A Novel Inverter Topology and its Power Balancing Optimization

Abstract

Aiming at the problems of poor quality of the output voltage waveform of the existing multi-level inverters and many switching devices and DC power supplies, a novel cascadable basic unit topology is proposed. The proposed topology consists of three input DC power supplies and eight switches, forming an H half-bridge and an auxiliary bidirectional switch by adding 2 DC power supplies in the traditional H-bridge topology. The advantage of this topology is that it can be used in symmetric and asymmetric voltage source configurations, which can effectively extend the life of the inverters and reduce the production cost. The basic unit topology is cascaded in series to form a multilevel inverter topology to generate higher voltage levels, and its power balance strategy is proposed. The strategy can be described as follows: Firstly, several groups of pulse signals are generated by the traditional LS-PWM modulation strategy in which the modulation wave is compared with several groups of carriers, then a logic operation on the pulse signals is performed to obtain the drive signal of each switch, and the inverter is driven to achieve output power balance. A lot of Simulation and experiments verify the viability of the proposed topology and the effectiveness of the equalization strategy.