Adaptive Sliding Mode Controller (ASMC) for parallel VSCs in an AC Microgrid with PV, Wind, Diesel generation and Battery storage

An Adaptive Sliding Mode Controller (ASMC) for parallel VSCs to control output currents in a grid connected hybrid power system with PV, Wind and Diesel generation as the sources and Battery as the storage device with Energy Management Strategy (EMS) is proposed in this paper. PID controllers can take a long time to reach the desired output, particularly when the system is highly nonlinear or has significant time delays. SMC can produce high-frequency oscillations, also called chattering, which can cause excessive fluctuations in the plants and creates unnecessary variations in the output. Adaptive SMC is chosen to control output currents due to its straightforward structure and its property of elimination of chattering effect. It adapts to various disturbances and is less affected by upper-bound uncertainties. PV and wind systems are connected to the AC microgrid through an MPPT operated DC-DC converter and ASMC controlled VSC. Battery storage system is connected through bidirectional DC-DC converter and a ASMC controlled voltage source converter. Diesel generator is adopted as back up if the sources and storage systems are not available or unable to provide the power. Variable atmospheric conditions like irradiance, temperature and wind speed and variable load demand are considered to check the efficacy of proposed controller. Results are compared with conventional PI and SMC controllers in terms of peak overshoot, rise time, settling time and total harmonic distortion. System is simulated using MATLAB/SIMULINK and results are tabulated.