LCL-filter design for grid-connected three-phase PWM converter based on maximum current ripple

This paper proposes a new design method of LCL-filter for three-phase PWM voltage source inverter. Maximum converter-side current ripple is calculated by defining different modulation section of the adopted PWM strategy. In this way, the method can be easily extended to different converter topology and PWM strategy. Then the result is used to determine converter-side inductance. Once it is fixed, current attenuation passing from converter to grid at switching frequency and reactive power limitation equations are synthesized to design the minimum grid-side inductance and the proper range of resonance frequency. Then according to adopted PWM converter voltage spectrum, choose final resonance frequency to avoid the harmonic frequency spectrum distribution. A design example is given and the simulation and experiment results demonstrate the effectiveness of the method.