An inefficient heating method, system and vehicle for an electric drive of an electric vehicle

Abstract

The present invention provides an inefficient heating method, system and vehicle for an electric vehicle. The method includes the following steps: determining whether a preset heating condition is satisfied, and when the preset heating condition is satisfied, sending a heating instruction to the vehicle controller; judging the vehicle operation state according to a preset state judgment rule, where the vehicle operation state includes a parking state and a driving state; sending a parking inefficient heating instruction or a driving inefficient heating instruction to the motor controller, and the motor controller executes it and controls the electric drive system to enter a corresponding parking heating mode or driving heating mode according to the ambient temperature information. The purpose of the present invention is to improve the charging and discharging capabilities of the power battery through the inefficient heating of the electric drive system, and improve the temperature rise efficiency of the power battery while ensuring high thermal stability of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the field of automobiles, and in particular, to an inefficient heating method, system and vehicle for an electric drive of an electric vehicle. Background Art

[0002] As the main energy source of current electric vehicles, the available power and charging and discharging power of lithium-ion power batteries are significantly reduced by low-temperature environments, and low-temperature charging will accelerate battery attenuation and aging due to lithium plating on the anode. To restore the lithium-ion battery to a normal or optimal state, the battery heating function is particularly important. Therefore, it is possible to consider heating the power battery to an appropriate temperature to improve the charging and discharging ability and battery life of the power battery.

[0003] Among the models with power battery heating, the method of laying external heating materials such as PTC (positive temperature coefficient thermistor) and heating films for the power battery is mainly adopted, which increases the cost of the whole vehicle and also increases the weight of the whole vehicle, reducing the cruising range. Based on this situation, a variety of heating technologies for power batteries through the electric drive system have emerged.

[0004] One of the existing technologies is to equivalent the power battery as a resistor, capacitor, and ideal voltage source in series and parallel, and the inverter as an ideal current source. The system forms an RL resonance circuit, and the control target is to make the effective value of the current flowing through the bus as large as possible to increase the internal resistance heating of the battery to achieve the purpose of heating the power battery. However, this scheme depends more on the matching of the vehicle's high-voltage power circuit system. The temperature rise of the bus capacitor is relatively fast and it is difficult to reach the thermal equilibrium steady state, and thermal failure is likely to occur. In addition, the switching frequency of the power device during operation is basically fixed and the noise is large. Another existing technology is to add components outside the controller of the electric drive assembly to control the battery discharge and use the discharge current to complete self-heating. However, this scheme has high requirements for the control components of the motor controller and is not conducive to cost control. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide an inefficient heating method, system and vehicle for an electric drive of an electric vehicle, aiming to improve the charging and discharging ability of the power battery through inefficient heating of the electric drive system, and improve the temperature rise efficiency of the power battery while maintaining high thermal stability of the whole vehicle.

[0006] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0007] According to a first aspect of the present invention, there is provided an inefficient heating method for an electric drive of an electric vehicle, including the following steps:

[0008] Determine whether the preset heating condition is satisfied, and when the preset heating condition is satisfied, send a heating instruction to the vehicle controller; the preset heating condition is: judging that the vehicle is in an inefficient state according to the ambient temperature information, motor temperature information, power battery temperature and SOC value, and the vehicle continuously remains in the inefficient state for more than a preset time threshold;

[0009] Judge the vehicle running state according to the preset state judgment rule, and the vehicle running state includes a parking state and a driving state;

[0010] When it is determined that the vehicle is in the parking state: send a parking inefficient heating instruction to the motor controller, and adjust the vehicle water flow duty ratio to the preset parking water flow duty ratio; when the motor controller receives the parking inefficient heating instruction, control the motor oil pump to enter the first state of the oil pump; the motor controller controls the motor quadrature axis current to be 0, and controls the output of the corresponding direct axis current according to the ambient temperature information; when the motor controller receives the parking inefficient heating instruction, and judges that the motor speed does not exceed the preset parking heating speed threshold and the power device is in the on state, the electric drive system enters the corresponding parking heating mode according to the ambient temperature information;

