Method for testing switching voltage loss of IPM (Intelligent Power Module)

Abstract

The invention discloses a method for testing the switching voltage loss of an IPM (Intelligent Power Module), and relates to the technical field of the IPM. The method comprises the following steps: entering a control module, carrying out current control on a resistive load through a PI (Proportional Integral) controller, setting a test current frequency to be 0.1 Hz, and setting two switching frequencies F1 and F2 at the same time; and entering the test module, and passing through the conditions of fixed dead time and output current. According to the invention, the total voltage loss under different switching frequencies F1 and F2 is calculated through the first calculation unit according to a specific formula, the switching voltage loss is calculated through the second calculation unit, and due to the fact that the switching voltage loss is in direct proportion to the switching frequency of the power device, when only the switching frequency is changed, and dead time and output current are not changed, the switching frequency is changed. The dead-time voltage loss and the conduction voltage loss are not changed, so that the dead-time voltage loss and the conduction voltage loss can be eliminated by subtracting the total voltage loss of the double switching frequency from the total voltage loss of the double switching frequency, and the switching voltage loss can be accurately obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of IPM intelligent power modules, and in particular to a method for testing switch voltage loss of an IPM intelligent power module. Background Art

[0002] IPM intelligent power modules are widely used in modern power electronic systems. In actual operation, the total voltage loss of IPM intelligent power modules includes conduction voltage loss, switching voltage loss and dead time voltage loss. Switching voltage loss is generated during the turn-on and turn-off processes of power devices. At the moment of power device turn-on, it is necessary to overcome the influence of factors such as the device's junction capacitance and line inductance, which will produce certain voltage spikes and energy loss; in the turn-off process, due to the recombination of carriers and the effect of line parasitic parameters, voltage loss will also be caused. Moreover, the switching voltage loss is proportional to the number of switching times of the power device. The higher the switching frequency, the more switching times per unit time, and the greater the switching voltage loss.

[0003] Currently, in the existing technology, due to the switching voltage loss of the IPM intelligent power module, during actual use, this loss will cause output voltage deviation, thereby causing control error. If the switching voltage loss cannot be effectively tested, it will affect the accuracy and stability of the entire control system and reduce the performance of the equipment.

[0004] Therefore, a test method for IPM intelligent power module switch voltage loss is proposed to solve the above problem. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for testing the switch voltage loss of an IPM intelligent power module to solve the problems raised in the above background.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for testing the voltage loss of an IPM intelligent power module switch, comprising the following steps: Enter the control module, use the PI controller to control the current of the resistive load, set the test current frequency to 0.1Hz, and set two switching frequencies F1 and F2; By adopting the above technical solution and setting the test current frequency to 0.1Hz, the interference of motor inductance on the measurement results can be effectively reduced, and precise control of the test current can be achieved, ensuring that the test is carried out under stable current conditions, thereby improving the accuracy of the test results.

[0007] Enter the test module, and measure and calculate the total voltage Vloss1 and Vloss2 using two switching frequencies F1 and F2 under fixed dead time and output current. The switching voltage loss is calculated based on Vloss1 and Vloss2. By adopting the above technical solution, under fixed conditions, the total voltage loss at different switching frequencies F1 and F2 is calculated using a specific formula using a first calculation unit, and the switching voltage loss is calculated using a second calculation unit. Since the switching voltage loss is proportional to the number of switching times of the power device, when only the switching frequency is changed and the dead time and output current are not changed, the dead time voltage loss and the conduction voltage loss remain unchanged. Therefore, the total voltage loss of 1 times the switching frequency is subtracted from the total voltage loss of 2 times the switching frequency, the dead time and conduction voltage losses can be eliminated, and the switching voltage loss can be accurately obtained.

[0008] Enter the calibration module and repeatedly test the IPM intelligent power module switch voltage loss under the same test conditions. Record the switch voltage loss value obtained each time and calculate the standard deviation of the switch voltage loss value to determine the stability of the test data.

