Research on an improved virtual synchronous generator control strategy for VSC-HVDC supplying power to a passive network

The traditional double-closed-loop control system in a virtual synchronous generator controlled high-voltage DC generator (VSC-HVDC) system supplying power to a passive network cannot provide the necessary inertia and damping coefficient, whereas the traditional virtual synchronous generator (VSG) control can realize primary frequency regulation to provide frequency support of the system without the feature of error-free adjustment. To mitigate the inadequacies of the two methods, an improved frequency synchronous control (IFSC) is proposed. The control simplifies the traditional VSG controller, and error-free frequency regulation can be achieved without the detection of the active power. Meanwhile, the proposed method retains the two important parameters of VSG technology, namely the virtual inertia and damping coefficient, and inherits the excellent characteristics of the virtual synchronous machine. A simulation model is built on the MATLAB/Simulink platform, and two situations, i.e., normal working condition and the power change of load, are simulated and discussed. The simulation results show that, in the start-up process, IFSC control has a damping effect of power and frequency. The overshoots of power and frequency decrease and reach their stable values more quickly. When the load power changes, the power and frequency have inertia effect in the dynamic process and the proposed IFSC method achieves the frequency regulation and realizes error-free adjustment. (c) 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.