A Novel Sliding Mode Estimation for Microgrid Control With Communication Time Delays

This paper deals with the sliding mode estimation for microgrid with time delays. Delay has a great impact on large power grids' management for microgrid, which terribly reduces the stability and quality of microgrid. Random delay caused by load dependent congestion, constant transmission delay and constant delay in microgrid are considered in this paper. To eliminate the adverse effects of delays, a novel sliding mode estimation-based controller is designed to predict time delays and microgrid states, and to reject the disturbance of estimation errors. The mathematical inverter model containing electrical characteristics is regarded as the model of practical microgrid system. Delay estimation with learning parameter and state estimation are derived according to the inverter model. By regarding estimation errors as disturbance of sliding mode control (SMC), the control signal of SMC is adaptively changed in the sliding mode estimation-based control loop to ensure the stability of system and accuracy of estimation. Exponential reaching law (ERL) is implemented to improve the chattering issues and reaching performance of SMC. Lyapunov approach is exploited to analyze the stability of sliding motion. Finally, the proposed SMC strategy is validated by simulation experiments of a microgrid with time delays.