Control of Battery Charger for Electric Vehicles

The increasing environmental pollution caused by fossil fuel emissions from vehicles using internal combustion engines has spurred the development of electric vehicles. The power sources for the electric vehicles to operate are often stored in different types of batteries with different charging requirements. Most batteries are charged from the grid sources through AC/DC converters for charging battery packs. An effective charging system usually consists of a rectifier and a dual-active bridge (DAB). A typical controller consists of the control of DC bus, PFC (power factor correction), constant voltage (CV), and constant current (CC) for the battery. However, most conventional chargers only regulate the voltage or current of the battery when charging. These types are mainly suitable for lead acid types and the power factor correction has not been considered. Meanwhile, new generation battery packs as lithium-ion batteries require charge of CC at first. When the battery charging voltage reaches a certain voltage threshold, then switch to the mode of CV charge. Basing on the analysis of the battery charging requirements of electric vehicles, this paper presents a battery charger control solution with capability of CC and CV control as well as high power factor. The simulation results on MATLAB/Simulink have validated the effectiveness of the presented method.