A New Wind Turbine Interface to MVDC Collection Grid with High Frequency Isolation and Input Current Shaping
A new power electronic interface suitable for the integration of next-generation offshore wind turbines with medium voltage DC (MVDC) collection grids is introduced in this work. A practical design case study provides guidance for further development of the proposed interface. Detailed simulations show acceptable operation of the proposed approach from 25% to 100% rated power, including step changes in WTG input power. Simulation results demonstrate >0.95 displacement power factor magnitude, near sinusoidal WTG current, continuous output current, stiff DC link voltages, and inverter zero-current switching (ZCS).
Preliminary hardware results from a 250 Vdc, 700 W lab-scale prototype are introduced, demonstrating input rectifier boost characteristic with a dominant input current fundamental and >0.95 displacement power factor magnitude. The DC link current has a large peakto- average ratio as expected, and DC link capacitor voltage balance is achieved via adjustment of relative duty cycles between high- and low-side active rectifier switches.