[0011] When it is determined that the vehicle is in the driving state: send a driving inefficient heating instruction to the motor controller, and adjust the vehicle water flow duty ratio to the preset driving water flow duty ratio; when the motor controller receives the driving inefficient heating instruction, control the motor oil pump to enter the second state of the oil pump; the motor controller controls to reduce the motor efficiency, adjust the quadrature axis and direct axis current ratio according to the ambient temperature when the vehicle speed is in the first speed range, adjust the quadrature axis and direct axis current ratio according to the vehicle speed when the vehicle speed rises to the second speed range, and exit the heating mode when the vehicle speed further rises to the third range; when the motor controller receives the driving inefficient heating instruction, and judges that the motor speed is in the preset driving heating speed range and the power device is in the on state, the electric drive system enters the corresponding driving heating mode according to the ambient temperature information;

[0012] The calculation formula for the preset parking water flow duty ratio is: D_parking = k1 * ΔT + b1;

[0013] The calculation formula for the preset driving water flow duty ratio is: when the vehicle speed is in the preset low speed period, D_driving = k2 * ΔT + b2 + α * v; when the vehicle speed is in the preset high speed period, D_driving = min(Dmax, k3 * ln(ΔT) + b3);

[0014] D_parking is the preset parking water flow duty ratio, D_driving is the preset driving water flow duty ratio, k1, k2, k3 refer to the sensitivity coefficient of ΔT to the water flow, ΔT is the difference between the ambient temperature information and the power battery temperature, b1, b2, b3 refer to the basic duty ratio to ensure the minimum heat dissipation requirement, and α is the vehicle speed gain value;

[0015] The second state of the oil pump is as follows: when the ambient temperature is less than zero degree Celsius, n driving = n base + β * (T mot - 60); when the ambient temperature is greater than zero degree Celsius, n driving = n base * (1 - γ * v / 100); where n base is the base speed, β is the motor temperature gain value, γ is the attenuation coefficient of vehicle speed on the oil pump speed, v is the vehicle speed, and T mot is the motor temperature.

[0016] Preferably, the parking heating mode includes parking heating mode one and parking heating mode two. When the ambient temperature information is in the low range, enter parking heating mode one and output the parking heating power P11; when the ambient temperature information is in the high range, enter parking heating mode two and output the parking heating power P12 which is less than the parking heating power P1.

[0017] The driving heating mode includes driving heating mode one and driving heating mode two. When the ambient temperature information is in the low range, enter driving heating mode one and output the driving heating power P21; when the ambient temperature information is in the high range, enter driving heating mode two and output the driving heating power P22 which is less than the driving heating power P21.

[0018] Preferably, the preset state judgment rule is: when the vehicle is in N gear or P gear and the motor speed is 0, it is determined to be in the parking state; when the vehicle is in D gear or R gear and the motor speed is not 0, it is determined to be in the driving state.

[0019] Preferably, after the electric drive system enters the parking heating mode or the driving heating mode, the heat is transferred to the battery pack through the heat transfer between the lubricating oil and the coolant.

[0020] Preferably, for the electric drive system of the oil-cooled motor, after entering parking heating mode one, the motor controller controls the electric oil pump to run at speed n1, and after entering parking heating mode two, the motor controller controls the electric oil pump to run at speed n2, and speed n1 > speed n2.

[0021] Preferably, after the electric drive system enters the driving heating mode, it multiplexes the control loop of the normal operation mode and controls the current output through the driving heating look-up table data.

[0022] Preferably, in the preset heating conditions, the inefficient state is T env ≤ - 5°C, and T bat ≤ 10°C and the SOC value ≥ 20%, and the preset time threshold is 150 seconds;

[0023] In the calculation formula of the preset parking water flow duty ratio, k1 is 1.5 ± 0.2 and b1 is 50 ± 5;

[0024] The first state of the oil pump means that the motor oil pump speed is between 2500 - 3500 rpm;

[0025] When the vehicle is in the driving state, the motor controller controls the quadrature-axis current and the direct-axis current to satisfy the following equal relationship:

[0026] When the vehicle speed is in the first speed range, Id / Iq = 1.2 + 0.05*(T env + 20); when the vehicle speed is in the second speed range, Id / Iq = 0.8 - 0.03*v; when the vehicle speed is in the third speed range, the heating mode is directly exited; where, Id is the direct-axis current, Iq is the quadrature-axis current, and T env is the ambient temperature.

