A thermal management system of an electric drive system of a hybrid vehicle and a vehicle

Abstract

The application relates to a heat management system of an electric drive system of a hybrid vehicle and an automobile, comprising: a motor control module configured to acquire AC integration of an AC element or DC integration of a DC element from starting of the automobile to a t moment, compare the AC integration or the DC integration with a set AC integration threshold value or DC integration threshold value of the t moment, and adjust peak power or rated power of the electric drive system according to a comparison result, wherein the DC element includes but is not limited to a DC connector or a DC copper bar of a motor controller, and the AC element is a three-phase connector or a three-phase wire harness of the motor controller. According to the application, the peak power and the rated power of the electric drive system can be reasonably adjusted according to different ambient temperatures, the capacity of the electric drive system can be fully released, the thermal safety of the electric drive system can be ensured, and the system reliability can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy vehicles, in particular to hybrid vehicle technology. BACKGROUND

[0002] The hybrid vehicle, especially the plug-in hybrid vehicle with the electric drive system in the engine compartment. The plug-in hybrid vehicle has three working modes: HEV mode, that is, the engine and the drive motor work together, and the environment temperature of the electric drive system is mostly 85-105℃; EV mode, that is, the drive motor works independently, at this time the pure electric driving condition, and the environment temperature of the electric drive system is mostly below 65℃; fuel mode, the engine drives the vehicle, and the electric drive system generates power at a small power. The heat sources of the electric drive system are mainly: (1) the motor controller power circuit, including IGBT, support capacitor, AC copper bar, DC copper bar, etc.; (2) the drive motor, including motor stator and rotor magnetic steel, permanent magnet, winding, etc.; (3) the wire harness and connector that connects the battery and the motor controller, and the motor controller and the motor. The current or power that can be carried by the above heat sources is extremely related to the heat dissipation capacity. Among them, (1) is mainly related to the environment temperature and the temperature and flow of the electric controller cooling liquid, and the temperature of the cooling liquid is related to the environment temperature; (2) is mainly related to the temperature and flow of the cooling oil, and the temperature of the cooling oil is related to the environment temperature; (3) is located in the engine compartment, and the heat dissipation is mainly related to the environment temperature. When the plug-in hybrid vehicle works in HEV mode and EV mode, the rated power and peak power that can be carried by the electric drive system are different due to the different environment temperatures. Therefore, the performance of the electric drive system is extremely related to the environment temperature.

[0003] In the prior art, only the peak power and rated power of the electric drive system are calibrated, and in the process of driving the car, only the power of the electric drive system is specified not to exceed the peak power in the process of stepping on the accelerator, but under certain working conditions such as emergency braking and emergency acceleration, there is a risk of overheating. SUMMARY

[0004] One of the purposes of the present application is to provide a thermal management system of an electric drive system of a hybrid vehicle to solve the problem that the prior art is prone to overheating risk; the second purpose is to provide an automobile.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A thermal management system of an electric drive system of a hybrid vehicle, comprising:

[0007] The motor control module is configured to obtain AC integral of AC elements or DC integral of DC elements from the start of the automobile to the t moment, and compare with the set AC integral threshold or DC integral threshold of the t moment, and adjust the peak power or rated power of the electric drive system according to the comparison result, the DC elements include but are not limited to DC connectors or DC copper bars of the motor controller, and the AC elements are three-phase connectors or three-phase wire harnesses of the motor controller.

[0008] According to the above technical means, whether the current is too large is determined by obtaining the AC integral threshold or the DC integral threshold, when the current is too large, that is, the AC integral or the DC integral of the DC element is greater than the set AC integral threshold or DC integral threshold of the moment, then the peak power or rated power of the electric drive system is reduced, thereby reducing the risk of overheating under the working condition of sudden braking and sudden acceleration.

