Fuzzy-based coordinated control and parameter correction strategy for speed controller of PMSG wind turbine in frequency response

Abstract

The purpose of frequency response of PMSG wind turbine is to provide additional energy support to the power system’s frequency regulation demand through its rotor kinetic energy. However, the inherent control loop represented by the PMSG speed controller, and its inherent control purpose is to maintain a stable operation of the rotor speed, thus the difference between these two control blocks will lead to a conflict situation between frequency response performance and operation safety of the wind turbine. Therefore, a novel fuzzy-based coordinated control and parameter correction strategy for speed controller of PMSG wind turbine in frequency response is proposed in this paper. First, to clarify the function role of key parameters of the wind turbine in frequency response process, a mapping equivalence model consisting of wind turbine’s frequency response parameters and operation states is proposed by establishing the energy correspondence relationship between PMSG rotor kinetic energy, de-loading reserve by pitch angle control and power demand of frequency response. Then, the frequency response performances of the speed controller’s parameters are tested under various wind speeds. Moreover, based on the fuzzy logic algorithm, a dynamic operation strategy for the wind turbine’s speed controller is proposed to improve the frequency response performance, which alleviates its conflict against the PMSG frequency response control block. Finally, a simulation model is built to verify the proposed strategy under various wind scenarios. The test results demonstrate that the frequency response performance and the speed controller’s inherent control function of the PMSG-wind turbine can be effectively coordinated by deploying the proposed strategy, and the frequency support capability of the power system is effectively improved.