Study Of Ocean Current Power Generation System Using Disk Type Coreless Permanent Magnet Synchronous Generator

Among the renewable energy, ocean current energy is drawing increasing researchers’attention, and the power generation technology of ocean current energy is developingrapidly. In its developing process, some problems emerge, among which the choiceand design of generators used in ocean current power system are the most importantissue. To respond the National Ke Ji Xing Hai Project and solve this problem, theresearch focuses on the design of generator and its system which is suitable for oceancurrent energy system based on the background of Bohai Bay sea area.The research firstly analyses the major feathers of ocean current energy and itsrequirement for power generation. A detail comparison of different kinds of generatoris presented. Base on the analysis and the advantage of our research group, the disktype coreless permanent magnet synchronous generator (PMSG) is proposed to beused in the ocean current energy system. This kind of machine has high generatingefficiency and low starting resistance since its coreless and out-rotor structure, and isvery suitable to be applied in low-speed ocean current energy. According to the theoryof the disk type coreless PMSG, a300W prototype is designed. Finite element method(FEM) is used to analyse electromagnetic field of the machine. An experiment is alsooperated to test the prototype under different loads or speed, the result supports thefeasibility of the machine.The speed of ocean current is changing all the time, the electric power it generats isnot steady enough to be transferred to power grid directly, so it needs a converter totransform it before connected to the grid. In the research, a special control strategy isproposed to be applied in the directly coupled ocean current power generator system.The strategy adopts back to back PWM converter mode to control generator-side andgrid-side respectively. The control strategy of the ocean current energy system issimulated using Matlab/Simulink software. The simulation result demonstrates thatthe system can efficiently transfer the ocean current energy into electric powersteadily used in the power grid.