基于双滞环电流控制4桥臂静止无功发生器的研究

Research of STATCOM with Four Legs Based on Double Hysteresis Current Control Method

为了使静止无功发生器除了无功补偿以外,还具有消除谐波、零序和负序等有害电流的功能,对采用直接电流控制方法的静止无功发生器进行研究。选择4桥臂变流器作为静止无功发生器的主电路;建立了4桥臂静止无功发生器数学模型;改进了基于αβ0坐标系的双滞环电流控制方法;对此静止无功发生器方案进行了仿真研究,结果表明该静止无功发生器能够补偿不平衡系统的无功功率,同时能够有效地滤除系统中的谐波、负序和零序等有害电流。

For compensating harmonic, zero-sequence and negative-sequence currents besides reactive current, STATCOM which uses direct-current control was developed. Through comparing two accustomed structures of main circuit, a converter with four legs was selected as main circuit. The math model of STATCOM was established. A improved hysteresis current control based on αβ0 coordinate system was proposed to control the converter. The results of simulation show that the STATCOM not only can compensate reactive power, but also can eliminate the harmonic, zero-sequence and negative-sequence current effectively.