Junction temperature estimation method and device

Abstract

The invention provides a junction temperature estimation method and device which are applied to a motor controller, the motor controller comprises an inverter circuit, the inverter circuit comprises multiple phases of bridge arms, each phase of bridge arm comprises two sub-bridge arms, and each sub-bridge arm comprises a transistor and a diode. Temperature rise data corresponding to each sub-bridge arm is determined based on the detection data and temperature estimation results of transistors and diodes in each sub-bridge arm in the previous period, so that temperature estimation results of each sub-bridge arm in the current period are respectively determined based on the temperature rise data corresponding to each sub-bridge arm; the junction temperature estimation result of the inverter circuit in the current period is determined based on the temperature estimation result of each sub-bridge arm, the temperature rise data comprises first sub-temperature rise data used for representing thermal coupling of a transistor to a diode and second sub-temperature rise data used for representing thermal coupling of the diode to the transistor, and the junction temperature estimation result of the inverter circuit in the current period is determined based on the temperature estimation result of each sub-bridge arm; therefore, the junction temperature estimation precision of the inverter circuit can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of data processing, and in particular to a junction temperature estimation method and device. Background Art

[0002] In a motor controller, a DC power supply is usually converted into AC power through an inverter circuit and output to the motor to achieve precise control of the motor speed, direction, output torque, etc. Therefore, the safe and stable operation of the inverter circuit is an important factor affecting the control accuracy of the motor controller.

[0003] Among them, junction temperature is an important condition for judging whether the inverter circuit is in a safe and stable operating state. However, the existing junction temperature estimation method is difficult to ensure the estimation accuracy of the junction temperature, and thus cannot ensure the safe and stable operation of the inverter circuit, and also cannot ensure the control accuracy of the motor controller. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a junction temperature estimation method and device to solve the problem that the junction temperature estimation accuracy of the inverter circuit cannot be guaranteed in the prior art.

[0005] To achieve the above technical objectives, the present application provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present specification provides a junction temperature estimation method, which is applied to a motor controller, wherein the motor controller includes an inverter circuit, wherein the inverter circuit includes a multi-phase bridge arm, wherein each phase of the bridge arm includes two sub-bridge arms, and each sub-bridge arm includes a transistor and a diode, wherein the method includes:

[0007] Acquiring detection data of the inverter circuit in the current cycle;

[0008] Based on the detection data and the temperature estimation results of the transistors and the diodes in each of the sub-bridge arms in the previous cycle, determine the temperature rise data corresponding to each of the sub-bridge arms, the temperature rise data including first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode, and second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor;

[0009] Based on the temperature rise data corresponding to each of the sub-bridge arms, the temperature estimation results of each of the sub-bridge arms in the current cycle are determined respectively, and based on the temperature estimation results of each of the sub-bridge arms, the junction temperature estimation result of the inverter circuit in the current cycle is determined.

[0010] In one implementation, the temperature rise data corresponding to the sub-bridge arm further includes third sub-temperature rise data generated by the transistor itself and fourth sub-temperature rise data generated by the diode itself;

[0011] Determining temperature rise data corresponding to each of the sub-bridge arms based on the detection data and the temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, including:

[0012] Determine the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle;

[0013] The first sub-temperature rise data and the third sub-temperature rise data are determined based on the power loss of the transistor, and the second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode.

[0014] In one implementation, determining the first sub-temperature rise data and the third sub-temperature rise data based on the power loss of the transistor, and determining the second sub-temperature rise data and the fourth sub-temperature rise data based on the power loss of the diode includes:

[0015] Based on the power loss of the transistor and a first predetermined corresponding relationship, determining the first sub-temperature rise data and the third sub-temperature rise data; the first predetermined corresponding relationship includes a corresponding relationship between the power loss of the transistor and the first sub-temperature rise data and the third sub-temperature rise data; and,

[0016] The second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode and a second predetermined corresponding relationship; the second predetermined corresponding relationship includes a corresponding relationship between the power loss of the diode and the second sub-temperature rise data and the fourth sub-temperature rise data.

[0017] In one embodiment, the detection data includes a bus voltage of the inverter circuit, a first current and a first duty cycle of a transistor in each of the sub-bridge arms, and a second current and a second duty cycle of a diode in each of the sub-bridge arms;

[0018] Determining the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle, including:

[0019] Determine a first conduction voltage drop of the transistor and a first switching energy loss of the transistor based on a temperature estimation result of the transistor in a previous cycle, and determine a second conduction voltage drop of the diode and a second switching energy loss of the diode based on a temperature estimation result of the diode in a previous cycle;

[0020] Determining a conduction power loss of the transistor based on a first current of the transistor, a first duty cycle of the transistor, and a first conduction voltage drop of the transistor, and determining a switching power loss of the transistor based on a first switching energy loss of the transistor, the first current of the transistor, and a bus voltage of the inverter circuit;

[0021] Determine the conduction power loss of the diode based on the second current of the diode, the second duty cycle of the diode, the second conduction voltage drop of the diode and the dead time of the diode, and determine the switching power loss of the diode based on the second switching energy loss of the diode, the second current of the diode and the bus voltage of the inverter circuit;

[0022] The power loss of the transistor is determined based on the sum of the conduction power loss and the switching power loss of the transistor, and the power loss of the diode is determined based on the sum of the conduction power loss and the switching power loss of the diode.

[0023] In one implementation, based on the temperature rise data corresponding to each of the sub-bridge arms, respectively determining the temperature estimation result of each of the sub-bridge arms in the current cycle includes:

[0024] Based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected;

[0025] Determine the first temperature rise data of the transistor based on the sum of the second sub-temperature rise data after correction and the third sub-temperature rise data after correction, and determine the second temperature rise data of the diode based on the sum of the first sub-temperature rise data after correction and the fourth sub-temperature rise data after correction;

[0026] Based on the first temperature rise data of the transistor in the sub-bridge arm and the second temperature rise data of the diode in the sub-bridge arm, a temperature estimation result of the sub-bridge arm in a current cycle is determined.

[0027] In one implementation, determining a temperature estimation result of the sub-bridge arm in a current cycle based on first temperature rise data of the transistor in the sub-bridge arm and second temperature rise data of the diode in the sub-bridge arm includes:

[0028] Determine the temperature estimation result of the transistor in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the first temperature rise data of the transistor in the sub-bridge arm, and determine the temperature estimation result of the diode in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the second temperature rise data of the diode in the sub-bridge arm;

[0029] Based on the temperature estimation results of the transistors in the sub-bridge arm and the temperature estimation results of the diodes in the sub-bridge arm in the current cycle, the temperature estimation result of the sub-bridge arm in the current cycle is determined.

[0030] In one embodiment, a method for determining the coolant temperature of the bridge arm of each phase includes:

[0031] Acquiring a temperature detection value of a predetermined position of a target phase bridge arm;

[0032] Based on the temperature detection value and the temperature rise data corresponding to the target phase bridge arm in the previous cycle, the coolant temperature of the target phase bridge arm is determined; the temperature rise data corresponding to the target phase bridge arm in the previous cycle is determined based on the first temperature rise data of each transistor in the target phase bridge arm and the second temperature rise data of each diode in the previous cycle;

[0033] Based on the coolant temperature difference between each other phase bridge arm other than the target phase bridge arm and the target phase bridge arm, and the coolant temperature of the target phase bridge arm, the coolant temperature of each other phase bridge arm is determined respectively.

[0034] In one embodiment, based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected, including:

[0035] Based on the temperature estimation result of the transistor in the previous cycle, determine the estimated thermal resistance value of the transistor and the estimated value of the first cross thermal resistance, and based on the temperature estimation result of the diode in the previous cycle, determine the estimated thermal resistance value of the diode and the estimated value of the second cross thermal resistance; the first cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the transistor to the diode, and the second cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the diode to the transistor;

[0036] determining a first correction factor based on an estimated value and a configured value of the first cross thermal resistance, determining a second correction factor based on an estimated value and a configured value of the second cross thermal resistance, determining a third correction factor based on an estimated value and a configured value of the thermal resistance of the transistor, and determining a fourth correction factor based on an estimated value and a configured value of the thermal resistance of the diode;

[0037] Based on the first correction coefficient, the second correction coefficient, the third correction coefficient and the fourth correction coefficient, correction processing is performed on the first sub-temperature rise data, the second sub-temperature rise data, the third sub-temperature rise data and the fourth sub-temperature rise data respectively.

