Design and Optimization of a High-Frequency Oscillation Suppression Strategy for the Grid-Connected Inverter of a Permanent Magnet Direct Drive Wind Turbine

With the development of the new power system with a high proportion of new energy and a high proportion of power electronic equipment, various problems caused by high-frequency oscillation will seriously affect the daily normal operation of the power system. For the existing active oscillatory suppression strategies, the impedance characteristics of other frequency bands will be affected, which may cause new oscillation problems in other frequency bands, namely the negative effect of oscillatory suppression strategy. In response to such phenomena, we conducted research on the mechanism of negative effects and optimize the control strategies accordingly. First, an analysis model of the grid-connected inverter was established. The concept of the damping factor was proposed based on the relationship between passive damping and active damping. The feasibility of the oscillation suppression mechanism based on the damping factor was demonstrated, and the negative effect mechanism of the oscillation suppression strategy was clarified. Secondly, a control strategy based on the superposition of active damping was proposed, which not only solved the negative effect of the oscillation suppression strategy but also avoided the shift of the inherent resonance point. Finally, the theory was verified based on the MATLAB R2022a/Simulink simulation platform.