Optimal Design And Characteristic Analysis For Low-speed Permanent Magnet Synchronous Generator

Nowadays, huamn is increasing demand for energy year after year and realizedenvironmental pollution is serious than ever, as well as the development of powerelectronic technology, more and more people give rise to enormously interest inrenewable energy generation. For example, wind power generation system andwave power generation system. The fuction of generator in wind power and wavepower generation system is convert mechanical power to electrical power. Due tothe characteristics of wind and wave power generation system, generator ratedoperation speed run at low speed state. Therefore, research of Low SpeedPermanent Magnet Synchronous Generator(LS-PMSG) has great effect forimproving renewable energy power system economy and stable characteristics.Compared with the traditional permanent magnet generator, LS-PMSG has themerit of low voltage, high current and high torque. But the defect of large volume,low efficiency, high cost, high voltage regulation rate and low precision of dqmodel limit LS-PMSG application. According to the characteristics of LS-PMSG,this paper studied LS-PMSG revelent design theory and main characteristiccalculation formula, then propsed LS-PMSG design method. In the method ofdesign LS-PMSG, based on the theory of fractional slot concentrated winding, putsforward the optimal slot and pole combination. By select the optimal slot and polecombination, LS-PMSG can effectively reduce torque ripple, improve the windingcoefficient, improving the efficiency and can reduce the cost of the generator.In traditional permanent magnet generator electromagnetic calculation method,generator dimensions, performance parameters, loss and efficiency need repeatedcalculation by equivalent magnetic circuit calculation formula. It is increase thedesign cost and the design cycle. This paper just provide LS-PMSG maindimensions calculation method and formula, generator performance calculation andoptimization by use software RMxprt to relize. This can reduce generator designcycle and can improve design efficiency.Taking20kW LS-PMSG for example, the proposed design method andsoftware of RMxprt are used to design the generator, and then finite elementmethod are adopted to simulate LS-PMSG characteristics under different loads. Thesimulation results show that the output voltage, current and power satisfy therequirement of the generator, the magnetic flux density copper loss and iron loss are all in a reasonable range. Then the20kW LS-PMSG model were applied tothree-phase grid-connected wind power generation system. By softwareMatlab/simulink, analize the wnd power generation system and compare the systemperformance under different wind speed. According the simulation result, depict theoutput power fig and efficiency fig at different wind speed, verified LS-PMSGwind power generation system can stable operation at rated condition.