[0038] In one implementation, determining a junction temperature estimation result of the inverter circuit in a current cycle based on the temperature estimation result of each of the sub-bridge arms includes:

[0039] The maximum value of the temperature estimation results of each of the sub-bridge arms in the current cycle is used as the junction temperature estimation result of the inverter circuit in the current cycle.

[0040] In a second aspect, an embodiment of the present specification provides a junction temperature estimation device, which is applied to a motor controller, wherein the motor controller includes an inverter circuit, wherein the inverter circuit includes a multi-phase bridge arm, wherein each phase of the bridge arm includes two sub-bridge arms, and each of the sub-bridge arms includes a transistor and a diode, wherein the device includes:

[0041] A first processing module, used for acquiring detection data of the inverter circuit in a current cycle;

[0042] a second processing module, for determining temperature rise data corresponding to each of the sub-bridge arms based on the detection data and temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, wherein the temperature rise data includes first sub-temperature rise data for characterizing thermal coupling of the transistor to the diode, and second sub-temperature rise data for characterizing thermal coupling of the diode to the transistor;

[0043] The third processing module is used to determine the temperature estimation result of each sub-bridge arm in the current cycle based on the temperature rise data corresponding to each sub-bridge arm, and determine the junction temperature estimation result of the inverter circuit in the current cycle based on the temperature estimation result of each sub-bridge arm.

[0044] In a third aspect, an embodiment of the present specification provides an electronic device, the electronic device comprising at least one processor and at least one memory, the memory storing a computer program, and the computer program, when executed by the processor, implements a junction temperature estimation method as described in any one of the above items.

[0045] In a fourth aspect, an embodiment of the present specification provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the junction temperature estimation method as described in any one of the above items is implemented.

[0046] In a fifth aspect, an embodiment of the present specification provides a computer program product or a computer program, wherein the computer program product includes a computer program, and the computer program is stored in a computer-readable storage medium; the processor of the computer device reads the computer program from the computer-readable storage medium, and when the processor executes the computer program, it implements the junction temperature estimation method as described in any one of the above items.

[0047] It can be seen from the above technical scheme that the embodiment of the present application provides a junction temperature estimation method and device for a motor controller, the motor controller includes an inverter circuit, the inverter circuit includes a multi-phase bridge arm, each phase bridge arm includes two sub-bridge arms, and each sub-bridge arm includes a transistor and a diode. The method obtains the detection data of the inverter circuit in the current cycle, and determines the temperature rise data corresponding to each sub-bridge arm based on the detection data and the temperature estimation results of the transistors and diodes in each sub-bridge arm in the previous cycle, so as to determine the temperature estimation results of each sub-bridge arm in the current cycle based on the temperature rise data corresponding to each sub-bridge arm, and determine the junction temperature estimation result of the inverter circuit in the current cycle based on the temperature estimation results of each sub-bridge arm, wherein the temperature rise data includes a first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode, and a second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor, so that in the process of estimating the junction temperature of the inverter circuit, the thermal coupling between the transistor and the diode in each sub-bridge arm can be comprehensively considered, thereby achieving an effective improvement in the junction temperature estimation accuracy of the inverter circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0049] Figure 1 A schematic flow chart of a junction temperature estimation method provided for an implementation of this specification.

[0050] Figure 2 A schematic diagram of the structure of an inverter circuit provided in an implementation manner of this specification.

[0051] Figure 3 A schematic diagram of the structure of a junction temperature estimation device provided in an embodiment of this specification. DETAILED DESCRIPTION

[0052] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of this specification shall have the common meanings understood by persons with ordinary skills in the field to which this specification belongs. The words "first", "second" and similar words used in the embodiments of this specification do not indicate any order, quantity or importance, but are only used to avoid confusion of constituent elements.

[0053] Unless the context requires otherwise, throughout the specification, "plurality" means "at least two", and "including" is interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples", "specific examples" or "some examples" are intended to indicate that a particular feature, structure, material or characteristic associated with the embodiment or example is included in at least one embodiment or example of the specification. The schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0054] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this specification.

[0055] Overview

[0056] As described in the background technology, in a motor controller, a DC power supply is usually converted into AC power through an inverter circuit and output to the motor to achieve precise control of the motor speed, direction, output torque, etc. Therefore, the safe and stable operation of the inverter circuit is an important factor affecting the control accuracy of the motor controller. Among them, the junction temperature is an important condition for judging whether the inverter circuit is in a safe and stable operating state.

[0057] Existing junction temperature estimation methods usually use the third-order Foster thermal resistance model to estimate the junction temperature of the inverter circuit. Although this model has certain conveniences in theoretical analysis and preliminary design, it cannot fully capture the complex thermal behavior of the inverter circuit under actual working conditions, and thus cannot guarantee the accuracy of the junction temperature estimation of the inverter circuit, and thus cannot guarantee the safe and stable operation of the inverter circuit, and also cannot guarantee the control accuracy of the motor controller.

[0058] In order to solve the problem that the traditional method cannot guarantee the junction temperature estimation accuracy of the inverter circuit, in the technical solution of the present application, a junction temperature estimation solution for a motor controller is provided, the motor controller includes an inverter circuit, the inverter circuit includes a multi-phase bridge arm, each phase bridge arm includes two sub-bridge arms, each sub-bridge arm includes a transistor and a diode, the solution obtains the detection data of the inverter circuit in the current cycle, and determines the temperature rise data corresponding to each sub-bridge arm based on the detection data and the temperature estimation results of the transistors and diodes in each sub-bridge arm in the previous cycle, so as to determine the temperature estimation results of each sub-bridge arm in the current cycle based on the temperature rise data corresponding to each sub-bridge arm, and determine the junction temperature estimation result of the inverter circuit in the current cycle based on the temperature estimation results of each sub-bridge arm, wherein the temperature rise data includes a first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode, and a second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor, so that in the process of estimating the junction temperature of the inverter circuit, the thermal coupling between the transistor and the diode in each sub-bridge arm can be comprehensively considered, thereby achieving an effective improvement in the junction temperature estimation accuracy of the inverter circuit.

[0059] Based on the above inventive concept, the junction temperature estimation method provided in the embodiment of this specification is exemplarily described below.

[0060] Exemplary Methods

[0061] The embodiment of the present specification provides a junction temperature estimation method, which is applied to a motor controller, wherein the motor controller includes an inverter circuit, wherein the inverter circuit includes a multi-phase bridge arm, wherein each phase of the bridge arm includes two sub-bridge arms, and each sub-bridge arm includes a transistor and a diode, such as Figure 1 As shown, the method includes:

[0062] S101, acquiring detection data of the inverter circuit in the current cycle.

[0063] Specifically, the motor controller may include an inverter circuit, which is used to convert the DC power output by the DC power supply into AC power and then output it to the motor to achieve precise control of the motor speed, direction, output torque, etc. The inverter circuit may include a multi-phase bridge arm, and for any one-phase bridge arm, the bridge arm may include two sub-bridge arms, and the two sub-bridge arms may be arranged up and down, for example, the two sub-bridge arms may be an upper bridge arm and a lower bridge arm respectively. The connection point of the two sub-bridge arms may be connected to the corresponding input terminal in the motor.

[0064] For any sub-bridge arm, the sub-bridge arm may include a transistor and a diode, and the transistor and the diode may be connected in parallel, for example, they may be connected in reverse parallel. The transistor may be an IGBT (Insulate-Gate Bipolar Transistor), or a MOSFET (Metal-Oxide Semiconductor Field Effect Transistor), etc., and may be specifically set according to actual needs.

[0065] refer to Figure 2 Taking a three-phase motor as an example, the inverter circuit includes a U-phase bridge arm 201, a V-phase bridge arm 202 and a W-phase bridge arm 203. The two ends of the U-phase bridge arm 201, the V-phase bridge arm 202 and the W-phase bridge arm 203 are respectively connected to the positive electrode and the negative electrode of the power supply 204. The U-phase bridge arm 201, the V-phase bridge arm 202 and the W-phase bridge arm 203 each include two sub-bridge arms arranged up and down. The connection points of the two sub-bridge arms are respectively connected to the U-phase input terminal, the V-phase input terminal and the W-phase input terminal of the motor 205. Each sub-bridge arm includes a transistor VT connected in reverse parallel. g and diode VD g , g is a positive integer, g∈[1,6].

