A pulse width calculation method, and a double-pulse test system and method

Abstract

The application provides a pulse width calculation method based on a double-pulse test platform, comprising the following steps: setting a target current I target and a target voltage U target of a power circuit to which the double-pulse test platform is directed; acquiring a bus capacitance value C, a load inductance value L and a load parasitic resistance value R of the power circuit; and calculating a pulse width under the target current and the target voltage by using the bus capacitance value, the load inductance value and the load parasitic resistance value. The application uses MATLAB to solve transcendental equations on the basis of LabVIEW, so as to obtain an accurate charging pulse width and a set voltage, solve the problem of inaccurate voltage and current of a main power circuit, solve the problem of deviation between a module set test point and an actual working condition in double-pulse testing, and more accurately realize calibration of the main power circuit, thereby improving the test speed of the double-pulse test platform.

Description

Technical Field

[0001] This invention relates to the field of power module testing technology, and in particular to a pulse width calculation method and a dual-pulse testing system and method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the motor drive (referred to as electric drive) as one of the core components of new energy vehicles has received increasing attention and the reliability requirements are extremely high. Moreover, in the actual use scenarios of electric vehicles, such as frequent acceleration and braking, the operating conditions of the motor are also very complex.

[0003] In existing solutions, the dual-pulse test method can usually be used to dynamically test the power module in the electric drive, and a large number of dual-pulse tests can be performed on electric drives in automotive scenarios to obtain data on electric drives in automotive scenarios under different operating conditions, so as to provide the basic data required for optimized design.

[0004] Therefore, in the dual-pulse test scheme, the pulse parameters used to measure the dynamic characteristics of the power module, such as pulse width and pulse voltage, are very important test bases, and their accuracy largely determines the accuracy of the test results.

[0005] Therefore, obtaining accurate pulse parameters as a basis for testing has become the primary issue in the new energy vehicle industry for conducting dual-pulse testing. Summary of the Invention

[0006] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a pulse width calculation method and a dual-pulse testing system and method with higher accuracy.

[0007] This invention discloses a pulse width calculation method based on a dual-pulse test platform, comprising: setting the target current I of the power circuit targeted by the dual-pulse test platform. target and target voltage U target Obtain the bus capacitance C, load inductance L, and load parasitic resistance R of the power circuit; calculate the pulse width at the target current and target voltage using the bus capacitance, load inductance, and load parasitic resistance values.

[0008] Preferably, the step of calculating the pulse width at the target current and the target voltage using the bus capacitance, load inductance, and load parasitic resistance includes: solving the following two sets of equations to calculate the target current I. target and the target voltage U target The pulse width t below pulse :

[0009]

[0010] Among them, V set This is the set value for the initial voltage of the capacitor.

[0011] Preferably, the target current I is calculated and solved using MATLAB based on the two sets of equations. target and the target voltage U target The pulse width t below pulse .

[0012] The present invention also discloses a double-pulse test method, which uses LabVIEW to perform the double-pulse test based on the pulse width obtained by the above-mentioned pulse width calculation method.

[0013] The present invention also discloses a dual-pulse testing system for implementing the above-described dual-pulse testing method, comprising a hardware testing platform, a computing module connected to the hardware testing platform, and a testing module. The computing module calculates and obtains the pulse width of the target current and the target voltage of the hardware testing platform, and the testing module performs dual-pulse testing on the hardware testing platform based on the pulse width.

[0014] Preferably, it also includes a data acquisition module, which includes a data acquisition unit and an oscilloscope. The data acquisition unit acquires current and voltage data and uploads the current and voltage data to the oscilloscope, the calculation module, and the test module.

[0015] The present invention also discloses a computer-readable storage medium storing computer-executable instructions configured to be executed to perform the method.

