Performance Analysis of a Cascaded DC-DC Converter for Light Electric Vehicle Charging Applications

This work presents a cascaded high-current DC-DC converter which is demonstrated as a battery charger. In the proposed topology, a synchronous buck converter is combined with a series capacitor synchronous buck converter, resulting in a quadratic current gain. Hence, it is deemed suitable for high-current applications. Functioning of the converter is demonstrated in charging of a 24 V, 10 A h Lithiumion (Li-ion) battery using constant-current constant-voltage (CC/CV) charging. The given system is simulated using the SimPowerSystems toolbox of MATLAB Simulink. It is observed that the converter operates in line with the charging algorithm and demonstrates a 93.3% charging efficiency. The purpose of this study is to explore a converter topology which can be implemented as part of a non-isolated off-board charger for low-power two/three-wheeler electric vehicles such as e-bikes and e-rickshaws. A good charging efficiency for this topology reinforces its use in public transportation charging, especially electric three-wheelers. Oftentimes, drivers of electric three-wheelers may face downtime during peak hours due to discharged vehicles. Success of this topology can potentially result in alleviation of this issue faced by drivers.