Traction inverter IGBT junction temperature calculation method, device, equipment, medium and program
By collecting and discretizing the electrical parameters of the traction inverter and combining them with an electrothermal model to calculate the IGBT junction temperature, the speed and accuracy issues of IGBT device junction temperature assessment in the existing technology have been solved, thus improving the life prediction and reliability assessment of the traction inverter.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2026-03-27
AI Technical Summary
Existing technologies make it difficult to quickly and accurately assess the junction temperature of IGBT devices in electric rail traction systems, affecting the life prediction and reliability assessment of traction inverters.
By collecting the bus voltage, RMS output current, modulation ratio, and power factor of the traction inverter, the total average loss of the IGBT device is calculated and discretized. The IGBT junction temperature for each discrete cycle is then calculated using an electrothermal model.
It enables rapid and accurate calculation of IGBT junction temperature, improving the accuracy of traction inverter life prediction and reliability assessment.
Smart Images
Figure CN121741418A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of power electronics reliability analysis and condition monitoring technology, and in particular to a method, apparatus, equipment, medium and program for calculating the junction temperature of IGBTs in a traction inverter. Background Technology
[0002] Insulated-gate bipolar transistors (IGBTs) are widely used in large-scale power conversion systems in fields such as electric rail traction, DC power transmission, and new energy. As a core component of these systems, their reliability has become a concern due to their increasingly widespread application. Traction inverters operate under harsh and unstable conditions for extended periods, subjecting IGBTs to stresses from humidity, heat, and vibration, which affect their health and lifespan. According to relevant surveys, IGBT failures account for the highest proportion of traction converter failures in HXD1, HXD1C, and HXD1D electric locomotives. Therefore, assessing the operating status and reliability of IGBT devices directly impacts the safe and stable operation of the traction system and the overall life-cycle maintenance costs.
[0003] Existing research has shown a strong correlation between IGBT lifespan and junction temperature, with cyclic thermal stress within the IGBT package being the primary cause of aging failure. Current IGBT lifespan prediction relies on rainflow counting to statistically analyze the thermal load on the IGBT module, combined with a lifespan model to derive fatigue damage and expected lifespan. Traction inverters typically operate on power lines for hundreds to thousands of kilometers daily, generating a massive amount of junction temperature fluctuation thermal load data. Therefore, improving the speed of junction temperature calculation while maintaining the accuracy of the results is crucial for traction inverter lifespan prediction and reliability assessment. Summary of the Invention
[0004] This disclosure provides a method, apparatus, device, medium, and program for calculating the junction temperature of an IGBT in a traction inverter, enabling rapid and accurate calculation of the junction temperature of the traction inverter under long-term operational profiles.
[0005] Firstly, this disclosure provides a method for calculating the junction temperature of IGBTs in a traction inverter, including:
[0006] Collect the bus voltage, RMS value of output current, output current frequency, modulation ratio, and power factor of the traction inverter;
[0007] Based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor, calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle;
[0008] The average loss is discretized to obtain pulse waveforms corresponding to multiple discrete periods. The loss value corresponding to each pulse waveform is calculated. The size of the discrete period is determined according to the set number of discrete periods and the output current frequency.
[0009] Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, the IGBT junction temperature corresponding to each discrete cycle is calculated.
[0010] In some implementations, based on the bus voltage, the RMS value of the output current, the modulation ratio, and the power factor, the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle is calculated, including:
[0011] Based on the RMS value of the output current, the modulation ratio, and the power factor, calculate the average on-state loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0012] Based on the bus voltage, the effective value of the output current and the actual junction temperature of the IGBT devices, calculate the average switching loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0013] The sum of the average on-state loss and the average switching loss is calculated to obtain the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0014] In some implementations, the average loss is discretized to obtain pulse waveforms corresponding to multiple discrete periods, including:
[0015] The total average loss within one output fundamental cycle is equivalent to a half-sine waveform.
[0016] The half-sine waveform is dispersed at equal intervals to obtain rectangular pulse waveforms corresponding to multiple discrete periods.
[0017] In some implementations, the loss value corresponding to each pulse waveform is calculated using the following formula:
[0018]
[0019] In the formula, P i The loss value corresponding to the pulse waveform in the i-th discrete period is described, where k represents the set number of discrete periods, and P av This represents the total average loss.
