Study On Single-phase Grid-Connected Inverter Control System Of Middle-Small Size Wind Power

As a clean and renewable energy, wind energy attracts great attention in the aspect of new energy application around the world, the technology of wind power grid-connected has become the hot points in international research. The inverter is the key of grid-connected operation, which affects the utilization efficiency of wind energy and control system stability. This dissertation mainly focuses on single-phase grid-connected inverter control system of middle-small size wind power, the circuit topology, control method, parameter selection and other aspects are analyzed and studied. And a 3kW model machine is produced.Firstly, this dissertation discusses the existing wind power grid-connected scheme, proposing uncontrolled rectifier+BOOST DC+Full-bridge inverter topology , and analysing the circuit working principle. In the control strategies, the voltage and current double closed-loop control is applied to keep the DC voltage stable; the inverter part adopts current closed-loop control, using the synchronous phase-locked technology to make the output current track the grid voltage. Meanwhile, in order to reduce the interference, adding the grid voltage feedforward control. Besides the mathematical model of control system is established, designing the digital controller.Secondly, the main circuit parameters of 3kW wind power grid-connected inverter are made an exact calculation according to the system design requirements; the control circuit board based on dsPIC30F6010 is designed, and the hardware circuit diagram and software flow chart are given.Finally, the entire control system of wind power single-phase grid-connected inverter is simulated and is experimented. The results show that the system is reliable and has a good performance, which achieve the expected goals. So it proves that the grid-connected scheme is feasible and theoretical analysis is correct.