Model Predictive Control-Based Virtual Inertia Emulator for an Islanded Alternating Current Microgrid

Conventional primary control employs outer-loop droop and inner-loop cascaded linear control to realize local voltage regulation and power-sharing of an islanded ac microgrid. However, it has a complex structure, limited dynamic response, and a rapid rate of change of frequency when disturbances occur. This article resolves these issues by proposing a model predictive control-based virtual synchronous generator (VSG-MPC). An improved finite-set MPC is first proposed for the inner loop, achieving simplified control structure, faster dynamic response, enhanced bandwidth and stability, as well as improved current limitation. In the outer control loop, a simplified VSG without a phase-locked loop is employed to realize active power-sharing and inertia emulation. The merits above are verified by a description function of MPC and the frequency-domain response of the overall VSG. Simulation and experimental results verify the feasibility of the proposed method.

Automated summary

This article proposes a model predictive control-based virtual synchronous generator system to address the issues in conventional control methods such as complex structure, limited dynamic response, and rapid frequency changes. Improved finite-set MPC is used for the inner loop, while a simplified VSG is employed for the outer loop to achieve power-sharing and inertia emulation. Simulation and experimental results confirm the feasibility and effectiveness of the proposed method.