Neutral point static clamping voltage-sharing circuit for three-level inverter

Abstract

The invention discloses a neutral point static clamping voltage-sharing circuit for a three-level inverter. The neutral point static clamping voltage-sharing circuit comprises a stack structure of four transistors, wherein a node A is at the joint of the first transistor and the second transistor; a node C is at the joint of the second transistor and the third transistor and serves as a voltage output end; a node B is at the joint of the third transistor and the fourth transistor; direct-current voltage DC+ and direct-current voltage DC- are connected at two ends of the stack structure of fourtransistors respectively; a series capacitor C1 and a series capacitor C2 in parallel to the stack structure of four transistors are connected between the direct-current voltage DC+ and the direct-current voltage DC-; and a parallel circuit is connected between the node A and the node B. The voltage uniformity of the insulated gate bipolar transistors can be guaranteed at static state, overvoltage breakdown damage is prevented, the circuit is simple, reliable, stable in operation and small in occupied space, any type and specification of the insulated gate bipolar transistor of any type and specification can be protected by adjusting the resistance value of a resistor R, and the circuit has great application prospects.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a static clamp voltage equalizing circuit for a three-level frequency converter. Background technique [0002] The existing diode-clamped three-level circuit can only effectively clamp and protect two of the four IGBTs on one phase, that is, the two IGBT tubes 1 and 4 cannot protect the two IGBTs 2 and 3 , This greatly increases the probability of overvoltage damage to the two IGBTs 2 and 3, causing serious losses. Contents of the invention [0003] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a three-level frequency converter midpoint static clamp voltage equalizing circuit which solves the problem that two IGBTs of the diode-clamped three-level circuit 2 and 3 cannot be clamped and protected . [0004] In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present inventi...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a three-level frequency converter midpoint static clamp voltage equalizing circuit which solves the problem that two IGBTs of the diode-clamped three-level circuit 2 and 3 cannot be clamped and protected

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