Control of Variable Speed WECS-PV-BES Based Microgrid with Grid Synchronization

This paper deals with variable speed WECS (Wind Energy Conversion System)/PV (Photovoltaic) and BES (Battery Energy Storage) based microgrid. The proposed microgrid operates in standalone as well as in grid connected mode to feed the local loads uninterruptedly. The mode of switching operation of it requires the robust and fast PLL to maintain the power quality. Therefore, a SOGI-WIF (Second Order Generalized Integrator- With in-loop Filter) based modified SRF-PLL is used for mode of switching operation such as islanded mode to grid connected mode and vice versa. The LSC (Load Side Converter) is used to feed the load in standalone mode and in grid connected mode. In grid connected mode, the LSC is gated using the robust and fast modified least mean square (MLMS) based control algorithm and in standalone mode LSC switched to PR (Proportional Resonant) control. The response of LSC control algorithm is fast against the load unbalance and solar insolation change in island as well in grid connected modes. Under grid fault condition, the microgrid is synchronized to the diesel generator to feed the local load uninterruptedly. The proposed system is developed in the laboratory and test results are demonstrated the steady state and dynamic performance of microgrid under unbalanced load and grid abnormal conditions.