[0009] By adopting the above technical solution, the repeating unit repeatedly tests the IPM intelligent power module switch voltage loss under the same test conditions and records the switch voltage loss value each time to avoid errors caused by the randomness of a single test, and at the same time calculates the standard deviation of multiple switch voltage loss values.

[0010] Furthermore, the test module includes a control unit, an acquisition module, a first calculation unit and a second calculation unit.

[0011] Furthermore, the control module is used to fix the dead time through PWM signal generator hardware, and the output current is fixed through a PI controller.

[0012] Furthermore, the acquisition module is used to monitor the voltage and current changes during the switching process in real time through a power analyzer, and then calculate the power loss during the switching process, and then convert the switching loss voltage by combining the time integration method, and observe the voltage waveform during the dead time through an oscilloscope, and measure the voltage value and related current value during the dead time by cooperating with a current probe, calculate the power loss during the dead time according to the power formula, and then obtain the dead time loss voltage, and accurately measure the on-resistance value with a milliohm meter, and then combine the actual current value in the circuit to calculate the on-resistance voltage according to the formula V=IR, where I represents current and R represents on-resistance.

[0013] By adopting the above technical solution, the voltage and current changes of the switching process are monitored in real time with the help of a power analyzer, the switching loss voltage is calculated by combining time integration, and the dead zone data is measured with an oscilloscope and a current probe to calculate the dead zone loss voltage. The on-resistance can also be accurately measured to calculate the on-loss voltage, and the module operation data can be fully obtained to provide a stable foundation for the follow-up.

[0014] Furthermore, the first calculation unit is used to calculate the total voltages Vloss1 and Vloss2 when the switching frequencies are in the F1 and F2 states, and the calculation steps are as follows: Step 1: Calculate the total voltage V loss 1 when the switching frequency is in the F1 state. The calculation formula is as follows: V1=V a +V b +V c ; Where V1 represents the total voltage loss V1 at the switching frequency F1, V a Represents the switching loss at the switching frequency F1, V b Represents dead zone loss, V c represents conduction loss; Step 2: Calculate the total voltage V loss 2 when the switching frequency is in the F2 state. The calculation formula is as follows: V2=V z +V b +V c ; Where V2 represents the total voltage V loss at the switching frequency F2 state, V z Represents the switching loss at the switching frequency F2, V b Represents dead zone loss, V c Represents conduction loss.

[0015] Furthermore, the second calculation unit calculates the switch voltage loss based on Vloss1 and Vloss2, wherein Vloss2 is equal to 2 times Vloss1, and the calculation formula is as follows: V O =V2-V1; Among them, V O represents the calculated switching voltage loss, V2 represents the total voltage V loss 2 when the switching frequency is in the F2 state, and V1 represents the total voltage V loss 1 when the switching frequency is in the F1 state.

[0016] Furthermore, the calibration module includes a repeating unit, a standard unit and a comparison unit.

[0017] Furthermore, the repeating unit is used to repeatedly test the switch voltage loss of the IPM intelligent power module under the same test conditions for multiple times, and record the switch voltage loss value obtained each time.

[0018] Furthermore, the calibration unit is used to calculate the standard deviation of the voltage loss values ​​through multiple switching operations, and the calculation formula is as follows: Where σ represents the standard deviation, n represents the number of switch voltage loss values ​​involved in the calculation, and X i represents the i-th measurement value, Represents the average value of the switching voltage loss values ​​involved in the calculation.

[0019] Furthermore, the comparison unit is used to compare the calculated standard deviation with a set standard deviation threshold (0.02v). When the calculated standard deviation is lower than the standard deviation threshold, it indicates that the data is stable; if the calculated standard deviation is higher than the set threshold, it indicates that the data is abnormal.

[0020] By adopting the above technical solution, the comparison unit compares the calculated standard deviation with the set standard deviation threshold. When the standard deviation is lower than the threshold, it indicates that the test data is stable and the results are reliable; if it is higher than the threshold, it indicates that the data is abnormal and there is a problem that needs further investigation, which effectively ensures the stability and reliability of the test data.

