非理想电网下PWM整流器的多谐振控制研究

Research on the multiple resonant control in PWM rectifier under non-ideal power source

针对非理想电网电压不对称并含有低次谐波成分,使三相脉冲宽度调制（PWM）整流器的电网电流不对称且严重畸变而影响其正常运行的问题,提出一种PI＋多谐振控制的电流控制方法。首先建立了PWM整流器旋转坐标系下的数学模型,并分析了非理想三相电网电压在旋转坐标系下的特性,然后在传统电压、电流双闭环控制的基础上,提出在电流控制环路的PI控制器上叠加多谐振控制的方法,以实现电网电流谐波的抑制和三相电流平衡控制,给出了各电流控制器的参数设计方案,进而分析了提出的控制策略的鲁棒性。最后针对10 k W的PWM整流器平台,进行了非理想电网下的仿真和实验验证。结果表明,该方法能大幅改善非理想电网电压下整流器的网侧电流质量。

In view of asymmetry and the low harmonic component in the non-ideal grid voltage,the current in the pulse width modulation（ PWM） rectifier is asymmetrical and distorting seriously. As a result,the normal operation of the rectifier is affected. In this paper,PI＋ multiple resonant control of grid side current in rectifier is pointed out. Firstly,the modeling of the PWM rectifier is established under the synchronous rotational reference frame. The characteristics of non-ideal three-phase grid voltage in rotating coordinate system are analyzed. And then,based on the traditional control strategy of voltage and current control,the multiple resonant controllers are pointed out in the current control loop to realize the elimination of the current harmonics and balance the three-phase currents in the grid side.How to design the parameters of controllers are introduced in detail. The robustness of the control system by the use of multiple resonant controllers is analyzed. At last,simulation and experiment results from a 10 k W PWM rectifier prototype are used to verify the effectiveness of the proposed control strategy. The results show that the proposed control strategy can greatly improve the grid side current＇s quality of rectifier under non-ideal grid voltage.