Design of Virtual Synchronous Generator

Following images are shown the VSG model.

In here, a Virtual Synchronous Generator (VSG) model was designed and implemented to enhance grid stability by effectively regulating active power injection based on frequency dynamics. The system operates as follows:

1. Frequency and Rate of Change of Frequency (RoCoF) Extraction

   • A Phase-Locked Loop (PLL) is employed to extract real-time grid frequency and RoCoF.

   • These signals are then fed into the VSG control block to compute the reference active power (P_VSG​) based on the governing swing equation.

2. Active Power Control and Current Reference Generation

   • The reference active power (P_VSGP​) is used to determine the direct-axis reference current (Id∗​) through an analytical transformation (According to the second equation). Since reactive power does not control in the VSG model, the reactive power (Q) is set to zero.

3. Current Control and Voltage Regulation

   • The PI controllers regulate the direct and quadrature-axis current components according to the mismatch between their reference values (Id, Iq), converting them into corresponding voltage values (In here reference Id value take as zero).

   • These voltage values, along with the grid voltages (Vd, Vq), are used to compute the reference direct and quadrature voltage components.

4. Voltage Synthesis and PWM Modulation

   • The computed reference voltages are transformed into a three-phase AC voltage reference signal.

   • This signal is then fed into a Pulse Width Modulation (PWM) controller, which drives a three-phase inverter, ensuring synchronized power injection into the grid.

Research Paper