[0020] In some implementations, the size of the discrete period is 1 / 2kf0, where f0 represents the output current frequency and k represents the set number of discrete periods.
[0021] In some implementations, based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, the IGBT junction temperature for each discrete cycle is calculated, including:
[0022] Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, the junction temperature rise, contact temperature rise, heat sink temperature rise and cooling system water temperature of the IGBT device in each discrete cycle are calculated.
[0023] The IGBT junction temperature is obtained by calculating the sum of the junction temperature rise, contact temperature rise, heat sink temperature rise, and cooling system water temperature for each discrete cycle.
[0024] Secondly, this disclosure provides a device for calculating the junction temperature of an IGBT in a traction inverter, comprising:
[0025] The data acquisition module is used to acquire the bus voltage, RMS value of output current, output current frequency, modulation ratio, and power factor of the traction inverter.
[0026] The total loss calculation module is used to calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor.
[0027] The discrete equivalent module is used to discretize the average loss to obtain pulse waveforms corresponding to multiple discrete periods, and calculate the loss value corresponding to each pulse waveform. The size of the discrete period is determined according to the set number of discrete periods and the output current frequency.
[0028] The junction temperature calculation module is used to calculate the IGBT junction temperature for each discrete cycle based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform.
[0029] Thirdly, this disclosure provides a computer device including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described in the first aspect.
[0030] Fourthly, this disclosure provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the method described in the first aspect.
[0031] Fifthly, this disclosure provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method described in the first aspect.
[0032] This disclosure provides a method, apparatus, equipment, medium, and program for calculating the junction temperature of IGBTs in traction inverters. It collects the bus voltage, RMS value of the output current, output current frequency, modulation ratio, and power factor of the traction inverter, and calculates the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle. The average loss is discretized to obtain pulse waveforms corresponding to multiple discrete cycles, and the loss value corresponding to each pulse waveform is calculated. Based on the electrothermal model of the traction inverter IGBT devices and the loss value corresponding to each pulse waveform, the IGBT junction temperature corresponding to each discrete cycle is calculated. This provides a fast and accurate calculation of the junction temperature of IGBT devices in traction inverters under long-term mission profiles, improving both the calculation speed and the accuracy of the results, thus facilitating the life prediction and reliability assessment of traction inverters. Attached Figure Description
[0033] The present disclosure will be described in more detail below based on embodiments and with reference to the accompanying drawings:
[0034] Figure 1 This is a schematic diagram of a typical topology of a traction inverter provided in an embodiment of this disclosure;
[0035] Figure 2 A schematic diagram illustrating the principle of using a rectangle to represent the equivalent loss of IGBT devices in the conventional method provided in this disclosure embodiment;
[0036] Figure 3 This is a schematic diagram illustrating the equivalent principle of loss discretization provided in the embodiments of this disclosure;
[0037] Figure 4 This is a schematic diagram of the electrothermal model of the traction inverter IGBT module provided in the embodiments of this disclosure;
[0038] Figure 5 The effective value of the output current and the output current frequency are provided in the embodiments of this disclosure;
[0039] Figure 6 The modulation ratio and power coefficient provided in the embodiments of this disclosure;
[0040] Figure 7 Heat sink temperature data provided for embodiments of this disclosure;
[0041] Figure 8 The equivalent duty cycle under SVPWM modulation provided in the embodiments of this disclosure;
[0042] Figure 9 The average throughput loss provided for embodiments of this disclosure;
[0043] Figure 10 The average switching loss provided for embodiments of this disclosure;
[0044] Figure 11 Discretized loss waveforms provided for embodiments of this disclosure;
[0045] Figure 12 The IGBT junction temperature for each discrete period provided in the embodiments of this disclosure;
[0046] Figure 13 Comparison of calculation results of different methods under the same conditions provided in the embodiments of this disclosure;
[0047] Figure 14 A flowchart illustrating a method for calculating the junction temperature of an IGBT in a traction inverter, as provided in this embodiment of the disclosure;
[0048] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation
[0049] To enable those skilled in the art to better understand the technical solutions of this disclosure, and to fully understand and implement the process of how this disclosure applies technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, not all embodiments. The embodiments of this disclosure and the various features within them can be combined with each other without conflict, and the resulting technical solutions are all within the protection scope of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort should fall within the protection scope of this disclosure.
