Design and Implementation of Three-Winding Coupled Inductor Applied in High Step-Up DC/DC Converter Combined with Voltage Multipliers

By combining a coupled inductor with voltage multipliers, the voltage gain of a boost converter can be improved significantly. This method has good application prospects in renewable energy generation and in DC microgrids. A coupled inductor is the core component of the high step-up DC/DC converter and has serious impact on its performance. However, shortage in the methods used to design the coupled inductor have limited the applications of such converters. By analyzing the operating modes of the high step-up DC/DC converter with a three-winding coupled inductor combined with two voltage multipliers, accurate and simplified models of currents in the three windings are established. Furthermore, a design methodology for a multi-winding coupled inductor is put forward, in which a method of calculating the boost inductance and product areas (AP) and a method for selecting the magnetic core are established. The influence of winding arrangements and loss evaluations of the coupled inductor are also investigated. Finally, a 200 W prototype converter with an input of 20 V and output of 200 V is prepared and tested. The correctness of the current models of and design methods used on coupled inductor are verified. More important, the method proposed to design multi-winding coupled inductors can be applied to design high step-up DC/DC converters with different topologies.