| The permanent magnet synchronous generator(PMSG)has the advantages of high efficiency,convenient maintenance,superior control performance such as,with the rapid development of power electronic technology,direct drive permanent magnet synchronous generator technology has gradually become the focus of research in the field of waste heat power generation,such as measuring the transmission and has been widely used.However,in the PMSG-PWM converter system,a series of high order harmonics generated by SVPWM modulation leads to the increase of PMSG loss,the performance of the generator and the power generation efficiency.In this paper,the harmonic loss of a permanent magnet synchronous generator with rated power 840kw and rated speed 4200r/min is studied.Firstly,based on the structure and work principle PMSG-PWM converter system,the SVPWM has carried on the analysis to the modulation process in time and space harmonics and get all the harmonics in the stator magnetic motive force of the rotating speed and the direction.The PMSG finite element model is established by ANSYS software,and the SVPWM modulation model which is built in the combined MATLAB is used to build the simulation model of the whole system.Secondly,the effects of SVPWM modulation parameters on the stator losses are calculated and analyzed.Harmonic copper consumption model is mainly considering the skin effect caused by conductor,the electric field strength with the effects of the penetration depth,the harmonic iron loss calculation model based on traditional bertotti iron consumption of discrete model and the finite element simulation analysis of the PMSG core tooth and yoke of the magnetic field distribution,determine the alternating magnetization mainly occurs in the teeth and yoke existing alternating magnetic field and a rotating magnetic field,through the magnetic flux density of the decomposition of the considering rotational magnetization harmonic effect of iron loss calculation model.Through the joint simulation calculation and analysis of the effect of SVPWM modulation parameters of losses in the stator,the results show that with the increase of modulation ratio and load ratio and PMSG stator loss decrease,modulation ratio of copper consumption change greater,carrier ratio stator core loss effect is more obvious.Lastly,the influence of SVPWM modulation parameters on the rotor eddy current loss is calculated and analyzed.Rotor eddy current loss mechanism and gives two different coordinate needle table paste type permanent magnet synchronous motor rotor eddy current loss analytical method of calculation model.When using step finite element analysis on two different rotor structure of permanent magnet motor rotor eddy current loss of analysis and comparison.The results show that the surface mounted permanent magnet motor permanent magnet eddy current loss was significantly greater than that of built-in type of,so the general table paste type motor permanent magnet surface will be the protection jacket layer,permanent magnet built-in can reduce the eddy current loss.According to the research object,the SVPWM modulation parameters are changed,the results show that the rotor eddy current loss can be reduced effectively and the performance and efficiency of the generator can be improved by appropriately increasing the modulation ratio and the carrier frequency. |
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