[0009] Further, the method for setting the AC integral threshold or the DC integral threshold is:

[0010] On the bench, the environmental temperature and the outflow temperature of the cooling medium in the cabin under the thermal hazard working condition are calibrated;

[0011] The current value of the DC element or the current value of the AC element at the t moment is obtained;

[0012] The temperature coefficient is obtained, and the DC integral value or the AC integral value at the t moment is obtained according to the temperature coefficient and defined as the AC integral threshold or the DC integral threshold of the moment.

[0013] Further, the method for obtaining the temperature coefficient is:

[0014]

[0015] Wherein, The temperature coefficient is represented by T;

[0016] The environmental temperature influence coefficient is represented by T;

[0017] The cooling medium temperature influence coefficient is represented by T;

[0018] The thermal hazard working condition environmental temperature is represented by T;

[0019] The measured cabin environmental temperature is represented by T;

[0020] The thermal hazard engineering cooling medium inflow temperature is represented by T;

[0021] The measured cooling medium inflow temperature is represented by T.

[0022] Further, if the temperature signal of the ambient temperature or the temperature of the cooling medium is unreliable, then is 1; if both are reliable, and , then , if both are reliable, and , then ;

[0023] wherein represents the calibrated minimum temperature coefficient value, represents the calibrated maximum temperature coefficient value.

[0024] Further, the system further comprises:

[0025] a cooling liquid flow control module configured for cooling flow control of the motor controller or the motor, the method of the cooling flow control of the motor controller or the motor being:

[0026] calculating the required cooling flow of the motor controller or the motor;

[0027] when the calculated cooling flow is less than or equal to the minimum flow threshold, the output cooling flow is the minimum flow threshold; when the calculated cooling flow is greater than or equal to the maximum flow threshold, the output cooling flow is the maximum flow threshold; when the calculated cooling flow is between the minimum flow threshold and the maximum flow threshold, if the calculated cooling flow is a positive integer, the output calculated cooling flow is output; if the calculated cooling flow has a decimal, the output cooling flow value is greater than the calculated cooling flow and is a positive integer, and the difference between the output cooling flow value and the integer part of the calculated cooling flow is 1.

[0028] According to the above technical means, by discrete segmented cooling liquid flow supply, compared with the real-time change of the cooling liquid flow of the prior art, the cooling system loss is optimized, and the whole vehicle system fuel consumption is reduced

[0029] Further, the method of calculating the required cooling flow of the motor controller or the motor is:

[0030] obtaining the heat generation and heat dissipation of the motor controller or the motor;

[0031] According to the temperature difference of the cooling medium entering and exiting the motor controller or the motor, the required cooling flow is obtained by the following formula:

[0032]

[0033] wherein dt represents the cooling liquid flow calculation period;

[0034] represents the heat generation amount;

[0035] represents the temperature difference;

[0036] represents the cooling water channel heat dissipation coefficient, which is measured by a bench test.

[0037] Further, the temperature difference acquisition method is:

[0038] If , then ;

[0039] If , then ;

[0040] wherein represents the temperature when the cooling liquid flows out, represents the temperature when the cooling liquid flows in, represents the preset minimum temperature difference.

[0041] An automobile is configured with the above system.

[0042] The beneficial effects of the present application are:

[0043] On one hand, the present application can reasonably adjust the peak power and rated power of the electric drive system according to different ambient temperatures, fully release the capacity of the electric drive system; on the other hand, the present application ensures the thermal safety of the electric drive system, improves the system reliability; at the same time, by controlling the cooling flow, the present application realizes the segmented cooling flow request, optimizes the cooling system loss, and reduces the vehicle system fuel consumption. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is an electric drive system block diagram;

[0045] Figure 2 is a flow chart of the cooling liquid flow control module controlling the motor controller cooling flow;

[0046] Figure 3 is a flow chart of the cooling liquid flow control module controlling the motor cooling flow;

[0047] Figure 4 is a direct current current integral control flow chart of the motor control module;

[0048] Figure 5 is an alternating current current integral control flow chart of the motor control module.

