变速恒频风力发电机用交流励磁电源的研究

Investigation of AC Excitation Power Supply Used in VSCF Wind-Power Generator

变速恒频风力发电系统追踪最大风能过程中,双馈发电机将在同步速上下运行,这就要求交流励磁电源应有良好的输入、输出特性和能量双向流动的能力。在分析了其他变频器的局限性后,指出了双PWM变频器是交流励磁的最佳电源方案,详细地讨论了电压型双PWM变频器的工作原理与控制策略。实验结果表明,这种变频器可以很好地满足交流励磁发电机变速恒频运行的要求。

In the process of tracing maximum wind-energy of a variable-speed constant-frequency(VSCF)wind-power generation system, the Doubly-Fed Generator(DFG)will operate below and above the synchronous speed very often, which requires the AC excitation power supply to possess excellent input and output performance and the bi-direction flowing ability of energy. In this paper, a back-to-back PWM converter is considered as the optimum scheme of AC excitation power supply and its operation principle and control strategy are discussed in detail. Experiments demonstrate that this kind of frequency converter is capable of satisfying the VSCF operation demands of an AC excited wind-power generator.