Method, device and system for determining the junction temperature of an IGBT module

Abstract

The present application discloses a method, device and system for determining the junction temperature of an IGBT module, relating to the technical field of electric vehicles. The method includes: periodically obtaining a first voltage signal representing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of a temperature sensor through a filtering circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module; periodically collecting the operating parameters of the IGBT module and the operating parameters of a motor, where the motor is the motor driven by the motor controller where the IGBT module is located; determining a current rolling filtering coefficient according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor; and determining the junction temperature of the IGBT module according to a plurality of adjacent first voltage signals and a plurality of adjacent rolling filtering coefficients. The solution of the present application improves the calculation accuracy of the junction temperature of the IGBT module.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular, to a method, device, and system for determining the junction temperature of an IGBT module. Background Art

[0002] The power of an electric vehicle comes from a drive motor, which converts the electrical energy of a power battery into mechanical energy to achieve vehicle movement. For a motor controller, the power conversion module is a core component. Currently, mainstream pure electric vehicles at home and abroad all use Insulated Gate Bipolar Transistors (IGBTs) as power conversion modules. Under the condition that the performance parameters of the IGBT module remain unchanged, how to "squeeze" its performance, that is, to maximize its performance without increasing the hardware cost of the drive system and without damaging the system life, is the goal pursued by current pure electric vehicle manufacturers and motor controller suppliers. In this context, the estimation of the junction temperature of the IGBT module has become a research hotspot in the industry. The estimation of the junction temperature helps to fully "squeeze" the performance of the IGBT module, so that it can fully release its performance within the range of the safe junction temperature without affecting the module life. At present, generally, the junction temperature is directly measured by destroying the encapsulation layer of the IGBT module and mounting an NTC thermistor on the surface of the IGBT and the freewheeling diode. This method has the characteristics of directness, reliability, effectiveness, and good real-time performance, so it is commonly used for junction temperature measurement in the data acquisition stage. Although it has the above characteristics, this method is severely interfered by the interference generated during the operation of the IGBT module. As is well known, in the normal operating state, the IGBT module controls the passage of large currents at a high frequency. This high-frequency switching current will cause great interference to the thermistor mounted on the surface of its chip, seriously affecting the acquisition of the true temperature signal of the temperature sensor of the IGBT module. Summary of the Invention

[0003] The purpose of the present application is to provide a method, device, and system for determining the junction temperature of an IGBT module, so as to solve the problem that the junction temperature of the IGBT module obtained in the prior art is inaccurate.

[0004] To achieve the above object, the present application provides a method for determining the junction temperature of an IGBT module, including:

[0005] Periodically obtaining a first voltage signal representing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module;

[0006] Periodically collect the operating parameters of the IGBT module and the operating parameters of the motor, where the motor is the motor driven by the motor controller where the IGBT module is located;

[0007] Determine the current rolling filter coefficient according to the operating parameters of the IGBT module and the operating parameters of the motor collected currently;

[0008] Determine the junction temperature of the IGBT module according to a plurality of adjacent first voltage signals and a plurality of adjacent rolling filter coefficients.

[0009] Optionally, the method further includes:

[0010] Filter the currently acquired first voltage signal according to a plurality of adjacent first voltage signals.

[0011] Optionally, the operating parameters of the IGBT module include the switching frequency and the thermal loss power, and the operating parameters of the motor include the motor output torque;

[0012] Determine the current rolling filter coefficient according to the operating parameters of the IGBT module and the operating parameters of the motor collected currently, including:

[0013] Determine the current switching frequency filter coefficient according to the currently collected switching frequency;

[0014] Determine the current output torque filter coefficient according to the currently collected motor output torque;

[0015] Determine the current thermal loss filter coefficient according to the currently collected thermal loss power;

[0016] Determine the current rolling filter coefficient according to the current switching frequency filter coefficient, the current output torque filter coefficient, and the current thermal loss filter coefficient.

[0017] Optionally, determining the current output torque filter coefficient according to the currently collected motor output torque includes:

[0018] Calculate the current motor speed according to the currently collected motor output torque;

[0019] Obtain the maximum external characteristic torque corresponding to the motor speed;

[0020] Determine the current output torque filter coefficient according to the currently collected motor output torque and the maximum external characteristic torque.

[0021] Optionally, determining the junction temperature of the IGBT module according to a plurality of adjacent first voltage signals and a plurality of adjacent rolling filter coefficients includes:

[0022] Obtain N + 1 adjacent first voltage signals and N adjacent rolling filter coefficients, where the N rolling filter coefficients correspond to the first voltage signals except the first one among the N + 1 first voltage signals;

[0023] Determine the junction temperature of the IGBT module according to the N + 1 first voltage signals and the N rolling filter coefficients; where N is a positive integer.

