Integration of Photovoltaic with Series/Parallel Connection of Batteries using Modified Johnson Converter

The present investigation shows the application of a modified Johnson converter for battery charging. The modified Johnson converter can provide the voltage gain of either polarity for different duty ratio ranges. Another advantage of this converter is that it can be used for both stepped up and stepped down output voltage. After analyzing the converter in non-ideal modes of operation, the design aspects for the inductor and capacitor were looked into details. A closed-loop controller is developed using various transfer functions. The hardware results of the converter are shown using a DC voltage source and resistive load. The integration of photovoltaic and batteries using a modified Johnson converter is the highlight of the present investigation. For this integration, a PI controller for current reference control is designed. The step up and step down profile of output voltage is used for charging the batteries in series or parallel. Simulation studies show the charging of the batteries of 96V and 12V, while PV is sourcing power at the maximum power point. The hardware result of the studies is in progress.