The Interaction Between Active Power and Synchronization Loops of PMSG Within Electromechanical Timescale

The interaction between the control links of the permanent magnet synchronous generator (PMSG) is one of the important factors that cause the instability of the PMSG grid-connected system. However, most of the researches on interaction focus on the electromagnetic timescale, and the electromechanical timescale is less involved. This paper analyzes the interaction between the active power loop and the synchronization loop of the PMSG within electromechanical timescale. Firstly, the simplified small-signal model of the PMSG single-machine infinite-bus system within electromechanical timescale is established. Then, the equivalent Heffron-Phillips model of the PMSG is proposed, and the interaction between the active power loop and the synchronization loop is quantitatively analyzed by the damping torque method. It is found that the active power loop can ‘slow down’ the dynamics of the synchronization loop, so that it belongs to electromechanical timescale. These findings provide some new insights into the interaction between the active power loop and the synchronization loop of the PMSG.