[0024] An embodiment of the present application further provides a device for determining the junction temperature of an IGBT module, including:

[0025] An acquisition module, configured to periodically acquire a first voltage signal characterizing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of a temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor that collects the junction temperature of the IGBT module;

[0026] An acquisition module, configured to periodically acquire the operating parameters of the IGBT module and the operating parameters of a motor, where the motor is a motor driven by a motor controller where the IGBT module is located;

[0027] A first determination module, configured to determine a current rolling filter coefficient according to the currently acquired operating parameters of the IGBT module and the operating parameters of the motor;

[0028] A second determination module, configured to determine the junction temperature of the IGBT module according to multiple adjacent first voltage signals and multiple adjacent rolling filter coefficients.

[0029] Optionally, the device further includes:

[0030] A processing module, configured to filter the currently acquired first voltage signal according to multiple adjacent first voltage signals.

[0031] Optionally, the operating parameters of the IGBT module include a switching frequency and a thermal loss power, and the operating parameters of the motor include a motor output torque;

[0032] The first determination module includes:

[0033] A first determination sub-module, configured to determine a current switching frequency filter coefficient according to the currently acquired switching frequency;

[0034] A second determination sub-module, configured to determine a current output torque filter coefficient according to the currently acquired motor output torque;

[0035] A third determination sub-module, configured to determine a current thermal loss filtering coefficient according to the currently collected thermal loss power;

[0036] A fourth determination sub-module, configured to determine a current rolling filtering coefficient according to the current switching frequency filtering coefficient, the current output torque filtering coefficient, and the current thermal loss filtering coefficient.

[0037] Optionally, the second determination sub-module includes:

[0038] A calculation unit, configured to calculate a current motor speed according to the currently collected motor output torque;

[0039] An acquisition unit, configured to acquire a maximum external characteristic torque corresponding to the motor speed;

[0040] A determination unit, configured to determine a current output torque filtering coefficient according to the currently collected motor output torque and the maximum external characteristic torque.

[0041] Optionally, the second determination module includes:

[0042] An acquisition sub-module, configured to acquire N + 1 adjacent first voltage signals and N adjacent rolling filtering coefficients, where the N rolling filtering coefficients correspond to first voltage signals other than the first first voltage signal among the N + 1 first voltage signals;

[0043] A fifth determination sub-module, configured to determine the junction temperature of the IGBT module according to the N + 1 first voltage signals and the N rolling filtering coefficients; where N is a positive integer.

[0044] An embodiment of the present application further provides a system for determining the junction temperature of an IGBT module, including: a temperature sensor, a filtering circuit, and a device for determining the junction temperature of the IGBT module as described above;

[0045] Wherein, the temperature sensor is connected to the input end of the filtering circuit, and the device for determining the junction temperature of the IGBT module is connected to the output end of the filtering circuit.

[0046] An embodiment of the present application further provides a system for determining the junction temperature of an IGBT module, including: a processor, a memory, and a program stored on the memory and executable on the processor, where the program, when executed by the processor, implements the steps of the method for determining the junction temperature of the IGBT module as described above.

[0047] An embodiment of the present application further provides a readable storage medium, where a program is stored on the readable storage medium, and when the program is executed by a processor, the steps of the method for determining the junction temperature of the IGBT module as described above are implemented.

[0048] The above technical solution of this application has at least the following beneficial effects:

[0049] For the method for determining the junction temperature of the IGBT module in the embodiment of this application, first, a first voltage signal representing the junction temperature of the IGBT module is periodically obtained, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor that collects the junction temperature of the IGBT module; second, the operating parameters of the IGBT module and the operating parameters of the motor are periodically collected, where the motor is the motor driven by the motor controller where the IGBT module is located; third, according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor, the current rolling filter coefficient is determined; finally, according to a plurality of adjacent first voltage signals and a plurality of adjacent rolling filter coefficients, the junction temperature of the IGBT module is determined. In this way, firstly, the temperature sensor mounted on the IGBT and the freewheeling diode can collect the junction temperature of the IGBT module in real time, and the high-frequency interference in the voltage signal corresponding to the junction temperature is filtered through a hardware circuit, avoiding the deterioration of the dynamic characteristics of the voltage signal; secondly, the junction temperature of the IGBT module is estimated according to the first voltage signal and the rolling filter coefficient, so that the dynamic characteristics of the filtered junction temperature signal of the IGBT module match the working conditions of the motor controller, improving the accuracy of estimating the junction temperature of the IGBT module. Description of the Drawings

[0050] Figure 1 It is a schematic flowchart of the method for determining the junction temperature of the IGBT module in the embodiment of this application;

[0051] Figure 2 It is a circuit diagram of the filter circuit in the embodiment of this application;

[0052] Figure 3 It is a schematic structural diagram of the device for determining the junction temperature of the IGBT module in the embodiment of this application. Detailed Embodiments

[0053] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the protection scope of this application.

