A decentralized model predictive control for multiple distributed generators in the islanded mode of operation
The increasing penetration of distributed and renewable generation presents power systems with a challenge of accommodating multiple inverter-based generators. Distributed generators (DGs), capable of operating in the islanded mode, are often installed in microgrids. However, a control system for operating multiple DGs in the islanded mode using voltage-sourced converter (VSC) is a real challenge under uncertainties in load parameters, unbalanced phase conditions, and transients. This paper proposes a novel approach to decentralized control of multiple DGs. This approach is based on a combination of a voltage controller using model predictive control (MPC) and a fast current controller using discrete time sliding mode controller (DSMC) for limiting the inverter currents under overload conditions. Performance of the proposed control system is compared with a robust servomechanism program (RSP) controller. The proposed control strategy provides fast tracking, robustness, and fast transient recovery in voltage and current under 1) short circuit conditions, 2) load transients and 3) unbalanced loads. Various scenarios including reference signal tracking and robustness against the load perturbations are considered. Results are presented and discussed.