Research On Design And Control System For Bearingless Switched Reluctance Motors

A switched reluctance motor has simple structure, high efficiency and satisfactory robustness. It is very suitable for running at high speeds, with high temperatures and in bad environments. Moreover, the switched reluctance motor has a good feature as bearingless motors, in practice, switched reluctance motors are well known for vibration and noise caused by the fairly high radial force, the bearingless technology is quite possible to take advantage of the inherent high radial force for rotor shaft magnetic suspension.In this paper, it is devoted to study on Bearingless Switched Reluctance Motor (BSRM) system. It mainly discusses the operation principles and control schemes of BSRM system. The control characteristics of the BSRM under no load condition are analyzed. In view of the characteristics of radial force and electrical-torque for BSRM with load, the control strategy based on the relationship between average torque and radial force and the mathematical model for this control strategy are discussed in details.This paper gives the electromagnetic design of a bearingless switched reluctance motor, including principles of parameters design and motor designing flow. After the optimization of motor structure, radial force, electrical-magnetic torque, inductance and flux of a BSRM working in a cycle are analyzed employing the Finite Element Method (FEM) by using Ansys software. BSRM`s electrical-magnetic designs are verified by the results of simulation, theoretical calculation and measuring experiments on the designed prototype.According to the control characteristics of the BSRM, its controlling system is designed and analyzed, including power converters, digital controller hardware circuit, digital controller software programs. Power converter circuits of main winding and radial force winding based on the H-bridge asymmetric type converter & the four bridges converter are analyzed, debugged. The digital controller based on digital signal process (DSP) and complex programmable logic devices (CPLD) are analyzed.In terms of the whole platform of the proposed system, the experimental platform is tested with control strategy of fixed-turn-on angle and changing-advanced angle, the good suspension performance results validate the reliability of the proposed system.