1. www.technologyfuturae.com M ULTIPLE R EFERENCE F RAME A NALYSIS OF A M ULTISTACK V ARIABLE - R ELUCTANCE S TEP PER M OTOR By Prabu.T Edited By Sarath S Nair www.technologyfuturae.com

2. C ONTENT Introduction Stepper motor operating principle Multistack V-R stepper motor Multiple reference frame analysis Applications Conclusion Reference

3. www.technologyfuturae.com I NTRODUCTION : The stepper motor is used widely in motion control systems where it is often operated in a continuous or constant speed mode rather than in a stepping mode. A multistack variable-reluctance stepper motor is analyzed using the concept of multiple reference frames An average-value model is developed using the concept of multiple reference frames

4. www.technologyfuturae.com S TEPPER MOTOR OPERATING PRINCIPLE When the winding on a certain phase is excited (energized) the rotor will rotate, seeking alignment with the excited phase winding, such that maximizing the inductance of that phase. This position is the stable equilibrium position of rotor where the net torque is zero.

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6. M ULTISTACK V-R STEPPER MOTOR Multi-stack variable-reluctance motors are widely used to give smaller step sizes. The motor is divided along its axial length into magnetically isolated sections stacks, and each of these sections can be excited by a separate winding..

7. www.technologyfuturae.com The stator of each stack consists of Npoles and each pole has a number of teeth x and carries a phase winding. The teeth on the different stator stacks are misaligned. The rotor stacks have number of teeth equals to stator teeth number but they are aligned O PERATION OF MULTI STACK MOTOR

8. www.technologyfuturae.com M ULTIPLE REFERENCE FRAME ANALYSIS :

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12. www.technologyfuturae.com MACHINE EQUATION -2 ƟR

13. www.technologyfuturae.com C ONT..

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15. www.technologyfuturae.com MACHINE EQUATION 4 ƟR

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19. www.technologyfuturae.com A VERAGE VALUE MODEL :

20. www.technologyfuturae.com A PPLICATIONS : Robotics CNC Machines Computer peripherals Business applications Process Control

21. www.technologyfuturae.com C ONCLUSION : Operation of various stepper motor is discussed. A multistack variable-reluctance stepper motor is analyzed using the concept of multiple reference frames The method of multiple reference frames has been Extended to provide an average-value model This model can be used as an unique tool to aid in the design of the machine as well as in the design of the controls associated with the electronic drive system.

22. www.technologyfuturae.com R EFERENCE : [1]P. J. Clarkson and P. P. Acarnley, "Simplified Approach to the Dynamic Modeling of Variable- Reluctance Stepping Motors," IEE Proc., Vol. 136,PartB, No. 1, January 1989, pp. 1-10. [2] S. D. Sudhoff, Member Multiple Reference Frame Analysis of a Multistack Variable- Reluctance Stepper Motor IEEE Transactions on Energy Conversion, Vol. 8, No. 3, September 1993 [3] S. D. Sudhoff and P. C. Krause, "Analysis of Steady- State Operation of a Multistack Variable-Reluctance Stepper Motor Using qdO Variables," accepted for IEEE Transactions on Energy Conversion.

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