[0021] The present invention has the following beneficial effects: 1. In the present invention, the control module uses a PI controller to control the current of the resistive load and sets the test current frequency to 0.1 Hz, which can effectively reduce the interference of the motor inductance on the measurement results, realize precise control of the test current, ensure that the test is carried out under stable current conditions, and improve the accuracy of the test results. In addition, the dead time is fixed by the PWM signal generator hardware, and the output current is fixed by the PI controller, which ensures the consistency of the test conditions from the hardware level. During multiple tests, the errors caused by dead time and output current fluctuations are avoided, and the reliability and repeatability of the test results are enhanced. At the same time, the acquisition module uses a power analyzer to monitor the voltage and current changes of the switching process in real time, combines time integration to calculate the switching loss voltage, uses an oscilloscope with a current probe to measure the dead zone data to calculate the dead zone loss voltage, and can also accurately measure the on-resistance to calculate the on-loss voltage, and comprehensively obtain the module operation data.

[0022] 2. In the present invention, the total voltage loss at different switching frequencies F1 and F2 is calculated using a first calculation unit according to a specific formula under fixed regulation, and the switching voltage loss is calculated using a second calculation unit. Since the switching voltage loss is proportional to the number of switching times of the power device, when only the switching frequency is changed without changing the dead time and the output current, the dead time voltage loss and the conduction voltage loss remain unchanged. Therefore, the dead time and conduction voltage losses can be eliminated by subtracting the total voltage loss of 1 times the switching frequency from the total voltage loss of 2 times the switching frequency, thereby accurately obtaining the switching voltage loss.

[0023] 3. In the present invention, the repetitive unit repeatedly tests the IPM intelligent power module switch voltage loss under the same test conditions and records the switch voltage loss value each time to avoid errors caused by the randomness of a single test. At the same time, the standard deviation of the multiple switch voltage loss values ​​is calculated, and the comparison unit compares the calculated standard deviation with the set standard deviation threshold. When the standard deviation is lower than the threshold, it indicates that the test data is stable and the result is reliable; if it is higher than the threshold, it indicates that the data is abnormal and there is a problem that needs further investigation, which effectively ensures the stability and reliability of the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a method for testing switch voltage loss of an IPM intelligent power module according to the present invention; Figure 2 This is a framework diagram of a method for testing switch voltage loss of an IPM intelligent power module according to the present invention; Figure 3 This is a schematic diagram of the error voltage compensation measurement principle of a test method for IPM intelligent power module switch voltage loss in the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Implementation See also Figure 1 and Figure 2 The present invention provides a technical solution: a method for testing the switch voltage loss of an IPM intelligent power module, comprising the following steps: Enter the control module, use the PI controller to control the current of the resistive load, set the test current frequency to 0.1Hz, and set two switching frequencies F1 and F2; Specifically, such as Figure 3 As shown in the figure, when the resistance value is known, the voltage control error of the inverter is interference. The PI controller is used to suppress the interference due to the voltage control error and follow the current command value. At this time, the output of the PI controller is the voltage control error compensation mode. However, because the condition R0=R is established, R0 here is the load resistance value set in the control program. In actual use, it will be affected by the motor inductance. In order to reduce the influence of inductive reactance, the frequency of the test current can be reduced. Therefore, the frequency of the measured current is set to about 0.1Hz.

[0027] Enter the test module, and measure and calculate the total voltage Vloss1 and Vloss2 using two switching frequencies F1 and F2 under fixed dead time and output current. The switching voltage loss is calculated based on Vloss1 and Vloss2. Specifically, the switching voltage loss is caused by the switching signal of the power device and is proportional to the number of switching times of the power device. Based on this characteristic, by only changing the switching frequency without changing the dead time and the output current, the dead time voltage loss and the on-state voltage loss remain unchanged. Therefore, the total voltage loss of 1 times the switching frequency can be subtracted from the total voltage loss of 2 times the switching frequency to eliminate the dead time voltage loss and the on-state voltage loss, thereby obtaining the switching voltage loss.