[0054] The terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of this application can be implemented in an order other than those illustrated or described herein. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the associated objects before and after.

[0055] The following combines the drawings and details the method for determining the junction temperature of the IGBT module provided by the embodiments of this application through specific embodiments and their application scenarios.

[0056] As Figure 1 shown, it is a schematic flowchart of the method for determining the junction temperature of the IGBT module according to the embodiments of this application. The method includes:

[0057] Step 101: Periodically obtain a first voltage signal characterizing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filtering circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module;

[0058] Here, it should be noted that in the embodiments of this application, the temperature sensor is a thermistor mounted on the surface of the IGBT and the freewheeling diode. In this way, the junction temperature of the IGBT module can be directly, reliably, effectively and real-timely collected.

[0059] Step 102: Periodically collect the operating parameters of the IGBT module and the operating parameters of the motor, where the motor is the motor driven by the motor controller where the IGBT module is located;

[0060] Here, it should be noted that the operating parameters of the IGBT module and the operating parameters of the motor collected in this step are operating parameters related to the junction temperature of the IGBT module, such as: the operating frequency of the IGBT module, the heat dissipation power, the output torque of the motor, etc.

[0061] Step 103: Determine the current rolling filtering coefficient according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor;

[0062] In this step, by determining the rolling filtering coefficient according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor, the coefficient can adjust the dynamic response of the rolling filtering according to the above three parameters, so that the dynamic characteristics of the filtered IGBT junction temperature signal match the working conditions of the motor controller.

[0063] Here, it should be noted that the current working parameters used to obtain the current rolling filter coefficient in this step can be the working parameters after preprocessing. For example, for each working parameter, it can be the parameter after smoothing processing (filtering processing) of multiple adjacent working parameters collected periodically. In this way, the problem that the obtained rolling filter coefficient is inaccurate due to a certain acquisition error can be avoided.

[0064] Step 104: Determine the junction temperature of the IGBT module according to multiple adjacent first voltage signals and multiple adjacent rolling filter coefficients.

[0065] For the method for determining the junction temperature of the IGBT module in the embodiment of the present application, first, periodically obtain a first voltage signal characterizing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module; second, periodically collect the working parameters of the IGBT module and the working parameters of the motor, where the motor is the motor driven by the motor controller where the IGBT module is located; third, determine the current rolling filter coefficient according to the currently collected working parameters of the IGBT module and the working parameters of the motor; finally, determine the junction temperature of the IGBT module according to multiple adjacent first voltage signals and multiple adjacent rolling filter coefficients. In this way, on the one hand, it realizes that the temperature sensor mounted on the IGBT and the freewheeling diode collects the junction temperature of the IGBT module in real time, and filters the high-frequency interference in the voltage signal corresponding to the junction temperature through a hardware circuit, avoiding the deterioration of the dynamic characteristics of the voltage signal; on the other hand, estimating the junction temperature of the IGBT module according to the first voltage signal and the rolling filter coefficient makes the dynamic characteristics of the filtered junction temperature signal of the IGBT module match the working conditions of the motor controller, improves the accuracy of estimating the junction temperature of the IGBT module, provides a basis for the subsequent temperature analysis of the IGBT module junction temperature on the real vehicle, and improves the accuracy of the temperature estimation of the IGBT module junction temperature on the real vehicle.

[0066] Here, in combination with Figure 2 , the structure of the filter circuit used in the embodiment of the present application is described:

[0067] As Figure 2 shown, the filter circuit is a classic second-order low-pass filter circuit, and the filter circuit includes:

[0068] Operational amplifier A;

[0069] A first resistor R1 and a second resistor R2 connected in series, where one end of the second resistor R2 is connected to the non-inverting input terminal of the operational amplifier A, and one end of the first resistor R1 forms the input terminal of the filter circuit and is connected to the temperature sensor;

[0070] The first capacitor C1 has one end connected between the first resistor R1 and the second resistor R2, and the other end connected to the output terminal of the operational amplifier A;

[0071] The second capacitor C2 has one end connected to the inverting input terminal of the operational amplifier A and the other end grounded;

[0072] Wherein, the inverting input terminal of the operational amplifier A is connected to the output terminal of the operational amplifier A; the power supply terminal of the operational amplifier A is connected to the analog power supply VSS.

