Investigation On New Topology And Control Strategy Of PMSG-based Wind Power System

Wind power generation is the most economical among the renewable energy, which has been used widely in the world. Wind energy conversion system (WECS) based on Permanent magnet synchrounous generator (PMSG) has good prospects and potential for wind power application particularly in offshore field because of its good operation performance, high reliability, low maintenance cost and storng grid adaptability. The large capacity wind power system (5-10MW) is the development trend of the future and high-perfomance full power converter is a key to buid the large system based on PMSG. The robustness and fault tolerance of WECS operation and higher standard of grid connection have been more important with the development of offshore wind power. Therefore, the full power converter building, high-performance control strategy, as well as fault-tolerance operation control will be the key technologies. This paper investigates two new topologies of PMSG based wind power system and its control algorithms by theoretical analysis, simulation modeling and experimental validation.Firstly, a new topology WECS based on open-winding PMSG (OW-PMSG) has been build in this paper. The mathematical model in the synchronous rotating coordinate of the OW-PMSG and the voltage space vector of the two cascaded converter has been analyzed. Then, two vector control strategies based on sensorless control and different space vector pulse width modulation (SVPWM) have been designed for the OW-PMSG in proposed system. The operation performance of the system and the avaibility of the proposed control metholdes have been validated compared with the vector control of star-winding PMSG by Matlab simulations and the 5.5kw prototype experiments.Secondly, the single-phase fault-tolerant operation strategies of the machine side converter in the OW-PMSG wind power system have been investigated. The voltage space vectors of the resconstructed fault converter have been analyzed by methmetical modeling. Two sensorless vector control alogrithmes based on different SVPWM manner for the OW-PMSG fault-tolerant operation have been proposed. The operation performance of the fault-tolerant system and the validity of the proposed control metholdes have been studyed by Matlab simulations and the 5.5kw prototype experiments.Lastly, a new WECS based on dual 3-phase-winding PMSG (DW-PMSG) fed by-half controlled converters (HCC) has been build. The vector control strategy based on complementary current control and rotor position/speed estimation has been designed with the mathematical modeling of DW-PMSG. The operation performance of the proposed WECS and control methold has been investigated compared with the DW-PMSG WECS fed by full controlled converters (FCC) by Matlab simulations and the 5.5kw prototype experiments. The WECS based on DW-PMSG fed by HCC and its control method also are studied as the converter fault-tolerant operation strategy of the wind power system based on DW-PMSG fed by FCC.