Novel overmodulation strategy for unequal power sharing in a cascaded H-bridge converter
摘要
This study presents a novel overmodulation strategy for enhancing the unequal power-sharing capability among modules in three-phase cascaded H-bridge (CHB) converters. The proposed method selectively overmodulates higher-loaded modules in one phase while compensating for distortions in the other two phases, ensuring sinusoidal output currents and maintaining power quality. The strategy effectively redistributes power among modules by dynamically adjusting the modulation signals, even allowing some modules to be deactivated when necessary. This optimization improves the performance of CHB inverters under varying load conditions. The proposed strategy overcomes the limitations of conventional modulation techniques, such as sinusoidal pulse width modulation and third-harmonic injection. Experimental results validate the effectiveness of the method, demonstrating its potential for power routing in energy storage systems (ESSs) where the state of charge (SoC) among ESS modules is significantly unbalanced.