一种LCCL滤波器及其在半桥电力有源滤波器中的应用

提出一种新型高阶电力滤波器,将其命名为LCCL滤波器。与传统的LCL滤波器相比,LCCL滤波器通过在网侧电感支路并联一个小电容,使网侧电感与并联电容在开关频率处发生并联谐振。谐振使LCCL滤波器网侧支路在开关频率处呈现无穷大的阻抗,相比LCL滤波器可以更好地抑制开关频率附近电网电流纹波,减小电网电流THD。与LLCL滤波器相比,LCCL滤波器具有较好的抑制参数变化的能力,在考虑电网内阻抗时,拥有更好的高频纹波抑制性能。同时,可以更容易地进行基于电容电流反馈有源阻尼的控制器设计。LCCL滤波器作为电压源型逆变器(VSI)与电网的接口,可应用于PWM整流器、有源电力滤波器(APF)和通用电能质量控制器(UPQC)等多种场合。通过以半桥APF为例,讨论了LCCL滤波器的参数选择方法和控制器设计。最后,通过仿真和实验验证了LCCL滤波器的可行性。

An LCCL Filter for a Half-Bridge Active Power Filter

In this paper, a novel high order power filter is proposed, named the LCCL filter. Compared with the traditional LCL filter, the LCCL filter composes a parallel resonant branch loop at the switching frequency by paralleling a small capacitor with the line side inductor. The parallel resonance enables the line side branch loop to exhibit infinite impedance at the switching frequency. Particularly, it can attenuate the switching frequency current ripple components much better than the LCL filter, thus decreases THD in source current. Compared with the LLCL filter, the LCCL filter performs well considering the case where parameters are not fixed and exhibits better attenuation ability in the high frequency domain when the source impedance is considered. Besides, a capacitor current feedback based active damping controller is easy to design on the LCCL filter. As an interface between voltage source inverter (VSI) and the grid, the LCCL filter can be applied to the PWM rectifier, active power filter (APF), and unified power quality controller (UPQC). A half-bridge APF is taken as an example in this paper to discuss the parameter selection method and the controller design method based on the LCCL filter. At last, simulation and experimental results validate the feasibility of the proposed LCCL filter.