Time-Sharing Dual-Mode Control Strategy for Two-Stage Single-Phase Grid-Tied PV Inverter

A time-sharing dual-mode control strategy for conventional single-phase two-stage grid-tied photovoltaic inverter is investigated in this paper. By comparing the PV and grid voltage, the two stages will operate at high frequency switch-mode in turns in every half grid cycle, but never at the same. The operational principle of time-sharing dual-mode sinewave PWM modulation scheme is firstly elaborated. Moreover, the advantage in improving the efficiency of the system is proved in a quantitative way with the usage of loss analysis. Besides, the integration of Maximum Power Point Tracking (MPPT) method with the adopted control strategy is also discussed. The effectiveness of the theoretical analysis is verified with the use of Matlab-Simulink and proved from a practical point of view.