CC-CV Charging Control Based on Modified Hamiltonian Control Law for EV Application

This paper proposes constant current-constant voltage (CC-CV) charging control based on Hamiltonian control law with a state observer for a bidirectional buck-boost converter on an EV charger. The CC-CV charging scheme is mainly utilized to charge lithium-ion batteries on an electric vehicle. In CC mode, the battery is charged with a preset value until the battery voltage reaches the desired equalized voltage. During CV mode, equalized current is used to maintain battery voltage to equalize the battery. In this work, equalization current requires the actual battery voltage, desired battery voltage, and the battery current for its calculation. Additionally, a state observer is implemented to estimate voltage across uncertainties of resistance and the battery current. Also, it can enhance the performance of the proposed control scheme and minimize the required sensors. Furthermore, the 1 kW prototype of the bidirectional buck-boost converter is developed to demonstrate the feasibility of the proposed controlled scheme.