摘要
采用LCL滤波的并网变换器对高次谐波具有良好的衰减效果,但是LCL滤波器为无阻尼三阶系统,易发生谐振。通过加入阻尼电阻和有源阻尼可以抑制振荡,但阻尼电阻会增加系统的损耗,而有源阻尼需要增加传感器。基于状态空间法建立LCL滤波器的离散状态空间模型,针对LCL滤波器的特性,采用状态反馈配置系统极点来增加系统的阻尼,从而抑制LCL滤波系统的谐振,实现系统的稳定控制。通过引入"虚拟电阻"的方法对并网电流的闭环极点进行配置,根据此极点求得系统的状态反馈矩阵,在z平面分析系统的稳定性和动态响应特性。最后,通过搭建的基于LCL滤波器的并网变换器进行验证,实验结果证明所提控制方法的可行性。
The LCL filter is effective in the reduction of switching frequency harmonics, however the third-order LCL filter is undamped system and instability. In order to overcome this problem, the use of a damping resistor and active damping were often used, but the damping resistor will result in the power consumption and the method of active damping needs more sensors compared to the standard control. The discrete state space model was built for the LCL filter and its characteristics was analyzed. Based on the proposed model, multi-variable full state feedback was introduced to guarantee the stability of inner loop by increasing the system damping, then suppressed the resonant of the LCL filter system. A novel method of the pole assignment based on virtual resistor was proposed to aming the state feedback matrix. The stability and response of the system was analyzed in z plane. Finally, experimental results verify the availability and correctness of the proposed control strategy.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2011年第36期8-15,237,共8页
Proceedings of the CSEE
基金
国家电网公司科技项目(DG71-10-007)~~
