基于滑动平均滤波的三相并网逆变器多谐振控制器

Multi Resonance Controller of Three-phase Grid-connected Inverter Based on Moving Average Filter

为了降低三相LCL型并网逆变器中高次谐波和网侧背景谐波对并网电流电能质量的影响,提出了一种基于滑动平均滤波器的多谐振(multi resonance based on moving average filter,MR-MAF)控制器。首先根据滑动平均滤波器的频域特性设计控制器,使其具有近似比例积分多谐振控制器的结构,实现谐波抑制。然后,引入2个可调系数,对该控制器控制性能进行灵活调整。最后,通过仿真和样机实验,验证了所提MR-MAF控制器在谐波抑制和提高电能质量方面的有效性。结果表明,与经典的比例积分多谐振控制器相比,本文提出的控制器不仅可以在保持相同动态性能的情况下并联多个谐振项,而且稳态性能更优,谐波含量由6.8%降至4%。因此,本文所提控制器具有结构简单且抑制谐波频带范围宽的特点,可为改善三相并网逆变器在多谐波环境下的控制性能提供参考。

In order to reduce the influence of high-order harmonic and grid side background harmonic on the power quality of grid current of the three phases LCL grid-connected inverter,this paper presents a multi resonance controller based on moving average filter(MR-MAF).Firstly,the controller is designed according to the frequency domain characteristics of MAF,so that it possesses the similar structure with the proportional integral multi resonance(PIMR)controller through mathematical equivalent substitution.Then,by introducing two adjustable coefficients,the MR-MAF controller can obtain the flexible adjustment of the control performance.Finally,the validity and the effectiveness of the proposed method are verified by simulation and experimental results.The results show that,compared with the traditional PIMR controller,the MR-MAF controller can not only parallel multiple resonant terms with the same dynamic performance,but also has the better steady-state performance,and the harmonic content is reduced from 6.8%to 4%.Therefore,the controller has much lower complexity when suppressing wide frequency band harmonics,which can provide reference for improving the control performance of three-phase grid-connected inverters in the multi-harmonic condition.