[0073] Here, the working process of the filtering circuit is described:

[0074] Based on the virtual short and virtual open principles of the operational amplifier, it can be known that the potentials of the non-inverting input terminal and the inverting input terminal of the operational amplifier are equal, that is: V + = V - = V0; where, V + is the voltage of the non-inverting input terminal, V - is the voltage of the inverting input terminal, and V0 is the voltage of the output terminal.

[0075] At this time, the second current flowing through the second capacitor C2 can be calculated as: i2 = V0 × S × C2, where i2 is the second current and C2 is the capacitance value of the second capacitor.

[0076] According to the virtual short and virtual open principles of the operational amplifier, the current flowing into the non-inverting input terminal is 0, so the current flowing through the second resistor R2 is also i2. Based on this, the voltage at the connection point of the first resistor R1 and the second resistor R2 can be calculated as: V = V0 + i2 × R2.

[0077] After obtaining the voltage V, the first current flowing through the first capacitor C1 can be calculated according to the Thevenin voltage law: After arrangement, it is obtained that: i1 = S × C1 × R2 × i2. Here, i1 is the first current, C1 is the capacitance value of the first capacitor, and R2 is the resistance value of the second resistor.

[0078] Similarly, according to the Thevenin voltage law, the current flowing through the first resistor R1 can be calculated as: i0 = (V S - V0 - R2 × i2) / R1.

[0079] According to the Thevenin current law, i0 = i1 + i2.

[0080] According to the above several formulas, the transfer function of the filtering circuit can be obtained as:

[0081]

[0082] When keeping the amplitude of the input signal unchanged and changing the frequency to make the output signal drop to 0.707 times of the maximum value, in terms of frequency response characteristics, the -3dB point is the cut-off frequency, which is a special frequency used to describe the frequency characteristic index. According to Figure 2 For the shown filter circuit, in this transfer function, the resistance value of R1 is 6.8K, the resistance value of R2 is 6.8K, the capacitance value of C1 is 6.8nF, and the capacitance value of C2 is 3.3nF. Through calculation, it can be obtained that the cut-off frequency corresponding to this filter circuit is 5.02kHz. The reason for not adopting a lower cut-off frequency is to prevent the dynamic characteristics of the temperature signal from deteriorating.

[0083] Furthermore, this filter circuit also includes a Schottky diode module D. The chip model of the Schottky diode module D is BAT54SQ-7-F. This chip is composed of two Schottky diodes connected in series. The functions of these two Schottky diodes are to prevent the filter circuit from being damaged due to abnormal signals to be filtered at the input end of the filter circuit. Among them, the positive pole of the Schottky diode module D is grounded, the negative pole of the Schottky diode module D is connected to the analog power supply, and the connection end between the two Schottky diodes in the Schottky diode module D is connected to the non-inverting input terminal.

[0084] Take Figure 2 as an example. When a non-expected large positive voltage signal (much larger than the 5V power supply voltage) appears at the input end of the filter circuit, the generated impact current will feedback to the 5V power supply through the Schottky diode module D. At this time, the voltage at the non-inverting input terminal of the operational amplifier A will not be higher than the sum of the 5V power supply voltage and the conduction voltage drop of the diode; when a non-expected large negative voltage signal (much smaller than 0V) appears at the input end of the filter circuit, the direction of the generated impact current is from the ground terminal through the Schottky diode module D to the input end of the filter circuit. At this time, the voltage at the inverting input terminal of the operational amplifier A will not be lower than the negative value of the diode conduction voltage drop. This circuit precisely utilizes this characteristic of the Schottky diode to implement protection and prevent damage to the filter circuit caused by non-expected input of the filtered signal.

[0085] This filter circuit also includes: a third resistor R3, one end of which is connected to the input end of this filter circuit and the other end is grounded; among them, the third resistor R3 plays a role of pulling down. That is, when there is no signal input from the temperature sensor, the input end of this filter circuit is pulled down to the low level state to prevent non-expected output of the temperature voltage signal.

[0086] This filter circuit also includes: a third capacitor, one end of which is connected to the power supply terminal of the operational amplifier A and the other end is grounded. This third capacitor C3 is a decoupling capacitor used to ensure the stability of the power supply for the operational amplifier.

[0087] As an alternative implementation, the method further includes: filtering the currently acquired first voltage signal according to a plurality of adjacent first voltage signals.

[0088] In this alternative implementation, by filtering the currently acquired first voltage signal, unreasonable voltage signals can be removed, avoiding inaccurate determination of the junction temperature due to abnormal acquired signals.