[0066] In the implementation, during the operation of the motor controller, the junction temperature of the inverter circuit can be estimated according to a predetermined cycle, so as to determine whether the inverter circuit is in a safe and stable operating state according to the junction temperature estimation result. In the current cycle, the detection data of the inverter circuit may include parameter values ​​of various operating parameters of the inverter circuit, and each operating parameter may characterize the operating state and output characteristics of the inverter circuit. For example, each operating parameter may include the bus voltage of the inverter circuit, the current and duty cycle of each transistor in the inverter circuit, and the current and duty cycle of each diode in the inverter circuit. Among them, the current of each transistor and diode can be detected by a current sensor. In addition, the duty cycle of each transistor and diode in the inverter circuit can be determined by the SVPWM (Space Vector Pulse Width Modulation) method, wherein the sum of the duty cycle of the transistor in the upper bridge arm and the duty cycle of the transistor in the lower bridge arm can be 1, and the duty cycle of the transistor in the upper bridge arm can be the same as the duty cycle of the diode in the lower bridge arm. In addition, the bus voltage of the inverter circuit can be detected by a voltage sensor.

[0067] For any working parameter of the working parameters of the inverter circuit, multiple data of the working parameter in the current cycle can be obtained, and each data can be processed to obtain the parameter value of the working parameter. For example, equivalent normalization processing can be performed on multiple data of the working parameter in the current cycle, and the equivalent normalization processing results of each data can be averaged to obtain the parameter value of the working parameter, thereby effectively ensuring the validity of the determination results of the parameter values ​​of the working parameters of the inverter circuit.

[0068] Among them, the equivalent normalization processing method may include: determining the value interval of the working parameter in the current cycle according to the maximum and minimum values ​​of each data of the working parameter in the current cycle, and determining multiple marking points in the value interval based on a predetermined interval. For any data of the multiple data of the working parameter in the current cycle, a vector including the proportional coefficient of the data at each marking point can be used as the equivalent normalization processing result of the data. Among them, the sum of the proportional coefficients of the data at each marking point is 1, that is, the value of the data can be represented by each marking point and the proportional coefficient of the data at each marking point, which can be specifically shown as formula (1):

[0069]

[0070] Among them, d i is the i-th data of the working parameter in the current cycle, b j is the jth landmark point, J is the number of landmark points, 1≤j≤J, k ij is d i In b j The proportionality factor on .

[0071] For example, if the value interval of the parameter in the current cycle is [0, 300], then multiple marker points can be (0, 100, 200, 300) respectively. When the data is 10, the proportional coefficient of the data at marker point 0 is 0.9, the proportional coefficient at marker point 100 is 0.1, and the proportional coefficients at marker point 200 and marker point 300 are both 0. Therefore, the equivalent normalization processing result of the data is (0.9, 0.1, 0, 0).

[0072] S102. Based on the detection data and the temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, determine the temperature rise data corresponding to each of the sub-bridge arms, the temperature rise data including first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode, and second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor.

[0073] Specifically, for any sub-bridge arm, the temperature rise data corresponding to the sub-bridge arm may include a first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode in the sub-bridge arm, that is, the first sub-temperature rise data may be the temperature of the diode increased compared to the reference temperature due to the heat generated by the transistor during operation. The temperature rise data corresponding to the sub-bridge arm may also include a second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor in the sub-bridge arm, that is, the second sub-temperature rise data may be the temperature of the transistor increased compared to the reference temperature due to the heat generated by the diode during operation. The reference temperature may be a coolant temperature, or a radiator temperature, etc., which may be set according to actual needs.

[0074] In implementation, the temperature rise data corresponding to each sub-bridge arm in the current cycle can be determined based on the detection data of the inverter circuit in the current cycle and the temperature estimation results of the transistors and the temperature estimation results of the diodes in each sub-bridge arm in the previous cycle. For example, for any sub-bridge arm, the power loss of the transistor in the sub-bridge arm and the power loss of the diode in the sub-bridge arm can be determined based on the detection data of the inverter circuit in the current cycle and the temperature estimation results of the transistors and the temperature estimation results of the diodes in the sub-bridge arm in the previous cycle, and the temperature rise data corresponding to the sub-bridge arm can be determined based on the power loss of the transistors and the power loss of the diodes in the sub-bridge arm, so that the temperature rise data corresponding to each sub-bridge arm in the current cycle can be determined quickly and effectively.

[0075] It can be understood that when the current cycle is the first cycle, the temperature estimation results of the transistors and the temperature estimation results of the diodes in each sub-bridge arm in the previous cycle may be default values.

[0076] S103, based on the temperature rise data corresponding to each of the sub-bridge arms, respectively determine the temperature estimation result of each of the sub-bridge arms in the current cycle, and based on the temperature estimation result of each of the sub-bridge arms, determine the junction temperature estimation result of the inverter circuit in the current cycle.

[0077] Specifically, for any sub-bridge arm, the temperature estimation result of the sub-bridge arm in the current cycle may include the temperature estimation result of the transistor in the sub-bridge arm, may also include the temperature estimation result of the diode in the sub-bridge arm, and may also include the temperature estimation result of the transistor and the temperature estimation result of the diode in the sub-bridge arm at the same time. In addition, the temperature estimation result of the sub-bridge arm may also be determined based on the temperature estimation result of the transistor and the temperature estimation result of the diode in the sub-bridge arm.

[0078] As an optional implementation, based on the temperature rise data corresponding to the sub-bridge arm, the temperature estimation results of the transistor and the temperature estimation results of the diode in the sub-bridge arm can be determined respectively, and the temperature estimation result of the sub-bridge arm can be determined according to the temperature estimation results of the transistor and the temperature estimation results of the diode in the sub-bridge arm. For example, the maximum value or average value of the temperature estimation results of the transistor and the temperature estimation results of the diode in the sub-bridge arm can be used as the temperature estimation result of the sub-bridge arm.

[0079] Thus, the temperature estimation result of each sub-bridge arm in the inverter circuit can be obtained, wherein the maximum value or average value of the temperature estimation results of each sub-bridge arm can be used as the junction temperature estimation result of the inverter circuit in the current cycle, so as to judge whether the inverter circuit is in a safe and stable operating state according to the junction temperature estimation result of the inverter circuit in the current cycle.

[0080] It can be seen that through the method of the embodiment of the present application, in the process of estimating the junction temperature of the inverter circuit, the thermal coupling between the transistors and the diodes in each sub-bridge arm can be comprehensively considered, thereby achieving an effective improvement in the estimation accuracy of the junction temperature of the inverter circuit.

[0081] In a feasible implementation manner, the temperature rise data corresponding to the sub-bridge arm also includes third sub-temperature rise data generated by the transistor itself and fourth sub-temperature rise data generated by the diode itself;

[0082] Based on the detection data and the temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, the temperature rise data corresponding to each of the sub-bridge arms is determined, including:

[0083] Determine the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle;

[0084] The first sub-temperature rise data and the third sub-temperature rise data are determined based on the power loss of the transistor, and the second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode.

[0085] Specifically, the third sub-temperature rise data generated by the transistor itself can be the temperature of the transistor increased by the heat generated during the operation of the transistor itself compared to the reference temperature. The fourth sub-temperature rise data generated by the diode itself can be the temperature of the diode increased by the heat generated during the operation of the diode itself compared to the reference temperature.

[0086] During implementation, for any sub-bridge arm, the power loss of the transistor in the sub-bridge arm can be determined based on the detection data of the inverter circuit in the current cycle and the temperature estimation result of the transistor in the sub-bridge arm in the previous cycle. At the same time, the power loss of the diode in the sub-bridge arm can be determined based on the detection data of the inverter circuit in the current cycle and the temperature estimation result of the diode in the sub-bridge arm in the previous cycle.

[0087] The power loss of the transistor may include the conduction power loss of the transistor, the switching power loss of the transistor, or the sum of the conduction power loss and the switching power loss of the transistor. Meanwhile, the power loss of the diode may include the conduction power loss of the diode, the switching power loss of the diode, or the sum of the conduction power loss and the switching power loss of the diode.

