A voltage-controlled semiconductor device series voltage equalization method and voltage equalization circuit

Abstract

The present invention relates to the technical field of power electronics, and in particular to a voltage equalization method and a voltage equalization circuit for series connection of voltage-controlled semiconductor devices, wherein the method includes: collecting the voltage signal between the first pole and the second pole of each semiconductor device connected in series , calculate a reference voltage signal according to the voltage signals of multiple semiconductor devices, respectively calculate the error compensation signals between the multiple voltage signals and the reference voltage signal; feedback control the voltage control signal output by the corresponding controllable drive power supply according to the error compensation signal, So that multiple semiconductor devices are turned on or off at the same time, so as to achieve the effect of voltage equalization. The method reduces the introduction of stray parameters and also reduces the cost, and at the same time has small power loss, high efficiency and good voltage equalization effect.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a voltage equalizing method and a voltage equalizing circuit of a voltage-controlled semiconductor device in series. Background technique [0002] With the development of semiconductor technology, voltage-controlled power semiconductor devices represented by IGBTs and MOSFETs are widely used in high-power applications such as flexible DC transmission, grid-connected large-scale renewable energy, and medium and high voltage AC drives. However, the voltage that a single power semiconductor device can withstand is limited. For applications with high voltage levels, it is necessary to connect power semiconductor devices in series to form a basic unit with a higher withstand voltage level. In addition, the switch unit composed of power semiconductor devices connected in series can withstand high voltage, and at the same time, it can also improve the problem of slow turn-off ...

AI Technical Summary

Problems solved by technology

Compared with the passive snubber method, this method has little effect on the switching speed of the device, but it can only avoid overvoltage at both ends of the device, and cannot control the voltage balance during the dynamic process. In addition, the clamp circuit will flow when it is triggered. over a larger current, resulting in higher power loss

There is also research on connecting an active voltage clamping circuit between the series switch tubes to make the switch tubes interact with each other, thereby playing a voltage equalizing role, but the circuit is complicated and difficult to implement, and the impact on the switching speed is also increased.

[0005] It can be seen that the dynamic voltage equalization method for direct series connection of power semiconductor devices in the prior art still has certain defects and needs to be improved.

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