[0027] Preferably, it further includes that when it is recognized that the motor temperature and the IGBT junction temperature exceed the preset exit threshold, an exit heating instruction is sent to the vehicle controller.

[0028] According to the second aspect of the present invention, there is provided an electric drive low-efficiency heating system for an electric vehicle, including an information acquisition module, a vehicle operation judgment module, and an execution module;

[0029] The information acquisition module is used to acquire ambient temperature information, motor temperature information, power battery temperature, and SOC value;

[0030] The vehicle operation judgment module is used to judge the vehicle operation state, generate and send a parking low-efficiency heating instruction and a driving low-efficiency heating instruction;

[0031] The execution module is used to execute the parking low-efficiency heating instruction and the driving low-efficiency heating instruction, adjust the vehicle water flow duty ratio through the vehicle controller, control the motor current output, the motor oil pump speed through the motor controller, and control the electric drive system to enter the parking heating mode or the driving heating mode.

[0032] According to the third aspect of the present invention, there is provided a vehicle, including: a vehicle thermal management system, a vehicle controller, a motor controller, an electric drive system, and the above-mentioned electric drive low-efficiency heating system for an electric vehicle.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. Through special step designs such as vehicle state judgment, generation and execution of heating instructions, and entering the heating mode according to the ambient temperature, the present invention ensures the thermal balance and thermal safety of the whole vehicle, achieves the power battery temperature rise target at a faster rate, reduces the energy consumption in the low-efficiency mode to the greatest extent, and increases the vehicle endurance.

[0035] 2. The present invention does not need to modify the vehicle's high-voltage power circuit, does not affect the vehicle control module, and does not require external components such as heating films, and realizes the power battery temperature rise requirement in a low-temperature environment with high cost performance, reducing the vehicle cost.

[0036] 3. The present invention determines whether the heating condition is satisfied by adding multi-parameter coupling, considering the ambient temperature, battery pack temperature, SOC, and temperature difference duration, which can effectively avoid mis-triggering of heating and comprehensively consider the difference between the temperature of the battery pack itself and the ambient temperature.

[0037] 4. The present invention also greatly improves the control accuracy through a dynamic coupling logic by means of a special calculation formula for the duty ratio of the vehicle's total water flow and a calculation function for the pump speed.

[0038] 5. The present invention further dynamically correlates the vehicle speed and current ratio during driving, solving the problems of continuous inefficient heating in high-speed conditions, the risk of motor demagnetization and thermal runaway, and the lack of speed adaptability control in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Other features, objects, and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0040] Figure 1 It is a schematic flowchart of the method described in Embodiment 1;

[0041] Figure 2 It is a schematic structural diagram of the system described in Embodiment 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, all directional indications (such as up, down, left, right, front, back, bottom...) in the present application are only used to explain the relative positional relationship and movement of components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0045] Embodiment 1

[0046] This embodiment provides an inefficient heating method for the electric drive of an electric vehicle, as Figure 1 shown, including the following steps:

[0047] In a low-temperature environment, obtain the ambient temperature information T env , motor temperature information T mot , power battery temperature T bat , SOC value (state of charge of the battery), determine whether the preset heating condition is satisfied, and when the preset heating condition is satisfied, send a heating instruction to the vehicle controller, and the heating instruction is used to transfer the heating demand of the power battery. The sending of the instruction can be completed by the vehicle thermal management system. The following specifically describes the judgment process of the preferred preset heating condition, which is divided into the following steps:

[0048] In step A1, obtain and based on the ambient temperature information T env , motor temperature information T mot , power battery temperature T bat and SOC value to determine whether the vehicle is in an inefficient state; the inefficient state is T env ≤ -5°C, and T bat ≤ 10°C and the SOC value ≥ 20%;

