Research On Operating Characteristics And Electromagnetic Design Of A Novel Three-Phase Two-Valued Capacitor Induction Motor

Efficient use of energy is the strategic issue concerned together by countries all over the world. It is shown that electric energy used up by motors is more than sixty percent of industrial power consumption in developed countries, and then the close attention has been focused on the energy-saving technologies for electric motor systems. This dissertation makes a comprehensive study on a novel three-phase two-valued capacitor induction motor which has the unique advantages of high efficiency and energy-saving. The study includes theoretical analysis, numerical computation and experimental investigation.Based on the comprehensive analysis on the magnetomotive force in the air gap of the three-phase two-valued capacitor motor, the research on the excellent performances of the motor in high power factor and low stray loss was made, and the further engineering analysis on the working capacitor, which is the key characteristic parameter, has been suggested.The dissertation constructed the numerical analysis method of field-circuit coupled system which studies the dynamic performance of electric motor system. Focusing on the complicated finite element model of this new type motor, the simulation analyses were carried by the direct-coupled transient finite element method and the indirect-coupled harmonic finite element method respectively, and the analytical results are in good agreement with the test results.Based on rotating magnetomotive force theory, the dissertation presented the theoretical analysis on equivalent circuit model and the related performance equations of the motor. Therefore, the dissertation has constructed the electromagnetic design program for this new type induction motor to meet the needs of engineering.In order to realize the optimizing design, an Improved Particle Swarm Optimization algorithm (IPSO) is proposed to enhance the global search ability. Taking case study for starting torque optimization of the prototype, the anticipant optimization result of high starting torque is gained efficiently and precisely by modifying the dimensions of the stator slot with the combined optimization strategy which is constructed by combining IPSO and the simplex method with analytical method of equivalent circuit model and electromagnetic numerical computation method respectively.Experimental studies including the operating performance of 750 W prototype, speed control performance of 5.5 kW prototype, type tests and the efficient energy-saving tests in pumping device of 22 kW and 30 kW prototypes not only have significantly verified the theoretical and numerical analyses in the dissertation, but also have shown that this new type of induction motor has a series of excellent properties of high power factor, high starting torque, energy-saving and benefits for the grid and the related electrical equipments in reactive compensation.