Design and application of permanent magnet synchronous motor with integrated mechanism for belt lift systems

Induction motors and geared reducer systems coupled to these motors are widely used in elevator drive machines. These systems have low energy efficiency. They also need engine rooms due to their large volume. In recent years, the widespread application of rare earth element magnets and developments in drive technologies have led to the expansion of permanent magnet synchronous motors (SMSM) in elevator drive machines. SMSMs operate with a direct drive method without the use of a gearbox. Elevator carriers are most commonly steel ropes. However, due to the diameter of the steel ropes used in elevators, sheave diameters can be at least 240 mm. This situation leads to low speed and high torque requirements of the SMSM to be designed. In recent years, steel wire rope belts with smaller diameters in a flat shell have been used instead of using steel wire ropes in one piece. In this way, reducing the pulley diameters by 100 mm is possible. Belt elevator drive systems are a new and recent concept that is less noisy and more efficient than rope systems, providing high cabin comfort. In this thesis, the design, analyses, and production of a new SMSM for a belt elevator drive machine for eight persons, 630 kg cabin payload, one m/s cabin speed, 4.5 kW output power, and 107.4 Nm rated torque has been carried out directly on the rail without using the machine chassis. Unlike conventional methods, the integration of the motor with the elevator transport system is provided directly on the rails. An elevator machine design in IE4 efficiency class, with low torque ripple, mounted on the rail, not requiring machine chassis construction, able to distribute the total weight of the system to the carrier and counterweight guide rails in a balanced way, low volume and mass, produced by laser cutting method from plate sheets instead of casting, providing minimum machining usage has been revealed. Analytical calculations and magnetic modelling of the SMSM have been carried out, considering the volume constraints concerning the mechanical design. The two most important criteria to be considered in elevator drive motors are high efficiency and passenger comfort. These objectives considered a design with efficiency above 91% and torque ripple below 1%. Based on the obtained values and using the finite element method (FEM), the stator slot opening, magnet thickness, embrace ratio, stator tooth thickness, and air gap values were optimized by genetic algorithm (GA). In addition, the stepped slide was applied to the magnets of the optimized design to reduce torque ripple. According to the results, an SMSM design with an 18/20 slot/pole combination with 0.61% torque ripple and 90.97% efficiency was obtained. By thermal analyses, the average temperature values of different components of the motor were determined. In S1 operation under full load, it was observed that the windings reached 116°C, the stator core 84°C, the magnets 76°C and the rotor 75°C in the thermal regime. The motor has been proven to operate in a thermally safe region. Three-dimensional (3D) solid modelling of the design of the elevator drive machine has been carried out for its proper placement in the elevator shaft. Structural analyses were performed on the motor casing, shaft, and stator teeth according to the determined static loads. Before proceeding to the production stages, the shaft design suitable for the prototype elevator machine was carried out in 3D. The effects of the loads on the guide rails and connection brackets of the rail-mounted elevator drive machine in the shaft were investigated. The structural analyses performed with FEM for machine components and shaft design showed that the safety coefficient was above 5. The manufacturing of the structurally verified design was carried out. The manufactured prototype motor has been tested with a test rig with a loading motor, and the opposite EMF, cogging torque, and performance tests have been carried out. According to the test results, the efficiency value was 89.98%, and the cogging torque was 0.78 Nm peak to peak (pk2pk). Thus, the experimental results confirmed the FEM analysis solutions. A sinusoidal opposite EMF was obtained.