Research On High Power Permanent Magnet Synchronous Generator In Electric Vehicle

Permanent magnet synchronous generator (PMSG) became the first choice ofvehicle generators with the advantages of small size, high power density, highoperating efficiency and strong environmental adaptability. This paper studiesproblems of electromagnetic field computation, inductance computation, operationperformances analysis, losses and temperature field computations on high-powerPMSG in electric vechicles.Combined with high power automotive PMSG system structural features andthe design parameters given, a PMSG model is built and then its electromagneticcharacteristic is calculated with finite element method (FEM). Contrast withdifferent types of external load on the generator output power, the necessity andparameters analysis of the three phase bridge PWM rectifier load is given.In order to minimize the inherent voltage regulation of the generator, throughvector analysis, it points out that reducing the armature resistance and d-axis q-axissynchronous reactance while increasing inverse saliency is the key to reduce thevoltage regulation. Finite element calculation of inductance is used to calculate thed-axis and q-axis synchronous reactance for deeper understanding of the generator’sperformance. Based on this analysis, the impact of the generator’s structureparameters on its inductance is carried out, including the pole-arc coefficient, thepermanent magnet depth and the airgap length.As an important parameter of the PMSG design and the heat source of theanalysis of the temperature field calculation, the losses analys is of great essential.The finite element method (FEM) is introduced to compute the core loss, thearmature winding copper loss and the permanent magnet eddy loss under differentoperating conditions. The influnence of the type of load and the speed on the lossesare studied.Finally, as an important factor influencing the PMSG’s performancecharacteristic, the temperature field is calculated by FEM in order to ensure that thegenerator works in a secure and proper temperature range. Furthermore, theinfluence of different types of load and eddy current losses of perment magnets onthe temperature distribution is given.