IGBT switch instant surge suppression apparatus and method for PWM current converting system

Abstract

The invention provides an IGBT switch instant surge suppression apparatus and method for a PWM current converting system. The method comprises the following steps: a total stray inductance value LTotal of the PWM current converting system in a stray inductance extraction time slot t1-t2 is obtained, an IGBT equivalent circuit model is built based on the total stray inductance value LTotal and characteristics of the PWM current converting system, the IGBT equivalent circuit model comprises a non-inductive absorbing thin film capacitor CSnubber used for suppressing IGBT switch instant surges, a direct current bus stray inductance value LDC-Link of the PWM current converting system is obtained based on the IGBT equivalent circuit model, a capacitance value of the non-inductive absorbing thin film capacitor CSnubber is obtained based on the direct current bus stray inductance value LDC-Link, an IGBT surge voltage change preset value [delta]V2 and an IGBT work current IC, and the IGBT switch instant surges can be suppressed via the non-inductive absorbing thin film capacitor CSnubber. The IGBT switch instant surge suppression apparatus and method for the PWM current converting system can be used for effectively suppressing the IGBT switch instant surges.

Description

technical field [0001] The invention relates to the technical field of PWM conversion, in particular to an IGBT switch transient surge suppression device of a PWM conversion system and a method for suppressing an IGBT switch transient surge of a PWM conversion system. Background technique [0002] In the PWM converter system, the IGBT usually operates in a high-frequency switching state. The high di / dt and the parasitic inductance of the DC bus work together to cause a serious inter-electrode voltage spike when the IGBT is turned off transiently, even exceeding the IGBT. The voltage withstand value, such as figure 1 As shown, thereby deteriorating the electrical stress, switching loss and electromagnetic interference of the IGBT. At the same time, the existence of system stray parameters may also lead to changes in the equivalent topology and parameters of the main circuit, which in turn will lead to deviations in the impedance characteristics of the system, resulting in di...

AI Technical Summary

Problems solved by technology

Such as the Hefner model and the Kraus model rely on the internal physical mechanism of the component, which can accurately characterize the dynamic and static performance of the IGBT. However, it needs to be based on a clear understanding of its internal structure, and the physical model parameters are many and complex, and involve a lot of calculus transform

As far as the functional model is concerned, it only needs to take into account the external characteristics of the IGBT, so the physical meaning is not clear, which is not conducive to parameter adjustment and extraction

However, in the traditional stray parameter extraction method, the various stages of the switching transient process are not distinguished in detail, which can easily lead to inaccurate parameter extraction, and thus cannot scientifically attenuate the surge voltage, accompanied by serious oscillation phenomenon

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