[0016] Compared with existing technologies, the above technical solution has the following advantages:

[0017] 1. This invention addresses the dual-pulse test platform by using MATLAB to solve the transcendental equations based on LabVIEW, thereby obtaining accurate charging pulse width and set voltage. This solves the problem of insufficient accuracy of voltage and current in the main power circuit, thus resolving the issue of deviation between the module's set test points and actual operating conditions in dual-pulse testing. It enables more accurate calibration of the main power circuit and improves the testing speed of the dual-pulse test platform. Attached Figure Description

[0018] Figure 1 A schematic diagram of a test circuit for a power device according to an embodiment of the present invention;

[0019] Figure 2 A pulse diagram for the dual-pulse test provided by the present invention. Detailed Implementation

[0020] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0022] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0023] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0024] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0026] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0027] See appendix Figure 1 A schematic diagram of a test circuit for a power device according to one embodiment shows that, under ideal test conditions, an energy transfer relationship model between inductors and capacitors can be obtained. Based on this model, theoretical values ​​of pulse parameters can be calculated. However, the aforementioned pulse parameters are obtained under ideal conditions, while actual situations are not always ideal. This can lead to significant deviations in the test, reflecting differences between the set operating conditions and the actual operating conditions.

[0028] For example, several factors can contribute to the deviation: deviations in inductance and capacitance values; parasitic parameters in the circuit; various delays caused by imperfections in the device under test (DUT) and its driving characteristics; saturation voltage drop in the DUT; in actual operation, energy is not entirely provided by the capacitor, but also by the power supply; and voltage drop exists on the line from the power supply to the capacitor. Furthermore, the higher the voltage applied across the DUT, the greater the impact of the turn-on time deviation.

[0029] Therefore, the pulse parameters obtained based on the existing scheme may differ significantly from the pulse parameters under actual operating conditions when performing double-pulse testing under set operating conditions. This results in a large deviation between the dynamic characteristics of the power device under test obtained from the double-pulse test and the actual characteristics of the device itself. In other words, the accuracy of the test results is not high, and it may also bring fatal reliability risks to the power module designed and optimized based on these test results.

[0030] This invention optimizes the pulse width calculation method, introduces parasitic resistance parameters, and further optimizes the correlation between current and pulse width. By using the optimized two-equation system to calculate the pulse width, it solves the problem of insufficient accuracy of the main power circuit voltage and current based on RC modeling. This enables more accurate calibration of the main power circuit and improves the testing speed of the dual-pulse test platform.

[0031] Specifically, the present invention discloses a pulse width calculation method based on a dual-pulse test platform, comprising: setting the target current I of the power circuit targeted by the dual-pulse test platform. target and target voltage U target The system obtains the bus capacitance C, load inductance L, and load parasitic resistance R of the power circuit; and calculates the pulse width at the target current and target voltage using the bus capacitance, load inductance, and load parasitic resistance. Compared to existing technologies, this system incorporates consideration of the parasitic resistance R.

[0032] Furthermore, the pulse width calculation is made more accurate by optimizing the calculation formula: Solve the following two sets of equations to calculate the target current I. target and target voltage U target The pulse width t below pulse (Appendix) Figure 2 (Charging pulse in the middle):

[0033]

[0034] Among them, V set Here, x is the set value for the initial voltage of the capacitor, and x is the discharge time constant. y is the inductance and capacitance coefficient. The pulse width t can be solved by simultaneously solving the two transcendental equations mentioned above. pulse .

[0035] Furthermore, the target current I is calculated and solved using MATLAB based on the two equations. target and target voltage U target The pulse width t below pulse Specifically, MATLAB code is designed to allow for the rapid calculation of the pulse width t directly through MATLAB. pulse For example, in MATLAB, input the target current I. target Target voltage U target Inductance L, V set Equivalent value, the output pulse width t pulse (Appendix) Figure 2 (charging pulses in the middle).

[0036] Furthermore, this invention also discloses a dual-pulse testing method, which obtains an accurate pulse width t based on the pulse width calculation method described above. pulse Then, the pulse width t pulse The data is input into a test platform for testing; this invention uses LabVIEW for testing.

[0037] The present invention also discloses a dual-pulse testing system for implementing the above-mentioned dual-pulse testing method, including a hardware testing platform, a computing module and a testing module connected to the hardware testing platform. The computing module calculates and obtains the pulse width under the target current and target voltage of the hardware testing platform, and the testing module performs dual-pulse testing on the hardware testing platform based on the pulse width.

