A 2.2 kW SiC based high frequency battery charger for substation backup power supply

This paper presents a 2.2 kW two-stage, high frequency AC-DC converter for substation battery charging with Nickel-Cadmium (NiCd) battery. Detailed analytical calculation of the converter parameters, analysis, and simulation studies are carried out to demonstrate the performance of the proposed system. As, substation converters are required to be naturally cooled to eliminate additional mechanical component like cooling fans, SiC (Silicon Carbide) switches are used for this project. These switches have much higher thermal limit compared to the Si based switches and losses are also quite low at higher switching frequencies. It helps to improve the overall efficiency of the AC-DC converter as well. Control strategy is developed to operate the battery charger in both CC and CV mode. Detailed list of parameters used for this proposed system is also presented.