Finite state machine control and power quality enhancement using Goertzel filter for multifunctional battery energy storage system

Abstract

This study presents the design and control of a multifunctional battery energy storage system (BESS) to provide reactive power and harmonics compensation in grid-connected and uninterrupted supply modes to loads during grid non-availability. The BESS comprises of a bidirectional DC–DC converter and a grid-connected voltage source converter (VSC). The bidirectional converter is controlled to provide the battery charging and to maintain constant DC link voltage. The VSC uses a multimode controller and the finite state machine (FSM) based logic for mode transitions. The multimode controller uses a sliding Goertzel transform based filter for grid-connected mode and voltage controller for standalone mode of operation. The FSM logic monitors the system parameters using a voltage and the rate of change of frequency for deciding the mode of operation and for smooth transition between these modes. Simulated and test results validate the effectiveness of the proposed control in achieving the set objectives.