[0050] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0051] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.
[0052] Figure 1 A typical topology for a traction inverter is shown, employing SVPWM (Space Vector Pulse Width Modulation). Under long-term operational profiles, the junction temperature of the traction inverter fluctuates frequently, significantly impacting its lifespan. Therefore, accurately and efficiently assessing the junction temperature of the traction inverter is a pressing issue that needs to be addressed.
[0053] Example 1
[0054] Figure 14 This is a flowchart illustrating a method for calculating the junction temperature of an IGBT in a traction inverter, as provided in an embodiment of this disclosure. Figure 14 As shown, a method for calculating the junction temperature of an IGBT in a traction inverter includes:
[0055] Step S11: Collect the bus voltage V of the traction inverter dc Output current RMS value Output current frequency f o Modulation ratio m and power factor At the same time, it can also collect the radiator temperature T. h This is used to calculate the IGBT junction temperature in subsequent steps.
[0056] Step S12: Based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor, calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0057] In some implementations, the total average loss of all IGBT devices in the traction inverter over one output fundamental cycle is calculated based on the bus voltage, RMS output current, modulation ratio, and power factor, including:
[0058] Step S12a: Based on the effective value of the output current, the modulation ratio, and the power factor, calculate the average on-state loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0059] First, the duty cycle under SVPWM modulation is equivalently represented by SVPWM with third harmonic injection. The equivalent duty cycle function is as follows:
[0060]
[0061] In the formula, D(t) represents the equivalent duty cycle, t represents the sampling time, and ω represents the modulation wave angular frequency.
[0062] Then, calculate the on-state loss.
[0063] The formula for calculating on-state loss is as follows:
[0064]
[0065] In the formula, P cond U represents the conduction loss. dc i(t) represents the DC bus voltage, and i(t) represents the actual output phase current.
[0066] From equations (1) and (2), we can obtain:
[0067]
[0068] In the formula, P av,cond This represents the average on-state loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0069] Step S12b: Based on the bus voltage, the effective value of the output current, and the actual junction temperature of the IGBT devices, calculate the average switching loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0070]
[0071] In the formula, P av,sw f represents the average switching loss. sw Indicates the switching frequency, U0, R, a, b, c, K V K T V represents the fitting parameters for the switching loss curve. dc_base Nominal voltage, T j Actual junction temperature of the chip, T j_base Nominal junction temperature.
[0072] Step S12c: Calculate the sum of the average conduction loss and the average switching loss to obtain the total average loss P of all IGBT devices in the traction inverter within one output fundamental cycle. av P av =P av.cond +P av.sw .
[0073] Step S13: Discretize the average loss to obtain pulse waveforms corresponding to multiple discrete periods, and calculate the loss value corresponding to each pulse waveform.
[0074] In some implementations, the average loss is discretized to obtain pulse waveforms corresponding to multiple discrete periods, including:
[0075] Step S13a: Equivalent the total average loss within one output fundamental cycle to a half-sine waveform.
[0076] Traditional methods use a rectangle to represent the equivalent loss of IGBT devices, the principle of which is as follows: Figure 2 As shown, this equivalent method only roughly calculates the loss value within 1 / 2f0 cycle, resulting in inaccurate calculations. To achieve rapid junction temperature calculation with comprehensive and accurate results and minimal computational load, this embodiment employs a loss discretization equivalent method to represent the average loss of the IGBT device. Since the third harmonics of each phase automatically cancel each other out at the motor neutral point, the output current of each phase is a sinusoidal waveform. In a single sinusoidal output cycle, the upper and lower IGBT devices each conduct for only half a cycle. Therefore, the IGBT loss within a single sinusoidal output cycle is equivalent to a half-sine wave, i.e., a half-wave period.
[0077] Step S13b: Disperse the half-sine waveform at equal intervals to obtain rectangular pulse waveforms corresponding to multiple discrete periods.
[0078] Building upon the previous approach of equating the total average loss within one output fundamental cycle to a half-sine wave, we further equate the half-sine wave to multiple rectangular pulse waveforms at equivalent frequencies based on equidistant dispersion. The principle is as follows: Figure 3 As shown.
