Generalized VSG Control Strategy for Active Power Transient Characteristic Optimization of Voltage Source Inverter

Abstract

Both droop control and virtual synchronous generator (VSG) control can be widely seen used in voltage source inverter. Among them, the virtual inertia and damping characteristics VSG control has the ability to provide virtual inertia factors that droop control does not have, but its active power response speed is very slow, and there is a large overshoot. Aiming at the problem of poor active power transient characteristics of VSG control, a generalized VSG control strategy is proposed. First, the article analyzes the transient characteristics of the active power-frequency loop of droop control and VSG control, and derives the generalized VSG control strategy. Then, according to the system model, the influence of the pole-zero point of the main controller of generalized VSG control strategy on the frequency response speed, the response speed and overshoot of active power is analyzed. And on this basis, a parameter design parameter design method is given, which can eliminate active power overshoot and make the active power response as fast as possible while keeping the frequency response speed unchanged. Finally, an inverter grid-connected bench was built to verify the effectiveness and feasibility of the proposed generalized VSG control strategy.