Study of a new DC voltage equalising circuit for five-level neutral point clamped-voltage source inverter

Abstract EN

This paper presents a new clamping bridge to solve capacitor balancing problems in Five Level Neutral-Point-Clamped Voltage Source Inverter (NPC VSI) and realize the equalization in the DC capacitor voltage.

The voltage balancing circuit consists of four bidirectional switches and two inductances.

This solution avoids capacitor unbalancing problem, leads to a simpler implementation and presents high equalization efficiency and increases the reliability of the drive system.

Simulation results show the effectiveness of our method.

The cascade studied is a two two-level PWM rectifier- five-level NPC VSI- Permanent Magnet Synchronous Machine.