Highly efficient ZCS boost converter used in rechargeable batteries

This work develops a highly efficient zero-current-switching (ZCS) boost converter used in rechargeable batteries. An auxiliary power switch in series with the resonant tank enables the semiconductor devices in the charger circuit are to be turned on and off by soft switching. The developed charger topology practically eliminates the charging current ripple in the battery, maximizing battery life without increasing the volume of the converter. Therefore, a battery charger with the proposed ZCS boost converter can be operated with low switching power losses. No additional voltage or current stresses are caused on the auxiliary switch or auxiliary diode. Additionally, the proposed ZCS boost converter for rechargeable batteries has a simple structure, low cost, light weight, ease of control, and high efficiency. The operating principles and design procedure are analyzed and discussed in detail. The optimal values of the pertinent properties of the resonant components are determined from the characteristic curve and the electric functions that are obtained from the circuit configuration. Simulation results and experimental results obtained using a laboratory prototype demonstrates the feasibility of the proposed topology. Finally, a prototype circuit that is designed for a 24V-50Ah lead-acid battery bank is built and tested to confirm the theoretical predictions. The maximum charging efficiency of the proposed topology throughout the overall charging period is 95.8%. Experimental results reveal the satisfactory performance of the proposed topology, which is especially suitable for battery charging applications.