Regulation of active and reactive power of a virtual oscillator controlled inverter

Abstract

Utilisation of variable distributed energy sources in a microgrid necessitates control of active power and is enhanced by the control of reactive power. A control technique to regulate the active and reactive power of a virtual oscillator controlled inverter is presented. Current feedback gain of the virtual oscillator controlled inverter is used to regulate the active or reactive power. In order to achieve the desired power set-point, a PI controller is used to tune the current feedback gain. An approximate local stability analysis is presented using the system linearisation and eigenvalues analysis. Constraints on the virtual oscillator controller and system parameters are identified to ensure the stability of the system. Global stability of the system is investigated by determining a Lyapunov function using the sum-of-squares technique. Simulation and experimental results are presented for both the cases of active and reactive power control of a virtual oscillator controlled inverter to verify the analytical analysis and to demonstrate the effectiveness of the proposed control scheme.