[0049] In step A2, if it is recognized that the vehicle is in an inefficient state, start the comprehensive judgment timer, and after the vehicle continuously remains in the inefficient state for more than the preset time threshold, send a heating instruction to the vehicle controller. The setting range of the preset time threshold can be [120, 180] seconds, preferably 150 seconds, covering the battery thermal inertia period and reducing the probability of heating mis-triggering. It is determined that the battery temperature change lags behind the ambient temperature, and it is necessary to ensure stable temperature sampling;

[0050] Judge the vehicle running state according to the preset state judgment rule. The preset state judgment rule is: when the vehicle is in N gear or P gear and the motor speed is 0, it is determined to be in the parking state; when the vehicle is in D gear or R gear and the motor speed is not 0, it is determined to be in the driving state. Among them, N gear is the neutral gear, D gear is the forward gear, and R gear is the reverse gear. The judgment of the vehicle running state can be completed by the vehicle controller.

[0051] Depending on the different vehicle running states, this embodiment provides corresponding inefficient heating methods for the electric drive. The following specifically describes the inefficient heating method for the electric drive when the vehicle is in the parking state. When it is determined that the vehicle is in the parking state:

[0052] Send a parking inefficient heating instruction to the motor controller, and at the same time increase the vehicle water flow duty ratio to the preset parking water flow duty ratio;

[0053] The calculation formula for the preset parking water flow duty ratio is: D_parking = k1 * ΔT + b1, where:

[0054] D_parking is the preset parking water flow duty ratio, k1 refers to the sensitivity coefficient of ΔT to the water flow, and ΔT is the difference between the ambient temperature information T env and the temperature T of the power battery bat , and b1 refers to the basic duty ratio to ensure the minimum heat dissipation requirement. Through the bench test of the cooling system, adjust ΔT and the duty ratio D_parking, record the heat dissipation power, fit k1 and b1. The coefficient k1 is preferably 1.5 ± 0.2, and b1 is preferably 50 ± 5, which can ensure that for every 1°C increase in ΔT, the duty ratio increases by about 1.5%, and the basic heat dissipation capacity covers the working condition at -20°C;

[0055] When the motor controller receives the parking low-efficiency heating instruction, it controls the motor oil pump to enter the first state of the oil pump, increases the rotational speed output, and the rotational speed of the motor oil pump is between 2500 - 3500 rpm;

[0056] Input the ambient temperature information, the motor controller controls the quadrature axis current of the motor to be 0, and controls the corresponding direct axis current output according to the ambient temperature information;

[0057] According to the parking heating start rule, the electric drive system enters the parking heating mode, including parking heating mode one and parking heating mode two, and the heating power of different parking heating modes is different. The parking heating start rule is: when the motor controller receives the parking low-efficiency heating instruction, and judges that the motor speed does not exceed the preset parking heating speed threshold, and the power device is in the on state, then enter the corresponding parking heating mode according to the ambient temperature information.

[0058] Specifically, according to different ambient temperature information, when the ambient temperature information is in the low range, for example, in the range of (-20°C, -10°C), the motor controller only outputs the direct axis voltage U d1 when generating waves, and does not output the quadrature axis voltage U q , only the excitation current I is generated inside the motor d1 , and the torque current I is not generated q , making the motor in a stationary state. According to the mathematical model (formula one) of the traditional permanent magnet synchronous motor (PMSM), no torque is output. At this time, the parking heating power P11 is output, and enter parking heating mode one. When the ambient temperature information is in the high range, for example, in the range of (-10°C, 10°C), the motor controller only outputs Ud2 when generating waves, does not output Uq, only the excitation current Id2 is generated inside the motor, and the torque current Iq is not generated. At this time, the parking heating power P12 is output, and enter parking heating mode two. The parking heating power P12 is less than the parking heating power P11.

[0059] Formula one:

[0060]

[0061] In Equation (1), u d and u q are the voltages on the d-axis and q-axis respectively, i d , i q are the currents on the d-axis and q-axis respectively, R s is the stator resistance, L d , L q are the inductances on the d-axis and q-axis respectively, ω is the electrical angular velocity of the motor, ψ is the magnetic flux generated by the permanent magnet, T e is the electromagnetic torque, and P is the number of pole pairs of the motor.