[0049] Wherein, 1-engine compartment; 11-motor controller assembly, 111-supporting capacitor, 112-direct current copper bar, 113-IGBT module, 114-three-phase copper bar; 12-three-phase connector; 13-environmental temperature sensor; 14-three-phase wire harness connected with the motor and the controller; 15-electric drive gearbox, 151-driving motor. DETAILED DESCRIPTION

[0050] Other advantages and benefits of the present application will become apparent to those skilled in the art upon consideration of the disclosure or can be learned by practice of the application. The application can be realized and achieved by means of the structures and combinations described in this specification and can be realized and achieved by means of structures and combinations regardless of their detailed disclosure. The preferred embodiments are only for illustrating the application, and are not intended to limit the scope of protection of the application.

[0051] It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present application, and only the components related to the present application are shown in the drawings, rather than the number, shape and size of the components when actually implemented. The actual implementation of each component may be arbitrarily changed in terms of shape, number and proportion, and the layout pattern of the components may be more complex.

[0052] The embodiment provides a thermal management system of an electric drive system of a hybrid vehicle, comprising a motor control module and a cooling liquid flow control module. The motor control module is configured to obtain an alternating current integral of an alternating current element or a direct current integral of a direct current element from vehicle starting to t moment, and compare the alternating current integral or the direct current integral with a set alternating current integral threshold value or direct current integral threshold value at the moment, and adjust peak power or rated power of the electric drive system according to a comparison result. The direct current element includes but is not limited to a direct current connector or a direct current copper bar of a motor controller. The alternating current element is a three-phase connector or a three-phase wire harness of the motor controller.

[0053] The cooling liquid flow control module is configured for cooling flow control of the motor controller or cooling flow control of the motor. The method for the cooling flow control of the motor controller or the cooling flow control of the motor is as follows.

[0054] The required cooling flow of the motor controller or the motor is calculated.

[0055] When the calculated coolant flow rate is less than or equal to the minimum flow rate threshold, the output coolant flow rate is the minimum flow rate threshold; when the calculated coolant flow rate is greater than or equal to the maximum flow rate threshold, the output coolant flow rate is the maximum flow rate threshold; when the calculated coolant flow rate is between the minimum and maximum flow rate thresholds, if the calculated coolant flow rate is a positive integer, the calculated coolant flow rate is output; if the calculated coolant flow rate has a decimal, the output coolant flow rate value is greater than the calculated coolant flow rate and is a positive integer, and the difference between the output coolant flow rate value and the integer part of the calculated coolant flow rate is 1.

[0056] Specifically:

[0057] See Figure 1 The diagram shown is a block diagram of the electric drive system of the present invention. This embodiment is applied to a plug-in hybrid electric vehicle and includes an engine compartment 1, a motor controller assembly 11, a supporting capacitor 111, a DC copper busbar 112, an IGBT module 113, a three-phase copper busbar 114, a three-phase connector 12, an ambient temperature sensor 13, a three-phase wiring harness 14 connecting the motor and the controller, an electric drive gearbox 15, and a drive motor 151.

[0058] See Figure 2 This invention relates to a method for controlling the coolant flow rate of a motor controller using a motor control module. Specifically:

[0059] S11. Based on the fact that the heat generated by the motor controller mainly comes from IGBT switching losses, conduction losses, and DC copper busbar conduction losses, a formula for calculating the heat generation of the motor controller is derived. dt is the cooling flow calculation period, I is the effective value of the drive motor current, which is obtained in real time by the motor controller current sensor, k1 represents the heat generation coefficient of the IGBT equivalent resistance, k2 represents the heat generation coefficient of the IGBT conduction losses and switching losses, and k3 represents the heat dissipation coefficient of the cooling water channel. The parameter k3 is confirmed through experiments.

[0060] The motor controller's heat dissipation is mainly achieved through coolant. The heat dissipation formula is derived, where T2 and T3 are the inlet and outlet temperatures of the coolant, respectively, which are collected in real time by temperature sensors.