[0079] The mathematical expression for the loss of the equivalent half-sine waveform is:
[0080]
[0081] In the formula, P a The peak value of the equivalent loss is represented by P, where P represents the loss and f0 represents the frequency of the equivalent output current. This is related to the average loss P. av The relationship can be expressed by the following formula:
[0082]
[0083] Step S14: Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, calculate the IGBT junction temperature corresponding to each discrete cycle.
[0084] Based on the principle of equal impulse, the loss P of the i-th rectangular pulse waveform after equidistant discretization is... i Represented as:
[0085]
[0086] In the formula, P i The loss value corresponding to the pulse waveform in the i-th discrete period is described, where k represents the set number of discrete periods, and P av This represents the total average loss.
[0087] The size of the discrete period can be determined based on the set number of discrete periods and the output current frequency. For equally spaced discrete periods, the discrete period is 1 / 2kf0. A larger value for the number of discrete periods, k, results in higher calculation accuracy but also increases the computational burden. Therefore, a trade-off must be struck to maintain both a certain level of accuracy and high computational efficiency. As indicated in the IGBT datasheet, the thermal response time constant of its chip layer is typically in the millisecond range; therefore, the discrete period can be expressed in milliseconds. Setting the discrete period to 10ms, the expression for the value of k is:
[0088]
[0089] Therefore, in some implementations, Equation (8) is used to calculate the loss value corresponding to each pulse waveform.
[0090] In some implementations, based on the electrothermal model of the traction inverter IGBT devices and the loss values corresponding to each pulse waveform, the IGBT junction temperature for each discrete cycle is calculated, including:
[0091] Step S14a: Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, calculate the junction temperature rise, contact temperature rise, heat sink temperature rise and cooling system water temperature of the IGBT device in each discrete cycle.
[0092] The electrothermal model of the traction inverter IGBT module is as follows: Figure 4 As shown, R I1 ~R I4 For IGBT thermal resistance; C I1 ~C I4 For IGBT heat capacity; R D1 ~R D4 For diode thermal resistance; C D1 ~C D4 For diode thermal capacitance; R g C g These are the thermal resistance and thermal capacity of the thermal grease, respectively; R h and C h These are the thermal resistance and heat capacity of the water-cooled radiator, respectively; T w This refers to the radiator water temperature.
[0093] The temperature rise of each structural layer and the IGBT junction temperature in the i-th discrete cycle are:
[0094]
[0095] In the formula: T represents the junction-to-case temperature rise of the IGBT device in the i-th discrete cycle; i c_h T represents the contact temperature rise during the i-th discrete cycle; i h_wT represents the temperature rise of the heat sink in the i-th discrete cycle; i w This represents the water temperature of the cooling system during the i-th discrete period.
[0096] Step S14b: Calculate the sum of the junction temperature rise, contact temperature rise, heat sink temperature rise, and cooling system water temperature of the IGBT device for each discrete cycle to obtain the IGBT junction temperature corresponding to each discrete cycle.
[0097]
[0098] In the formula: This represents the junction temperature of the IGBT device in the i-th discrete cycle.
[0099] The method in this embodiment is applicable to the calculation of IGBT junction temperature in rail traction inverters. It enables rapid calculation of IGBT junction temperature with accurate results and low computational load. It improves both the speed of junction temperature calculation and the accuracy of the results, which is of great reference value for the life prediction and reliability assessment of traction inverters.
[0100] Example 2
[0101] Based on the above embodiments, this disclosure provides a traction inverter IGBT junction temperature calculation device, comprising:
[0102] The data acquisition module is used to acquire the bus voltage, RMS value of output current, output current frequency, modulation ratio, and power factor of the traction inverter.
[0103] The total loss calculation module is used to calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle, based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor.
[0104] The discrete equivalent module is used to discretize the average loss to obtain pulse waveforms corresponding to multiple discrete periods, and calculate the loss value corresponding to each pulse waveform. The size of the discrete period is determined according to the set number of discrete periods and the output current frequency.
[0105] The junction temperature calculation module is used to calculate the IGBT junction temperature for each discrete cycle based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform.
