Study on Passive Filter in Wind Power Converter

This paper analyzes the generation mechanism of common-mode and differential-mode voltage in the wind power converter; designs a new type of passive filter which adopts LRC structure in both rectifier side and inverter side, and equips common-mode inductors. According to the bus common-mode inductor common-mode currents to ground principle the same direction, the use of common-mode current to a coil produces a magnetic field which increases with the damping characteristics of the coil, the effective attenuation of the system to the ground noise currents, with strong common-mode rejection effect. The LRC branch structure directly grounded neutral point, with common-mode and differential-mode rejection characteristics. In 2 MW full scale power wind power converter unit tests show: the proposed filter structure, taking into account the cost, volume can effectively suppress common-mode and differential-mode voltage. According to the proposed filter structure developed full scale power converter product application, verify the correctness and effectiveness of the passive filter topology.