[0089] Specifically, the filtering process can be performed as follows:

[0090] First, acquire the first voltage signals of the previous n (such as 12) sampling periods, and delete the largest m (such as 2) voltage values and the smallest m voltage values among the n first voltage signals.

[0091] Second, filter the remaining n - 2m first voltage signals. Specifically, the filtering can be performed according to the following formula:

[0092]

[0093] where V int is the filtered first voltage signal, and V0(i) is the i-th first voltage signal after screening.

[0094] In the embodiments of the present application, by screening the first voltage signal output by the filter circuit, the acquisition signals that are severely interfered can be artificially removed, preventing the influence of severe interference signals on the filtering of the voltage signal representing the junction temperature; on this basis, based on the dynamic change characteristics of the IGBT module junction temperature, that is, the junction temperature of the IGBT module will not mutate or oscillate discontinuously in a very short time, average value filtering is performed on the remaining first voltage signals. In this way, the influence of interference signals on the overall temperature voltage signal can be effectively reduced, ensuring the accuracy of subsequent temperature analysis.

[0095] As an alternative implementation, the operating parameters of the IGBT module include the switching frequency and the thermal loss power, and the operating parameters of the motor include the motor output torque;

[0096] Step 103, determining the current rolling filter coefficient according to the currently acquired operating parameters of the IGBT module and the operating parameters of the motor, includes:

[0097] Step one: determining the current switching frequency filter coefficient according to the currently acquired switching frequency;

[0098] Specifically, this step can determine the switching frequency filter coefficient according to the following formula:

[0099]

[0100] where Hmax With H min represent the maximum and minimum values of the preset IGBT module switching frequency, that is, the switching frequency H is in the range of [H max , H min . According to the above formula, when the switching frequency of the IGBT module gradually increases from H min to H max , the switching frequency filtering coefficient K of the IGBT module H varies linearly in the range of [0.5, 0.8]. Considering that when the switching frequency of the IGBT module is relatively high, the change rate of its junction temperature rise is also greater. Therefore, the embodiment of the present application achieves this purpose by adaptively adjusting the switching frequency filtering coefficient, that is, as the switching frequency of the IGBT module increases, the final filtering signal is adjusted by increasing the switching frequency filtering coefficient, so that the resolved temperature value can truly reflect the change state of the IGBT module's junction temperature (relaxing the change gradient limit of the junction temperature).

[0101] Step 2: Determine the current output torque filtering coefficient according to the currently collected motor output torque;

[0102] Step 3: Determine the current heat loss filtering coefficient according to the currently collected heat loss power;

[0103] Specifically, this step can determine the heat loss filtering coefficient according to the following formula:

[0104]

[0105] where P represents the heat loss power of the IGBT module in the current state; P max and P min represent the maximum and minimum values of the preset heat loss power of the IGBT module, that is, P is in the range of [P max , P min . According to the above formula, when the heat loss power of the IGBT module gradually increases from P min to P max , the heat loss filtering coefficient K of the IGBT module P varies linearly in the range of [0.55, 0.75]. Considering that when the heat loss power of the IGBT module is relatively high, the change rate of its junction temperature rise is also greater. Therefore, the embodiment of the present application achieves this purpose by adaptively adjusting the heat loss filtering coefficient, that is, as the heat loss power of the IGBT module increases, the final filtering signal is adjusted by increasing the heat loss filtering coefficient, so that the resolved temperature value can truly reflect the change state of the IGBT junction temperature (relaxing the change gradient limit of the junction temperature).

[0106] Step 4: Determine the current rolling filter coefficient according to the current switching frequency filter coefficient, the current output torque filter coefficient, and the current heat loss filter coefficient.

[0107] Specifically, this step can determine the rolling filter coefficient according to the following formula:

[0108] K S = 0.35K H + 0.2K T + 0.45K P

[0109] where K S represents the rolling filter coefficient. It can be seen that this rolling filter coefficient is the weighted calculation result of the switching frequency filter coefficient, the output torque filter coefficient, and the heat loss power filter coefficient. The reason for weighting the above three coefficients is that the dynamic influences of the switching frequency of the IGBT module, the motor output torque, and the heat loss power of the IGBT module on the junction temperature of the IGBT module are different. The rolling filter coefficient finally calculated by different weights in the embodiments of the present application can further approximate the change characteristics of the IGBT junction temperature. Here, it should be noted that the weights in the above formula can be adjusted according to actual needs.