[0062] Furthermore, for the electric drive system of the oil-cooled motor, after entering Parking Heating Mode 1, the motor controller controls the electric oil pump to operate at a speed of n1, and after entering Parking Heating Mode 2, the motor controller controls the electric oil pump to operate at a speed of n2, and n1 > n2.

[0063] The following specifically describes the electric drive low-efficiency heating method when the vehicle is in the driving state. When it is determined that the vehicle is in the driving state:

[0064] Send a driving low-efficiency heating command to the motor controller, and at the same time increase the vehicle water flow duty ratio to the preset driving water flow duty ratio;

[0065] The calculation method of the preset driving water flow duty ratio is as follows: when the vehicle speed is within the preset low-speed period (e.g., the vehicle speed is less than 50 km / h), D_driving = k2 * ΔT + b2 + α * v; when the vehicle speed is within the preset high-speed period (e.g., the vehicle speed is greater than or equal to 50 km / h), D_driving = min(Dmax, k3 * ln(ΔT) + b3); where D_driving is the preset driving water flow duty ratio, k2 and k3 are the sensitivity coefficients of ΔT to the water flow, ΔT is the difference between the ambient temperature information T env and the temperature T bat of the power battery, b2 and b3 are the basic duty ratios to ensure the minimum heat dissipation requirement, and α is the vehicle speed gain value;

[0066] After receiving the driving low-efficiency heating command from the vehicle controller, the motor controller controls the motor oil pump to enter the second state of the oil pump, specifically:

[0067] When T env ≤ 0°C, n_driving = n_base + β * (T mot - 60); when T envWhen the temperature is above 0°C, the rotational speed of the oil pump during driving \(n_{driving}=n_{base}(1 - \gamma\times v / 100)\); where \(n_{base}\) is the base rotational speed, which is 2800 rpm; \(\beta\) is the motor temperature gain value, preferably \(\beta = 20\) rpm / °C; \(\gamma\) is the attenuation coefficient of the vehicle speed on the rotational speed of the oil pump, representing the proportion by which the rotational speed of the oil pump decreases when the vehicle speed increases by 100 km / h, preferably \(\gamma = 0.3\); \(v\) is the vehicle speed; \(T\) mot is the motor temperature information;

[0068] Input the ambient temperature information. The motor controller controls the reduction of the motor efficiency, and controls the output of the corresponding quadrature-axis current and direct-axis current according to the ambient temperature information and the vehicle speed. When the vehicle speed is in the first speed range, the quadrature-axis to direct-axis current ratio is adjusted according to the ambient temperature. When the vehicle speed rises to the second speed range, the quadrature-axis to direct-axis current ratio is adjusted according to the vehicle speed. When the vehicle speed further rises to the third range, the heating mode is exited; More specifically, the quadrature-axis to direct-axis current ratio should satisfy the following equivalent relationship:

[0069] When the vehicle speed is in the first speed range (such as less than 30 km / h), \(I_d / I_q = 1.2 + 0.05\times(T\) env + 20); When the vehicle speed is in the second speed range (such as between 30 - 80 km / h), \(I_d / I_q = 0.8 - 0.03\times v\); When the vehicle speed is in the third speed range (such as greater than 80 km / h), the heating mode is directly exited; where \(I_d\) is the direct-axis current, \(I_q\) is the quadrature-axis current, and \(T\) env is the ambient temperature;

[0070] According to the driving heating start rule, the electric drive system enters the driving heating mode, including driving heating mode one and driving heating mode two, and there are differences in the heating power of different driving heating modes. The driving heating start rule is: The motor controller receives the driving low-efficiency heating instruction, and judges that the motor speed is in the preset driving heating speed range, and the power device is in the on state, and enters the corresponding driving heating mode according to the ambient temperature information. Similar to the parking heating start rule, according to the ambient temperature information, it enters driving heating mode one or driving heating mode two. When the ambient temperature information is in the low range, it enters driving heating mode one and outputs the driving heating power \(P_{21}\); When the ambient temperature information is in the high range, it enters driving heating mode two and outputs the driving heating power \(P_{22}\) which is less than the driving heating power \(P_{21}\).

