Method for extracting stray parameters of laminated bus bar based on frequency characteristics of SiC MOSFET

Abstract

The invention discloses a method for extracting stray parameters of a laminated bus bar based on frequency characteristics of a SiC MOSFET. The method comprises the following steps of firstly settingup a SiC MOSFET double-pulse test platform, and externally connecting the section under test of the laminated bus bar to the test platform; connecting multiple sets of additional capacitors in parallel at both ends of the SiC MOSFET, using the frequency information of oscillation in the off-voltage waveform of the SiC MOSFET before and after the additional capacitors are connected in parallel to obtain the resonance angular frequencies of multiple sets of equivalent circuit models, and further calculating the stray inductance and parasitic capacitance of the laminated bus bar to achieve the extraction of stray parameters of the laminated bus bar. The invention utilizes the high switching speed characteristics of the SiC MOSFET to excite obvious off-voltage oscillations. Compared with the traditional indirect measurement method, the measurement deviation caused by human factors is reduced. In addition, the invention can measure the stray inductance and parasitic capacitance in any section of the laminated bus bar, and the measurement is more flexible and comprehensive.

Description

technical field [0001] The invention relates to the technical field of power electronics testing, in particular to a method for extracting stray parameters of laminated busbars based on the frequency characteristics of SiC MOSFETs. Background technique [0002] As a common electrical connector in power electronic converters, laminated busbars are widely used in high-voltage and large-capacity occasions such as flexible direct current transmission, new energy power generation and grid connection. The application of laminated busbars greatly reduces the stray inductance in the power device commutation circuit, that is, the power device to the DC support capacitor circuit. The device has a high switching speed, and the switching process has a high current change rate di / dt During the turn-off process, the voltage spikes borne by the device are reduced, thereby reducing switching loss and electromagnetic interference problems, and ensuring the reliable operation of the device an...

AI Technical Summary

Problems solved by technology

However, whether it is a differential method or an integral method, there are the following problems in measuring stray parameters: 1. It does not have the ability to measure the parasitic capacitance of laminated busbars; 2. It is necessary to manually select measurement points or integration intervals. Affect the accuracy of the test; 3. The supporting capacitors and power devices used in the test are located on the laminated busbar, and only the stray inductance of the commutation circuit of the power device can be measured, and the stray in any section of the laminated busbar cannot be extracted. inductance

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