Design Of The Six-phase Double Stator Permanent Magnet Synchronous Generator For Offshore Wind Turbines

As a main form of making use of wind energy, offshore wind power has been attracting much research and attention. Muti-phase direct-driven Permanent Magnet Synchronous Generator eliminates the gearbox and uses the permanent magnet excitation, so it has simple structure and its number of phase is extended. It has high efficiency and reliability when applied to offshore wind power. In this paper,an offshore six-phase double stator permanent magnet synchronous generator (DSPMSG) is designed.First of all, the basic structure and operating principle of six-phase DSPMSG are analysed in depth. The definition of multi-phase machine, winding connection and harmonic analysis are given. A mathematical model of the six-phase DSPMSG is established.The equivalent magnetic circuit, the equivalent circuit, phasor diagram, and the balance of power and torque of six-phase DSPMSM are obtained after the analysis of magnetic circuit structure and electromagnetic features. Then a six-phase DSPMSG is designed with the method of field-circuit combination after discussing the design of the main dimensions of the generators, permanent magnet,stator, rotor and windings, thus getting the electromagnetic design scheme. The finite element model of six-phase DSPMSG is established with ANSYS software after basic theory of the finite element analysis method and analysis steps are introduced, and its magnetic field distribution and operation characteristics at no-load and rated load are analyzed and compared with a six-phase single stator PMSG with the same exterior size.The results show that the six-phase DSPMSG electromagnetic design scheme by the method of the circuit-field combination meets the basic design requirements. The six-phase DSPMSG has a higher power density and torque density, fully takes advantage of the internal space of rotor, and has higher space and material utilization ratio. Therefore, the proposed six-phase DSPMSG is a very attractive candidate as an offshore wind generator and has important research significance and broad application prospect.