| Based on permanent magnet adjustable speed drive(PMASD),a new type of permanent magnet speed regulation and energy-saving technology,has been gradually applied in the energysaving reconstruction of aged large pump and fan system,promoting the energy-saving and consumption-reducing of many industry fields.It is of great theoretical and engineering significance to study the topological structure,magnetic flux regulation method and rapid and accurate analysis method of electromagnetic characteristics of PMASD.In this dissertation,four kinds of PMASDs with new type structures are originally proposed by applying the concepts of hybrid excitation and mechanical flux adjustment in permanent magnet speed regulation and energy-saving technology,based on the analysis of the research results of PMASD at home and abroad.They feature that the air-gap fluxes can be readily regulated to adjust load speed,avoiding the relatively complicated mechanical operation through the axial shifting of the permanent magnet rotor or conductor rotor in the traditional PMASDs.The main research work of this dissertation is as follows:(1)The background and significance of this research on permanent magnet speed regulation and energy-saving technology are expounded systematically.The research status of PMASD is analyzed comprehensively,and the existing problems and deficiencies are overall summarized.(2)Based on the analysis of the geometric structure and magnetic circuit characteristics of four typical PMASDs,the corresponding analytical models are established to predict their no-load and on-load air-gap flux density distributions,air-gap permeance,and output torque.All of the analytical results are verified by finite element analysis(FEA).(3)Based on the consequent-pole PMR,a hybrid-excited and a mechanical flux adjustable consequent-pole PMASDs are proposed to regulate the torques of the drives by regulating the current of the field winding and the axial position of the employed non-rotary mechanical flux adjuster(MFA),respectively.Their structural characteristics and operating principles are described particularly.An analytical model is established to predict the electromagnetic characteristics of the drives efficiently,and the predicted results are then verified by FEA.In addition,the influences of main structural parameters on the output torque of the drive are studied to obtain a more reasonable design scheme.(4)Based on the concept of mechanical flux adjustment,two interior PMASDs with the nonslotted and slotted CRs are respectively proposed to adjust the load speed by shifting a non-rotary MFA rather than a rotary one.The structure characteristics and operating principles of the drives are described in detail,and an analytical model is then established.The analytical prediction of magnetic field distributions,eddy current distributions and output torque-slip characteristics are verified by finite element analysis.The optimal structure parameters and pole-slot matching scheme of the PMASD with a slotted CR are studied by analyzing the sensitivity of the structural parameters of the drive.A principle prototype is manufactured to test the predicted torque-slip characteristics of the drive.(5)The mechanical and electric energy conversion mechanism of power-fed type PMASD is deeply analyzed and the mathematical model for this kind of drive is established.The steady-state electromagnetic characteristics of the drive under different duty cycles of IGBT are studied and analyzed.The electromagnetic characteristics are experimentally measured on the experimental platform,verifying the reliability and accuracy of the proposed mathematical model.The work of this dissertation lays a certain theoretical and technical foundation for the further theoretical research and engineering application of PMASD. |
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