Lyapunov-Based Finite Control Set Applied to an EV Charger Grid Converter Under Distorted Voltage

Abstract

Electric vehicle (EV) adoption has increased significantly as a result of growing efforts to combat climate change. The vehicle-to-grid (V2G) mode of operation can significantly reduce the intermittency of power demand from EV chargers by using the fleet as a distributed energy resource. However, operating under distorted grid voltage, the stability of the EV charger control system can be compromised. To address this issue, this work proposes a predictive direct power control (DPC) based on the Lyapunov stability theory for an EV charger grid-side converter. The controller employs Lyapunov stability concepts for discrete-time systems to converge controlled variables to reference values, rejecting grid voltage disturbance. Experimental tests were conducted on an EV charger workbench to evaluate the performance of the control method. The power reference was calculated to enhance power quality by injecting a smooth sinusoidal current into the grid, compensating for voltage distortion. The results show that the active and reactive power are performing efficiently within an acceptable operating margin while maintaining the total harmonic distortion (THD) within the 5% band. The feasibility of the control method was validated during the discharge cycle of the EV battery. In addition, the proposed controller outperformed the classical PI controller.