Study On The Key Technique Of Permanent Magnet Linear Synchronous Motor

Along with the demands of high and ultra-high speed, exactitude and ultra-exactitude in the development of numerical control machining technique, Permanent Magnet Linear Synchronous Motor (PMLSM) as direct drive in the field of precision positioning has had widely applications. Compared with the conventional rotary motor and scroll lever, the linear motor's servo system has removed the bad effects which are caused by the mechanical gearing. Because of structural speciality, it needs to improve the motor's thrust and thrust density hardly during design process, and adopt any kinds of effective methods to reduce the thrust undulation of linear motor. Otherwise zero transmission will lose its originally expected meanings. This thesis's works circumfuse study on the key technique of PMLSM, the main work including the following sections.Firstly, in order to reduce the volume and increase the thrust density of the motor, the present wide used multi-pole, fewer tooth structure and windings have been analyzed and studied. The paper presents a reasonable design of the structure and windings of PMLSM, and concludes the application of this kind of special windings in linear motor, moreover, extends this kind of windings to generalization. The harmonic wave of back-EMF during non-load state of the motor has been analyzed too. And it's proved this kind of winding has higher fundamental wave winding coefficients and lower harmonic wave content.Secondly, aims at the detent force brought by end effect and cogging effect of linear motor, the paper presents some optimal steps. With the method of using concentrated and fractional-slot windings combined with permeance modulation, the paper gives a phase-shifting modulation to the permeance wave between teeth and slots, this eliminates cogging force effectively. For the sake of reduce the end force brought by the special end effect of linear motor, the paper presents a method of optimizing elementary length to modulate the phase of permeance of two ends, and optimizes the elementary length. On the basis of optimizing elementary length, the paper presents a method of face to face moving two modules to reduce the end force. And based on the above works, the wave plot of Detent Force between one pole distance has been given.At last, through the modules comparison of traditional windings and this kind of special windings, the paper proposes a kind of coefficients computing method of this special winding motor. After measuring the real non-load back-EMF and compared it with theoretical value, it's found the error is less than 1%. The author also deduced electromagnetic power and thrust equation and so on. On the basis of discussing force angle characteristic, the paper deeply analyzes the effect to electromagnetic power and thrust caused by frequency, and analyzes the motor's running characteristic of the state of vector controlling too. Furthermore, the author programmed the electromagnetic computing program, and analysis the motor during vector controlled state with finite element method. A new developed PMLSM is also given.