Open Access

ARTICLE

Power Balance Control Strategy of Cascaded H-Bridge Multilevel Inverter Based on Improved Harmonic Injection

Feng Zhao, Haonan Xu^*, Xiaoqiang Chen, Ying Wang

School of Automation and Electrical Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China

* Corresponding Author: Haonan Xu. Email:

(This article belongs to the Special Issue: Construction and Control Technologies of Renewable Power Systems Based on Grid-Forming Energy Storage)

Energy Engineering 2025, 122(12), 4987-5000. https://doi.org/10.32604/ee.2025.068714

Received 04 June 2025; Accepted 08 August 2025; Issue published 27 November 2025

Abstract

The cascaded H-bridge (CHB) multilevel inverter has become one of the most widely used PV inverter topologies due to its high voltage processing capability and high quality output power. Grid-connected PV system due to external conditions such as PV panel shading, PV component damage, can lead to PV output power imbalance, triggering the system over-modulation phenomenon, which in turn leads to grid-connected current waveform distortion. To this end, an improved power balance control strategy is proposed in this paper. Firstly, according to the different modulation ratios of each H-bridge module, a suitable harmonic injection method is used to keep the peak value of the modulating waveform always at 1; then an inverse triangular trapezoidal waveform is injected to optimize the modulating waveform, which further improves the output voltage waveform, reduces the THD value of the grid-connected currents, and maintains the stability of power inside the CHB system. Purpose. Simulation verifies the effectiveness and feasibility of this power balance control strategy.

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Keywords

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