Power Smoothing of a Variable-speed Wind Turbine Generator

• Published in: International journal of control, automation, and systems 2021, Automation, and Systems, 19(1), , pp.11-19
• Main Authors: Yang, Dejian, Kang, Yong Cheol, Park, Jung-Wook, Lee, Young Il, Song, Seung-Ho
• Format: Article
• Language: English
• Subjects: Control; Deceleration; Engineering; Frequency control; Frequency deviation; Linear functions; Maximum power tracking; Mechatronics; Proportional control; Robotics; Rotor speed; Smoothing; Turbogenerators; Wind turbines; 제어계측공학
• ISSN: 1598-6446; 2005-4092
• DOI: 10.1007/s12555-019-0507-5

This paper presents a power-smoothing scheme of a variable-speed wind turbine generator (VSWTG) that employs separate control gains for the over-frequency section (OFS) and under-frequency section (UFS). In the proposed scheme, an additional proportional control loop based on the system frequency deviation operating in conjunction with maximum power point tracking operation is used. In the OFS, to improve the energy-storing capability, the scheme suggests the gain of the frequency deviation control loop, which is set to be monotonously decreasing with the rotor speed while being significantly larger than that in the UFS. In the UFS, to improve the energy-releasing capability while preventing over-deceleration, the gain of the frequency deviation control loop is set to be a linear function of the rotor speed. The simulation results under continuously varying wind speeds with different wind patterns and wind speeds clearly demonstrate that the proposed scheme significantly mitigates the output power fluctuations of a VSWTG. The proposed scheme keeps the frequency within a narrow range, thereby reducing the required primary frequency control reserve for regulating the frequency under normal operations.