Stability and modal analysis of a DFIG-based wind energy conversion system under stator voltage vector control

• Developed a DFIG-based WECS mathematical model based on stator voltage. • Proposed the conclusion that the GSC is not involved in the oscillation mode. • A week nonlinear feature caused by the inverter’s parameters in wide-frequency. • The key result of this paper has been confirmed online utilizing HIL equipment. In a double-fed induction generator-based wind energy conversion system (DFIG-based WECS) with a stator flux orientation , a nonlinear wind power generation system based on stator voltage vector control, is established and analyzed in this paper for modal and stability analysis in response to the effect of the observation error of the magnetic chain of a doubly-fed induction motor. First, a dynamic model of a DFIG-based WECS was created, and its oscillation modes and participation factors were examined in order to account for both rotor-side and grid-side control. Second, a mathematical model for a WECS that considers only the rotor-side converter was built and evaluated. This included a theoretical analysis of the grid-side converter’s control loop, which was not involved in oscillations through participation variables. Concurrently, time-domain simulation analysis and tiny signal analysis techniques were used to validate the fundamental characteristics of the WECS and a possible route for inverter control settings to create wide-band oscillations. Finally, two dynamic mathematical models and the stability of the DFIG-based WECS under a stator voltage were verified on the hardware in the loop(HIL) simulation platform. Both simulations and experiments confirm that the established DFIG-based WECS has good grid-connection performance, that the dynamic process of the GSC (grid-side converter, GSC)does not participate in the oscillatory mode. This work provides a theoretical basis for the conversion and application of wind energy.