[0106] In some implementations, the total average loss of all IGBT devices in the traction inverter over one output fundamental cycle is calculated based on the bus voltage, RMS output current, modulation ratio, and power factor, including:
[0107] Based on the RMS value of the output current, the modulation ratio, and the power factor, the average on-state loss of all IGBT devices in the traction inverter within one output fundamental cycle is calculated; based on the bus voltage, the RMS value of the output current, and the actual junction temperature of the IGBT devices, the average switching loss of all IGBT devices in the traction inverter within one output fundamental cycle is calculated; and the sum of the average on-state loss and the average switching loss is calculated to obtain the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle.
[0108] In some implementations, the average loss is discretized to obtain pulse waveforms corresponding to multiple discrete periods, including: converting the total average loss within one output fundamental period into a half-sine waveform; and discretizing the half-sine waveform at equal intervals to obtain rectangular pulse waveforms corresponding to multiple discrete periods.
[0109] In some implementations, Equation (8) is used to calculate the loss value corresponding to each pulse waveform.
[0110] In some implementations, based on the electrothermal model of the traction inverter IGBT devices and the loss values corresponding to each pulse waveform, the IGBT junction temperature for each discrete cycle is calculated, including:
[0111] Based on the electrothermal model of the IGBT device in the traction inverter and the loss value corresponding to each pulse waveform, the junction temperature rise, contact temperature rise, heat sink temperature rise, and cooling system water temperature of the IGBT device in each discrete cycle are calculated; the sum of the junction temperature rise, contact temperature rise, heat sink temperature rise, and cooling system water temperature of the IGBT device in each discrete cycle is calculated to obtain the IGBT junction temperature corresponding to each discrete cycle.
[0112] This embodiment is applicable to the calculation of IGBT junction temperature in rail traction inverters, enabling rapid calculation of IGBT device junction temperature with accurate results and minimal computational complexity.
[0113] Example 3
[0114] Based on the above embodiments, this embodiment provides an application example.
[0115] Step 1: Set the DC bus voltage V of the traction inverter dc The voltage is 1800V, and the effective value of the output current of the traction inverter is collected. Output current frequency f o ,like Figure 5 As shown, the modulation ratio m and power factor j are as follows: Figure 6 As shown, the radiator temperature T w Data such as Figure 7 As shown.
[0116] Step 2: Calculate the equivalent duty cycle under SVPWM modulation based on equation (1), for example, the third harmonic injection. Figure 8 As shown.
[0117] Step 3: Calculate the average on-state loss of the IGBT device based on equation (3). Figure 9 As shown.
[0118] Step 4: The average switching loss of the IGBT device for one output fundamental cycle, calculated based on equation (4), is as follows: Figure 10 As shown.
[0119] Step 5: Based on equations (7) and (8), obtain the discretized loss waveform as follows: Figure 11 As shown.
[0120] Step 6: Calculate the IGBT junction temperature for each discrete period based on the equivalent electrothermal model, as shown below. Figure 12 As shown.
[0121] Figure 13 The table below shows a comparison curve of the calculation results from different methods under the same conditions:
[0122]
[0123] It can be seen that the junction temperature calculated by the method proposed in this embodiment is basically consistent with the result obtained by the electrothermal simulation software. It also improves the junction temperature calculation speed and the accuracy of the calculation results, which is crucial for the life prediction and reliability assessment of traction inverters. However, it is significantly faster than the electrothermal simulation software. While traditional methods are less time-consuming, they have higher errors and inaccurate calculation results.
[0124] Example 4
[0125] Based on the above embodiments, this embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described in the above embodiments.
[0126] In some embodiments of this example, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the method described in the above embodiments.
[0127] In some embodiments of this example, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described in the above embodiments.
[0128] The processor may include, but is not limited to, one or more processors or microprocessors. Each processor may be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic component, for executing the methods in the above embodiments.
[0129] Computer-readable storage media can be implemented by any type of volatile or non-volatile storage device or a combination thereof. Computer-readable storage media may include, but are not limited to, random access memory (RAM), read-only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, and computer storage media (e.g., hard disks, floppy disks, solid-state drives, removable disks, CD-ROMs, DVD-ROMs, Blu-ray discs, etc.).
