2013 3rd International Conference on Electric Power and Energy Conversion Systems, Yildiz Technical University,Istanbul, Turkey,October 2-4,2013 Comparative Design of Direct Drive PM Synchronous Motors in Gearless Elevator Systems Hicret Yeti�, Hande Boztepeli, YusufYa�a, Erkan Me�e Yildiz Technical University Faculty of Electrical and Electronics Engineering Department of Electrical Engineering Istanbul, Turkey hicretyetis@gmail.com, handeboztepeli@gmail.com, yasa@yildiz.edu.tr, emese@yildiz.edu.tr Abstract- In today's world electrical machines become irreplaceable for human beings to continue daily routines. Due to the features such as high eiciency, high starting torque, and silent working, permanent magnet synchronous motors (PMSM) are becoming more common in many applications. One of these applications is gearless elevator system where PMSM seems to be the best candidate so far. In this paper, comparative design ofPMSM for gearless elevator has been investigated. Maxwell 2D Finite element analysis sotware has been used in this study. With comparative design, the inluence of pole count on the machine performance is studied. Also, material consumption, weight and costs of two machines have been compared. Keywords; pmsm, machine design, direct drive, gearless elevator system, mxwell I. INTRODUCTION Subject of energy eiciency become more of an issue day by day in many industry and domestic applications. Developing technology in energy eiciency enables new and better solutions instead of classical solutions in elevator systems. Gearless elevator systems driven by permanent magnet synchronous motor have many advantages compared to traditional systems. Due to highly sensitive absolute encoder coupled to motor and closed loop driver system providing sensitive control, PMSM based gearless elevators show high performance at liting up, stopping and moving. Thanks to torque and speed control which are implemented more eiciently compared to asynchronous motors, programmed speed-time curve - under all weight conditions- can be realized precisely. As a result exact and comfortable approach to loor can be achieved. Beside comfort, one of the most important feature of gearless elevator systems driven by PMSM is providing energy conservation compared to systems designed with traditional asynchronous motor and gear box 11 I. Gearless elevators can be designed with smaller electric motors for the same weight capacity. The reduction can be as high as 50 %. This paper presents PMSM design used in elevator systems. As a irst step, elevator system requirements are determined. Based on these requirements motor torque and speed values are calculated. Then, commonly used stator diameter and axial length numbers are investigated by using commercial product datasheets. These numbers are used for all of altenative designs. In other words, comparative design does not include the comparison of stator diameter and axial length of different designs. In the comparative design technique, pole count, magnet shape, slot geometry can be considered as most inluential on the eficiency. II. REQUIREMENTS OF ELEVATOR SYSTEMS The major requirements in the motor design of gearless elevator systems are torque and speed. These two parameters can be calculated by operating speed, cabin weight capacity, type of suspension and pulley diameter of designed elevator system. 121 For some given elevator speciications such as 325 kg (for 4 people) weight capacity, 1m/s cabin velocity, 2: 1 suspension ratio following motor requirements can be calculated. Tmotor = [rpulley x g x(Mcarry)ju X]] (2.1) Where, pulley : The radius of drive pulley (m) (0.12 m), g: The force of gravity (m/s 2 ) (9.88 /s 2 ) Mcarry: Maximum carrying capacity (kg) (325 kg) u: The coeficient for suspension type. I for direct suspension, 2 for 2: 1 suspension. Design was carried out for u=2. ]: Well and rope system eiciency (80%) Tmotor = [0.12 x 9.88x(325)j2 x 0,80] 978-1-4799-0688-8/13/$31.00 ©2013 IEEE