Eps motor temperature estimation method and system, electronic equipment and medium

Abstract

The invention relates to the technical field of eps motors, and discloses an eps motor temperature estimation method and system, electronic equipment and a medium, and the method comprises the steps: inputting different currents for an eps motor, and obtaining the temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data, measured by a thermistor, of a circuit board of the eps motor when different currents are input into the eps motor; calculating a thermal resistance parameter of each preset component in the electronic winding according to the temperature rise data corresponding to each current; obtaining the temperature of the circuit board, and constructing a state-space equation according to the temperature of the circuit board and each thermal resistance parameter; the current environment temperature is obtained according to the state-space equation, and the Eps motor temperature is estimated according to the current environment temperature. On the premise that a hardware environment temperature sensor is not added, the circuit board temperature measured by the thermistor on the circuit board is used as an actual measurement reference quantity to observe the environment temperature, so that the estimation error of the motor temperature is reduced.

Description

Background Art

[0002] Since the electric power steering system (EPS motor) is a short-time working system, it may occasionally cause severe heating due to continuous high torque working conditions, so a temperature protection function is required. Since EPS motors usually do not have stator winding temperature sensors, the motor winding temperature must be estimated. The temperature rise model of the equivalent thermal circuit method is often used to estimate the temperature of the EPS motor, which has the advantages of small calculation amount and acceptable error; however, this method can only calculate the temperature rise, and will cause large temperature errors when the external ambient temperature changes over a large range, such as the difference in ambient temperature between the parking garage and the outdoors in extreme conditions, and restarting under high temperature conditions of the circuit board will lead to inaccurate ambient temperature judgment and large changes.

[0003] If the ambient temperature cannot be detected, the EPS motor temperature estimation error will be large. Summary of the invention

[0004] In order to overcome the problem that the ambient temperature cannot be detected when estimating the temperature of the EPS motor, resulting in a large error in the temperature estimation of the EPS motor, the present invention provides an EPS motor temperature estimation method, system, electronic device and medium.

[0005] In a first aspect, in order to solve the above technical problems, the present invention provides an EPS motor temperature estimation method, comprising:

[0006] Input different currents to the EPS motor and obtain temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data of a circuit board of the EPS motor measured by a thermistor during the period when different currents are input to the EPS motor;

[0007] Calculate the thermal resistance parameters of each preset component in the electronic winding according to the temperature rise data corresponding to each current;

[0008] Obtain the circuit board temperature, and construct a state space equation based on the circuit board temperature and various thermal resistance parameters; the state space equation characterizes the relationship between the circuit board temperature and the ambient temperature of the EPS motor;

[0009] The current ambient temperature is obtained according to the state space equation, and the EPS motor temperature is estimated based on the current ambient temperature.

[0010] In a second aspect, the present invention provides an EPS motor temperature estimation system, comprising:

[0011] A temperature rise data acquisition module is used to input different currents to the EPS motor and obtain temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data of the circuit board of the EPS motor measured by the thermistor during the period when different currents are input to the EPS motor;

[0012] A thermal resistance parameter determination module is used to calculate the thermal resistance parameters of each preset component in the electronic winding according to the temperature rise data corresponding to each current;

[0013] The state space equation building module is used to obtain the circuit board temperature and build the state space equation according to the circuit board temperature and various thermal resistance parameters; the state space equation characterizes the relationship between the circuit board temperature and the ambient temperature of the EPS motor;

[0014] The EPS motor temperature estimation module is used to obtain the current ambient temperature according to the state space equation and estimate the EPS motor temperature according to the current ambient temperature.

[0015] The beneficial effects of the present invention are as follows: by inputting different currents into the EPS motor, the temperature rise data corresponding to each current can be recorded, and the thermal resistance parameters of each preset component can be calculated, and then the state space equation can be constructed to obtain the relationship between the circuit board temperature, the temperature of each component and the ambient temperature, and finally the current ambient temperature can be obtained through the state space equation, so as to estimate the EPS motor temperature according to the current ambient temperature. The present application only uses the circuit board temperature measured by the thermistor on the circuit board as the actual reference quantity to observe the ambient temperature without adding a hardware ambient temperature sensor, so as to reduce the error of the motor temperature estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 A schematic flow chart of a method for estimating temperature of an EPS motor according to an embodiment of the present invention;

[0018] Figure 2 The temperature rise data diagram corresponding to different current inputs to the SPE motor;

[0019] Figure 3 is the equivalent thermal circuit diagram;

[0020] Figure 4 is the state observer of the EPS motor temperature;

[0021] Figure 5 It is a comparison chart of the estimated value and the actual value of the ambient temperature;

[0022] Figure 6 A schematic diagram of the structure of an EPS motor temperature estimation system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following examples are provided to further explain and supplement the present invention and do not constitute any limitation to the present invention.

