潮流能发电并联逆变器零序环流抑制方法研究

REASEARCH OF PARALLEL INVERTER ZERO SEQUENCE CIRCUITING CURRENT SUPPRESSION METHOD OF TIDAL CURRENT ENERGY GENERATION

为提高潮流能发电系统功率等级,三相逆变器采用多模块并联技术。为抑制并联运行时的零序环流,通过建立和分析零序环流闭环控制模型可知:零序环流闭环控制中的主要扰动为零序调制电压。针对扰动为频谱离散的周期性信号的特性,提出一种新的零序环流抑制方法。该方法利用梳状滤波器代替传统的增益恒定的反馈函数,来提高谐波频率处的反馈增益从而提高系统抗扰动的能力。通过在梳妆滤波器中增加低通滤波器来提高系统稳定性,并提出通过减小延时时间对波峰频率矫正的方法;通过降低直流增益防止电网零序电压漂移。仿真和实验结果证明该方法能有效抑制零序环流。

Multi-module parallel topology was adopted in the three phase inverter to increase the power capacity of tidal current energy generation. It is known that zero sequence modulation voltage is the main disturbance through construction and analysis of zero sequence circuiting current closed-loop control model. The frequency spectrum of disturbance is discrete. A novel zero sequence circuiting current suppression method was proposed. The traditional constant gain feedback function was replaced by comb-like filter in the method, which has high harmonic gain and improve the performance. Low pass filter was adopted in the comber-like filter to improve the stability, and the delay time was reduced to adjust the peak frequency. The zero-frequency gain was decreased to avoid zero sequence voltage drift. The simulation and experiment results verify that zero sequence circuiting current is suppressed effectively.