Current-Ripple-Free Module Integrated Converter With More Precise Maximum Power Tracking Control for PV Energy Harvesting

摘要

In this paper, a passive ripple canceling circuit (PRCC) is proposed to eliminate the output power reduction effect of photovoltaic (PV) systems caused by the current ripple of the PV converters. Special features of the proposed PRCC include having low-cost simple modular structure and being independent of the duty ratio control of the main power circuit. Hence, it can be easily integrated to the main power circuit to achieve zero input current ripple, yielding less filter size, loss, and fast response. Meanwhile, the linear line maximum power point tracking (MPPT) control is also integrated with the proposed module integrated converter (MIC) to achieve instantaneous tracking response. Finally, a 90-W laboratory prototype is constructed to verify the effectiveness of the proposed principle. It is seen that the resulting peak-to-peak input current ripple is reduced to about 2% of the original dc converter input ripple. In other words, the input current ripple is almost zero. As a result, the harvested power of the proposed MIC can be increased by 7% as compared with that of the MIC without the proposed PRCC.