Expandable Non-Isolated Multi-Input Single-Output DC-DC Converter With High Voltage Gain and Zero-Ripple Input Currents

In this paper, an expandable non-isolated multi-input single-output DC-DC high voltage gain converter with the capability of cancelling input current ripples is proposed, which can be applied in photovoltaic (PV) systems. The proposed converter has several advantages including: 1) it provides a single voltage gain for the whole range of duty cycles; 2) the duty cycle’s operating range is not decreased when increasing the number of input stages; 3) it has a simple switching pattern, and all switches go on and off, simultaneously; 4) the current ripple of each input stage is eliminated for the whole range of duty cycles; 5) the output load has a common ground with all input voltage sources; and 6) the voltage stress on switches is low. In this paper, the proposed converter in a dual-input single-output (DISO) form is introduced at first, and its general form with multi-input single-output (MISO) is then analyzed. Following that, the voltage gain, voltage and current stresses on switches, diodes and capacitors, and input current ripple cancelling condition are calculated. Finally, experimental results are used to validate the calculated theoretical results.