[0088] Thus, the first sub-temperature rise data used to characterize the thermal coupling of the transistor to the diode and the third sub-temperature rise data generated by the transistor itself can be determined based on the power loss of the transistor in the sub-bridge arm. At the same time, the second sub-temperature rise data used to characterize the thermal coupling of the diode to the transistor and the fourth sub-temperature rise data generated by the diode itself can be determined based on the power loss of the diode in the sub-bridge arm. Considering that the power loss generated by the transistor and the diode during operation is the main source of heat, the first sub-temperature rise data and the third sub-temperature rise data are determined by the power loss of the transistor, and the second sub-temperature rise data and the fourth sub-temperature rise data are determined by the power loss of the diode, which can effectively ensure the accuracy of the determination results of the temperature rise data corresponding to each sub-bridge arm, and then according to the temperature rise data corresponding to each sub-bridge arm, the junction temperature of the inverter circuit can be accurately estimated.

[0089] In a feasible implementation manner, determining the first sub-temperature rise data and the third sub-temperature rise data based on the power loss of the transistor, and determining the second sub-temperature rise data and the fourth sub-temperature rise data based on the power loss of the diode includes:

[0090] Based on the power loss of the transistor and a first predetermined corresponding relationship, determining the first sub-temperature rise data and the third sub-temperature rise data; the first predetermined corresponding relationship includes a corresponding relationship between the power loss of the transistor and the first sub-temperature rise data and the third sub-temperature rise data; and,

[0091] The second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode and a second predetermined corresponding relationship; the second predetermined corresponding relationship includes a corresponding relationship between the power loss of the diode and the second sub-temperature rise data and the fourth sub-temperature rise data.

[0092] Specifically, the first predetermined correspondence may include the correspondence between the power loss of the transistor and the first sub-temperature rise data and the third sub-temperature rise data. For example, the first predetermined correspondence may include a first sub-correspondence and a second sub-correspondence. The first sub-correspondence may be used to characterize the correspondence between the power loss of the transistor and the first sub-temperature rise data, and the second sub-correspondence may be used to characterize the correspondence between the power loss of the transistor and the third sub-temperature rise data. Among them, the first sub-correspondence and the second sub-correspondence may be a function model or a network model, and the network model may be a neural network model or a filter network model, which may be set according to actual needs. Thus, according to the power loss of the transistor and the first predetermined correspondence, the first sub-temperature rise data and the third sub-temperature rise data can be determined quickly and accurately.

[0093] As an optional implementation, the first sub-correspondence and the second sub-correspondence can use a thermal resistance and heat capacitance equivalent filter network model to input the power loss of the transistor into the corresponding thermal resistance and heat capacitance equivalent filter network model, and simulate the heat transfer process through the thermal resistance and heat capacitance equivalent filter network model to obtain the first sub-temperature rise data or the third sub-temperature rise data, so as to further improve the accuracy of the determination results of the first sub-temperature rise data and the third sub-temperature rise data. It can be understood that the thermal resistance and heat capacitance equivalent filter network model characterizing the first sub-correspondence can be constructed based on the configuration value of the first cross thermal resistance between the transistor and the diode, and the thermal resistance and heat capacitance equivalent filter network model characterizing the second sub-correspondence can be constructed based on the thermal resistance configuration value of the transistor, and the thermal capacitance of different thermal resistance and heat capacitance equivalent filter network models can be preset values. The first cross thermal resistance between the transistor and the diode can be the equivalent thermal resistance of the thermal coupling of the transistor to the diode.

[0094] The second predetermined correspondence may include the correspondence between the power loss of the diode and the second sub-temperature rise data and the fourth sub-temperature rise data. For example, the second predetermined correspondence may include a third sub-correspondence and a fourth sub-correspondence. The third sub-correspondence may be used to characterize the correspondence between the power loss of the diode and the second sub-temperature rise data, and the fourth sub-correspondence may be used to characterize the correspondence between the power loss of the diode and the fourth sub-temperature rise data. The third sub-correspondence and the fourth sub-correspondence may be a function model or a network model. The network model may be a neural network model or a filter network model, which may be set according to actual needs. Thus, the second sub-temperature rise data and the fourth sub-temperature rise data may be determined quickly and accurately according to the power loss of the diode and the second predetermined correspondence.

[0095] As an optional implementation, the third sub-correspondence and the fourth sub-correspondence can adopt a thermal resistance and heat capacitance equivalent filter network model to input the power loss of the diode into the corresponding thermal resistance and heat capacitance equivalent filter network model, and simulate the heat transfer process through the thermal resistance and heat capacitance equivalent filter network model to obtain the second sub-temperature rise data or the fourth sub-temperature rise data, so as to further improve the accuracy of the determination results of the second sub-temperature rise data and the fourth sub-temperature rise data. It can be understood that the thermal resistance and heat capacitance equivalent filter network model characterizing the third sub-correspondence can be constructed based on the configuration value of the second cross thermal resistance between the transistor and the diode, and the thermal resistance and heat capacitance equivalent filter network model characterizing the fourth sub-correspondence can be constructed based on the thermal resistance configuration value of the diode, and the thermal capacitance of different thermal resistance and heat capacitance equivalent filter network models can be preset values. The second cross thermal resistance between the transistor and the diode can be the equivalent thermal resistance of the thermal coupling of the diode to the transistor.

[0096] In a feasible implementation manner, the detection data includes a bus voltage of the inverter circuit, a first current and a first duty cycle of the transistor in each of the sub-bridge arms, and a second current and a second duty cycle of the diode in each of the sub-bridge arms;

[0097] Determining the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle, including:

[0098] Determine a first conduction voltage drop of the transistor and a first switching energy loss of the transistor based on a temperature estimation result of the transistor in a previous cycle, and determine a second conduction voltage drop of the diode and a second switching energy loss of the diode based on a temperature estimation result of the diode in a previous cycle;

[0099] Determining a conduction power loss of the transistor based on a first current of the transistor, a first duty cycle of the transistor, and a first conduction voltage drop of the transistor, and determining a switching power loss of the transistor based on a first switching energy loss of the transistor, the first current of the transistor, and a bus voltage of the inverter circuit;

[0100] Determine the conduction power loss of the diode based on the second current of the diode, the second duty cycle of the diode, the second conduction voltage drop of the diode and the dead time of the diode, and determine the switching power loss of the diode based on the second switching energy loss of the diode, the second current of the diode and the bus voltage of the inverter circuit;

[0101] The power loss of the transistor is determined based on the sum of the conduction power loss and the switching power loss of the transistor, and the power loss of the diode is determined based on the sum of the conduction power loss and the switching power loss of the diode.

[0102] Specifically, the detection data of the inverter circuit in the current cycle may include the bus voltage of the inverter circuit, and may also include the first current and the first duty cycle of the transistor in each sub-bridge arm, and may also include the second current and the second duty cycle of the diode in each sub-bridge arm. The first duty cycle may be the ratio of the conduction time of the transistor in a switching cycle to the total duration of the switching cycle, wherein the effective value of the output voltage of the inverter circuit may be changed by adjusting the duty cycle of each transistor in the inverter circuit. The second duty cycle may be the ratio of the conduction time of the diode in a switching cycle to the total duration of the switching cycle, wherein when the transistor in the sub-bridge arm is turned off, a safe current release path may be provided by controlling the diode in the sub-bridge arm to be turned on, so as to achieve safe and effective control of the motor. That is, the sum of the conduction time of the transistor in the sub-bridge arm in a switching cycle and the conduction time of the diode in a switching cycle may be the total duration of the switching cycle.

[0103] In implementation, for any sub-bridge arm, the first on-state voltage drop and the first switching energy loss of the transistor can be determined based on the temperature estimation result of the transistor in the sub-bridge arm in the previous cycle. For example, the first on-state voltage drop and the first switching energy loss of the transistor can be determined based on the temperature estimation result of the transistor in the previous cycle and the predetermined corresponding relationship between the temperature estimation result of the transistor and the on-state voltage drop and the switching energy loss of the transistor. In addition, the first on-state voltage drop and the first switching energy loss of the transistor can also be determined by interpolation based on the first target data and the temperature estimation result of the transistor in the sub-bridge arm in the previous cycle, and the first target data can include the on-state voltage drop and the switching energy loss of the transistor at at least two preset temperatures.

[0104] At the same time, the second conduction voltage drop and the second switching energy loss of the diode can be determined based on the temperature estimation result of the diode in the sub-bridge arm in the previous cycle. For example, the second conduction voltage drop and the second switching energy loss of the diode can be determined based on the temperature estimation result of the diode in the previous cycle and the predetermined correspondence between the temperature estimation result of the diode and the conduction voltage drop and the switching energy loss of the diode. In addition, the second conduction voltage drop and the second switching energy loss of the diode can also be determined by interpolation based on the second target data and the temperature estimation result of the diode in the sub-bridge arm in the previous cycle. The second target data may include the conduction voltage drop and the switching energy loss of the diode at at least two preset temperatures. Optionally, the preset temperature may include 25°C and 150°C.

