Digital voltage regulation with flux balance control for sine wave inverters

A novel digital voltage regulation based on digital signal processor is proposed in the paper. According to the difference between digital-controlled and analog-controlled inverters, the reasons causing dynamic flux imbalance of output transformer are analyzed in detail. To avoid the infection of truncation error, which is one of the most predominant ingredient leading to flux imbalance in digital-controlled systems, methods used to guarantee the symmetry of the output of voltage regulator are proposed. And then a valid solution for flux balance by sampling the instantaneous primary current of the output transformer and introducing the on-line calculated bias current component into the voltage regulation arithmetic is presented. Design guidelines are provided and experimental results verify the excellent performance of the proposed method.