Centralized Active Power Decoupling Method for the CHB Converter With Reduced Components and Simplified Control
Rui Zhang, Shunliang Wang, Junpeng Ma, Peng Wang, Kejun Qin, Jinming Li, Tianqi Liu
Abstract
Cascaded H-bridge converters (CHBCs) are widely utilized in medium- and high-voltage systems. However, they present challenges such as large submodule (SM) capacitance and complex capacitor voltage balancing strategy. To improve converter power density and reduce hardware consumption, this letter proposes a new topology for CHBC, which features centralized active power decoupling (APD) capability. The periodic parallel connection and energy interaction between the SMs allows for double-line frequency power fluctuation suppression of all SMs through only one APD branch, leading to reduced components and simplified control. This letter provides a detailed analysis on the operating, modulation, and control strategies of the proposed topology. Experimental results are also presented to demonstrate the feasibility of this new circuit.