| In recent years, wind power generation technology has made remarkable progress, and becomes an important branch of new energy technology. Based on the Subjects of Supported Program of Anhui Province during the 10th Five-year Plan Period, and the Subjects of Supported Program of the Ministry of Science and Technology during the 11th Five-year Plan Period (No. 2006BAA01A20) , this paper makes a deep study on correlative key technologies of full power wind turbine converter used in MW level permanent magnet synchronous direct-drive wind power generation system, comprising the permanent magnet synchronous generator (PMSG) mathematical model, vector control strategy & its performance, speed sensorless control method, parameter identification of PMSG, generator simulator and experimental simulation of PMSG wind power generation system, and control sequence & coordinated control of direct-drive full power wind turbine converter. Within the above research scopes, some scientific achievements, which are of innovation significance at certain extent, have been achieved. The main research content included in this paper, can be listed as follows:1. In allusion to the electrical structure and other concerned emphases of PMSG used in the direct-drive system, mathematical model of three phases & six phases PMSG are established, while putting highly emphasis on the analysis of their respective characteristics. According to the model and equation built by theoretical analysis, the universal simulation model of PMSG is established by Matlab/Simulink, and corresponding simulation results are given by adopting the actual generator parameters. Three kinds of model mentioned above have built the theoretic and simulation platform for the further study directing towards the control strategy of PMSG.2. A MW level PMSG simulator is proposed: According to the mathematical model of MW level PMSG, the stator voltage & current characteristics of generator under diverse rotate speed, can be acquired, then three phase frequency converter is adopted to approximately simulate the stator voltage & current characteristics, which aiming at validating the characteristic/feature and capability/ability of the load-bearing. In this paper, control system design of the PMSG simulator is described in detail, and the simulation results testify its feasibility.3. The common vector control strategy of PMSG is studied in details, and its shortages in the actual engineering application of direct-drive PMSG system, are analyzed as well. In accordance with the actual parameters of the MW level PMSG, a compound vector control strategy is proposed in this paper. This method has realized the switching control of different vector control strategies while PMSG in the direct-drive system is running in diverse operating condition. Thus improving the system stability and power generation efficiency.4. Speed sensor-less control strategy of PMSG is investigated: In allusion to the given operating condition of PMSG in the direct-drive system, a speed sensor-less control method which combines phase-locked loop (PLL) and model reference self-adaptation, is proposed. It is simple to implement, while its identification is exact, and its implementation h as fulfilled the technical requirements of sensor-less control in the direct-drive system. Subsystem design of this method and corresponding simulation analysis are also given in this paper.5. Parameter identification of MW level PMSG is researched: It is necessary for vector control and speed sensor-less control methods to acquire the accurate PMSG parameters. In allusion to above requirement, this paper illustrates the typical parameter identification method of least squares, and then the analysis and simulation results point out that this method can achieve the exact parameter identification, but it is not suitable for engineering application. For this reason, a parameter identification method based on the speed sensor-less vector control, which has good practicability, is proposed in this paper, and theoretical analysis and simulation verification show the better performance in detail.6. Experimental simulation scheme of direct-drive system is investigated: three kinds of simulated traction scheme of PMSG under diverse power level are constructed, and corresponding experimental investigations are also carried out. For different experimental purpose, based on the above simulated traction systems,the feasibility and validity of the compound vector and speed sensor-less control strategies, proposed in this paper, are testified by the experimental results, thereby establishing the foundation for the further trial running of direct-drive system in wind farm. 7. Coordinated control strategy & control sequence of MW level direct-drive full power wind turbine converter are studied in this paper: In allusion to the hardware characteristic of full power converter and low voltage ride through (LVRT) capability which is essential in wind farm, coordinated control scheme among the net side, motor side and crowbar circuit in the DC side of full power wind turbine converter is investigated. In order to guarantee the trial running of full power converter, its control sequence is designed and achieved, it undergo half year's trial running experiment in the wind farm.
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