Novel SiC MOSFET oscillation suppression circuit applied to half-bridge circuit

Abstract

The invention discloses a novel SiC MOSFET oscillation suppression circuit applied to a half-bridge circuit. The circuit is characterized in that a direct current bus is connected with a drain electrode of a second SiC MOSFET, one end of a second clamping capacitor and one end of a first feedback module, and a source electrode of the second SiC MOSFET is connected with a negative electrode of a second collection diode, a load end, a positive electrode of the first collection diode and a drain electrode of a first SiC MOSFET; the positive electrode of the second collection diode and the other end of the second clamping capacitor are connected with one end of the second feedback module, and the negative electrode of the first collection diode is connected with one end of the first clamping capacitor and the other end of the first feedback module; the low-voltage source is connected with the source electrode of the first SiC MOSFET, the other end of the second clamping capacitor and the other end of the second feedback module, overvoltage can be effectively suppressed by the circuit, and the clamping capacitor in the circuit can feed energy back to the direct current side through theinductance branch and participates in the circuit process only when overvoltage is generated.

Description

technical field [0001] The invention relates to a novel SiC MOSFET oscillation suppression circuit, in particular to a novel SiC MOSFET oscillation suppression circuit applied to a half-bridge circuit. Background technique [0002] SiC MOSFET has excellent performances such as fast switching speed, low on-resistance, and high operating temperature, and is widely used in high-frequency, high-efficiency, and high-power-density power electronic equipment. During the application process, the high-frequency characteristics of SiC MOSFETs often lead to overvoltage and oscillation, which reduces the utilization rate of DC voltage, exacerbates electromagnetic compatibility problems, and reduces the stability of the system. [0003] In power electronic devices, traditional methods to suppress overvoltage and oscillation during switching of SiC MOFETs can be divided into three categories: using gate drive active control, reducing power loop parasitic inductance, and using snubber circ...

AI Technical Summary

Problems solved by technology

Therefore, reducing the power loop inductance is the most direct method to reduce overvoltage and suppress oscillation. When using this method, the distribution of power loop inductance is relatively complicated, and the inductance can be reduced to about 20nH at the maximum, and there will still be a certain overvoltage produce

The snubber circuit is a cost-effective solution to the problem of overvoltage and power oscillation. In the half-bridge structure, the design of the decoupling capacitor is simple and widely used, but it is easy to cause low-frequency oscillation

Some scholars have proposed a high-order RC snubber circuit to solve the low-frequency problem. The performance of the high-order snubber circuit is better, but the design is complicated, and no matter what kind of phase bridge arm snubber is used, the parasitic inductance of the bus bar will be decoupled from the commutation circuit, and the conduction of the power device losses will increase significantly

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