基于谐振控制器的并网谐波电流抑制研究

Design of Harmonic Current Suppression Strategy Based on Resonance Control

传统同步旋转坐标系下的比例积分(PI)控制策略理论上可以实现直流量的无静差控制,而对于电网电压畸变、死区时间等非理想并网工况引起的大量低次谐波电流的抑制能力有限,以至于变流电流不能满足并网谐波要求。针对并网谐波电流抑制,此处主要对电网电压畸变下并网变流器进行建模,以5/7次谐波为例推导其在基频d,q坐标系下的表现形式,进一步在PI控制器的基础上加入谐振控制策略,并分析控制对象的双边频域对称性,同时给出比例积分谐振(PIR)控制器的参数设计和数字化实现过程。最后通过仿真和实验验证了PIR控制策略的谐波抑制有效性。

The proportional-integral(PI) control strategy in the traditional synchronous rotating coordinate system can theoretically realize the control of direct current without static error,but the ability of restraining the large amount of low-order harmonic current caused by the grid voltage distortion,dead-time and other non-ideal grid-connected conditions is limited so that the converter can not meet the requirements of grid-connected harmonics.Aiming at gird-connected harmonic current suppression,the grid-connected converter under the voltage distortion of power grid is mainly modeled,taking the 5/7 th harmonics as an example to deduce expression in the fundamental frequency d,q coordinate system,furtherly,resonance control strategy is added on the basis of PI controller,analyzes the bilateral frequency domain symmetry of the control object,and gives the parameter design and digital realization process of proportionalintegral-resonance(PIR) controller.Finally,the harmonic suppression effectiveness of PIR control strategy is verified by simulation and experiment.