Research On Stability Control Of Micro-grid Based On Sliding Mode Control

Micro-grid integrates a high proportion of distributed energy.Micro-grid is an important part of the future smart grid,but there are also some problems with micro-grid,like poor power quality,negative impact on the main network.The development of energy storage system inverter control technology provides a new way to solve these problems.Energy storage system is named as micro-grid stability controller.Based on integrated micro-grid simulation system,which including photovoltaic generation system,micro turbine power generation system,stability controller,adaptive sliding mode control and inverse sliding mode control for micro-grid stability controller are studied.Adaptive sliding mode control combines adaptive method with sliding mode method to control the AC side current of stability controller inverter to achieve constant power control.Simulation results show that in grid-connected mode,adaptive sliding mode control can effectively track the reference power when system parameter is uncertain and external disturbance exists.The back-stepping sliding mode control combines back-stepping method with sliding mode method to control the AC side voltage of stability controller inverter to realize the constant voltage and constant frequency control.Simulation results show that in islanding mode,back-stepping sliding mode control can quickly and accurately track the reference voltage and frequency when external disturbance exists.Finally,the proposed adaptive sliding mode control and back-stepping sliding mode control are applied to micro-grid stable control strategy.In PSCAD/EMTDC.some micro-grid operation conditions are simulated,such as micro-power output growth,running mode conversion and power outage and load growth.Simulation results show that the stability control strategy of micro-grid based on sliding mode control can restrain the fluctuation of transmission power caused by fluctuation of power and load.It ensures the exchange power between micro-grid and main power grid can be controlled in grid-connected mode,and it is able to provide effectively voltage and frequency support to micro-grid in islanding mode.