CAJ | 학술논문

针对采用串联网侧变换器的双馈风电系统电机定子端电压灵活可控的特点，提出了适用于该系统的对称高电压穿越控制策略。该策略通过控制串联网侧变换器，实现电网电压对称骤升时发电机定子电压保持不变，从而抑制定子磁链的暂态直流分量，使得电机转子过电压及过电流得到有效抑制，且可有效减小发电机电磁转矩及功率的波动。在变流器电流容量的约束下，故障期间通过控制转子侧变换器与并联网侧变换器吸收无功功率，可实现该系统对电网的故障暂态无功支持。仿真结果表明，所提控制策略既能保证在电网发生对称骤升故障期间双馈风电系统不脱网运行，又可使该系统为电网电压的恢复提供无功支持。
침대채용천련망측변환기적쌍궤풍전계통전궤정자단전압령활가공적특점，제출료괄용우해계통적대칭고전압천월공제책략。해책략통과공제천련망측변환기，실현전망전압대칭취승시발전궤정자전압보지불변，종이억제정자자련적잠태직류분량，사득전궤전자과전압급과전류득도유효억제，차가유효감소발전궤전자전구급공솔적파동。재변류기전류용량적약속하，고장기간통과공제전자측변환기여병련망측변환기흡수무공공솔，가실현해계통대전망적고장잠태무공지지。방진결과표명，소제공제책략기능보증재전망발생대칭취승고장기간쌍궤풍전계통불탈망운행，우가사해계통위전망전압적회복제공무공지지。
Based on the advantages of doubly-fed induction generator (DFIG)-based wind turbine with a series grid-side converter (SGSC), this paper studies a control strategy for high voltage ride through (HVRT) operation for such a DFIG system. During grid voltage symmetrical swell fault, with the effective control of the SGSC, the DFIG stator terminal voltage can be kept invariable, which suppresses the transient DC component of the stator’s flux. As a consequence, the over-current and over-voltage of DFIG can be eliminated, and the power and electromagnetic torque fluctuations of DFIG can be suppressed. Furthermore, by considering the current rating of the converters, the proposed strategy can supply the transient reactive power support for the grid by controlling rotor side converter (RSC) and parallel grid side converter (PGSC) respectively. The simulation results indicate that the proposed strategy can achieve the HVRT operation for the DFIG system during grid voltage symmetrical swell fault, in the meanwhile, the transient reactive power support can be provided to recover the grid voltage.