[0024] The following describes an EPS motor temperature estimation method, system, electronic device and medium according to an embodiment of the present invention in conjunction with the accompanying drawings.

[0025] like Figure 1 As shown, the present invention provides an EPS motor temperature estimation method, comprising:

[0026] S1. Input different currents to the EPS motor and obtain temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data of a circuit board of the EPS motor measured by a thermistor during the period when different currents are input to the EPS motor.

[0027] S2. Calculate the thermal resistance parameters of each preset component in the electronic winding according to the temperature rise data corresponding to each current.

[0028] S3. Obtain the circuit board temperature, and construct a state space equation based on the circuit board temperature and various thermal resistance parameters; wherein the state space equation characterizes the relationship between the circuit board temperature and the ambient temperature of the EPS motor.

[0029] S4. Obtain the current ambient temperature according to the state space equation, and estimate the EPS motor temperature according to the current ambient temperature.

[0030] In this embodiment, by inputting different currents into the EPS motor, the temperature rise data corresponding to each current can be recorded, and the thermal resistance parameters of each preset component can be calculated, and then the state space equation is constructed to obtain the relationship between the circuit board temperature, the temperature of each component and the ambient temperature. Finally, the current ambient temperature is obtained through the state space equation, so as to estimate the EPS motor temperature according to the current ambient temperature. This application only uses the circuit board temperature measured by the thermistor on the circuit board as the measured reference quantity to observe the ambient temperature without adding a hardware ambient temperature sensor, so as to reduce the error of the motor temperature estimation.

[0031] Optionally, different currents are input to the EPS motor, and the temperature rise data corresponding to each current is obtained, including:

[0032] Input different currents for the spe motor;

[0033] When the SPE motor is rotated by inputting the current current, a step current AC signal with different preset amplitudes is input on the D axis of the phase current at preset time intervals until the temperature of the electronic winding exceeds the preset temperature, then the input of the step current AC signal is stopped, and the next current is input to the SPE motor after the ambient temperature drops to room temperature;

[0034] Record the temperature rise data of the EPS motor circuit board measured by the thermistor from the time the current is input to the SPE motor until the ambient temperature drops to room temperature.

[0035] In this embodiment, the preset time, preset temperature and preset amplitude can be set according to actual conditions. Preferably, in this embodiment, the preset time can be 100s, the preset temperature is 100°C, and the different preset amplitudes are 40A, 60A and 80A.

[0036] like Figure 2 As shown, the temperature rise data corresponding to different currents input to the SPE motor. It can be seen that three currents were input, and three sections of circuit board temperature rise data (time-winding temperature) that increased with time were obtained respectively.

[0037] Optionally, according to the temperature rise data corresponding to each current, the thermal resistance parameters of each preset component in the electronic winding are calculated, including:

[0038] According to the temperature rise data corresponding to each current, the relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is obtained through the thermal network model;

[0039] The relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is solved through the second-order thermal network model to determine the thermal resistance parameters of each preset component in the electronic winding.

[0040] In this embodiment, current is used as input and temperature is used as output. The data is imported into the MATLAB system identification toolbox for identification. The corresponding order is set to 2 in the toolbox, so that the relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is obtained through the thermal network model, as shown below:

[0041]

[0042] Wherein, Z(s) represents the relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient, S represents the complex vector of the transfer function, and a 0 、a 1 、b 0 、b 1 、b 2 is the thermal resistance coefficient of each preset, C 1 represents the heat capacity of the stator winding, C 2 represents the heat capacity of the stator core, R 1 Thermal resistance between stator winding and stator core, R 2 The thermal resistance between the stator core and the external environment, where C 1 , C 2 , R 1 , R 2 Represents various thermal resistance parameters.

[0043] In this embodiment, a 0 、a 1 、b 0 、b 1 、b2 Can be preset to a 0 =4.457e-05, a 1 =0.02381, b 0 =6.462e-06, b 1 =0.0113, b 2 =1.

