Asymmetrically Switched Modular CHB Inverters with High Frequency Control for Grid-Tied and Stand-Alone Applications

Abstract

Sinusoidal pulse width modulation (SPWM) techniques are commonly utilized in traditional multilevel inverter (MLI) designs through multi-carrier integration. This paper introduces an asymmetrically switched Cascaded H-Bridge MLI (CHBMLI) using multi-carrier pulse width modulation (MCPWM) control methods. The proposed CHB topology accommodates various DC input source configurations. Boolean algebra and logic simplifications are applied to design the switching inputs for each asymmetrical structure. This identifies control logics for all possible asymmetrical switching scenarios. This design reduces switch count and enhances power quality. The asymmetrical inverter is simulated with both resistive and inductive loads, and the 9 and 27-level trinary CHBMLI is further modeled for grid-tied power generation. Simulation results are validated through Hardware-in-the-Loop (HIL) testing, confirming the inverter’s feasibility and Total Harmonic Distortion (THD) performance. As a multistring inverter, this topology is ideal for solar energy integration, including both standalone and grid-tied operation.