V/f controlled Virtual PM Machine for Grid-connected Inverter

The paper proposes a V/f-controlled virtual PM synchronous generator (VSG). The V/f control is used as a speed control for permanent magnet synchronous motors (PMSM). However, speed control is unnecessary for the grid-tied operation because the power grid frequency cannot be controlled by the grid-tied inverter. A VSG provides the relationship between a motor torque, a load torque, and a rotation speed for a speed controller. Thus, the V/f controlled VSG achieves the grid-tied operation by a torque control of VSG. In this paper, control response and stability are analyzed by simplification. The experimental results with the 1-kW inverter demonstrate the validity of the proposed V/f controlled VSG.