An Improved Resonant Frequency Based Systematic LCL Filter Design Method for Grid-Connected Inverter

作者：Wu Tsai Fu^*; Misra Mitradatta; Lin Li Chiun; Hsu Chih Wei

来源：IEEE Transactions on Industrial Electronics, 2017, 64(8): 6412-6421.

DOI：10.1109/TIE.2017.2682004

• Damping
• design
• division-summation (D-Sigma) digital control
• harmonics
• inductance variation
• inverter
• LCL filter
• line impedance
• magnetic permeability
• resonant frequency
• stability

Resonant frequency of an LCL filter in a grid-connected inverter is an important factor for control stability and grid-injected current quality. However, the constraints on resonant frequency are usually considered as an afterthought in conventional filter design methods. The fact that resonant frequency is affected by both internal and external factors during operation makes it even more critical. Hence, an improved resonant frequency based systematic LCL filter design method is presented in this paper. A resonant frequency band is identified by considering grid-voltage harmonics and control stability boundary. The variation in resonant frequency due to inductive line impedance as well as magnetic permeability of inductor core is taken into account to define the constraints on LCL parameters. The LCL parameters are then systematically derived from the identified constraints with almost no iteration. A division-summation (D-Sigma) digital control method is used to validate the design method. Experimental results measured from a 5-kW single-phase grid-connected inverter have verified the effectiveness of the LCL filter design method over conventional methods.

• 出版日期2017-8
• 单位清华大学