| Wind energy resource is green energy of non-polluting and makes a least impact on the environment among kinds of energy. Therefore, in order to promote economic and social development and ease the conventional energy resources limited and the problem of environmental pollution, wind energy and other renewable resources have be paid attention to in various countries. Wind power generation system is an effective device which changes wind energy into electricity, so it is widely applied in various fields of national economy. With the rapid development of power electronics technology, its performance and reliability is improving more and more. Because direct-drive variable speed constant frequency wind power generation system is high efficiency, simple structure and stable operation, it is one of development trends and current research focus of wind power technology. This paper studies the direct-drive wind power technology based to permanent magnet generator.PWM inverter of direct drive wind power generation system changes power to alternating current of the constant frequency and constant voltage, so the design and manufacturing of PWM inverter are important and difficult. In this paper, mathematical modeling of PWM inverter is established and closed-loop control system of PWM inverter based to SVPWM is design. We also study the control strategy of direct drive wind power system.Firstly, the overall program of direct drive wind power system is designed. After comparing common topological structures of direct-drive wind power generation system, 10kW power converter main circuit is designed, then the device parameters of main circuit of PWM inverter are seleced.Secondly, the PWM inverter control strategy is studied and mathematical model of the topology of three-phase of VSR is analyzed. PI controller is designed according to the mathematical model and PI controller tuning method is introduced, which provides a theoretical basis for design of the control system.On the other hand, the hardware and software of control system of PWM inverter is designed, in hardware processing chip, TMS320LF2406 with dedicated high-performance digital signal in control areas is as the core controller, which the digital control system of inverter device is constructed to verify the control strategy and in software the paper also presents the parameters of the experimental system design and implementation of software flowchart of thought of the control. The digital control system constructed realized closed loop control of PWM inverter, output control of SVPWM and channel selection of inverter device power, plant protection, faults handling and so on.At last, laboratory systems are made and the experiment is carried out, which PWM inverter control waveforms are obtained, then the inverter controller closed-loop control system stability is analyzed.The results of the experiment have verified the correctness of the analysis and design. |
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