[0110] As a specific implementable manner, the above Step 2: Determine the current output torque filter coefficient according to the currently collected motor output torque, includes:

[0111] (A) Calculate the current motor speed according to the currently collected motor output torque;

[0112] (B) Obtain the maximum external characteristic torque corresponding to the motor speed;

[0113] (C) Determine the current output torque filter coefficient according to the currently collected motor output torque and the maximum external characteristic torque.

[0114] This optional implementation manner can specifically determine the output torque filter coefficient according to the following formula:

[0115]

[0116] where T represents the currently collected motor output torque; T max (ω) represents the maximum external characteristic torque corresponding to the motor speed ω, and ω is the motor speed. Considering that the motor external characteristic torque changes with the speed, in the above formula, the motor maximum external characteristic torque is a function of the motor speed. In addition, since T does not exceed the external characteristic torque limit, therefore According to this formula, as the motor output torque T gradually increases from 0 to the external characteristic torque T max(ω), the output torque filtering coefficient K T It linearly changes within the range of [0.35, 0.85].

[0117] Considering that when the output torque of the motor is large, the change rate of the junction temperature rise of the IGBT module is also larger. Therefore, this optional implementation method achieves this purpose by adaptively adjusting the output torque filtering coefficient, that is, as the output torque of the motor increases, the final filtered signal is adjusted by adjusting the output torque filtering coefficient, so that the resolved temperature value can truly reflect the change state of the IGBT junction temperature (relaxing the change gradient limit of the junction temperature).

[0118] As an optional implementation method, step 104, determining the junction temperature of the IGBT module according to multiple adjacent ones of the first voltage signals and multiple adjacent ones of the rolling filtering coefficients, includes:

[0119] Step 1: Obtain N + 1 adjacent first voltage signals, and N adjacent rolling filtering coefficients, where the N rolling filtering coefficients correspond to the first voltage signals except the first first voltage signal among the N + 1 first voltage signals;

[0120] Here, it should be noted that the correspondence between the first voltage signal and the filtering rolling coefficient in this step can be understood as the first voltage signal and the filtering rolling coefficient in the same control period being the corresponding first voltage signal and filtering rolling coefficient. Among them, the first of the first voltage signals is the first obtained first voltage signal among the N + 1 first voltage signals.

[0121] Among them, the control period can include multiple consecutive acquisition periods. One control period can obtain a first voltage signal and a rolling filtering coefficient, and the various working parameters used to obtain the rolling filtering coefficient are the parameters after processing the working parameters collected in multiple acquisition periods. In this way, the accuracy of obtaining the rolling filtering coefficient is improved.

[0122] Step 2: Determine the junction temperature of the IGBT module according to the N + 1 first voltage signals and the N rolling filtering coefficients; where N is a positive integer.

[0123] This optional implementation method can specifically determine the junction temperature of the IGBT module according to the following formula:

[0124]

[0125] Among them, V out represents the temperature voltage signal after rolling filtering; j represents the jth control period. It can be seen that the voltage signal representing the junction temperature obtained by filtering using the above formula is related to the rolling filtering coefficient K of the previous n - 2m control periods S, and the corresponding filtered first voltage signal V int It is related to this; the embodiments of the present application precisely use this rolling filtering method to obtain the final voltage signal representing the junction temperature. By adopting the above filtering method, the interference generated when the temperature sensor directly measures the junction temperature of the IGBT module can be effectively filtered out, and at the same time, the effective signal is retained, thus laying a solid foundation for the subsequent accurate temperature analysis, that is, the accurate measurement of the junction temperature of the IGBT module.

[0126] It should be noted that for the method for determining the junction temperature of the IGBT module provided by the embodiments of the present application, the execution subject can be a device for determining the junction temperature of the IGBT module, or a control module in the device for determining the junction temperature of the IGBT module that is used to execute the method for determining the junction temperature of the IGBT module. In the embodiments of the present application, taking the device for determining the junction temperature of the IGBT module to execute the method for determining the junction temperature of the IGBT module as an example, the method for determining the junction temperature of the IGBT module provided by the embodiments of the present application is described.

[0127] Figure 3 is a schematic structural diagram of the device for determining the junction temperature of the IGBT module according to the embodiments of the present application. The device includes:

[0128] An acquisition module 301, configured to periodically acquire a first voltage signal representing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor that collects the junction temperature of the IGBT module;

[0129] An acquisition module 302, configured to periodically acquire the operating parameters of the IGBT module and the operating parameters of the motor, where the motor is the motor driven by the motor controller where the IGBT module is located;

[0130] A first determination module 303, configured to determine the current rolling filter coefficient according to the currently acquired operating parameters of the IGBT module and the operating parameters of the motor;

[0131] A second determination module 304, configured to determine the junction temperature of the IGBT module according to a plurality of adjacent first voltage signals and a plurality of adjacent rolling filter coefficients.

