| Great attention has been paid on the development and utilization of renewable energy, and wind energy is one of the most cheap, the most promising green energy. Due to its unique advantages, the direct-drive wind power system has become an important direction of development and a hotspot research in the field of wind power technology. The converter is a necessary component and its structure and control is one of the key technologies in wind power system. There is huge wind power installed capacity in China at present. However, direct-drive wind power system converter technology is not mature enough, and still there are some gaps compared to foreign. Therefore it has great significance in studying permanent magnet direct drive wind power converter.Firstly, a detailed comparison of the advantages and disadvantages of the topology of the four kinds of wind converters is emerged in this paper, and selecting the double PWM converter is the object of this paper. Aiming at PMSG, the mathematical models are given in different coordinate systems. Secondly, the SVPWM method is adopted in converter control, and SVPWM simulation module is builded in MATLAB. Controlling the q-axis current and making the d-axis current to zero method is adopted to achieve maximum torque and efficiency of the generator on mac-side. Voltage outer and inner current are used to ensure that the DC bus voltage stay constant and grid power factor can be adjusted. The PI parameters are calculated on the mac-side and the grid-side at last. Finally, simulation model of the mac-side and the grid-side are builded in the MATLAB, then simulating is done to verify the correctness of the control strategy. Analyzing the grid simulation to verify stability and correctness of the system control is done at last.On the basis of the above research, debugging waveforms are given after debugging in direct drive wind power experiment platform to verify the correctness of control strategies and the stability of the system. |
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