Control method of fractional-order PI controller applied in electric vehicle to grid based micro-grid stabilization device

Electric vehicles has high-power on-board batteries which can be used to offset disturbances of distributed generation in micro-grid.Micro-grid has two typical operating states: grid-connected mode which provides energy interchange with the grid and islanded mode providing uninterruptible power supply services. The stability performance of micro-grid under the circumstances of large disturbance and states switching is a crucial technical index. However, conventional method of using classical PI controller often takes a long rise time and settling time, large overshoot and integral of error squared. To overcome these problems, this paper, therefore, proposes using fractional-order PI controller, which increases an adjustable parameter (the order of integral), to stabilize EV battery incorported micro-grid system. Analysis based on Bode diagram and simulation results from a micro-grid system are presented to demonstrate this method.