Coupled inductors design of the bidirectional non-inverting buck-boost converter for high-voltage applications

This work analyses the effects on the efficiency of the winding-to-winding capacitance of the coupled-inductor of the bidirectional non-inverting buck-boost converter in high-voltage applications. This converter presents many advantages that make it suitable for low-voltage hard-switching photovoltaic and fuel cell hybrid systems. However, experimental results obtained using the previously reported procedure to implement the coupled inductors show low-efficiency in high-voltage applications. A different implementation procedure of the coupled inductors, with lower winding-to-winding capacitance, is proposed. High-efficiency experimental results from a 400 V 1.6 kW prototype have been achieved over a wide operating voltage range, thanks to the use of SiC devices and the modified coupled inductors, confirming in this way its good potential as a building block also in high-voltage wide-gain-range applications.