[0105] The conduction power loss of the transistor can be determined based on the first current of the transistor, the first duty cycle of the transistor, the first conduction voltage drop of the transistor, and the conduction power loss determination model corresponding to the transistor. The conduction power loss determination model corresponding to the transistor can be a function expression, for example, it can be: on,Q =I 1 *V 1 *D 1 , where P on,Q is the conduction power loss of the transistor, I 1 、V 1 and D 1 They are respectively a first current, a first on-state voltage drop and a first duty cycle of the transistor.

[0106] At the same time, the switching power loss of the transistor can be determined based on the first switching energy loss of the transistor, the first current of the transistor, the bus voltage of the inverter circuit, and the switching power loss determination model corresponding to the transistor. The switching power loss determination model corresponding to the transistor can be a function expression, for example, it can be: sw,Q =Q 1 *I 1 *U dc / U dcs / T, where P sw,Q is the switching power loss of the transistor, Q 1 is the first switching energy loss of the transistor, U dc is the bus voltage, U dcs is the configuration value of the bus voltage, and T is the duration of the current cycle.

[0107] In addition, the conduction power loss of the diode can be determined based on the second current of the diode, the second duty cycle of the diode, the second conduction voltage drop of the diode, the dead time of the diode, and the conduction power loss determination model corresponding to the diode. The conduction power loss determination model corresponding to the diode can be a function expression, for example, it can be: on,D =I 2 *V 2 *(D 2 +T d / T), where P on,D is the conduction power loss of the diode, I 2 、V 2 and D 2 are the second current, the second conduction voltage drop and the second duty cycle of the diode, T d is the dead time of the diode.

[0108] At the same time, the switching power loss of the diode can be determined based on the second switching energy loss of the diode, the second current of the diode, the bus voltage of the inverter circuit, and the switching power loss determination model corresponding to the diode. The switching power loss determination model corresponding to the diode can be a function expression, for example, it can be: sw,D =Q 2 *I 2 *U dc / U dcs / T, where P sw,D is the switching power loss of the diode, Q 2 is the second switching energy loss of the diode.

[0109] In implementation, the sum of the conduction power loss of the transistor and the switching power loss of the transistor can be used as the power loss of the transistor, and the sum of the conduction power loss of the diode and the switching power loss of the diode can be used as the power loss of the diode. By fully considering the power losses of the transistor and the diode in different states, the accuracy of the determination results of the temperature rise data corresponding to each sub-bridge arm can be effectively improved.

[0110] In a feasible implementation manner, based on the temperature rise data corresponding to each of the sub-bridge arms, respectively determining the temperature estimation result of each of the sub-bridge arms in the current cycle includes:

[0111] Based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected;

[0112] Determine the first temperature rise data of the transistor based on the sum of the second sub-temperature rise data after correction and the third sub-temperature rise data after correction, and determine the second temperature rise data of the diode based on the sum of the first sub-temperature rise data after correction and the fourth sub-temperature rise data after correction;

[0113] Based on the first temperature rise data of the transistor in the sub-bridge arm and the second temperature rise data of the diode in the sub-bridge arm, a temperature estimation result of the sub-bridge arm in a current cycle is determined.

[0114] Specifically, for any sub-bridge arm, the first sub-temperature rise data and the third sub-temperature rise data may be corrected based on the temperature estimation result of the transistor in the sub-bridge arm in the previous cycle. For example, the first correction coefficient corresponding to the first sub-temperature rise data and the third correction coefficient corresponding to the third sub-temperature rise data may be determined based on the temperature estimation result of the transistor in the previous cycle, so as to correct the first sub-temperature rise data based on the first correction coefficient, and correct the third sub-temperature rise data based on the third correction coefficient. For example, the product of the first correction coefficient and the first sub-temperature rise data may be used as the first sub-temperature rise data after correction, and the product of the third correction coefficient and the third sub-temperature rise data may be used as the third sub-temperature rise data after correction.

[0115] At the same time, the second sub-temperature rise data and the fourth sub-temperature rise data can be corrected based on the temperature estimation result of the diode in the sub-bridge arm in the previous cycle. For example, the second correction coefficient corresponding to the second sub-temperature rise data and the fourth correction coefficient corresponding to the fourth sub-temperature rise data can be determined based on the temperature estimation result of the diode in the previous cycle, so as to correct the second sub-temperature rise data based on the second correction coefficient, and correct the fourth sub-temperature rise data based on the fourth correction coefficient. For example, the product of the second correction coefficient and the second sub-temperature rise data can be used as the second sub-temperature rise data after correction, and the product of the fourth correction coefficient and the fourth sub-temperature rise data can be used as the fourth sub-temperature rise data after correction.

[0116] In implementation, the sum of the second sub-temperature rise data after correction processing and the third sub-temperature rise data after correction processing can be used as the first temperature rise data of the transistor, so as to determine the first temperature rise data of the transistor by fully considering the thermal coupling of the diode in the sub-bridge arm to the transistor and the heat generated by the transistor itself, which can effectively improve the accuracy of the determination result of the first temperature rise data of the transistor.

[0117] At the same time, the sum of the first sub-temperature rise data after correction processing and the fourth sub-temperature rise data after correction processing can be used as the second temperature rise data of the diode, so as to determine the second temperature rise data of the diode by fully considering the thermal coupling of the transistor in the sub-bridge arm to the diode and the heat generated by the diode itself, which can effectively improve the accuracy of the determination result of the second temperature rise data of the diode.

[0118] Among them, the temperature estimation result of the sub-bridge arm in the current cycle can be determined based on the first temperature rise data of the transistor in the sub-bridge arm and the second temperature rise data of the diode in the sub-bridge arm. For example, the temperature estimation result of the transistor can be determined based on the first temperature rise data of the transistor and the reference temperature of the bridge arm where the sub-bridge arm is located, and the temperature estimation result of the diode can be determined based on the second temperature rise data of the diode and the reference temperature of the bridge arm where the sub-bridge arm is located, and the temperature estimation result of the sub-bridge arm in the current cycle can be determined based on the temperature estimation result of the transistor in the sub-bridge arm and the temperature estimation result of the diode in the sub-bridge arm, thereby effectively improving the accuracy of the temperature estimation results of each sub-bridge arm.

[0119] In a feasible implementation manner, determining a temperature estimation result of the sub-bridge arm in a current cycle based on first temperature rise data of the transistor in the sub-bridge arm and second temperature rise data of the diode in the sub-bridge arm includes:

[0120] Determine the temperature estimation result of the transistor in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the first temperature rise data of the transistor in the sub-bridge arm, and determine the temperature estimation result of the diode in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the second temperature rise data of the diode in the sub-bridge arm;

[0121] Based on the temperature estimation results of the transistors in the sub-bridge arm and the temperature estimation results of the diodes in the sub-bridge arm in the current cycle, the temperature estimation result of the sub-bridge arm in the current cycle is determined.

[0122] Specifically, for any phase bridge arm in the inverter circuit, the coolant temperature of the phase bridge arm may be the temperature of the coolant at the coolant inlet of the phase bridge arm. The coolant temperature of the phase bridge arm may be determined based on the temperature detection value of a predetermined position in the phase bridge arm, or based on the coolant temperature of other phase bridge arms and the coolant temperature difference between the phase bridge arm and other phase bridge arms, and may be set specifically according to actual needs.

[0123] In implementation, for any sub-bridge arm, the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the first temperature rise data of the transistor in the sub-bridge arm can be used as the temperature estimation result of the transistor in the sub-bridge arm in the current cycle. At the same time, the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the second temperature rise data of the diode in the sub-bridge arm can be used as the temperature estimation result of the diode in the sub-bridge arm in the current cycle. That is, the coolant temperature is used as the reference temperature to determine the temperature estimation result of the transistor in the corresponding sub-bridge arm and the temperature estimation result of the diode, so there is no need to set a temperature sensor at each transistor and diode in the inverter circuit, thereby effectively reducing the demand for temperature sensors while ensuring the accuracy of the junction temperature estimation result of the inverter circuit, greatly reducing the difficulty of junction temperature estimation of the inverter circuit.