[0044] Optionally, the relationship between the thermal resistance parameters of each preset component and the preset thermal resistance coefficient is solved by a second-order thermal network model to determine the thermal resistance parameters of each preset component in the electronic winding, and the calculation formula is:

[0045]

[0046] Among them, a 0 、a 1 、b 0 、b 1 、b 2 is the thermal resistance coefficient of each preset, C 1 represents the heat capacity of the stator winding, C 2 represents the heat capacity of the stator core, R 1 Thermal resistance between stator winding and stator core, R 2 The thermal resistance between the stator core and the external environment, where C 1 , C 2 , R 1 , R 2 Represents various thermal resistance parameters.

[0047] In this embodiment, the relationship between the thermal resistance parameters of each preset component and the preset thermal resistance coefficient is solved by a second-order thermal network model, and the thermal resistance parameters of each preset component in the electronic winding are finally obtained as shown in Table 1 below:

[0048] Table 1

[0049] Thermal parameters Measured value unit R1 0.024 ℃ / W R2 6.8 ℃ / W C1 42 J / ℃ C2 42.4 J / ℃

[0050] Optionally, a state space equation is constructed according to the circuit board temperature and various thermal resistance parameters. The state space equation formula is as follows:

[0051]

[0052] C=[0 1 0],D=0

[0053] x=[T 1 T 2 T 0 ] T , u=P

[0054] Among them, x represents the temperature of each preset component in the electronic winding, T represents the transposed matrix, y represents the circuit board temperature, T1 , T 2 Respectively represent the temperature of each preset component in the electronic winding, T 0 represents the ambient temperature, P represents the stator winding copper loss, and A, B, C, and D represent the coefficients of the state space equation respectively.

[0055] The derivation process of the state space equation in this embodiment is as follows:

[0056] like Figure 3 As shown, the equivalent thermal circuit diagram of the EPS motor is constructed, where C 1 represents the heat capacity of the stator winding, C 2 represents the heat capacity of the stator core, R 1 Thermal resistance between stator winding and stator core, R 2 Thermal resistance between stator core and external environment, T 1 Indicates the stator winding temperature, T 2 Indicates the stator core temperature, T 0 represents the ambient temperature and P represents the stator winding copper loss.

[0057] With stator winding temperature and stator core temperature x = [T 1 T 2 ] T , as well as the stator winding copper loss and ambient temperature u=[PT 0 ] T As input, the state equation can be obtained as follows:

[0058]

[0059] In this embodiment, the state space equation is constructed with the help of the state observer, such as Figure 4 The figure shows the constructed state observer of the EPS motor temperature. The initial expression of the state observer can be expressed as:

[0060]

[0061] In order to observe the ambient temperature, it is necessary to add the ambient temperature variable T to the initial expression of the state space equation. 0 , because this term changes relatively slowly relative to the temperature of the EPS motor, it can be considered to be constant within a control cycle, that is, dT 0 / dt=0, therefore, the final state space equation obtained by combining the above formula (1) and formula (2) is:

[0062]

[0063] C=[0 1 0],D=0

[0064] x=[T1 T 2 T 0 ] T ,u=P

[0065] In this embodiment, the above-mentioned state space equation is used to make a judgment based on the observability criterion, and all its variables are observable; therefore, the variable value of the state space (ambient temperature) can be observed based on the actual value of its observed quantity (circuit board temperature).

[0066] Optionally, the current ambient temperature is obtained according to a state space equation, including:

[0067] Get the component temperature of each preset component on the EPS motor and the circuit board temperature in real time;

[0068] The current component temperatures and the current board temperature are input into the state space equation to determine the current ambient temperature.

[0069] In this embodiment, without adding a hardware ambient temperature sensor, only the circuit board temperature measured by the thermistor on the circuit board is used as a measured reference quantity to observe the ambient temperature, so as to reduce the error of the estimated motor temperature.

[0070] like Figure 5 As shown, the test was carried out at an ambient temperature of 12°C. When the EPS motor was reset and restarted at a winding temperature of 110°C, the ambient temperature (dotted line) estimated by an EPS motor temperature estimation method in this embodiment could gradually reach the actual ambient temperature (dashed line).