[0071] Furthermore, in the driving heating mode, the control loop of the normal operation mode can be reused, and the current output is controlled through the driving heating look-up table data. Only the look-up table (LUT) data needs to be replaced with the driving heating look-up table data, without additional hardware, and it can be flexibly controlled.

[0072] Whether the vehicle is in the parking state or the driving state, after the electric drive system enters the parking heating mode or the driving heating mode, heat is transferred to the battery pack through the lubricating oil and the coolant, playing a role in heating the battery pack. Specifically, the heat includes heat losses, such as the heat loss of the motor controller and the heat loss of the motor.

[0073] This embodiment may further include the judgment of the heating mode exit condition, that is: when it is recognized that the motor temperature and the IGBT (Insulated Gate Bipolar Transistor) junction temperature exceed the preset exit threshold, an exit heating instruction is sent to the vehicle controller to exit the heating mode.

[0074] This embodiment utilizes the heat generated by the component losses of the electric drive assembly, transfers the heat through the cooling system to supply heat for the power battery to heat, and controls the drive motor to operate in a low-efficiency range to increase the heating power. The purpose is to take into account the function implementation environment temperature, the cooling system intervenes to maximize the heating power, and at the same time there is no modification to the vehicle power system circuit, while having high thermal stability of the vehicle and enabling the power battery to meet the temperature rise requirements in the shortest time.

[0075] The present invention grades the heating mode according to the ambient temperature. While ensuring the thermal balance and thermal safety of the vehicle, it achieves the power battery temperature rise target at a faster rate, and at the same time reduces the energy consumption in the low-efficiency mode to the greatest extent, increasing the vehicle's endurance. There is no need to modify the vehicle's high-voltage circuit, nor does it affect the vehicle control module. There is no need for peripheral components such as heating films, and it realizes the power battery temperature rise requirement in a low-temperature environment with high cost performance, reducing the vehicle cost.

[0076] This embodiment effectively avoids heating mis-triggering by adding multi-parameter coupling to judge the heating conditions, considering factors including ambient temperature, battery pack temperature, SOC, and temperature difference duration, and comprehensively considering the temperature difference between the battery pack's own temperature and the ambient temperature. In addition, this embodiment also greatly improves the control accuracy through a special vehicle water flow duty ratio calculation formula and an oil pump speed calculation function, through dynamic coupling logic. Finally, in the driving state, this embodiment also dynamically correlates the vehicle speed and the current ratio to solve the risk of motor demagnetization and thermal runaway that may occur in the continuous low-efficiency heating under high-speed conditions, which is not involved in the speed adaptability control in the prior art.

[0077] Embodiment 2

[0078] This embodiment provides an electric drive low-efficiency heating system for an electric vehicle, which can implement an electric drive low-efficiency heating method for an electric vehicle described in Embodiment 1 through the cooperation of each module.

[0079] The structure of the system provided in this embodiment is as Figure 2As shown in the figure, it includes an information acquisition module, a vehicle operation judgment module, and an execution module. Among them: The information acquisition module is used to acquire ambient temperature information, motor temperature information, power battery temperature, and SOC value. The vehicle operation judgment module is used to judge the vehicle operation state, generate and send a parking low-efficiency heating instruction and a driving low-efficiency heating instruction. The execution module is used to execute the parking low-efficiency heating instruction and the driving low-efficiency heating instruction, adjust the vehicle water flow duty ratio through the vehicle controller, and control the motor current output, motor oil pump speed, and control the electric drive system to enter the parking heating mode or the driving heating mode through the motor controller.

[0080] It should be noted that the explanations of various implementation manners and beneficial effects of the above-mentioned Embodiment 1 for the method are also applicable to this embodiment. To avoid redundancy, no detailed expansion will be made here.

