交流励磁变速恒频风电系统运行研究

随着风电机组单机容量的不断增大,采用变桨距风力机实现最大风能捕获和利用的变速恒频发电已成为当前风电技术的研究热点.文中从理论到实践全面讨论了双馈发电机交流励磁变速恒频的发电原理、对交流励磁变频器的要求,以及为追踪最大风能捕获、实现发电机有功、无功功率独立调节和变速恒频下空载并网控制的定子磁场定向矢量控制策略.实验风电机组的空载、并网、同步速上、下的发电运行全面验证了所提出的交流励磁变速恒频关键风电技术的正确性,为大型风力机组的工程实现奠定了一定的理论及技术基础.

INVESTIGATION On AN AC EXCITED VARIABLE-SPEED CONSTANT-FREQUENCY WIND-POWER GENERATION SYSTEM

With the continuous increase of the capacity of a wind-power generator, the efficiency improvement of electric power generation has become a more and more important issue. The variable-speed constant-frequency (VSCF) power generation, which aims to reach maximum wind-energy capturing and utilization for a variable blade-pitch wind-turbine, is currently pursued topic about wind-power generation techniques. In this paper, the technical approach of AC excited doubly-fed induction generator is comprehensively investigated thoroughly, including the discussion on issues such as (1) the VSCF principle of the doubly-fed generator, (2) the demands of the PWM frequency-converter, which is used as the excitation source for the generator, (3)the independent regulation of active and reactive power output from the generator side, which is designed for the purpose of tracing the maximum wind-energy capturing and realized by the stator field orientation control strategy, (4) the no-load cutting-in control of the generator being connected into the grid. The experimental operation study of no-load, cutting-in grid and power generation below and above the synchronous speed are all examined in a laboratory set-up, which successfully verifies the correctness of the A. C excited VSCF key-technique proposed in the paper and lays a technical foundation for the engineering development of the large modern wind-power generator.