Development of a Permanent Magnet Generator with a Screw Rotor

• Main Authors: Hao-Jen Gu, 古皓仁
• Other Authors: Da-Chen Pang
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/78059002565064867779

碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 104 === 　　The purpose of this study is to develop a micro hydraulic generator with a special screw rotor combining screw impeller and permanent magnet rotor. This generator is especially suitable for low water head and low flow rate environment when conventional impeller type generator cannot be used. 　　The micro generator has a rotor outer diameter of 21.8mm and length to diameter ratio of 2. This study applies computer software Solidworks Flow Simulation and Taguchi method for parameter design of inlet guide blade and screw rotor. The helical angles of blade and screw both are chosen 20 degrees and the helical turns of screw is 1.75. 　　The micro generator has radial flux design with three-phase slotless winding. The JMAG software is used for electromagnetic analysis. The theoretical analysis results show the back EMF constant Kv is 96.3 µv/(rad/s) and back EMF is 36.3mV when operating at the speed of 3,600RPM. 　　The screw rotor is manufactured using five-axis machining center and embedded with 98 tiny permanents. The stator winding is made of flexible printed circuit board. The experimental back EMF constant Kv is 82.9 µv/(rad/s) and the error is 13.9%. 　　This study completes design, analysis, fabrication and testing of a micro generator. Because permanent magnet of the screw rotor is not made as one integrated part the magnetic leakage is severe. The magnetic leakage and friction of mechanical bearings are two major factors for low efficiency of this generator. It is suggested the inlet guide blade is added to the micro generator for field testing in the future.