[0124] Among them, the temperature estimation result of the sub-bridge arm in the current cycle can be determined based on the temperature estimation results of the transistors and the temperature estimation results of the diodes in the sub-bridge arm in the current cycle. For example, the maximum value or average value of the temperature estimation results of the transistors and the temperature estimation results of the diodes in the sub-bridge arm can be used as the temperature estimation result of the sub-bridge arm in the current cycle.

[0125] Optionally, the maximum value of the temperature estimation result of the transistor and the temperature estimation result of the diode in the sub-bridge arm may be used as the temperature estimation result of the sub-bridge arm, thereby effectively improving the validity of the temperature estimation result of the sub-bridge arm.

[0126] In a feasible implementation manner, a method for determining the coolant temperature of the bridge arm of each phase includes:

[0127] Acquiring a temperature detection value of a predetermined position of a target phase bridge arm;

[0128] Based on the temperature detection value and the temperature rise data corresponding to the target phase bridge arm in the previous cycle, the coolant temperature of the target phase bridge arm is determined; the temperature rise data corresponding to the target phase bridge arm in the previous cycle is determined based on the first temperature rise data of each transistor in the target phase bridge arm and the second temperature rise data of each diode in the previous cycle;

[0129] Based on the coolant temperature difference between each other phase bridge arm other than the target phase bridge arm and the target phase bridge arm, and the coolant temperature of the target phase bridge arm, the coolant temperature of each other phase bridge arm is determined respectively.

[0130] Specifically, in the process of determining the coolant temperature of each phase bridge arm, the coolant temperature of the target phase bridge arm can be determined first. The target phase bridge arm can be the bridge arm with the highest temperature among the bridge arms of each phase of the inverter circuit (such as the V phase bridge arm), or a designated bridge arm, or a randomly selected bridge arm, which can be set according to actual needs.

[0131] The predetermined position of the target phase bridge arm can be the position of a transistor or a diode in the target phase bridge arm, or can be other specified positions, which can be set according to actual needs. Optionally, the predetermined position can be the position of a transistor in the target phase bridge arm, for example, the temperature detection value of the predetermined position of the target phase bridge arm can be obtained by an NTC (Negative Temperature Coefficient Thermistor) sensor in the target phase bridge arm.

[0132] The temperature rise data corresponding to the target phase bridge arm can be determined based on the first temperature rise data of each transistor in the target phase bridge arm and the second temperature rise data of each diode. For example, the maximum value of the first temperature rise data of each transistor in the target phase bridge arm and the second temperature rise data of each diode can be used as the temperature rise data corresponding to the target phase bridge arm.

[0133] In implementation, the coolant temperature of the target phase bridge arm can be determined based on the temperature detection value and the temperature rise data corresponding to the target phase bridge arm in the previous cycle. For example, the temperature compensation value can be determined based on the temperature rise data corresponding to the target phase bridge arm in the previous cycle, and the coolant temperature of the target phase bridge arm can be determined based on the temperature detection value and the temperature compensation value. Optionally, the temperature detection value and the temperature rise data corresponding to the target phase bridge arm in the previous cycle can be input into a predetermined temperature determination model to obtain the coolant temperature of the target phase bridge arm, so that the coolant temperature of the target phase bridge arm can be determined quickly and accurately. Among them, the temperature determination model can be a function expression, which can be specifically shown as formula (2):

[0134] T W =T NTC -C*ΔT b (2)

[0135] Where, T W is the coolant temperature of the target phase bridge arm; T NTC is the temperature detection value; ΔT b is the temperature rise data corresponding to the target phase bridge arm in the previous cycle; C is the compensation coefficient, which can be based on the thermal resistance R between the NTC sensor and the coolant A and the thermal resistance R between the transistor and the coolant B To determine, for example, C = R A / R B .

[0136] For any other phase bridge arm other than the target phase bridge arm, the coolant temperature of the other phase bridge arm can be determined based on the coolant temperature difference between the other phase bridge arm and the target phase bridge arm, and the coolant temperature of the target phase bridge arm. For example, the sum of the coolant temperature of the target phase bridge arm and the coolant temperature difference can be used as the coolant temperature of the other phase bridge arm.

[0137] Among them, the coolant temperature difference between the other phase bridge arm and the target phase bridge arm can be determined based on the power loss of the other phase bridge arm. For example, the product of the power loss of the other phase bridge arm and the predetermined flow coefficient can be used as the coolant temperature difference between the other phase bridge arm and the target phase bridge arm. The power loss of the other phase bridge arm can be the sum of the power losses of each transistor and each diode in the other phase bridge arm. The predetermined flow coefficient can be the ratio of the current coolant flow rate of the inverter circuit to the predetermined coolant flow rate. Thus, in the process of determining the coolant temperature of each other phase bridge arm according to the coolant temperature difference between each other phase bridge arm other than the target phase bridge arm and the target phase bridge arm and the coolant temperature of the target phase bridge arm, the influence of the ambient temperature on the determination result of the coolant temperature of each phase bridge arm can be effectively reduced, thereby further improving the accuracy of the determination result of the coolant temperature of each phase bridge arm.

[0138] In a feasible implementation manner, based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected, including:

[0139] Based on the temperature estimation result of the transistor in the previous cycle, determine the estimated thermal resistance value of the transistor and the estimated value of the first cross thermal resistance, and based on the temperature estimation result of the diode in the previous cycle, determine the estimated thermal resistance value of the diode and the estimated value of the second cross thermal resistance; the first cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the transistor to the diode, and the second cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the diode to the transistor;

[0140] determining a first correction factor based on an estimated value and a configured value of the first cross thermal resistance, determining a second correction factor based on an estimated value and a configured value of the second cross thermal resistance, determining a third correction factor based on an estimated value and a configured value of the thermal resistance of the transistor, and determining a fourth correction factor based on an estimated value and a configured value of the thermal resistance of the diode;

[0141] Based on the first correction coefficient, the second correction coefficient, the third correction coefficient and the fourth correction coefficient, correction processing is performed on the first sub-temperature rise data, the second sub-temperature rise data, the third sub-temperature rise data and the fourth sub-temperature rise data respectively.

[0142] Specifically, for any transistor, the estimated thermal resistance value of the transistor can be determined by interpolation based on the third target data and the temperature estimation result of the transistor in the previous cycle, and the third target data may include the thermal resistance value of the transistor at at least two preset temperatures. At the same time, the estimated value of the first cross thermal resistance can be determined by interpolation based on the fourth target data and the temperature estimation result of the transistor in the previous cycle, and the third target data may include the first cross thermal resistance value at at least two preset temperatures.

[0143] In addition, for any diode, the estimated thermal resistance value of the diode can be determined by interpolation based on the fifth target data and the temperature estimation result of the diode in the previous cycle, and the fifth target data may include the thermal resistance value of the diode at at least two preset temperatures. At the same time, the estimated value of the second cross thermal resistance can be determined by interpolation based on the sixth target data and the temperature estimation result of the diode in the previous cycle, and the sixth target data may include the second cross thermal resistance value at at least two preset temperatures.

[0144] In implementation, the ratio of the estimated value of the first cross thermal resistance to the configured value of the first cross thermal resistance can be used as the first correction coefficient, the ratio of the estimated value of the second cross thermal resistance to the configured value of the second cross thermal resistance can be used as the second correction coefficient, the ratio of the estimated value of the thermal resistance of the transistor to the configured value of the thermal resistance of the transistor can be used as the third correction coefficient, and the ratio of the estimated value of the thermal resistance of the diode to the configured value of the thermal resistance of the diode can be used as the fourth correction coefficient. Thus, the first sub-temperature rise data, the second sub-temperature rise data, the third sub-temperature rise data and the fourth sub-temperature rise data can be corrected based on the first correction coefficient, the second correction coefficient, the third correction coefficient and the fourth correction coefficient, respectively. In the process of estimating the junction temperature according to the corrected first sub-temperature rise data, the corrected second sub-temperature rise data, the corrected third sub-temperature rise data and the corrected fourth sub-temperature rise data, the accuracy of the junction temperature estimation result can be further improved.

[0145] In a feasible implementation manner, determining the junction temperature estimation result of the inverter circuit in the current cycle based on the temperature estimation result of each of the sub-bridge arms includes:

[0146] The maximum value of the temperature estimation results of each of the sub-bridge arms in the current cycle is used as the junction temperature estimation result of the inverter circuit in the current cycle.