[0130] Computer-readable storage media may also store at least one computer-executable program / instruction, such as computer-readable instructions. Computer-readable storage media include, but are not limited to, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Computer-readable storage media may include, for example, read-only memory (ROM), hard disk, flash memory, etc. For example, a non-transitory computer-readable storage medium may be connected to a computing device such as a computer, and then, when the computing device executes the computer-readable instructions stored on the computer-readable storage medium, the various methods described above can be performed.
[0131] In addition, the computer device may include (but is not limited to) a data bus, an input / output (I / O) bus, a display, and input / output devices (e.g., keyboard, mouse, speakers, etc.).
[0132] The processor can communicate with external devices via the I / O bus through wired or wireless networks.
[0133] In one embodiment, the at least one computer-executable instruction may also be compiled into or comprise a software product / computer program product, wherein one or more computer-executable instructions are executed by a processor to perform the steps of the various functions and / or methods in the embodiments described herein.
[0134] In the embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.
[0135] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.
[0136] While the embodiments disclosed herein are as described above, the foregoing content is merely for the purpose of facilitating understanding of this disclosure and is not intended to limit this disclosure. Any person skilled in the art to which this disclosure pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope of this disclosure; however, the scope of patent protection of this disclosure shall still be determined by the scope defined in the appended claims.
Claims
1. A method for calculating the junction temperature of an IGBT in a traction inverter, characterized in that, include: Collect the bus voltage, RMS value of output current, output current frequency, modulation ratio, and power factor of the traction inverter; Based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor, calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle; The average loss is discretized to obtain pulse waveforms corresponding to multiple discrete periods. The loss value corresponding to each pulse waveform is calculated. The size of the discrete period is determined according to the set number of discrete periods and the output current frequency. Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, the IGBT junction temperature corresponding to each discrete cycle is calculated.
2. The method according to claim 1, characterized in that, Based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor, calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle, including: Based on the RMS value of the output current, the modulation ratio, and the power factor, calculate the average on-state loss of all IGBT devices in the traction inverter within one output fundamental cycle. Based on the bus voltage, the effective value of the output current and the actual junction temperature of the IGBT devices, calculate the average switching loss of all IGBT devices in the traction inverter within one output fundamental cycle. The sum of the average on-state loss and the average switching loss is calculated to obtain the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle.
3. The method according to claim 1, characterized in that, Discretizing the average loss yields pulse waveforms corresponding to multiple discrete periods, including: The total average loss within one output fundamental cycle is equivalent to a half-sine waveform. The half-sine waveform is dispersed at equal intervals to obtain rectangular pulse waveforms corresponding to multiple discrete periods.
4. The method according to claim 1, characterized in that, The loss value corresponding to each pulse waveform is calculated using the following formula: In the formula, P i The loss value corresponding to the pulse waveform in the i-th discrete period is described, where k represents the set number of discrete periods, and P av This represents the total average loss.
5. The method according to claim 1, characterized in that, The size of the discrete period is 1 / 2kf0, where f0 represents the output current frequency and k represents the set number of discrete periods.
6. The method according to claim 1, characterized in that, Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, the IGBT junction temperature corresponding to each discrete cycle is calculated, including: Based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform, the junction temperature rise, contact temperature rise, heat sink temperature rise and cooling system water temperature of the IGBT device in each discrete cycle are calculated. The IGBT junction temperature is obtained by calculating the sum of the junction temperature rise, contact temperature rise, heat sink temperature rise, and cooling system water temperature for each discrete cycle.
7. A device for calculating the junction temperature of an IGBT in a traction inverter, characterized in that, include: The data acquisition module is used to acquire the bus voltage, RMS value of output current, output current frequency, modulation ratio, and power factor of the traction inverter. The total loss calculation module is used to calculate the total average loss of all IGBT devices in the traction inverter within one output fundamental cycle based on the bus voltage, the effective value of the output current, the modulation ratio, and the power factor. The discrete equivalent module is used to discretize the average loss to obtain pulse waveforms corresponding to multiple discrete periods, and calculate the loss value corresponding to each pulse waveform. The size of the discrete period is determined according to the set number of discrete periods and the output current frequency. The junction temperature calculation module is used to calculate the IGBT junction temperature for each discrete cycle based on the electrothermal model of the traction inverter IGBT device and the loss value corresponding to each pulse waveform.
8. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 6.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 6.
10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 6.