Online Model Parameter Correction for Improved ZVS and Current Regulation in DCM Grid-Tied Inverters with Average Current Control

This paper proposes an online correction method for model parameters –specifically the inductance value– used in the control of a grid-tied inverter operating in discontinuous current mode (DCM) with average current control. The method aims to improve current regulation and enhance zero voltage switching (ZVS) performance. It addresses the mismatches between the actual inverter-side inductance and the inductance assumed in the control model. The impact of such mismatches on the waveforms of both the inverter-side inductor current and the grid-side current is analyzed. Furthermore, a practical identification technique is introduced. It uses the valley switching detection feature commonly available in digital signal processors (DSPs) used for power electronics applications. Experimental results demonstrated the impact of the mismatch on ZVS performance and showed the parameter estimation performance using a common readily available DSP controller.