[0147] Specifically, the maximum value of the temperature estimation results of each sub-bridge arm in the current cycle can be used as the junction temperature estimation result of the inverter circuit in the current cycle. Therefore, in the process of judging whether the inverter circuit is in a safe and stable operating state based on the junction temperature estimation result of the inverter circuit, the validity of the judgment result of the operating state can be effectively guaranteed, and then the control accuracy of the motor controller can be further improved based on the judgment result.

[0148] Exemplary Devices

[0149] In an exemplary embodiment of the present specification, a junction temperature estimation device is also provided, which is applied to a motor controller, wherein the motor controller includes an inverter circuit, wherein the inverter circuit includes a multi-phase bridge arm, wherein each phase of the bridge arm includes two sub-bridge arms, and each sub-bridge arm includes a transistor and a diode, such as Figure 3 As shown, the device comprises:

[0150] A first processing module 301 is used to obtain detection data of the inverter circuit in a current cycle;

[0151] A second processing module 302 is used to determine temperature rise data corresponding to each of the sub-bridge arms based on the detection data and the temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, wherein the temperature rise data includes first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode, and second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor;

[0152] The third processing module 303 is used to determine the temperature estimation result of each sub-bridge arm in the current cycle based on the temperature rise data corresponding to each sub-bridge arm, and determine the junction temperature estimation result of the inverter circuit in the current cycle based on the temperature estimation result of each sub-bridge arm.

[0153] In a feasible implementation manner, the temperature rise data corresponding to the sub-bridge arm also includes third sub-temperature rise data generated by the transistor itself and fourth sub-temperature rise data generated by the diode itself;

[0154] The second processing module 302 is specifically used for:

[0155] Determine the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle;

[0156] The first sub-temperature rise data and the third sub-temperature rise data are determined based on the power loss of the transistor, and the second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode.

[0157] In a feasible implementation manner, the second processing module 302 is specifically configured to:

[0158] Based on the power loss of the transistor and a first predetermined corresponding relationship, determining the first sub-temperature rise data and the third sub-temperature rise data; the first predetermined corresponding relationship includes a corresponding relationship between the power loss of the transistor and the first sub-temperature rise data and the third sub-temperature rise data; and,

[0159] The second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode and a second predetermined corresponding relationship; the second predetermined corresponding relationship includes a corresponding relationship between the power loss of the diode and the second sub-temperature rise data and the fourth sub-temperature rise data.

[0160] In a feasible implementation manner, the detection data includes a bus voltage of the inverter circuit, a first current and a first duty cycle of the transistor in each of the sub-bridge arms, and a second current and a second duty cycle of the diode in each of the sub-bridge arms;

[0161] The second processing module 302 is specifically used for:

[0162] Determine a first conduction voltage drop of the transistor and a first switching energy loss of the transistor based on a temperature estimation result of the transistor in a previous cycle, and determine a second conduction voltage drop of the diode and a second switching energy loss of the diode based on a temperature estimation result of the diode in a previous cycle;

[0163] Determining a conduction power loss of the transistor based on a first current of the transistor, a first duty cycle of the transistor, and a first conduction voltage drop of the transistor, and determining a switching power loss of the transistor based on a first switching energy loss of the transistor, the first current of the transistor, and a bus voltage of the inverter circuit;

[0164] Determine the conduction power loss of the diode based on the second current of the diode, the second duty cycle of the diode, the second conduction voltage drop of the diode and the dead time of the diode, and determine the switching power loss of the diode based on the second switching energy loss of the diode, the second current of the diode and the bus voltage of the inverter circuit;

[0165] The power loss of the transistor is determined based on the sum of the conduction power loss and the switching power loss of the transistor, and the power loss of the diode is determined based on the sum of the conduction power loss and the switching power loss of the diode.

[0166] In a feasible implementation manner, the third processing module 303 is specifically used for:

[0167] Based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected;

[0168] Determine the first temperature rise data of the transistor based on the sum of the second sub-temperature rise data after correction and the third sub-temperature rise data after correction, and determine the second temperature rise data of the diode based on the sum of the first sub-temperature rise data after correction and the fourth sub-temperature rise data after correction;

[0169] Based on the first temperature rise data of the transistor in the sub-bridge arm and the second temperature rise data of the diode in the sub-bridge arm, a temperature estimation result of the sub-bridge arm in a current cycle is determined.

[0170] In a feasible implementation manner, the third processing module 303 is specifically used for:

[0171] Determine the temperature estimation result of the transistor in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the first temperature rise data of the transistor in the sub-bridge arm, and determine the temperature estimation result of the diode in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the second temperature rise data of the diode in the sub-bridge arm;

[0172] Based on the temperature estimation results of the transistors in the sub-bridge arm and the temperature estimation results of the diodes in the sub-bridge arm in the current cycle, the temperature estimation result of the sub-bridge arm in the current cycle is determined.

[0173] In a feasible implementation manner, the third processing module 303 is further used for:

[0174] Acquiring a temperature detection value of a predetermined position of a target phase bridge arm;

[0175] Based on the temperature detection value and the temperature rise data corresponding to the target phase bridge arm in the previous cycle, the coolant temperature of the target phase bridge arm is determined; the temperature rise data corresponding to the target phase bridge arm in the previous cycle is determined based on the first temperature rise data of each transistor in the target phase bridge arm and the second temperature rise data of each diode in the previous cycle;

[0176] Based on the coolant temperature difference between each other phase bridge arm other than the target phase bridge arm and the target phase bridge arm, and the coolant temperature of the target phase bridge arm, the coolant temperature of each other phase bridge arm is determined respectively.

[0177] In a feasible implementation manner, the third processing module 303 is specifically used for:

[0178] Based on the temperature estimation result of the transistor in the previous cycle, determine the estimated thermal resistance value of the transistor and the estimated value of the first cross thermal resistance, and based on the temperature estimation result of the diode in the previous cycle, determine the estimated thermal resistance value of the diode and the estimated value of the second cross thermal resistance; the first cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the transistor to the diode, and the second cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the diode to the transistor;

[0179] determining a first correction factor based on an estimated value and a configured value of the first cross thermal resistance, determining a second correction factor based on an estimated value and a configured value of the second cross thermal resistance, determining a third correction factor based on an estimated value and a configured value of the thermal resistance of the transistor, and determining a fourth correction factor based on an estimated value and a configured value of the thermal resistance of the diode;

[0180] Based on the first correction coefficient, the second correction coefficient, the third correction coefficient and the fourth correction coefficient, correction processing is performed on the first sub-temperature rise data, the second sub-temperature rise data, the third sub-temperature rise data and the fourth sub-temperature rise data respectively.

[0181] In a feasible implementation manner, the third processing module 303 is specifically used for:

[0182] The maximum value of the temperature estimation results of each of the sub-bridge arms in the current cycle is used as the junction temperature estimation result of the inverter circuit in the current cycle.

[0183] The junction temperature estimation device provided in this embodiment belongs to the same application concept as the junction temperature estimation method provided in the above embodiments of this application, and can execute the junction temperature estimation method provided in any of the above embodiments of this application, and has the corresponding functional modules and beneficial effects of executing the junction temperature estimation method. For technical details not fully described in this embodiment, please refer to the specific processing content of the junction temperature estimation method provided in the above embodiments of this application, and will not be repeated here.

[0184] Exemplary Devices

[0185] In an exemplary embodiment of the present specification, an electronic device is also provided, the electronic device comprising at least one processor and at least one memory, the memory storing a computer program, and the computer program, when executed by the processor, implements the junction temperature estimation method as described in any of the above embodiments.

[0186] Exemplary computer program products and storage media

[0187] In addition to the above-mentioned methods and devices, the junction temperature estimation method provided in the embodiments of the present specification may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the junction temperature estimation method according to various embodiments of the present specification described in the above-mentioned "Exemplary Method" section of the present specification.

[0188] The computer program product can be written in any combination of one or more programming languages ​​to write program codes for executing the operations of the embodiments of this specification, and the programming languages ​​include object-oriented programming languages, such as Java, C++, etc., and also include conventional procedural programming languages, such as "C" language or similar programming languages.

[0189] In addition, an embodiment of the present specification also provides a computer-readable storage medium on which a computer program is stored, and the computer program is executed by a processor to execute the steps of the junction temperature estimation method according to various embodiments of the present specification described in the above "Exemplary Method" section of the present specification.

[0190] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this specification can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0191] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0192] The above-mentioned embodiments only express several implementation methods of this specification, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the solutions provided by the embodiments of this specification. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of this specification, which all belong to the protection scope of this specification. Therefore, the protection scope of the patent of this specification shall be based on the attached claims.