[0061] The formula for calculating the heat generation of the motor controller is: ;

[0062] The formula for calculating the heat dissipation of the motor controller is: ;

[0063] S12 calculates the coolant temperature difference and assigns a reasonable value to ΔT1. C1 is the minimum temperature difference, and its value needs to be determined based on the heat dissipation structure. A larger thermal resistance results in a smaller value, and a smaller thermal resistance results in a larger value. The specific method is as follows:

[0064] like ,but ;

[0065] If , then ;

[0066] where represents a preset minimum temperature difference.

[0067] The third step S13, calculate the coolant flow rate.

[0068] Let , then the coolant flow rate .

[0069] S14, discretize the cooling flow rate. To avoid the low - efficiency use caused by the real - time dynamic adjustment of the coolant pump, the coolant flow rate is reasonably discretized. When the calculated flow rate (minimum flow threshold), ; when the calculated flow rate (maximum flow threshold), ; when V > Vmin and V < Vmax, V is rounded up to an integer. That is, when the calculated coolant flow rate is between the minimum flow threshold and the maximum flow threshold, if the calculated coolant flow rate is a positive integer, the calculated coolant flow rate is output; if the calculated coolant flow rate has a decimal, the output coolant flow rate value is greater than the calculated coolant flow rate and is a positive integer, and the difference between the output coolant flow rate value and the integer part of the calculated coolant flow rate is 1.

[0070] For example, when the calculated flow rate is 25.6 and 25.6 is between the maximum flow threshold and the minimum flow threshold, the output coolant flow rate is 26.

[0071] Among them, 0L means the controller is in the idle mode, that is, the IGBT off - state. As long as the motor controller is in the working state, the minimum flow rate is Vmin liters, so that the coolant pump always works to meet the response requirement that the cooling flow rate needs to increase rapidly when the motor controller is working. The advantages of this cooling flow rate control strategy: segmented cooling flow rate requests, optimize the cooling system loss, and reduce the vehicle system fuel consumption.

[0072] See Figure 3 for the method of the motor control module controlling the motor cooling flow rate.

[0073] S21, calculate the heat generated by the motor, subtract the motor output power from the motor input power, derive the motor controller heat generation calculation formula, where dt is the cooling flow calculation period, U is collected by the voltage sensor, I is collected by the current sensor, n is collected by the resolver sensor, Tq and θ are calculated by the relevant algorithm. The heat dissipation of the motor is mainly through the cooling oil, and the heat dissipation formula is derived, T4 and T5 are the cooling inlet and outlet oil temperatures, which are collected by the temperature sensor in real time, and k5 is a parameter related to the heat resistance of the motor oil cooling, which is confirmed by test k5 parameter.

[0074] The heat generation calculation formula is: ;

[0075] The heat dissipation calculation formula is: .

[0076] S22: Calculate the cooling oil temperature difference and reasonably assign ΔT2, C2 is the minimum temperature difference, which needs to be determined according to the heat dissipation structure, the larger the thermal resistance, the smaller the value, and the smaller the thermal resistance, the larger the value.

[0077] If , then ;

[0078] If , then ;

[0079] Where represents the preset minimum temperature difference.

[0080] Step 3 S23, calculate the cooling oil flow.

[0081] Let , .

[0082] S24, cooling flow discretization processing, in order to avoid real-time dynamic adjustment of the cooling oil pump, leading to low efficiency use, the cooling liquid flow is reasonably discretized. When the flow calculation value V

[0083] Wherein 0L is the controller in idle mode, that is, IGBT off state. As long as the motor controller is in working state, the minimum flow is Vmin liters, so that the cooling oil pump is always working to meet the cooling flow needs to increase quickly in response when the motor is working. The cooling flow control strategy has the advantages of segmented cooling flow request, optimized cooling system loss, and reduced vehicle system fuel consumption.