[0071] like Figure 6 As shown, the present invention provides an EPS motor temperature estimation system, comprising:

[0072] A temperature rise data acquisition module is used to input different currents to the EPS motor and obtain temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data of the circuit board of the EPS motor measured by the thermistor during the period when different currents are input to the EPS motor;

[0073] A thermal resistance parameter determination module is used to calculate the thermal resistance parameters of each preset component in the electronic winding according to the temperature rise data corresponding to each current;

[0074] The state space equation building module is used to obtain the circuit board temperature and build the state space equation according to the circuit board temperature and various thermal resistance parameters; the state space equation characterizes the relationship between the circuit board temperature and the ambient temperature of the EPS motor;

[0075] The EPS motor temperature estimation module is used to obtain the current ambient temperature according to the state space equation and estimate the EPS motor temperature according to the current ambient temperature.

[0076] Optionally, the temperature rise data acquisition module is specifically used for:

[0077] Input different currents for the spe motor;

[0078] When the SPE motor is rotated by inputting the current current, a step current AC signal with different preset amplitudes is input on the D axis of the phase current at preset time intervals until the temperature of the electronic winding exceeds the preset temperature, then the input of the step current AC signal is stopped, and the next current is input to the SPE motor after the ambient temperature drops to room temperature;

[0079] Record the temperature rise data of the EPS motor circuit board measured by the thermistor from the time the current is input to the SPE motor until the ambient temperature drops to room temperature.

[0080] Optionally, the thermal resistance parameter determination module is specifically used to:

[0081] According to the temperature rise data corresponding to each current, the relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is obtained through the thermal network model;

[0082] The relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is solved through the second-order thermal network model to determine the thermal resistance parameters of each preset component in the electronic winding.

[0083] Optionally, the thermal resistance parameter determination module is specifically used to:

[0084] The relationship between the thermal resistance parameters of each preset component and the preset thermal resistance coefficient is solved by the second-order thermal network model to determine the thermal resistance parameters of each preset component in the electronic winding. The calculation formula is:

[0085]

[0086] Among them, a 0 、a 1 、b 0 、b 1 、b 2 is the thermal resistance coefficient of each preset, C 1 represents the heat capacity of the stator winding, C 2 represents the heat capacity of the stator core, R 1 Thermal resistance between stator winding and stator core, R 2 The thermal resistance between the stator core and the external environment, where C 1 , C 2 , R 1 , R 2 Represents various thermal resistance parameters.

[0087] Optionally, a state-space equation building block is provided, specifically for:

[0088] According to the circuit board temperature and various thermal resistance parameters, the state space equation is constructed. The state space equation formula is as follows:

[0089]

[0090] C=[0 1 0],D=0

[0091] x=[T 1 T 2 T 0 ] T , u=P

[0092] Among them, x represents the temperature of each preset component in the electronic winding, T represents the transposed matrix, y represents the circuit board temperature, T 1 、T 2 Respectively represent the temperature of each preset component in the electronic winding, T 0 represents the ambient temperature, P represents the stator winding copper loss, and A, B, C, and D represent the coefficients of the state space equation respectively.

[0093] Optionally, the EPS motor temperature estimation module is specifically used to:

[0094] Get the circuit board temperature of the circuit board on the EPS motor in real time;

[0095] The current circuit board temperature is input into the state-space equation to determine the current ambient temperature.

[0096] An embodiment of the present invention also provides a computing device, including a memory, a manager, and a program stored in the memory and running on the manager. When the manager executes the program, some or all steps of the above-mentioned EPS motor temperature estimation method are implemented.

[0097] Among them, the computing device can be a computer, and correspondingly, its program is computer software. The above-mentioned parameters and steps in the computing device of the present invention can refer to the parameters and steps in the embodiment of an EPS motor temperature estimation method above, and will not be repeated here.

[0098] Those skilled in the art know that the present invention can be implemented as a system, method or computer program product. Therefore, the present disclosure can be specifically implemented in the following forms, namely: it can be complete hardware, it can be complete software (including firmware, resident software, microcode, etc.), or it can be a combination of hardware and software, generally referred to as "circuit", "module" or "system" herein. In addition, in some embodiments, the present invention can also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium contains computer-readable program code. Computer-readable storage media can be, for example, but not limited to - electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above.

[0099] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0100] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for estimating temperature of an EPS motor, characterized in that: include: Input different currents to the EPS motor, and obtain temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data of the circuit board of the EPS motor measured by thermistor during the period when the EPS motor is input with different currents; Calculating the thermal resistance parameters of each preset component in the electronic winding according to the temperature rise data corresponding to each current; Obtain the circuit board temperature, and construct a state space equation based on the circuit board temperature and various thermal resistance parameters; wherein the state space equation characterizes the relationship between the circuit board temperature and the ambient temperature of the EPS motor; The current ambient temperature is obtained according to the state space equation, and the temperature of the EPS motor is estimated according to the current ambient temperature.

