交流励磁发电机励磁电源管压降引起的谐波及其消除方法的研究

交流励磁发电机由于能够实现有功、无功和转速的独立调节，在改善超高压电力系统的稳定性以及变速恒频发电等领域有着广泛的应用前景。交—直—交电压源变频器以其优良的输出特性可用作这类发电机的励磁电源。交流励磁发电机励磁电压较低，因励磁主回路器件(如IGBT)自身特性的影响，使得这类变频器在低压输出时，输出电压波形发生严重畸变，导致交流励磁发电机的转子电流谐波增大，定子输出电压、电流谐波增加。该文详细分析了由器件特性引起的谐波增大的机理，提出了管压降补偿的方法。仿真与实验结果均说明分析是正确的，提出的补偿方法是有效的。

ANALYSIS AND ELIMINATION METHOD OF HARMONICS PRODUCED BY FORWARD VOLTAGE DROP OF ACEG EXCITATION POWER SOURCE

There is broad prospect for improving the stabilities of extra-high voltage power systems and generation at a constant frequency but a variable speed with the independent regulating abilities of real and reactive power and speed realized by a.c. excited generators (ACEG). AC-DC-AC voltage source converters can be used as excitation power supplies for such generators with their excellent output characteristics. The excitation voltage is rather low for ACEG. As the influences of excitation main circuit device'(such as IGBT) characteristics, the output voltage waveforms of such converters are distorted badly when they are used under low voltage conditions, and this will lead the increments of harmonics of rotor current, stator output voltage and current in ACEG. In this paper, the mechanism of harmonic increments caused by device characteristics are analyzed in detail, and the compensation algorithm of a forward voltage drop is proposed. The simulation and experimental results in the paper shown that the cause of harmonics increments in the ACEG systems are weakened. Experimental tests are also used to verify the compensation method.