Study On The Control Strategy Of Bearingless Switched Reluctance Motor With Radial Load

Bearingless Swtiched Reluctance Motor (BSRM) integrates the advantages of magnetic bearings and Switched Reluctance Motor (SRM), and has great applied potential in machine tools with high speed, turbine molecular pump, eccentric machine, flywheel, aeronautic high speed and super high speed starter/generator system. For a good suspension performance and anti-jamming abilities of radial forces and torque, the control strategy with radial load is studied, which can also expand the operating area of BSRM.Two classical mathematic models are introduced by analyzing the accuracy of the two models. The inductances, coefficients of radial forces, and coefficients of torque are given to compare the two models. Based on the above analyse, a control strategy for BSRM with radial load is studied in detail. The optimized flow chart and maps of control parameters and control scheme are given, respectively.Due to the limitations of the above control strategy such as complicated formulae deduction, complex control models, and high demand of controller resources storage capacity, fuzzy logic control is introduced to solve these problems. According to its multi-variable, nonlinear and high coupling, a fuzzy logic controller suitable for BSRM is designed. The BSRM could operate stably with the above fuzzy logic controller under no-load, exerting radial load and step acceleration respectively. Experiments identify the effectiveness of the fuzzy logic controller.The radial windings configuration is optimized when their topologies are three-phase half-bridge converters. Three-phase half-bridge converters have two split capacitors and its midpoint voltage would unbalance under asymmetric radial load, which would even influence the operation of BSRM. A group of optimal windings structures suitable for three-phase half-bridge power converter has been obtained by optimizing the radial windings configuration of the BSRM. Based on the optimized radial windings, the imbalance of midpoint voltage is alleviated heavily. The experimental results verify the correctness of the theoretic analysis.