2. The method according to claim 1, characterized in that Different currents are input to the EPS motor, and the temperature rise data corresponding to each current is obtained, including: Inputting different currents to the spe motor; When the SPE motor is rotated by inputting the current current, a step current AC signal with different preset amplitudes is inputted on the D axis of the phase current at preset intervals until the temperature of the electronic winding exceeds the preset temperature, then the input of the step current AC signal is stopped, and the next current is inputted to the SPE motor after the ambient temperature drops to room temperature; Record the temperature rise data of the circuit board of the EPS motor measured by the thermistor from the time the current is input into the SPE motor until the ambient temperature drops to room temperature.

3. The method according to claim 1, characterized in that According to the temperature rise data corresponding to each current, the thermal resistance parameters of each preset component in the electronic winding are calculated, including: According to the temperature rise data corresponding to each current, the relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is obtained through a thermal network model; The relationship between the thermal resistance parameters of each preset component and each preset thermal resistance coefficient is solved through the second-order thermal network model to determine the thermal resistance parameters of each preset component in the electronic winding.

4. The method according to claim 3, characterized in that: The relationship between the thermal resistance parameters of each preset component and the preset thermal resistance coefficient is solved by the second-order thermal network model to determine the thermal resistance parameters of each preset component in the electronic winding. The calculation formula is: Among them, a0, a1, b0, b1, and b2 are respective preset thermal resistance coefficients, C1 represents the thermal capacity of the stator winding, C2 represents the thermal capacity of the stator core, R1 represents the thermal resistance between the stator winding and the stator core, and R2 represents the thermal resistance between the stator core and the external environment, among which C1, C2, R1, and R2 represent respective thermal resistance parameters.

5. The method according to claim 4, characterized in that According to the circuit board temperature and various thermal resistance parameters, the state space equation is constructed. The state space equation formula is as follows: C=[0 1 0],D=0 x=[T1 T2 T0] T ,u=P Among them, x represents the temperature of each preset component in the electronic winding, T represents the transposed matrix, y represents the circuit board temperature, T1 and T2 represent the temperature of each preset component in the electronic winding, T0 represents the ambient temperature, P represents the stator winding copper loss, and A, B, C, and D represent the coefficients of the state space equation respectively.

6. The method according to any one of claims 1 to 5, characterized in that: Obtaining the current ambient temperature according to the state space equation includes: Get the circuit board temperature of the circuit board on the EPS motor in real time; The current circuit board temperature is input into the state-space equation to determine the current ambient temperature.

7. An EPS motor temperature estimation system, characterized in that: include: A temperature rise data acquisition module is used to input different currents to the EPS motor and obtain temperature rise data corresponding to each current; wherein the temperature rise data is temperature rise data of the circuit board of the EPS motor measured by the thermistor during the period when the EPS motor inputs different currents; A thermal resistance parameter determination module, used to calculate the thermal resistance parameters of each preset component in the electronic winding according to the temperature rise data corresponding to each current; A state space equation building module is used to obtain the circuit board temperature and build a state space equation according to the circuit board temperature and various thermal resistance parameters; wherein the state space equation characterizes the relationship between the circuit board temperature and the ambient temperature of the EPS motor; The EPS motor temperature estimation module is used to obtain the current ambient temperature according to the state space equation and estimate the EPS motor temperature according to the current ambient temperature.

8. The system according to claim 7, characterized in that The temperature rise data acquisition module is specifically used for: Inputting different currents to the spe motor; When the SPE motor is rotated by inputting the current current, a step current AC signal with different preset amplitudes is inputted on the D axis of the phase current at preset intervals until the temperature of the electronic winding exceeds the preset temperature, then the input of the step current AC signal is stopped, and the next current is inputted to the SPE motor after the ambient temperature drops to room temperature; Record the temperature rise data of the circuit board of the EPS motor measured by the thermistor from the time the current is input into the SPE motor until the ambient temperature drops to room temperature.

9. A computing device comprising a memory, a processor, and a program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the steps of an EPS motor temperature estimation method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a terminal device, the terminal device executes the steps of an EPS motor temperature estimation method as claimed in any one of claims 1 to 6.

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