Model-Based Current Sharing Approach for DCM Interleaved Flyback Micro-Inverter

Current sharing control is a challenge for a discontinuous conduction mode (DCM) micro-inverter based on interleaved flyback topology. To solve this problem, this study proposes a novel and systemic model-based approach. Firstly, an accurate fourth-order model is presented for the interleaved flyback circuit, which takes the two flybacks’ parameter mismatch and coupling into account. Secondly, based on the presented model, a continuous time sliding mode current controller is proposed to tackle the output imbalance caused by parameter mismatch, coupling and disturbance. The proposed controller is derived from the Lyapunov function without switching conditions. Finally, the effectiveness of the proposed model and control method is validated by simulation tests using MATLAB/SIMULINK. Simulation results show that the proposed approach improves the current sharing for the interleaved flyback micro-inverter when compared to the conventional current sharing approach.