Improving the stability of SEIG based microgrids with predominance of dynamic loads by using supercapacitor-based storage

This paper focuses on improving the dynamic behaviour of a microgrid (MG) supplied by a self-excited induction generator (SEIG) when feeding mainly induction motors (IMs) of significant power. In order to sustain the MG during the transitory regime induced by the IMs connection, a short-term energy storage system based on a supercapacitor (SC) is added to the MG control system. Also, a stepped capacitor bank is employed to compensate the reactive power required by the dynamic loads. A voltage source inverter (VSI), having on its DC side a Dump Load (DL), is responsible for the MG voltage and frequency stability during steady-state. When the DC voltage decreases under a certain threshold, the SC system starts injecting power into the VSI DC-link, thus improving the stability of the MG parameters. Simulations are used to validate the effectiveness of the proposed control structure.