speed for degraded heating of the motor under the current driving conditions is determined; Before the target speed of the motor changes to the target speed of the de-efficiency heating, the initial value of the noise reduction parameter that matches the current driving condition is read from the pre-stored control parameter set and preloaded; The current target speed of the motor is adjusted to change towards the target speed of the degraded heating according to a preset rule; During the current target speed change process and the operation phase after reaching the target speed for degraded heating, the operating status feedback signal of the motor is collected in real time and an evaluation function is constructed. The value of the noise reduction parameter is used as the optimization variable, and the minimum value of the evaluation function is taken as the optimization objective. The specific value of the noise reduction parameter is adjusted in real time within the preset parameter constraint range of the noise reduction parameter. The evaluation function includes at least heating power-related terms and noise-related terms, and the weight of each related term is dynamically allocated according to the current driving conditions.

2. The method for controlling the degraded heating of a motor according to claim 1, characterized in that, The conditions under which the degraded heating function is activated include: The ambient temperature where the vehicle is located is lower than the first preset temperature threshold. The vehicle's power battery temperature is below the second preset temperature threshold; The vehicle's power battery SOC is higher than the preset charge threshold. The vehicle's air conditioning system requested heating, but the actual output power of the PTC heater could not meet the heating needs of the passenger compartment. The current speed of the motor is within the preset motor speed range and the current output torque of the motor is within the preset motor torque range.

3. The method for controlling motor efficiency degradation due to heating according to claim 1 or 2, characterized in that, The current driving conditions include cold start, urban low-speed, and high-speed driving conditions, and the weight allocation strategies for each condition are as follows: Under cold start conditions, the weight of the heating power-related item is higher than the weight of the noise-related item; Under low-speed urban conditions, the weight of the heating power-related term is equal to the weight of the noise-related term; Under high-speed driving conditions, the weight of the noise-related item is higher than the weight of the heating power-related item.

4. The method for controlling motor efficiency degradation due to heating according to claim 3, characterized in that, The noise reduction parameters include harmonic injection amplitude and dead zone compensation gain; The harmonic injection amplitude is the amplitude of the 5th harmonic component and the amplitude of the 7th harmonic component injected into the theoretical output current of the motor determined based on the target speed of the degraded heating. The preset constraint range of the harmonic injection amplitude is 5% to 10% of the theoretical output current of the motor determined based on the target speed of the degraded heating. The dead-time compensation gain is the gain coefficient used to compensate for voltage distortion caused by the dead time of the inverter. The preset constraint range for the dead zone compensation gain is 10% to 20% of the nominal compensation value.

5. The method for controlling motor efficiency degradation due to heating according to claim 4, characterized in that, The steps of adjusting the specific value of the noise reduction parameter in real time within the preset parameter constraints, with the noise reduction parameter as an adjustable variable and the evaluation function as the optimality objective, include: Based on the current parameter value of the noise reduction parameter, parameter search is performed in the increasing and decreasing directions with a preset iteration step size, resulting in four search directions: increasing harmonic injection amplitude, decreasing harmonic injection amplitude, increasing dead zone compensation gain, and decreasing dead zone compensation gain. Calculate the current parameter value and the evaluation function value corresponding to each of the search directions; Compare the evaluation function values ​​corresponding to each search direction with the current parameter value. If the evaluation function value of at least one search direction is less than the evaluation function value of the current parameter value, then select the search direction that minimizes the evaluation function value as the parameter adjustment direction, and update the values ​​of the harmonic current injection amplitude and / or the dead time compensation gain with the preset iteration step size. If the evaluation function value corresponding to all search directions is greater than or equal to the evaluation function value corresponding to the current parameter value, then the values ​​of the harmonic current injection amplitude and the dead time compensation gain remain unchanged. Repeat the above search and comparison process until the evaluation function value converges to a local optimum or reaches the preset maximum number of iterations.

6. The method for controlling motor efficiency degradation due to heating according to claim 5, characterized in that, During the real-time adjustment of the harmonic current injection amplitude and the dead time compensation gain, if a certain search direction causes the harmonic current injection amplitude to exceed the preset value range of the harmonic injection amplitude and / or the dead time compensation gain to exceed the preset value range of the dead time compensation gain, then the search direction is discarded, and only the evaluation function values ​​within the effective search directions are calculated and compared. If the current value of the harmonic current injection amplitude is located at the upper or lower limit of the preset range of the harmonic injection amplitude, and / or the current value of the dead time compensation gain is located at the upper or lower limit of the preset range of the dead time compensation gain, if the search direction that exceeds the corresponding preset range is discarded and all valid search directions cause the evaluation function value to increase, then the current values ​​of the harmonic current injection amplitude and the dead time compensation gain are determined to be local optimal values ​​under the constraint condition, and parameter adjustment is stopped. When the operating state of the motor changes and the value of the evaluation function rises again, the optimization process aimed at minimizing the value of the evaluation function is restarted, and parameter optimization continues under the new operating state of the motor.

7. The method for controlling motor efficiency degradation due to heating according to claim 1, characterized in that, The pre-stored control parameter set is a noise optimization MAP table obtained through bench calibration. The noise optimization MAP table stores the target speed for reduced heating and the initial values ​​of noise reduction parameters under different driving conditions.

8. The method for controlling motor efficiency degradation due to heating according to claim 1, characterized in that, The current target speed of the motor changes towards the degraded heating target speed according to a preset gradient, and the gradient is configured to shorten the duration of the noise degradation range while ensuring heating efficiency.

9. A device for controlling the degraded heating performance of an electric motor, characterized in that, include: The target speed determination module is used to determine the target speed of the motor under the current driving conditions in response to the activation of the motor's de-efficiency heating function. The noise reduction parameter preloading module is used to read a set of initial values ​​of noise reduction parameters that match the current driving conditions from the pre-stored control parameter set and preload them before the target speed of the motor changes to the target speed of the de-efficiency heating. The speed change module is used to change the current target speed of the motor to the target speed of the degraded heating according to a preset rule; The evaluation function construction module is used to collect the motor's operating status feedback signal in real time and construct the evaluation function during the current target speed change process and after reaching the degraded heating target speed. An optimization module is used to adjust the specific value of the noise reduction parameter in real time within the preset parameter constraint range of the noise reduction parameter, with the value of the noise reduction parameter as an adjustable variable and the evaluation function as the target. The evaluation function includes at least heating power-related terms and noise-related terms, and the weight of each related term is dynamically allocated according to the current driving conditions.

10. A vehicle, characterized in that, Includes the motor de-efficiency heating control device as described in claim 9.

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