| Direct drive wind turbine because of its high energy conversion efficiency, high reliability, and flexible network power control, etc., become the following double-fed wind power generation wind turbine technology, after an important research direction. However, the current mainstream MW direct drive wind turbine, the converter of the control unit and its core is still dependent on imports, which greatly restricted the further development of wind power industry. Therefore, this focus on direct drive wind turbine full power converter technology and network expansion theory study on the network side converter and the motor-side converter control strategy design and analysis of, and verified by simulation theoretical research is correct.Firstly, the paper focuses on the three-level diode clamped inverter topology, the three-level inverter SVPWM modulation algorithm in depth. Through a large number of simulations of the three-level inverter model, obtained the feasibility of the three-level SVPWM method applied to the inverter, its output phase voltage waveform closer to sine wave, and greatly reduce the harmonic pollution at the same switching frequency.Secondly, established a mathematical model of wind turbine; modeling in MATLAB/simulink according to this mathematical model, the characteristics of the wind turbine simulation was analysised.Thirdly, the introduction of permanent magnet synchronous generator mathematical modeling procedure were made; studied the control strategy of the generator side using the formula of mathematical models, the control process used the PI regulator, so it presents a calculation based on transfer function PI regulator parameters.Fourthly, in the three-level inverter grid control, use outer voltage loop and dual inner current loop control system, realize the DC voltage and grid current control, and achieve unity power factor control according to sinusoidal wave current. Use Matlab/Simulink simulation tool for validation. |
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