Research On High Speed PM Generator System And Its DC/DC Converter

Micro turbine engine (MTE) can be used as effective high-speed propulsion system for miniatureUAVs and missiles, and it can also be used in distributed power system with high energy density bycombining with fuel cell. MTE needs power supply to provide power to its accessories and electronicequipments in the practical application. Therefore, it is necessary to develop a kind of flexible,high-efficiency and portable generator to match it. Nevertheless, general motor is not available inMTE’s application due to the high speed and tough working environment. High-speed motor has lotsof assets, so it will be a good choice in MTE system.High-speed motor has a wide application prospect in the fields like aerospace, high-speedmanufacturing, centrifugal pumps, compressors, flywheel energy storage, medical equipments and soon. Permanent magnet synchronous generator (PMSG) possesses a simple, firm structure and highreliability, and it also has a strong ability in fault tolerance. However, there are still many technicalproblems in the motor’s structure, efficient drive, core loss and protection, which limit the high-speedmotor’s development and application.This dissertation focuses on basic research for the theory and application of high-speed PMSGsystem and its DC/DC converter, in order to lay the foundation for the high speed PMSG systemdesign and engineering application. According to empirical formula and magnetic circuit method, thePMSG’s dimension, structure, assembly mode, the material of stator and rotor are confirmed initially.On the basis of regular electromagnetic design process and the finite element calculation ofmulti-physics field by Ansoft Maxwell12and Ansys, the magnetic field distribution, flux density ofair gap, output voltage and other parameters are obtained. The loss of the stator and rotor wereanalyzed and calculated with Ansys, the core loss distribution in stator was obtained based on thecalculation of static magnetic field and material’s B-P character. The eddy current distribution in rotorwas obtained based on modeling in eddy current fields. This dissertation developed a kind of wideinput voltage range DC/DC converter, with the main circuit Buck topology and auxiliary powersupply Flyback converter. Firstly, the basic topology and the principle of the converter are introduced.The detail working mode is also presented. With the analysis and comparison with other PWM controlmodes, the drawbacks and assets of the voltage control mode and current control mode are discussedin this article. Secondly, the key design process of the converter is discussed. Based on theoretical analysis of the system, a high-speed PMSG with a volume of31cm~3and a500W DC/DC converterare manufactured. The experimental results verify the correctness of the system.