Power Balance Control Method With Phase Disposition for Cascaded H-bridge Inverter Based on Control Degrees of Freedom Combination

Affiliation of Author(s):自动化学院

Journal:Zhongguo Dianji Gongcheng Xuebao

Abstract:Phase disposition (PD) modulation method, compared with carrier phase shift (CPS), is better in terms of harmonic performance of line-line voltage for cascaded H-bridge multilevel inverter, but it results in power imbalance among cascaded cells. In order to solve this problem, this paper proposed a novel power balance strategy with PD modulation method. Firstly, the traditional PD modulation method was modified based on the modulation wave control degree of freedom, which can effectively reduce the number of carriers and roughly balance the active power of different cells. And then the carrier control degree of freedom was taken into consideration. By adjusting the arrangement of the carrier in the vertical direction, the secondary adjustment of every cell's output voltage is realized without changing the output voltage characteristic of the inverter and the power balance is achieved in one output cycle. This paper, taking three cells cascaded multilevel inverter as the example, gave the definition of power balance and the mechanism of power imbalance in traditional PD modulation and analyzed the principle of the proposed modulation method. Simulation and experimental results verified the validity of the proposed strategy. © 2017 Chin. Soc. for Elec. Eng.

ISSN No.:0258-8013

Translation or Not:no

Date of Publication:2017-12-05

Co-author:Na, Xianlong,Xu, Yaming,Sun, Jianbo

Correspondence Author:cz

Date of Publication:2017-12-05