Research On Three-Level Medium Voltage Wind Power Convertor

The energy problem has become one of the most critical issues of the modern society with the development of productivity. The contradiction between human and nature trends to be increasingly serious. Wind power represents one of the renewable resources as its rich quantities and relatively mature technology. Thus, wind power generation technology has been taken into account all over the world. In the future development, Permanent magnetic synchronous generator direct-driven full-power wind generation technology will become the most important technology in offshore wind farm.Full-power wind generation technology needs to be developed to satisfy the requirement of offshore wind farm as the higher power scale (in MWs). If the traditional low-voltage convertor is involved in the wind power systems, the power loss caused by the current is no more acceptable. On the other hand, the power electronics devices at present still cannot tolerant such a high current. If a parallel topology is involved in the wind power systems, several problems such as loop current, efficiency becomes more serious and should be taken into account. Increasing the voltage of convertor is the best method to increase the power scale of wind power system.Medium voltage convertor technology is able to decrease the current stress of power electronics devices, and improve the efficiency and reliability of the system. This paper mostly studies the application of medium voltage convertor technology in wind power systems. This paper compares several different medium voltage convertor topologies, and chooses 3-level NPC as the most convenient topology in wind power system. What is more, this paper designs a control platform based on DSP&FPGA, and finishes a prototype in laboratory to prove the feasibility of program.This paper can be divided into four parts: first, introduces several different topologies of medium voltage convertor, second, establishes the mathematical model of grid-side and generator-side convertor, and gives the vector control scheme of both sides, third, this paper finishes the design of medium voltage wind power convertor, including control platform, high-voltage IGBT driver, and main circuits design. At last, this paper gives the experimental results of a 100KW prototype.