The Study Of Measurement On Thrust And Vertical Force Of Linear Induction Motor Used Maglev Principle

Single-sided linear induction motor (SLIM) was widely applied in industrial world, of which thrust and vertical force are primary operating indexes, esp. of single-sided SLIM in Linear Metro. However, the measuring methods for that are rather varied and without unified measure criterion. The existing measuring methods in some universities and institutions, as far as authors know, can be generalized into the following characteristic: In thrust measurement, no matter load measuring method or acceleration one, the measured SLIM are most supported by Wheel-on-Rail so that thrust can not be measured accurately because of the influence of the friction between wheel and rail; As for vertical force measurement, it is difficult and even infeasible to measure under existing method, which is usually computed by theory formula instead. Its measurement has always likeness difference from reality consequently.In view of facts above, this paper presents the method of measuring thrust and vertical force of SLIM based on maglev principle. It applies the principle of maglev to fix air gap between the SLIM's primary and secondary coil. It is known that the acceleration of SLIM can be measured by use of position sensors installed on it, and then the thrust performance of SLIM under decided air gap can be obtained. According to the current of electromagnet controlled the SLIM to suspend and the preset air gap, the electromagnetic force of controlled electromagnet can be calculated. And vertical force of measured SLIM can be obtained after gravity is been subtracted. Therefore, the method has the following features: The Measuring of thrust is accurate because of eliminating influence of the friction between wheel and rail. Vertical force of SLIM can be measured easily and accurately as well.The paper focused on this test method, carried out a feasibility analysis, and alsodesigned and built a SLIM dynamic performance test platform using maglev principle.At the same time, we analyzed and designed the controller of testing platform for thelinear motor and maglev system separately. At last, we completed the design ofhardware and software of magnetic suspension control system .It proved to achievegood control result.