[0132] The device for determining the junction temperature of the IGBT module according to the embodiments of the present application. First, the module 301 periodically obtains a first voltage signal representing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module; Second, the acquisition module 302 periodically acquires the operating parameters of the IGBT module and the operating parameters of the motor, where the motor is the motor driven by the motor controller where the IGBT module is located; Third, the first determination module 303 determines the current rolling filter coefficient according to the currently acquired operating parameters of the IGBT module and the operating parameters of the motor; Finally, the second determination module 304 determines the junction temperature of the IGBT module according to a plurality of adjacent first voltage signals and a plurality of adjacent rolling filter coefficients. In this way, on the one hand, the temperature sensor mounted on the IGBT and the freewheeling diode can collect the junction temperature of the IGBT module in real time, and the high-frequency interference in the voltage signal corresponding to the junction temperature can be filtered through the hardware circuit, avoiding the deterioration of the dynamic characteristics of the voltage signal; on the other hand, the junction temperature of the IGBT module is estimated according to the first voltage signal and the rolling filter coefficient, so that the dynamic characteristics of the filtered junction temperature signal of the IGBT module match the working conditions of the motor controller, improving the accuracy of estimating the junction temperature of the IGBT module.

[0133] Optionally, the device further includes:

[0134] A processing module, configured to filter the currently acquired first voltage signal according to a plurality of adjacent first voltage signals.

[0135] Optionally, the operating parameters of the IGBT module include the switching frequency and the thermal loss power, and the operating parameters of the motor include the motor output torque;

[0136] The first determination module 303 includes:

[0137] A first determination sub-module, configured to determine the current switching frequency filter coefficient according to the currently acquired switching frequency;

[0138] A second determination sub-module, configured to determine the current output torque filter coefficient according to the currently acquired motor output torque;

[0139] A third determination sub-module, configured to determine the current thermal loss filter coefficient according to the currently acquired thermal loss power;

[0140] A fourth determination sub-module, configured to determine the current rolling filter coefficient according to the current switching frequency filter coefficient, the current output torque filter coefficient, and the current thermal loss filter coefficient.

[0141] Optionally, the second determination sub-module includes:

[0142] A calculation unit, configured to calculate a current motor speed according to a currently acquired output torque of the motor;

[0143] An acquisition unit, configured to acquire a maximum external characteristic torque corresponding to the motor speed;

[0144] A determination unit, configured to determine a current output torque filtering coefficient according to the currently acquired output torque of the motor and the maximum external characteristic torque.

[0145] Optionally, the second determination module 304 includes:

[0146] An acquisition sub-module, configured to acquire N + 1 adjacent first voltage signals and N adjacent rolling filtering coefficients, where the N rolling filtering coefficients correspond to the first voltage signals except the first one among the N + 1 first voltage signals;

[0147] A fifth determination sub-module, configured to determine the junction temperature of the IGBT module according to the N + 1 first voltage signals and the N rolling filtering coefficients; where N is a positive integer.

[0148] The device for determining the junction temperature of the IGBT module provided by the embodiment of the present application can implement Figures 1 to 2 each process of the method embodiment and achieve the same technical effect. To avoid repetition, it will not be elaborated here.

[0149] The embodiment of the present application further provides a system for determining the junction temperature of an IGBT module, where the system includes a temperature sensor, a filtering circuit, and the device for determining the junction temperature of the IGBT module as described above;

[0150] wherein, the temperature sensor is connected to the input end of the filtering circuit, and the device for determining the junction temperature of the IGBT module is connected to the output end of the filtering circuit.

[0151] The embodiment of the present application further provides a system for determining the junction temperature of an IGBT module, including: a processor, a memory, and a program stored on the memory and executable on the processor, where when the program is executed by the processor, it implements the steps of the method for determining the junction temperature of the IGBT module as described above.

[0152] The embodiment of the present application further provides a readable storage medium, where a program is stored on the readable storage medium, and when the program is executed by a processor, it implements each process of the method embodiment for determining the junction temperature of the IGBT module and achieves the same technical effect. To avoid repetition, it will not be elaborated here. Wherein, the readable storage medium is, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc, etc.

