| Permanent Magnet Linear Synchronous Motor (PMLSM) has the advantages of high thrust density, fast response, high reliability, high efficiency, good controllability and high precision. It is widely used in the precision motion platform. Realize long stroke movement with high speed and the location accuracy of micron order, submicron order. Due to the primary iron core break lengthways, linear motor has the unique longitudinal end effect, and under the influence of slot effect, transverse edge effect, overhang effect and so on, gap magnetic field occur a lot of distortion. Under the restrictions of the existing processing and manufacturing, installation accuracy and the artificial factors, the magnetic field distribution in three dimensional space of PMLSM exist asymmetry, engender the parasitic force or moment, make the motor system produce vibration and noise. In this paper a PMLSM that based on precision motion platform as the research object, aim at the above problems, consider slot effect, end effect and overhang effect to carry out the research of the magnetic field accurate analysis, three dimensional electromagnetic force analysis, performance parameter analysis and optimal design for PMLSM.Firstly, establish analysis model for PMLSM based on permanent magnet equivalent magnetization method and armature winding equivalent surface current method respectively, according to the symmetric and asymmetric boundary conditions to get permanent magnet excitation magnetic field and armature reaction magnetic field for air core and slotless PMLSM. Considering the topological structure of core opening alveolus and permanent magnet skewed, establish analysis model considering slot effect and skewed effect respectively, deduce air gap permeance relative distribution function and the parameter equivalent transform formula for skewed and V-shaped skewed magnetic pole structure, reaching permanent magnet excitation magnetic field and armature reaction magnetic field for iron core PMLSM. In combination with different boundary conditions, the magnetic field analytical method of PMLSM that consider slot effect and skewed effect has a wide range of adaptability. The above analysis laid a theoretical foundation for the following magnetic field accurate analysis method of PMLSM considering the end effect.On account of short primary and long secondary PMLSM mover iron core are effective length in both longitudinal and transverse direction, motor in longitudinal end and transverse edge magnetic field occur a lot of distortion, aiming at longitudinal end effect, transverse edge effect and overhang effect respectively to research. On the basis of longitudinal end effect static model, establish core end fictitious boundary method that can simulate longitudinal end effect, obtain Short primary iron core PMLSM longitudinal end regional magnetic field distribution during mover in motion. Establish iron core PMLSM transverse edge effect analysis model considering overhang effect, research and reveal the influence rule on overhang effect mechanism and different overhang length to transverse edge magnetic field, and analyze the internal relations of transverse edge effect and overhang effect.Use the equivalent magnetic charge method and image method to accurately analyze the three dimensional no load air gap magnetic field of air core PMLSM, analyze the influence rule on overhang effect to air-gap magnetic field. At last, establish accurate analysis method of consider all kinds of effects to realize PMLSM magnetic field.On the basis of magnetic field analytical method of PMLSM that considering slot effect, skewed effect, end effect and overhang effect, commonly and representative air core and iron core PMLSM in precision motion platform as the specific research object. Carry out the research of three-dimensional electromagnetic force. First, state the definition of the parasitic force for PMLSM and its main generating reason, reveal the mechanism of production of the parasitic force and its wave for PMLSM. Deduce the expression of three dimensional electromagnetic force for air core PMLSM, research and reveal the change rule of the electromagnetic force in winding overhang and the transverse parasitic force occurred when the lateral deviation to primary and secondary happened. Later, use the Maxwell stress method in improved integral path to deduce the iron core PMLSM location force, no load normal force, electromagnetic thrust and load normal force; On the basis of establishing the analysis model for skewed permanent magnet equivalent to current-carrying conductor, deduce the expression for the lateral parasitic force of skewed iron core PMLSM, reveal the lateral force of skewed iron core PMLSM and its generating mechanism of fluctuation, and study the influence rule on electromagnetic parameters such as different pole/slot ratio, Slope length of permanent magnet, overhang length and phase current parameters to lateral force and its fluctuation. Developed the test platform for rotating servo motor+ballscrew deputy load air bearing and tested the prototype for PMLSM.Finally, bass on the application background of the precision motion platform, confirm crucial performance parameters for air core and iron core PMLSM respectively, carry out the research of the aspects such as performance analysis, multiobjective optimization design and the performance comparisons and assessment for the two kinds of motor.To air core PMLSM, analyze the best pole/slot ratio for non-overlapping and overlapping concentrated winding motor; research and reveal the influence rule of the structure and size for permanent magnet and armature winding to the thrust per volume, thrust per coils quantity, motor constant and thrust ripple. To iron core PMLSM, put forward separation method for slot effect and longitudinal end effect, deduce the analytic expression of slot location force and slot effect no load normal force, end position force and end effect no load normal force, obtain the effect law about rectangle, skewed and V-shaped permanent magnet structure for the two kinds of positioned force and load normal force. Then let the non-overlapping winding air core PMLSM as example, carry out the study of motor multiobjective optimization design on the basis of the combination of multiple population genetic algorithm(MPGA) and weight coefficient. At last, proceed performance comparison and assessment to air core PMLSM and iron core PMLSM, and summarized the model selection norm of PMLSM that based on precision motion platform. |
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