A Study on Frequency Control and Active Power Control of Wind Turbine Generation System for PMSG

Abstract

-This paper proposes active power control and frequency support control schemes of wind turbine generation system by using modified Maximum Power Point Tracking(MPPT) of Permanent Magnet Synchronous Generator(PMSG). Most wind turbine generation system is completely decoupled from the power system and power output control with pitch control. According to the frequency deviation, however, MPPT control can not contribute to the frequency change of the power system due to its active power output control. For solving this, the de-loaded(DL) control scheme is constructed for the frequency support control, which is based on applying the active power output control in the rotor speed control of PMSG. The rotor speed by used in the proposed DL control scheme is increased more than the optimal rotor speed of MPPT, and then this speed improvement increases the saved kinetic energy(KE). In order to show the effectiveness of the proposed control scheme, the case studies have been performed using the PSCAD/EMTDC. The results show that the proposed active power output control scheme(DL control and KE discharge control) works properly and the frequency response ability of the power system can be also improved with the frequency support of wind farm.

Coordinated control of rotor kinetic energy and pitch angle for large‐scale doubly fed induction generators participating in system primary frequency regulation

“…To ensure the real-time balance of power in the power system, considering that the active output of wind power is difficult to predict, the standby power of the system is required to increase synchronously with the scale of wind power development and the corresponding reserve capacity is configured to guarantee the safety and stability of the power system operation [1]. Since the synchronous operation of the doubly-fed generator with power grid through the converter, the frequency of the generator rotor and the power grid is completely decoupled, so it cannot directly respond to system frequency variations like a synchronous generator [2][3][4][5]. Hence, the frequency regulation power is fully borne by the traditional synchronous generator.…”