Generalized Power Decoupling Control for Single-Phase Differential Inverters With Nonlinear Loads

Differential inverters provide a cost-effective solution to the second-order ripple power issue in single-phase systems. Most existing differential inverter-based power decoupling methods are for linear loads, which may not work well for nonlinear loads. When supplying nonlinear loads, differential inverters may suffer from harmonics at the ac terminal, which may propagate to the dc side and deteriorate the performance of power decoupling. In this paper, the harmonic mitigation is realized by reshaping capacitor voltages, and it is applied to buck-, boost-, and buck-boost-type differential inverters with detailed harmonics compensation capacity analysis. Then, a feedback linearization-based dc current feedback control scheme is proposed to realize the harmonic mitigation; hence, both the dc-side ripple power and the nonlinearity found in differential inverters can be decoupled simultaneously. The proposed control scheme is developed based on a generalized half-bridge model and can be applied to buck-, boost-, or buck-boost-type differential inverters with minor revisions. Experimental results are presented to validate the performance of the proposed control scheme and theoretical analysis.