Fractional-Order PID Based Outer Loop Control for G2V/V2G Systems in Plug-in Electric Vehicle Applications

Abstract

The increasing adoption of Plug-in Electric Vehicles (PEVs) and the rise of Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) technologies require highly robust and efficient bidirectional AC–DC converters capable of maintaining stable DC link voltage and high-power quality. Conventional proportional–integral (PI) controllers remain widely used for outer-loop regulation; however, their integer-order nature limits performance under abnormal grid and input conditions, and abrupt bidirectional power-flow transitions. To address these limitations, this work proposes a fractional-order proportional integral–derivative (FOPID) controller as the outer-loop regulator for a bidirectional AC–DC converter supporting G2V/V2G operation. To improve resilience to grid disruptions, parameter uncertainties, and system nonlinearities, fractional orders are analytically adjusted. The suggested FOPID controller greatly enhances transient response, steady-state accuracy, DC-link voltage stability, and total harmonic distortion (THD), according to a comparison with the traditional PI controller. The FOPID-based scheme's practical efficacy is confirmed by hardware-in-the-loop validation, which shows improved overall performance for real-time PEV charging and V2G support as well as smoother bidirectional transitions.