Fundamental Theory Analysis And Simulation Research On PMSM With Opposite Rotation Dual Rotors

Permanent magnet synchronous machine (PMSM) with opposite-rotation dual rotors (ORDR) has characteristics of single electrical port input and dual mechanical ports output, which can be applied to counter-propeller propulsion system of underwater vehicle, since it can simplify system structure, decrease volume, reduce mass and cost, moreover, improve reliability without brush and slip-ring. However, comparing with conventional electric machine, many fundamental theories and scientific problems should have been researched and resolved, since its structure is significant difference and research is at the start stage. The fundamental theory problems about PMSM with ORDR are studied in this thesis as follows.Firstly, in view of two opposite-rotation main magnetic fields generated by dual rotors, particular electromagnetic model and electromechanical energy conversion relationship were established. PM position varies due to opposite-rotation, and then periodic variance of radial flux circuit in stator core is occurred. Introducing variable reluctance to equivalent magnetic loop, which realize parameter variance instead of PM position variance, so the model can accurately manifest the magnetic field of PMSM with ORDR. This type of machine can be equivalent to two conventional machines which is main magnetic circuit in parallel and opposite phase order winding in series, and electromagnetic torque is produced by interaction of armature and PM magnetic fields. According to electromagnetic model, two d-q axis steady vector relationship is obtained, and then based on the redefined power (?)gle, the particular power angle characteristic of PMSM with ORDR between dual power angles and electromagnetic power is induced.Secondly, Aiming at characteristics of mechanical structure and electromagnetic relationship, mathematic model is established and computer simulation is finished. Two equivalent machine mathematic models based on d-q axis are established, then, considering restraint relationship-same currents for two equivalent machines, the mathematic model of machine with single electric port and dual mechanical ports is achieved by combining two equivalent machine models. This machine performance and parameter effects on efficiency and power factor are researched through computer simulation analysis, and can obtain conclusion that in case of two same back-EMFs and their sum approaching source voltage high efficiency and power factor can be obtained for same load, otherwise, winding resistance variance has little effect on them.Finally, PMSM with ORDR electromagnetic design thoughts whose order is from inner part to outer part, is proposed based on the fundamental theory research, one 6 poles 11 kW prototype is designed, then, its electromagnetic field has been analyzed by FEM software, so rationality of design method is verified.