Single-ended Resonant Inverter for Active Balancing System

This paper presents research of a single-ended resonant DC-DC converter used for charging and equalizing the voltages across Li-Ion cells connected in series. This converter is a part of active voltage equalization system. Each cell is galvanically isolated from the power side of the converter by means of high frequency transformer. The transformer has one primary and two secondary windings. The main secondary winding supplies synchronous voltage doubler rectifier (SVDR). By using such a rectifier, the efficiency of the converter is improved. Standard half-bridge driver is used to drive the MOSFET transistors of the synchronous rectifier. The power supply for this half-bridge driver needs to be independent. That's why auxiliary winding is needed in the secondary side of the transformer. In this work is also studied the influence of the additional secondary winding, used to supply the half-bridge driver. Experimental data of working of the single ended resonant DC-DC converter for charging of Li-Ion battery are presented.