[0153] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0154] The above are the preferred embodiments of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle described in the present application, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A method for determining the junction temperature of an IGBT module, characterized in that, Including: Periodically obtaining a first voltage signal representing the junction temperature of the IGBT module, where the first voltage signal is the voltage after filtering the output voltage of the temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module; Periodically collecting the operating parameters of the IGBT module and the operating parameters of the motor, where the motor is the motor driven by the motor controller where the IGBT module is located; Determining a current rolling filter coefficient according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor; Performing a rolling filter process on adjacent first voltage signals by using adjacent multiple rolling filter coefficients to determine the junction temperature of the IGBT module; The operating parameters of the IGBT module include the switching frequency and the thermal loss power, and the operating parameters of the motor include the motor output torque; Among them, determining the current rolling filter coefficient according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor includes: Determining a current switching frequency filter coefficient according to the currently collected switching frequency and the preset change range of the switching frequency, where the larger the currently collected switching frequency, the larger the switching frequency filter coefficient; Determining a current output torque filter coefficient according to the currently collected motor output torque; Determining a current thermal loss filter coefficient according to the currently collected thermal loss power and the preset change range of the thermal loss power, where the larger the currently collected thermal loss power, the larger the thermal loss filter coefficient; Determining the current rolling filter coefficient according to the current switching frequency filter coefficient, the current output torque filter coefficient, and the current thermal loss filter coefficient.

2. The method according to claim 1, wherein The method further includes: Filtering the currently obtained first voltage signal according to adjacent multiple first voltage signals.

3. The method according to claim 1, characterized in that, Determining the current output torque filter coefficient according to the currently collected motor output torque includes: Calculating a current motor speed according to the currently collected motor output torque; Obtaining the maximum external characteristic torque corresponding to the motor speed; Determining the current output torque filter coefficient according to the currently collected motor output torque and the maximum external characteristic torque.

4. The method according to claim 1, wherein Performing a rolling filter process on adjacent first voltage signals by using adjacent multiple rolling filter coefficients to determine the junction temperature of the IGBT module includes: Obtaining N + 1 adjacent first voltage signals and N adjacent rolling filter coefficients, where the N rolling filter coefficients correspond to the first voltage signals other than the first first voltage signal among the N + 1 first voltage signals; Performing a rolling filter process on the N + 1 first voltage signals by using the N rolling filter coefficients to determine the junction temperature of the IGBT module; where N is a positive integer.

5. A device for determining the junction temperature of an IGBT module, characterized in that, Including: An acquisition module, configured to periodically acquire a first voltage signal representing the junction temperature of an IGBT module, where the first voltage signal is a voltage obtained by filtering the output voltage of a temperature sensor through a filter circuit, and the temperature sensor is a temperature sensor for collecting the junction temperature of the IGBT module; A collection module, configured to periodically collect the operating parameters of the IGBT module and the operating parameters of a motor, where the motor is a motor driven by a motor controller where the IGBT module is located; A first determination module, configured to determine a current rolling filter coefficient according to the currently collected operating parameters of the IGBT module and the operating parameters of the motor; A second determination module, configured to perform a rolling filter process on multiple adjacent first voltage signals by using multiple adjacent rolling filter coefficients to determine the junction temperature of the IGBT module; Wherein, the operating parameters of the IGBT module in the first determination module include a switching frequency and a heat loss power, and the operating parameters of the motor include a motor output torque; The first determination module includes: A first determination sub-module, configured to determine a current switching frequency filter coefficient according to the currently collected switching frequency and a preset change range of the switching frequency, where the larger the currently collected switching frequency, the larger the switching frequency filter coefficient; A second determination sub-module, configured to determine a current output torque filter coefficient according to the currently collected motor output torque; A third determination sub-module, configured to determine a current heat loss filter coefficient according to the currently collected heat loss power and a preset change range of the heat loss power, where the larger the currently collected heat loss power, the larger the heat loss filter coefficient; A fourth determination sub-module, configured to determine a current rolling filter coefficient according to the current switching frequency filter coefficient, the current output torque filter coefficient, and the current heat loss filter coefficient.

6. A system for determining the junction temperature of an IGBT module, characterized in that, Includes: A temperature sensor, a filter circuit, and a determining device for the junction temperature of the IGBT module as described in claim 5; Wherein, the temperature sensor is connected to the input end of the filter circuit, and the determining device for the junction temperature of the IGBT module is connected to the output end of the filter circuit.

7. A system for determining the junction temperature of an IGBT module, characterized in that, Includes: A processor, a memory, and a program stored on the memory and executable on the processor, where when the program is executed by the processor, the steps of the method for determining the junction temperature of the IGBT module as described in any one of claims 1 to 4 are implemented.

8. A readable storage medium, characterized in that, A program is stored on the readable storage medium, and when the program is executed by a processor, the steps of the method for determining the junction temperature of the IGBT module as described in any one of claims 1 to 4 are implemented.

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