Claims

1. A junction temperature estimation method, characterized in that: Applied to a motor controller, the motor controller includes an inverter circuit, the inverter circuit includes a multi-phase bridge arm, each phase of the bridge arm includes two sub-bridge arms, each of the sub-bridge arms includes a transistor and a diode, and the method includes: Acquiring detection data of the inverter circuit in the current cycle; Based on the detection data and the temperature estimation results of the transistors and the diodes in each of the sub-bridge arms in the previous cycle, determine the temperature rise data corresponding to each of the sub-bridge arms, the temperature rise data including first sub-temperature rise data for characterizing the thermal coupling of the transistor to the diode, and second sub-temperature rise data for characterizing the thermal coupling of the diode to the transistor; Based on the temperature rise data corresponding to each of the sub-bridge arms, the temperature estimation results of each of the sub-bridge arms in the current cycle are determined respectively, and based on the temperature estimation results of each of the sub-bridge arms, the junction temperature estimation result of the inverter circuit in the current cycle is determined.

2. The method according to claim 1, characterized in that The temperature rise data corresponding to the sub-bridge arm also includes third sub-temperature rise data generated by the transistor itself and fourth sub-temperature rise data generated by the diode itself; Determining temperature rise data corresponding to each of the sub-bridge arms based on the detection data and the temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, including: Determine the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle; The first sub-temperature rise data and the third sub-temperature rise data are determined based on the power loss of the transistor, and the second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode.

3. The method according to claim 2, characterized in that The first sub-temperature rise data and the third sub-temperature rise data are determined based on the power loss of the transistor, and the second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode, including: Based on the power loss of the transistor and a first predetermined corresponding relationship, determining the first sub-temperature rise data and the third sub-temperature rise data; the first predetermined corresponding relationship includes a corresponding relationship between the power loss of the transistor and the first sub-temperature rise data and the third sub-temperature rise data; and, The second sub-temperature rise data and the fourth sub-temperature rise data are determined based on the power loss of the diode and a second predetermined corresponding relationship; the second predetermined corresponding relationship includes a corresponding relationship between the power loss of the diode and the second sub-temperature rise data and the fourth sub-temperature rise data.

4. The method according to claim 2, characterized in that: The detection data includes the bus voltage of the inverter circuit, the first current and the first duty cycle of the transistor in each of the sub-bridge arms, and the second current and the second duty cycle of the diode in each of the sub-bridge arms; Determining the power loss of the transistor and the power loss of the diode in the sub-bridge arm based on the detection data and the temperature estimation results of the transistor and the diode in the sub-bridge arm in the previous cycle, including: Determine a first conduction voltage drop of the transistor and a first switching energy loss of the transistor based on a temperature estimation result of the transistor in a previous cycle, and determine a second conduction voltage drop of the diode and a second switching energy loss of the diode based on a temperature estimation result of the diode in a previous cycle; Determining a conduction power loss of the transistor based on a first current of the transistor, a first duty cycle of the transistor, and a first conduction voltage drop of the transistor, and determining a switching power loss of the transistor based on a first switching energy loss of the transistor, the first current of the transistor, and a bus voltage of the inverter circuit; Determine the conduction power loss of the diode based on the second current of the diode, the second duty cycle of the diode, the second conduction voltage drop of the diode and the dead time of the diode, and determine the switching power loss of the diode based on the second switching energy loss of the diode, the second current of the diode and the bus voltage of the inverter circuit; The power loss of the transistor is determined based on the sum of the conduction power loss and the switching power loss of the transistor, and the power loss of the diode is determined based on the sum of the conduction power loss and the switching power loss of the diode.

5. The method according to claim 2, characterized in that: Based on the temperature rise data corresponding to each of the sub-bridge arms, respectively determining the temperature estimation results of each of the sub-bridge arms in the current cycle, including: Based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected; Determine the first temperature rise data of the transistor based on the sum of the second sub-temperature rise data after correction and the third sub-temperature rise data after correction, and determine the second temperature rise data of the diode based on the sum of the first sub-temperature rise data after correction and the fourth sub-temperature rise data after correction; Based on the first temperature rise data of the transistor in the sub-bridge arm and the second temperature rise data of the diode in the sub-bridge arm, a temperature estimation result of the sub-bridge arm in a current cycle is determined.

6. The method according to claim 5, characterized in that Determining a temperature estimation result of the sub-bridge arm in a current cycle based on first temperature rise data of the transistor in the sub-bridge arm and second temperature rise data of the diode in the sub-bridge arm includes: Determine the temperature estimation result of the transistor in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the first temperature rise data of the transistor in the sub-bridge arm, and determine the temperature estimation result of the diode in the sub-bridge arm in the current cycle based on the sum of the coolant temperature of the bridge arm where the sub-bridge arm is located and the second temperature rise data of the diode in the sub-bridge arm; Based on the temperature estimation results of the transistors in the sub-bridge arm and the temperature estimation results of the diodes in the sub-bridge arm in the current cycle, the temperature estimation result of the sub-bridge arm in the current cycle is determined.

7. The method according to claim 6, characterized in that The method for determining the coolant temperature of the bridge arm of each phase includes: Acquiring a temperature detection value of a predetermined position of a target phase bridge arm; Based on the temperature detection value and the temperature rise data corresponding to the target phase bridge arm in the previous cycle, the coolant temperature of the target phase bridge arm is determined; the temperature rise data corresponding to the target phase bridge arm in the previous cycle is determined based on the first temperature rise data of each transistor in the target phase bridge arm and the second temperature rise data of each diode in the previous cycle; Based on the coolant temperature difference between each other phase bridge arm other than the target phase bridge arm and the target phase bridge arm, and the coolant temperature of the target phase bridge arm, the coolant temperature of each other phase bridge arm is determined respectively.

8. The method according to claim 5, characterized in that Based on the temperature estimation result of the transistor in the previous cycle, the first sub-temperature rise data and the third sub-temperature rise data are corrected, and based on the temperature estimation result of the diode in the previous cycle, the second sub-temperature rise data and the fourth sub-temperature rise data are corrected, including: Based on the temperature estimation result of the transistor in the previous cycle, determine the estimated thermal resistance value of the transistor and the estimated value of the first cross thermal resistance, and based on the temperature estimation result of the diode in the previous cycle, determine the estimated thermal resistance value of the diode and the estimated value of the second cross thermal resistance; the first cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the transistor to the diode, and the second cross thermal resistance is used to characterize the equivalent thermal resistance of the thermal coupling of the diode to the transistor; determining a first correction factor based on an estimated value and a configured value of the first cross thermal resistance, determining a second correction factor based on an estimated value and a configured value of the second cross thermal resistance, determining a third correction factor based on an estimated value and a configured value of the thermal resistance of the transistor, and determining a fourth correction factor based on an estimated value and a configured value of the thermal resistance of the diode; Based on the first correction coefficient, the second correction coefficient, the third correction coefficient and the fourth correction coefficient, correction processing is performed on the first sub-temperature rise data, the second sub-temperature rise data, the third sub-temperature rise data and the fourth sub-temperature rise data respectively.

9. The method according to any one of claims 1 to 8, characterized in that: Determining a junction temperature estimation result of the inverter circuit in a current cycle based on the temperature estimation result of each of the sub-bridge arms includes: The maximum value of the temperature estimation results of each of the sub-bridge arms in the current cycle is used as the junction temperature estimation result of the inverter circuit in the current cycle.

10. A junction temperature estimation device, characterized in that: Applied to a motor controller, the motor controller includes an inverter circuit, the inverter circuit includes a multi-phase bridge arm, each phase of the bridge arm includes two sub-bridge arms, each of the sub-bridge arms includes a transistor and a diode, and the device includes: A first processing module, used for acquiring detection data of the inverter circuit in a current cycle; a second processing module, for determining temperature rise data corresponding to each of the sub-bridge arms based on the detection data and temperature estimation results of the transistors and diodes in each of the sub-bridge arms in the previous cycle, wherein the temperature rise data includes first sub-temperature rise data for characterizing thermal coupling of the transistor to the diode, and second sub-temperature rise data for characterizing thermal coupling of the diode to the transistor; The third processing module is used to determine the temperature estimation result of each sub-bridge arm in the current cycle based on the temperature rise data corresponding to each sub-bridge arm, and determine the junction temperature estimation result of the inverter circuit in the current cycle based on the temperature estimation result of each sub-bridge arm.

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