A Novel Multi-level Medium Voltage Converter Designed for Medium Voltage Wind Power Generation System

A novel back to back cascaded medium voltage converter is proposed for wind power generation. In the generator side, it is a H-bridge cascaded converter, which employs the vector control based on rotor flux orient to drive the medium induction generator. In the grid side, a series of two-level voltage source converters are used to support an isolated DC voltage for each H-bridge cell in the generator side, which is controlled by the PWM rectifier algorithm. With the novel converter, generators in the wind power can directly work in a 3~10 KV voltage system instead of the conventional 690 V system, which makes it impossible for a wind turbine to product a larger power such as 3 MW or 5 MW. The application not only improves the efficiency and the safety of the system, but also reduces the use of the cable and the cost greatly. To validate the fitness, some simulations are done in MATLAB/SIMULINK. The results are satisfactory.