[0028] Enter the calibration module and repeatedly test the IPM intelligent power module switch voltage loss under the same test conditions. Record the switch voltage loss value obtained each time and calculate the standard deviation of the switch voltage loss value to determine the stability of the test data.

[0029] The testing module includes a control unit, an acquisition module, a first calculation unit and a second calculation unit.

[0030] The control module is used to fix the dead time through the PWM signal generator hardware, and the output current is fixed through the PI controller.

[0031] The acquisition module is used to monitor the voltage and current changes during the switching process in real time through a power analyzer, and then calculate the power loss during the switching process. The time integration method is then used to convert the switching loss voltage. The voltage waveform during the dead time is observed through an oscilloscope. The voltage value and related current value during the dead time are measured by using a current probe. The power loss during the dead time is calculated according to the power formula, and the dead time loss voltage is obtained. The milliohm meter accurately measures the on-resistance value. Combined with the actual current value in the circuit, the on-state loss voltage is calculated according to the formula V=IR, where I represents current and R represents on-resistance.

[0032] The first calculation unit is used to calculate the total voltage Vloss1 and Vloss2 under the switching frequency F1 and F2 states. The calculation steps are as follows: Step 1: Calculate the total voltage V loss 1 when the switching frequency is in the F1 state. The calculation formula is as follows: V1=V a +V b +V c ; Where V1 represents the total voltage loss V1 at the switching frequency F1, V a Represents the switching loss at the switching frequency F1, V b Represents dead zone loss, Vc represents conduction loss; Step 2: Calculate the total voltage V loss 2 when the switching frequency is in the F2 state. The calculation formula is as follows: V2=V z +V b +V c ; Where V2 represents the total voltage V loss at the switching frequency F2 state, V z Represents the switching loss at the switching frequency F2, V b Represents dead zone loss, V c Represents conduction loss.

[0033] The second calculation unit calculates the switch voltage loss based on Vloss1 and Vloss2, where Vloss2 is equal to 2 times Vloss1. The calculation formula is as follows: V O =V2-V1; Among them, V O represents the calculated switching voltage loss, V2 represents the total voltage V loss 2 when the switching frequency is in the F2 state, and V1 represents the total voltage V loss 1 when the switching frequency is in the F1 state.

[0034] In this embodiment, the control module uses a PI controller to control the current of the resistive load and sets the test current frequency to 0.1 Hz, which can effectively reduce the interference of the motor inductance on the measurement results, realize the precise control of the test current, ensure that the test is carried out under stable current conditions, improve the accuracy of the test results, and fix the dead time of the PWM signal generator hardware and the output current of the PI controller to ensure the consistency of the test conditions from the hardware level. In the process of multiple tests, the errors caused by the dead time and output current fluctuations are avoided, and the reliability and repeatability of the test results are enhanced. At the same time, the acquisition module uses the power analyzer to monitor the voltage and current changes of the switching process in real time. The switching loss voltage is calculated by time integration, and the dead zone data is measured with an oscilloscope and a current probe to calculate the dead zone loss voltage. The on-resistance can also be accurately measured to calculate the on-state loss voltage, and the module operation data is fully acquired. The total voltage loss at different switching frequencies F1 and F2 is calculated according to a specific formula through the first calculation unit, and the switching voltage loss is calculated through the second calculation unit. Since the switching voltage loss is proportional to the number of switching times of the power device, when only the switching frequency is changed without changing the dead zone time and output current, the dead zone time voltage loss and the on-state voltage loss remain unchanged. Therefore, the total voltage loss of 1 times the switching frequency is subtracted from the total voltage loss of 2 times the switching frequency to eliminate the dead zone and on-state voltage loss, and accurately obtain the switching voltage loss.

