Current Ripple Oriented Design of LCL Filter for Three-Phase Voltage-Source Converter with Different Wire Connections and Modulations

摘要

Wide range of parameters selection and multiple iterations are still needed in most of the existing design procedures of LCL-filter. Moreover, the current ripple cannot be accurately decided, and the damping resistance, which can affect the current ripple, control stability and filter losses, is hard to be optimized. To solve these problems, this paper presents more accurate calculations of maximum peak-to-peak current ripple on both sides of the filter under different power levels, wire connections and modulation strategies. The damping resistance is designed in a new manner to achieve an optimized damping ratio. Finally, grid-side inductance is calculated more accurately by considering the influence of damping resistance and the changing rate of current attenuation. The primary goal is to provide a more accurate, general and efficient design for LCL-filter with little iterations, and to ensure that the current ripples can be accurately estimated and be set as new design target.