[0038] Furthermore, it also includes a data acquisition module, which includes a data acquisition unit and an oscilloscope. The data acquisition unit collects current and voltage data and uploads the current and voltage data to the oscilloscope, the calculation module, and the test module.

[0039] The hardware testing platform may include, for example, a transformer, a rectifier, a capacitor, a charging resistor, a relay, a multilayer busbar, power devices, and a heating plate. The transformer, rectifier, charging resistor, and relay are connected in series to serve as the power input for the capacitor. The capacitor and power devices are respectively mounted on the multilayer busbar, and the charging resistor is connected in parallel with the capacitor. A controller receives instructions from the host computer and sends trigger pulse and latching commands to the power devices via optical fiber. The host computer, acting as the control command layer, transmits test conditions to the controller via a communication interface and transmits sampling conditions to the data acquisition unit and oscilloscope via the same interface. In this invention, LabVIEW is selected as the host computer, and a DSP controller is used as the controller.

[0040] An optional specific embodiment of a pulse testing method:

[0041] S1. Install the test module onto the stacked busbar, clamp the test probe onto the terminal to be tested, check the test circuit, and ensure that the control line and power line are isolated from the heating plate.

[0042] S2. Check if there are any short circuits in the wiring of the hardware test platform, and then check if the communication cable between the DSP controller and the computer, the drive power supply cable, and the computer and the oscilloscope are correctly connected.

[0043] S3. Turn on the LabVIEW host computer on the computer, then close the auxiliary power main switch of the hardware test platform, and then close the power switches of the oscilloscope, controller and drive in sequence.

[0044] S4. Set the temperature controller to the desired test temperature and close the temperature power switch of the temperature controller.

[0045] S5. Run the LabVIEW main interface, enter the test information, and click Start Test to enter the oscilloscope and parameter setting interface;

[0046] S6. Set the test temperature, test voltage and test current in the test condition input field, and then set the sampling conditions in the oscilloscope settings field.

[0047] S7. After closing the main power air switch, the dual-pulse test is completed automatically, and the oscilloscope data is automatically transmitted to the computer.

[0048] The present invention also discloses a computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured to be executed in a real-time manner.

[0049] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for calculating pulse width based on a dual-pulse test platform, characterized in that, include: Set the target current for the power circuit targeted by the dual-pulse test platform. and target voltage ; Obtain the bus capacitance value of the power circuit. Load inductance value Load parasitic resistance value ; The pulse width at the target current and the target voltage is calculated using the bus capacitance, load inductance, and load parasitic resistance. The step of calculating the pulse width at the target current and target voltage using the bus capacitance, load inductance, and load parasitic resistance includes: Solve the following two systems of equations to calculate the target current. and the target voltage The pulse width below : ； ； in, This is the set value for the initial voltage of the capacitor. , .

2. The pulse width calculation method for the dual-pulse test platform according to claim 1, characterized in that, The target current is calculated and solved using MATLAB based on the two equations. and the target voltage The pulse width below .

3. A double-pulse testing method, characterized in that, The double-pulse test is performed using LabVIEW based on the pulse width calculation method described in any one of claims 1-2.

4. A dual-pulse testing system, characterized in that, The method for implementing the dual-pulse test method according to claim 3 includes a hardware test platform, a computing module and a test module connected to the hardware test platform. The computing module calculates and obtains the pulse width of the target current and the target voltage of the hardware test platform, and the test module performs a dual-pulse test on the hardware test platform based on the pulse width.

5. The dual-pulse testing system according to claim 4, characterized in that, It also includes a data acquisition module, which includes a data acquisition unit and an oscilloscope. The data acquisition unit acquires current and voltage data and uploads the current and voltage data to the oscilloscope, the calculation module, and the test module.

6. A computer-readable storage medium, characterized in that, The device stores computer-executable instructions configured to, when executed, perform the method according to any one of claims 1 to 2.

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