Stability of battery energy storage system operating with diesel generator in a stand-alone microgrid

Abstract

In this paper, current control for ensuring a stability of battery energy storage system (BESS) is analyzed in a stand-alone microgrid which includes 50kW BESS and 50kW diesel generator. BESS with LCL filter is charged from the diesel generator when state of charge of battery bank is insufficient, and the current control of BESS may become unstable since a large synchronous inductance of diesel generator may generate a LCL filter resonance. No damping, Passive damping and active damping are applied to the current control so as to damp out a filter resonance and improve stability. Influence of the synchronous inductance is analyzed in the frequency domain and discrete time domain. The stable current control is guaranteed, and current waveforms are improved regardless of the significant synchronous inductance of diesel generator.