Estimation of Multi-Phase Currents Using DC Bus Current and Switching State

The voltage of solar cell strings can be controlled in residential photovoltaic systems using a multi-phase convertor. How-ever, multi-phase convertors require a few current sensors. The authors examined how to reduce the current sensor for each phase of a multi-phase convertor. This paper presents the analysis of a multi-phase convertor based on DC bus current, phase currents, and switching state, and it proposes an estimation method for multi-phase currents. The estimation method can be implemented with constant sampling frequency. Experimental results demonstrate the validity of the estimation method of multi-phase currents for current-controlled three-phase convertor.