Voltage/frequency control of microsources considering response characteristics of prime mover

In this paper, the frequency and voltage control is studied for the operation of islanded microgrids considering response characteristics of the prime mover of microsources with electronically interfaced converters. The prime mover is modelled as a first-order lag transfer function with a proportional differential (PD) controller. The lag transfer function, where the value of time constant represents response speed, is used to describe dynamics of the prime mover. PD controller is used to regulate the DC bus voltage. The voltage source inverter (VSI) regulates the voltage magnitude and frequency with a proportional integral (PI) controller. Simulations are carried out to demonstrate dynamics of the prime mover and its impact on VSI operation. The results show that high response rate of compressed air energy storage (CAES) can help microgrids to achieve stable and secure operation.