A sic MOSFET parallel drive circuit with dynamic adjustment of gate-source impedance and active current sharing

Abstract

The invention discloses a SiCMOSFET parallel drive circuit with dynamic adjustment of gate-source impedance and active current sharing. The current is indirectly measured by measuring the voltage drop of the shunt; the isolation and differential amplification of the measurement signal are realized by using a differential amplification isolation circuit; the current difference is used The feedback circuit performs current difference processing and signal feedback; NPN transistors, resistors, and capacitors are used to form a gate-source low-impedance circuit, and combined with the feedback signal, the dynamic adjustment of the drive loop impedance is realized. The invention can effectively suppress the uneven current phenomenon caused by the inconsistency of device parameters and large stray inductance in the circuit, achieve the purpose of active current equalization, and has the characteristics of good adjustment performance, strong real-time performance and low cost.

Description

technical field [0001] The invention relates to a SiC MOSFET parallel driving circuit. Background technique [0002] With the development of power electronics technology, in recent years, new materials have begun to be applied to power devices, among which SiC MOSFET is the typical representative. SiC MOSFET is the third-generation wide bandgap semiconductor power device. Compared with traditional Si power devices, SiC MOSFET has the advantages of high switching frequency, low switching loss, low on-state resistance, strong voltage resistance, and high temperature resistance. It can adapt to Applications with high voltage level and high power density. [0003] Although SiC MOSFET is widely used due to its excellent performance, due to the limitation of production process and manufacturing cost, compared with IGBT power devices, the flow capacity of a single SiC MOSFET is limited. In actual industrial production, it is often necessary to adopt multiple SiC MOSFET single-tub...

AI Technical Summary

Problems solved by technology

Due to the differences in device parameters, differences in power loop parasitic parameters, and differences in drive loop parameters, etc., when SiC MOSFETs are connected in parallel, there will be problems with unbalanced currents in each branch, including dynamic current imbalances caused by switching processes and static currents after conduction. The imbalance of current may cause harm to SiC MOSFET devices, mainly reflected in the difference in loss and current stress, which will cause a single device to be damaged due to loss and excessive stress for a long time, and even affect the safe operation of the entire system

[0004] Traditionally, measures such as coupled inductors are used to share current. Although the method is simple and the effect is good, it increases the voltage overshoot of the system and sacrifices the rising speed of the turn-on current.

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