[0081] Embodiment 3

[0082] This embodiment provides a vehicle, including: a vehicle thermal management system, a vehicle controller, a motor controller, an electric drive system, and an electric drive low-efficiency heating system for an electric vehicle described in Embodiment 2. The vehicle provided in this embodiment can realize an electric drive low-efficiency heating method for an electric vehicle described in Embodiment 1 through the cooperation of each component.

[0083] Among them, the vehicle controller is used to adjust the vehicle water flow duty ratio. The motor controller is used to execute the parking low-efficiency heating instruction and the driving low-efficiency heating instruction. The electric drive system is used to heat the battery pack after entering the parking heating mode or the driving heating mode. The explanations of the implementation manners and beneficial effects of the above-mentioned Embodiment 2 for an electric drive low-efficiency heating system for an electric vehicle are also applicable to the vehicle provided in this embodiment, so no further description will be given.

[0084] The vehicle provided in this embodiment also includes other components or other operation methods, which are all known to those skilled in the art, and will not be described in detail in this embodiment.

[0085] It should be noted that the explanations of various implementation manners and beneficial effects of the above-mentioned Embodiment 1 are also applicable to this embodiment. To avoid redundancy, no detailed expansion will be made here.

[0086] The specific embodiments of the present invention have been described above. Through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention.

Claims

1. An inefficient heating method for electric drive of electric vehicles, characterized in that: The steps include: Determine whether a preset heating condition is met, and send a heating instruction to the vehicle controller when the preset heating condition is met; the preset heating condition is: the vehicle is judged to be in an inefficient state based on the ambient temperature information, the motor temperature information, the power battery temperature and the SOC value, and the vehicle continues to be in an inefficient state for more than a preset time threshold; Determine the vehicle operation state according to a preset state determination rule, wherein the vehicle operation state includes a parking state and a driving state; When it is determined that the vehicle is in the parking state: a parking inefficient heating instruction is sent to the motor controller, and the vehicle water flow duty ratio is adjusted to the preset parking water flow duty ratio; The motor controller receives the parking inefficient heating instruction and controls the motor oil pump to enter the first oil pump state; The motor controller controls the motor's cross-axis current to be 0, and controls the output of the corresponding direct-axis current according to the ambient temperature information; the motor controller receives the parking inefficient heating instruction, and determines that the motor speed does not exceed the preset parking heating speed threshold, and the power device is in an open-tube state, then the electric drive system enters the corresponding parking heating mode according to the ambient temperature information; when it is determined that the vehicle is in the driving state: send the driving inefficient heating instruction to the motor controller, and the vehicle water flow duty cycle is adjusted to the preset driving water flow duty cycle; the motor controller receives the driving inefficient heating instruction, and controls the motor oil pump to enter the second state of the oil pump; the motor controller controls to reduce the motor efficiency, adjusts the cross-axis direct-axis current ratio according to the ambient temperature when the vehicle speed is in the first speed range, adjusts the cross-axis direct-axis current ratio according to the vehicle speed when the vehicle speed rises to the second speed range, and exits the heating mode when the vehicle speed further rises to the third range; the motor controller receives the driving inefficient heating instruction, and determines that the motor speed is in the preset driving heating speed range, and the power device is in an open-tube state, then the electric drive system enters the corresponding driving heating mode according to the ambient temperature information; The calculation formula of the preset parking water flow duty cycle is: D_parking=k1*ΔT+b1; The calculation formula of the preset driving water flow duty cycle is: when the vehicle speed is at a preset low speed, D_driving=k2*ΔT+b2+α*v; when the vehicle speed is at a preset high speed, D_driving=min(Dmax, k3*ln(ΔT)+b3); D_parking is the preset parking water flow duty cycle, D_driving is the preset driving water flow duty cycle, k1, k2, k3 refer to the sensitivity coefficient of ΔT to water flow, ΔT is the difference between the ambient temperature information and the power battery temperature, b1, b2, b3 refer to the basic duty cycle to ensure the minimum heat dissipation demand, α is the vehicle speed gain value; The second state of the oil pump is: when the ambient temperature is less than zero degrees, n driving = n base + β * (T mot -60); when the ambient temperature is greater than zero degrees, n driving = n base (1-γ * v / 100); where n base is the base speed, β is the motor temperature gain value, γ is the attenuation coefficient of vehicle speed to oil pump speed, v is the vehicle speed, T mot is the motor temperature.