[0084] Referring to Figure 4 , the method for setting the direct current integral threshold value is:

[0085] S31, through simulation and test, the current values under the conditions of 10s, 50s, 500s, 1000s, T 7max =105℃, and the temperature T 3max =65℃ of the outflowing cooling water are determined.

[0086] S32, through thermal model simulation and test, the parameters k6, k7, k8 (temperature coefficient values) are determined.

[0087] .

[0088] S33, the rationality of the k6 coefficient is checked.

[0089] If the signals of T7 or T3 are unreliable, then let k6=1; if reliable, and T7 , then k6=T7 , if both are reliable, and T7 , then k6=T7 ;

[0090] Wherein, represents the minimum temperature coefficient value calibrated when setting the direct current integral threshold value, represents the maximum temperature coefficient value calibrated when setting the direct current integral threshold value.

[0091] S34, the current integral value is calculated. The direct current integral control strategy has the advantage that the peak power and rated power of the motor controller can be reasonably adjusted according to different ambient temperatures and cooling liquid temperatures.

[0092] Wherein, represents the temperature coefficient;

[0093] represents the ambient temperature influence coefficient;

[0094] represents the cooling medium temperature influence coefficient;

[0095] represents the thermal hazard working condition ambient temperature;

[0096] ​Indicates the measured cabin environment temperature;

[0097] Indicates the heat damage engineering cooling medium inflow temperature;

[0098] Indicates the measured cooling medium inflow temperature.

[0099] That is, by the above method, the DC_I_10s current value, the DC_I_50s current value, the DC_I_500s current value, and the DC_1000s current value are defined, wherein 10s and 50s represent short-time capability, and 500s and 1000s represent long-time capability, the values of which are related to the environment temperature and the motor controller cooling liquid temperature. Since the DC plug and the DC copper bar do not have a temperature sensor, the corresponding limiting current values need to be calibrated at different environment temperatures and cooling temperatures through a test bench. In this embodiment, the DC integrals at 10s, 50s, 500s, and 1000s are calculated, and the “t time” is set to 10s, 50s, 500s, or 1000s. Taking 10s as an example, when the automobile is started for 10s or more, the current integral of the DC element exceeds DC_I_10s or DC_I_50s, and in order to not cause overheating, the peak power of the electric drive system is reduced; when the automobile is started for 500s or 1000s, the current integral of the DC element exceeds DC_I_500s or DC_I_1000s, and in order to not cause overheating, the rated power of the electric drive system is reduced.

[0100] Referring to Figure 5 , the method for setting the AC integral threshold value is:

[0101] In the first step S41, the current values at 10s, 50s, 500s, and 1000s are determined under the conditions of the heat damage working condition cabin environment temperature T7=105℃ and the oil temperature T3=85℃ through simulation and test.

[0102] In the second step S42, the parameters k9, k10, and k11 are determined through thermal model simulation and test.

[0103] .

[0104] In the third step S43, the k9 coefficient is reasonably checked.

[0105] If the signals of T7 or T5 are unreliable, then let be 1; if both are reliable, and , then , if reliable, and , then ;

[0106] wherein, represent the minimum temperature coefficient value of the AC integral threshold setting, represent the maximum temperature coefficient value of the AC integral threshold setting.

[0107] In the fourth step S44, the current integral value is calculated. The DC integral control strategy has the advantage that the peak power and the rated power of the motor can be reasonably adjusted according to different ambient temperatures and cooling oil temperatures.

[0108] That is, by the above-mentioned manner, the AC_I_10s current value, the AC_I_50s current value, the AC_I_500s current value and the AC_1000s current value are specified, wherein 10s and 50s represent short-time capability, and 500s and 1000s represent long-time capability, and the values are related to the ambient temperature and the motor controller cooling liquid temperature. Since the three-phase connector and the three-phase wire harness do not have a temperature sensor, the corresponding limiting current values need to be calibrated at different ambient temperatures and cooling temperatures by a test bench.

