Research On Direct Powenr Control And Communication Function Of Direct-drive PMSG WECS

With the decrease of primary energy and increasing seriousness of environmental pollution, the development of clean renewable energy has attracted great attention of many countries, one of which is the wind energy. Permanent Magnet Synchronous Generator (PMSG) has been widely applied because of its simple structure and control. As a simple algorithm with excellent dynamic performance, direct power control (DPC) strategy has been on focus and researched. Meanwhile, being an important technique in the information system of the smart grid, communication technique is widely researched and the research of communication system has great practical significance.Firstly, on the analysis of the main topologies of the PMSG, a mathematical model of the back-to-back PWM converters is built in the paper. And the vector control strategies of generator side converter and grid side converter are introduced respectively. Afterward, simulation models are built in Matlab/Simulink and related analysis is done.Secondly, on the basis of DPC strategy of grid side converter, two LUT-DPC solutions and two P-DPC solutions are demonstrated in detail respectively. Then a new P-DPC solution is proposed in the paper. Finally, a simulation model of the grid side converter operating in the grid-connected mode is made and some simulations are conducted using the three DPC solutions above, with their own characteristics after comparison.Thirdly, an experimental platform of PMSG wind energy conversion system is built with the setup of the hardware and the software design of the control system. Afterward, in the condition of grid-connected operation, some experiments are conducted aiming at the grid side converter, such as DPC experiment and vector control experiment. After the comparative experiment and analysis, the characteristics of different control solutions are concluded. Then, in the condition of islanded operation, the simulation of PMSG wind energy conversion system under DPC solution is conducted, while related experiment is also done on the platform. It confirms the feasibility of the new P-DPC solution in the condition of islanded operation.Lastly, the features and operating principle of the CAN bus are presented in detail. And the content of Modbus protocol and operating principle of SCI communication are demonstrated. Then the software design of the communication system is put specifically. Afterward, the DPC experiment with communication fiinction.is done and the reliability of the communication system is verified.