Nonlinear backstepping controller design for V2G applications with output LCL filters

Abstract

This paper presents a nonlinear backsteping control scheme to control the power injection into the grid from an electric vehicle as well as to improve the power quality. The proposed controller is design by considering the dynamical model of vehicle-to-grid (V2G) system along with the dynamics of an LCL filter. The control Lyapunov function is used to analyze the stability of the V2G system as the negative definiteness or semi-definiteness of its derivative indicates the stability of the system. Simulation results are carried out on a test V2G system using MATLAB/SIMULINK Sim-PowerSystems Toolbox. The performance of the proposed controller is compared with a similar backstepping controller used for the V2G system with an L filter in terms of both power injection capability into the grid and improvement in power quality. Simulation results demonstrate that the designed controller offers improved power quality with an LCL filter as compared to an L filter though there are no differences in the power injection capability. This improvement in power quality is demonstrated through the total harmonic distortion (THD) in the injected current into the grid.