The design of an LCL-filter for the three-parallel operation of a power converter in a wind turbine

This paper proposes a design scheme for an LCL-filter used for three-parallel operation in 2MW-wind turbines. An appropriate design method of the delta configured LCL-filter is also proposed to improve the output power quality in the system. A novel design method for the inner inductance of the LCL-filter is proposed in order to overcome the existing trial and error methods used in designing a filter. LCL-filters typically have a problem with a reduced power factor (PF), due to the capacitor used. To improve the poor PF, a simple compensation method is also proposed. The simulation results demonstrate that the grid current harmonics are low and the PF is improved.