Research On Control Of Dual Pwm Converter And Its Application To The Permanent Magnet Direct-drive Wind Power Generation System

As coal, oil, natural gas and other fossil fuel resources are depleting, energy security issues causing more and more extensive attention all over the world. In recent years, China’s wind power market continues to expand, the wind power industry has been developing rapidly. In the wind power generation system, the power converter which based on power electronics technology is the main device. Then, the device achieved flexible connection between the generator and the grid by controlling the converter and adjusting the generator speed. It is also of great significance to the wind power system’s stability and efficient operation.In this paper, the main study object is direct-drive permanent magnet wind power generation system. To do research through the mathematical model of dual PWM converter and its control strategy, and then using modeling and simulation to validate the correctness of the research.Comparative analysis of the common topologies on direct-drive permanent magnet wind power system converter. To summarize development status of inverter control technology. At last, the back-back voltage source dual-PWM converter is selected for the study. The mathematical models of the wind turbine, permanent magnet synchronous generator and PWM converter have analyzed and built in the reference coordinate transformation theory. This has provided a basis for the simulation analysis.It is study on the control strategies of grid side converter and machine side converter based on the mathematical model of converter control. Taking feed-forward decoupling scheme to achieve the active and reactive power decoupling control on grid side converter. This paper obtained a voltage and current double closed-loop controlling method based on grid voltage orientation. To achieve good torque control performance, using the zero d-axis current control strategy on the machine side converter. The stator current control strategy is obtained based on the rotor flux orientation vector control methods and vector control method. To design parameters of the system control parameters, communication filter inductor and DC capacitor. This can be provided a reference on the selection of parameters.According to the PI control fluctuation phenomenon appears in the DC bus voltage control, the ADRC control technology is applied to the grid side converter control system. Then responses rapidly the DC bus voltage and reached a stable value in the shortest time. Compared the voltage loop with PI regulator, it has better control quality and the steady-state accuracy.Established the simulation model by MATLAB. The simulation results show that the system has good dynamic response capability. The correctness and effectiveness of the proposed control strategy.which was verified.