Cascaded Low-Pass Filtering Algorithm-Based Control of Single-Phase Electric Vehicle Charger

Electric vehicles (EVs) are contemporary solutions for cutting carbon emissions from the automobile sector. Charging system availability is among the several factors that affect the adoption rate of EVs. Pulse width modulated (PWM) rectifiers are employed for the ac to dc conversion, and dc-dc converters are used for the regulated charging of EVs in single-phase EV chargers. To ensure grid synchronization of PWM rectifiers, phase-locked loop (PLL) algorithms are used. The PLL algorithm is required to perform accurately with faster dynamic response under normal as well as abnormal grid conditions. This paper reports a cascaded low-pass filter (CLPF) based PLL algorithm for the control of a PWM rectifier in a single-phase EV charger. The CLPF algorithm is easy to implement and accurately determines the phase angle of the grid voltage with a faster dynamic response. CLPF algorithm processes the grid voltage through a cascade pair of second-order low pass filters (LPFs) to filter out the harmonics and obtain orthogonal pairs of signals corresponding to the fundamental grid voltages. These signals are used to derive the phase angle and, consequently, the unit voltage template (UVT) corresponding to the fundamental grid voltage. The reference source current for the dc-link voltage regulation of the PWM rectifier is computed based on the error and CLPF-based derived UVT. A full bridge dc-dc converter is employed for the constant voltage or constant current charging of the EV battery. The performance of CLPF algorithm-based single-phase EV charger is performed under normal and distorted grid voltages for different charging conditions using MATLAB/SIMULINK validates unity power factor operation with sinusoidal source currents.