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Linear flux-switching permanent magnet (LFSPM) machines have high power density and simple robust stator structure,which shows significant potential in long stroke applications. However,linear motors are required to have high thrust density and low thrust ripple in many applications. Therefore,the research on the issues causing the thrust force ripple and corresponding suppression methods are important means to enhance the application potential of the LFSPM machines. Through the finite element analysis (FEA) method,the end effect of LFSPM machine is improved by using different structures of the additional teeth,and the end force is reduced. Based on this,different thrust ripple reduction methods are employed and compared to suppress different thrust ripple components of the LFSPM machine. In the process of comparison,a step (staggered tooth) displacement selection method is given. It shows that each structure can reduce the thrust force ripple while taking into account the average output thrust force. FEA verifies the universality of the proposed method,and it can be used in LFSPM machines with different structures to reduce the thrust force ripple while taking into account the average output thrust.

Aiming at the problem of structure parameters design of Halbaeh permanent magnetic array working on wall-climbing robots, an experimental study on adsorption force calculation was carried out. Adsorption force of ideal array was calculated firstly as a basis for followup correction methods. Then the optimal magnetization direction of each module in a full-symmetric discrete array was analyzed and the loss of adsorption force caused by discretization was calculated with Fourier analysis method. A simplified correction model of the end-effect was proposed for rapid calculation, by studying a method on distribution of magnetic induction on the reference line instead of global integration, and the calculation formula of adsorption force was modified considering the end-effect caused by the change of structure parameters. The test results indicate that the computed adsorption force basically tallies with measured force, with the average relative error less than 3.3%. [ABSTRACT FROM AUTHOR]

There is a special phenomenon in linear arc-shaped motor and linear induction motor with finite- length primary. Their no-load rotating ( translational ) speeds exceed the so-called synchronous speed. With a simplified single-sided linear induction motor( SLIM) as the research object,the mathematical model of the motor was established by using Maxwell's equations. Air gap and end region magnetic field distribution considering dynamic longitudinal end effect was calculated. A physical quantity"Equivalent electromagnetic pole pitch"considering the dynamic longitudinal end effects was proposed and correction coefficients corresponding to mechanical pole pitch with different number of poles was given. Finally,the rationality of the analytical method and validity of correction coefficients were verified by finite element method( FEM) simulation software and prototype testing. It can be concluded that no-load speed does not exceed the synchronous speed calculated by"Equivalent electromagnetic pole pitch"and just exceeds the synchronous speed calculated by mechanical pole pitch. It has some informative values to the theoretical research and development of linear induction motor. [ABSTRACT FROM AUTHOR]