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This paper presents the mechanical vibration and stress analysis of an axial flux permanent magnet (AFPM) motor for a high speed (30000 rev/min) rotor which is vertically suspended by active and hybrid magnetic bearings. In the analysis, a prototype AFPM motor with a double sided rotor and a coreless stator between the rotors are considered. Rotor disks of the motor are constructed of two 10 mm-thick steel disks with 6.35 mm-thick permanent magnets which represent around 70% of the total weight of the machine. Firstly, an analytical solution is carried out to determine natural frequencies of the rotor-shaft system. Then rotor disk thickness was determined based on a rotor axial displacement due to the attractive force between the permanent magnets placed on opposite rotor disks. Finally, 3D finite elements analysis (FEA) are carried out to verify the analytical results.

Along with technological developments and increasing population, people are in need of more energy sources. This need has led researchers to go towards new energy generation methods. One of these methods is hydrokinetic energy generation, which has been studied intensively in recent years. In this study, complete design of a hydrokinetic turbine that converts kinetic energy into mechanical and electrical energy with the most efficiency using tidal water is proposed. Moreover, an undershot water wheel system is designed to gain the least dissipationless conversion of kinetic energy. The design of the hydrokinetic energy generation system is developed considering the environmental and maintenance factors, maximum efficiency and buoyancy. Calculation for the velocity of the turbine is made by using Betz’s law, usually used for wind energy conversion systems. Conversion of obtained mechanical energy from the turbine to electrical energy is supplied by using a proper alternator system.

In this paper, an H ∞ controller is designed for disturbance attenuation of magnetically levitated steel plate. The system contains U-type hybrid electromagnet which constructed by using permanent magnet. A detailed model having nonlinear attraction force of a U-shaped hybrid electromagnet is presented and linearized for controller design purpose. Based on the linearized model, the H ∞ controller is designed to minimize air gap variation under unknown loading disturbances. Thereafter, a set of experiments conducted to compare performance of the H ∞ controller with our previously published I-PD controller on the same experimental setup.

In this study, a flexible conveyance system driven by linear motors and hybrid magnets for magnetic levitation is proposed. For modelling purposes, nonlinear analytic models are derived and extended to 3 axis of movement and controlled with those nonlinear equations. For energy efficiency, each pole is controlled with voltage driving zero power levitation method. Since the system only has displacement sensors for feedback, to fully control and understand the systems characteristics and disturbances, all axis are observed by disturbance observer and integrated to controller algorithm for better response and robustness, which is achieved multiplying the disturbance observer's output with system gain and feedforwarded. The proposed system and control algorithms are well confirmed by numerical results.