[0109] In the embodiment, the AC integral at 10s, 50s, 500s and 1000s is calculated, and the "t time" is 10s, 50s, 500s or 1000s. For example, when the automobile is started for 10s or 50s, the current integral of the AC element exceeds the AC_I_10s or the AC_I_50s, and the peak power of the electric drive system is reduced in order not to cause overheating. When the automobile is started for 500s or 1000s, the current integral of the AC element exceeds the AC_I_500s or the AC_I_1000s, and the rated power of the electric drive system is reduced in order not to cause overheating.

[0110] The embodiment also provides an automobile which is provided with the thermal management system of the electric drive system of the hybrid vehicle.

[0111] The above embodiments are only preferred embodiments for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation of the present application made by those skilled in the art based on the present application is within the protection scope of the present application.

Claims

1. A thermal management system of an electric drive system of a hybrid vehicle, comprising an electric machine control module, characterized in that: the electric machine control module is configured to obtain an AC integral of an AC element or a DC integral of a DC element from a start of the vehicle to a time t, and compare the AC integral or the DC integral with a set AC integral threshold or a set DC integral threshold at the time t, and adjust a peak power or a rated power of the electric drive system according to a comparison result, the DC element includes but is not limited to a DC connector or a DC copper bar of an electric machine controller, and the AC element is a three-phase connector or a three-phase harness of the electric machine controller; a method for setting the AC integral threshold or the DC integral threshold is: on a test bench, calibrating an ambient temperature and an outflow temperature of a cooling medium in a heat hazard condition of a nacelle; obtaining a current value of the DC element or a current value of the AC element at the time t; obtaining a temperature coefficient, and obtaining a DC integral value or an AC integral value at the time t according to the temperature coefficient and defining the DC integral value or the AC integral value as the AC integral threshold or the DC integral threshold at the time t; a method for obtaining the temperature coefficient is: + wherein denotes the temperature coefficient; represents the ambient temperature influence coefficient; represents the cooling medium temperature influence coefficient; T represents the temperature of the heat damage working condition environment; Tmeasured represents the measured cabin interior ambient temperature; Tin represents the temperature of the incoming thermal mitigation engineering coolant medium; represents the measured cooling medium inflow temperature; the system further comprises: a cooling liquid flow control module configured for cooling flow control of the electric machine controller or cooling flow control of the electric machine, and a method for the cooling flow control of the electric machine controller or the electric machine is: calculating a required cooling flow of the electric machine controller or the electric machine; when the calculated cooling flow is less than or equal to a minimum flow threshold, outputting the minimum flow threshold; when the calculated cooling flow is greater than or equal to a maximum flow threshold, outputting the maximum flow threshold; and when the calculated cooling flow is between the minimum flow threshold and the maximum flow threshold, if the calculated cooling flow is a positive integer, outputting the calculated cooling flow, and if the calculated cooling flow has a decimal, rounding up the calculated cooling flow to an integer; a method for calculating the required cooling flow of the electric machine controller or the electric machine is: obtaining a heat generation amount and a heat dissipation amount of the electric machine controller or the electric machine; obtaining the required cooling flow according to a temperature difference of the cooling medium entering and exiting the electric machine controller or the electric machine by the following formula: wherein dt represents a cooling flow calculation period; represents the amount of heat generated; represents the temperature difference; The cooling water channel heat dissipation coefficient is measured by a bench test.

2. The system of claim 1, wherein: If the temperature signal of the ambient temperature or the temperature of the cooling medium is not reliable, then the temperature signal of the ambient temperature or the temperature of the cooling medium is set to 0. is 1 ; if both are reliable and then is 1 ; if both are reliable and then is 1. wherein, represents a nominal minimum temperature coefficient value, represents a nominal maximum temperature coefficient value.

3. The system of claim 1, wherein: a method for obtaining the temperature difference is: If then ; If then ; wherein represents the temperature when the coolant flows out, represents the temperature when the coolant flows in, represents a preset minimum temperature difference.

4. An automobile characterized by comprising: the system is configured as claimed in any one of claims 1-3.

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