2. The inefficient electric drive heating method for electric vehicles according to claim 1, characterized in that: The parking heating mode includes parking heating mode 1 and parking heating mode 2. When the ambient temperature information is in the low range, the parking heating mode 1 is entered to output the parking heating power P11; when the ambient temperature information is in the high range, the parking heating mode 2 is entered to output the parking heating power P12 which is less than the parking heating power P1. The driving heating mode includes driving heating mode 1 and driving heating mode 2. When the ambient temperature information is in the low range, the driving heating mode 1 is entered and the driving heating power P21 is output; when the ambient temperature information is in the high range, the driving heating mode 2 is entered and the driving heating power P22 which is less than the driving heating power P21 is output.

3. The inefficient electric drive heating method for electric vehicles according to claim 1, characterized in that: The preset state judgment rule is: when the vehicle is in N gear or P gear and the motor speed is 0, it is judged to be in the parking state; when the vehicle is in D gear or R gear and the motor speed is not 0, it is judged to be in the driving state.

4. The inefficient electric drive heating method for electric vehicles according to claim 1, characterized in that: After the electric drive system enters the parking heating mode or driving heating mode, the heat is transferred to the battery pack through the lubricating oil and coolant.

5. The inefficient electric drive heating method for electric vehicles according to claim 2, characterized in that: For the electric drive system of the oil-cooled motor, after entering the parking heating mode 1, the motor controller controls the electronic oil pump to run at a speed n1. After entering the parking heating mode 2, the motor controller controls the electronic oil pump to run at a speed n2, and the speed n1>speed n2.

6. The inefficient electric drive heating method for electric vehicles according to claim 1, characterized in that: After the electric drive system enters the driving heating mode, the control loop of the normal operating mode is reused to control the current output through the driving heating lookup table data.

7. The inefficient electric drive heating method for electric vehicles according to claim 1, characterized in that: In the preset heating condition, the inefficient state is T env ≤-5℃, and T bat ≤10℃ and SOC value ≥20%, the preset time threshold is 150 seconds; In the calculation formula of the preset parking water flow duty cycle, k1 is 1.5±0.2, b1 is 50±5; The first state of the oil pump refers to the motor oil pump speed being between 2500-3500 rpm; In the driving state, the motor controller controls the quadrature-axis current and the direct-axis current to satisfy the following equivalent relationship: When the vehicle speed is in the first speed range, Id / Iq=1.2+0.05*(T env +20); when the vehicle speed is in the second speed range, Id / Iq=0.8-0.03*v; When the vehicle speed is in the third speed range, the heating mode is directly exited; where Id is the direct axis current, Iq is the quadrature axis current, and T env is the ambient temperature.

8. The inefficient electric drive heating method for electric vehicles according to claim 1, characterized in that: It also includes sending an exit heating instruction to the vehicle controller when it is identified that the motor temperature and IGBT junction temperature exceed the preset exit threshold.

9. An electric drive inefficient heating system for an electric vehicle, characterized in that: Used to execute the electric drive inefficient heating method for electric vehicles according to any one of claims 1 to 8, comprising an information acquisition module, a vehicle operation judgment module, and an execution module; The information acquisition module is used to obtain ambient temperature information, motor temperature information, power battery temperature and SOC value; The vehicle operation judgment module is used to judge the vehicle operation status, generate and send parking inefficient heating instructions and driving inefficient heating instructions; The execution module is used to execute the parking inefficient heating instructions and the driving inefficient heating instructions, adjust the water flow duty cycle of the vehicle through the vehicle controller, control the motor current output and the motor oil pump speed through the motor controller, and control the electric drive system to enter the parking heating mode or the driving heating mode.

10. A vehicle, characterized in that: include: A vehicle thermal management system, a vehicle controller, a motor controller, an electric drive system, and an electric drive inefficient heating system for an electric vehicle as described in claim 9.

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