[0035] Implementation 2 See also Figure 1 and Figure 2The present invention provides a technical solution: the calibration module includes a repeating unit, a standard unit and a comparison unit.

[0036] The repeat unit is used to repeatedly test the switch voltage loss of the IPM intelligent power module under the same test conditions and record the switch voltage loss value obtained each time.

[0037] The calibration unit is used to calculate the standard deviation of the voltage loss value through multiple switching operations. The calculation formula is as follows: Where σ represents the standard deviation, n represents the number of switch voltage loss values ​​involved in the calculation, and X i represents the i-th measurement value, Represents the average value of the switching voltage loss values ​​involved in the calculation.

[0038] The comparison unit is used to compare the calculated standard deviation with the set standard deviation threshold (0.02v). When it is lower than the standard deviation threshold, it means the data is stable. If it is higher than the set threshold, it means the data is abnormal.

[0039] In this embodiment, the repetition unit repeatedly tests the IPM intelligent power module switch voltage loss under the same test conditions and records the switch voltage loss value each time to avoid errors caused by the randomness of a single test. At the same time, the standard deviation of the multiple switch voltage loss values ​​is calculated, and the comparison unit compares the calculated standard deviation with the set standard deviation threshold. When the standard deviation is lower than the threshold, it indicates that the test data is stable and the result is reliable; if it is higher than the threshold, it indicates that the data is abnormal and there are problems that need further investigation, including slight fluctuations in the test environment, errors in the instrument, etc. The cause needs to be further investigated, which effectively ensures the stability and reliability of the test data.

[0040] In the present invention, a test method for the switch voltage loss of an IPM intelligent power module is provided. The control module uses a PI controller to control the current of a resistive load and sets the test current frequency to 0.1 Hz, which can effectively reduce the interference of the motor inductance on the measurement result, realize the precise regulation of the test current, ensure that the test is carried out under stable current conditions, improve the accuracy of the test result, and fix the dead time of the PWM signal generator hardware and the output current of the PI controller, thereby ensuring the consistency of the test conditions from the hardware level. In the process of multiple tests, the errors caused by the dead time and the output current fluctuation are avoided, and the reliability and repeatability of the test results are enhanced. At the same time, the acquisition module uses a power analyzer to monitor the voltage and current changes of the switching process in real time, combines time integration to calculate the switch loss voltage, uses an oscilloscope with a current probe to measure the dead zone data to calculate the dead zone loss voltage, and can also accurately measure the on-resistance to calculate the on-loss voltage, comprehensively obtain the module operation data, and calculate according to a specific formula through the first calculation unit. The total voltage loss under different switching frequencies F1 and F2 is calculated, and the switching voltage loss is calculated by the second calculation unit. Since the switching voltage loss is proportional to the number of switching times of the power device, when only the switching frequency is changed without changing the dead time and the output current, the dead time voltage loss and the conduction voltage loss remain unchanged. Therefore, the total voltage loss at 2 times the switching frequency is subtracted from the total voltage loss at 1 times the switching frequency to eliminate the dead time and conduction voltage loss, and accurately calculate the switching voltage loss; the repetition unit repeatedly tests the switching voltage loss of the IPM intelligent power module under the same test conditions and records the switching voltage loss value each time to avoid errors caused by the randomness of a single test. At the same time, the standard deviation of the multiple switching voltage loss values ​​is calculated, and the comparison unit compares the calculated standard deviation with the set standard deviation threshold. When the standard deviation is lower than the threshold, it indicates that the test data is stable and the results are reliable; if it is higher than the threshold, it indicates that the data is abnormal and there is a problem that needs further investigation, effectively ensuring the stability and reliability of the test data.

