A Reliable and Efficient Integration Topology for Autonomous Hybrid Systems using NSC

Abstract

In this work, two different Renewable Energy Sources (RES) are integrated to feed the local time varying load using a Nine Switch Converter (NSC) topology. The isolated system consists of a 22kW Self Excited Induction Generator (SEIG) based micro-hydro system and a Photovoltaic system. The system is also equipped with Battery Energy Storage and feeds power to a concentrated time varying load. The presence of DC-link in the NSC helps in independent control of power flow between the SEIG and load. The proposed system has two major advantages. Continuity of power to the load can be maintained even if the sources are disconnected, thereby enhancing the reliability of the system. Secondly, any disturbance on the load side doesn t affect the performance of the SEIG system and vice-versa. Two different decoupled control structures are developed for the control of the SEIG and the load sides voltage and frequency. This isolated system is subjected to different types of load, i.e. linear load, non-linear load and dynamic load and the performance of the autonomous hybrid system is evaluated. The uninterrupted power supply capability of the system is also examined by disconnecting both the SEIG and the PV sources from the system. The above mentioned system is simulated and validated using Matlab/Simulink environment.