基于准谐振控制器的零序环流抑制

The zero sequence circulating current suppression based on quasi resonant controller

针对三相逆变器直接并联运行时存在零序环流的问题,提出一种基于准谐振控制器的零序环流闭环控制方法。通过分别建立并分析逆变器独立工作和两台并联工作时零序环流闭环控制模型可知,PWM零序调制电压为主要扰动。理想的谐振控制器在谐振频率处增益无穷大,可以消除与谐振频率相同频率的扰动分量对闭环系统的影响。针对扰动为频谱离散的周期性信号的特性,控制器采用多谐振控制器并联的控制结构。在推导零序环流闭环控制等效模型和扰动传递函数的基础上,提出准谐振控制器设计方法。仿真和实验结果表明,该方法能够有效抑制零序环流。

Aiming at the zero sequence circuits,when inverters worked in parallel directly,a zero sequence circuiting current closed-loop control method based on quasi resonant controller is proposed.The zero sequence circulating current closed-loop control models of one inverter and two inverters were constructed and analyzed.The gain of ideal resonant controller is infinite at the resonant frequency,so the disturbance could be eliminated at the same frequency.The pulse width modulation（PWM） zero sequence modulation voltage is main disturbance,of which the frequency spectrum is discrete.Multiple resonant controllers which worked in parallel were adopted in the control loop.A resonant controller design method was proposed,based on the equivalent closed-loop control model of the zero sequence circuiting current and the disturbance transfer function.Simulation and experiment results testify that it suppresses the zero sequence circuiting current effectively.