[0041] It should be noted that, in this document, relational terms such as first and second, etc., are used only 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 terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0042] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing switch voltage loss of an IPM intelligent power module, characterized in that: The following steps are involved: Enter the control module, use the PI controller to control the current of the resistive load, set the test current frequency to 0.1Hz, and set two switching frequencies F1 and F2; Enter the test module, and measure and calculate the total voltage Vloss1 and Vloss2 using two switching frequencies F1 and F2 under fixed dead time and output current. The switching voltage loss is calculated based on Vloss1 and Vloss2. Enter the calibration module and repeatedly test the IPM intelligent power module switch voltage loss under the same test conditions. Record the switch voltage loss value obtained each time and calculate the standard deviation of the switch voltage loss value to determine the stability of the test data.

2. The method for testing switch voltage loss of an IPM intelligent power module according to claim 1, characterized in that: The test module includes a control unit, an acquisition module, a first calculation unit and a second calculation unit.

3. The method for testing switch voltage loss of an IPM intelligent power module according to claim 2, characterized in that: The control module is used to fix the dead time through PWM signal generator hardware, and the output current is fixed through a PI controller.

4. The method for testing switch voltage loss of an IPM intelligent power module according to claim 2, wherein: The acquisition module is used to monitor the voltage and current changes during the switching process in real time through a power analyzer, thereby calculating the power loss during the switching process, and then converting the switching loss voltage using a time integration method. The voltage waveform during the dead time is observed through an oscilloscope, and the voltage value and related current value during the dead time are measured by a current probe. The power loss during the dead time is calculated according to the power formula, and the dead time loss voltage is obtained. The milliohm meter accurately measures the on-resistance value, and then combines the actual current value in the circuit to calculate the on-loss voltage according to the formula V=IR, where I represents current and R represents on-resistance.

5. The method for testing switch voltage loss of an IPM intelligent power module according to claim 2, wherein: The first calculation unit is used to calculate the total voltage Vloss1 and Vloss2 under the switching frequency F1 and F2 states. The calculation steps are as follows: Step 1: Calculate the total voltage V loss 1 when the switching frequency is in the F1 state. The calculation formula is as follows: V1=V a +V b +V c ; Where V1 represents the total voltage loss V1 at the switching frequency F1, V a Represents the switching loss at the switching frequency F1, V b Represents dead zone loss, V c represents conduction loss; Step 2: Calculate the total voltage V loss 2 when the switching frequency is in the F2 state. The calculation formula is as follows: V2=V z +V b +V c ; Where V2 represents the total voltage V loss at the switching frequency F2 state, V z Represents the switching loss at the switching frequency F2, V b Represents dead zone loss, V c Represents conduction loss.

6. The method for testing switch voltage loss of an IPM intelligent power module according to claim 2, wherein: The second calculation unit calculates the switch voltage loss based on Vloss1 and Vloss2, where Vloss2 is equal to 2 times Vloss1, and the calculation formula is as follows: V O =V2-V1; Among them, V O represents the calculated switching voltage loss, V2 represents the total voltage V loss 2 when the switching frequency is in the F2 state, and V1 represents the total voltage V loss 1 when the switching frequency is in the F1 state.

7. The method for testing switch voltage loss of an IPM intelligent power module according to claim 1, characterized in that: The calibration module includes a repeating unit, a standard unit and a comparison unit.

8. The method for testing switch voltage loss of an IPM intelligent power module according to claim 7, characterized in that: The repeating unit is used to repeatedly test the switch voltage loss of the IPM intelligent power module under the same test conditions and record the switch voltage loss value obtained each time.

9. The method for testing switch voltage loss of an IPM intelligent power module according to claim 7, characterized in that: The calibration unit is used to calculate the standard deviation of the voltage loss values ​​through multiple switching operations. The calculation formula is as follows: Where σ represents the standard deviation, n represents the number of switch voltage loss values ​​involved in the calculation, and X i represents the i-th measurement value, Represents the average value of the switching voltage loss values ​​involved in the calculation.

10. The method for testing switch voltage loss of an IPM intelligent power module according to claim 7, characterized in that: The comparison unit is used to compare the calculated standard deviation with a set standard deviation threshold (0.02v). When the standard deviation is lower than the threshold, it means the data is stable. If it is higher than the threshold, it means the data is abnormal.

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