M.R. SHIRAVI; B. Ganji
Abstract
High-frequency coils are widely used in medical applications, such as Magnetic Resonance Imaging (MRI) systems. A typical medical MRI includes a local radio frequency transmit/receive coil. This coil is designed for maximum energy transfer or wave transfer through magnetic resonance. Mutual inductance ...
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High-frequency coils are widely used in medical applications, such as Magnetic Resonance Imaging (MRI) systems. A typical medical MRI includes a local radio frequency transmit/receive coil. This coil is designed for maximum energy transfer or wave transfer through magnetic resonance. Mutual inductance is a dynamic parameter that determines the energy quantity to be transferred wirelessly by electromagnetic coupling. Thus, it is essential to analyze the self and mutual inductances of this coil. Other parameters, including electromagnetic shielding, frequency, and distance, which influence voltage and power transfer are investigated here. Theoretical formulas and simulation models proposed in the present paper are implemented by using MATLAB and ANSYS MAXWELL and ANSYS SIMPLORER Finite Element (FE) packages for determining the performance and properties of the coil. So, the main goal is evaluating of software steps that simplify the design of RF resonance circuits. Also, experimental results are given for the validation of the proposed method. Consequently, Safety and efficiency are automatically maximized by following the best design considerations.
M. Ranjkesh; E. FallahChoolabi; M. Pourjafari
Abstract
Nowadays the use of the Switched Reluctance Motors (SRMs) has been considerably increased in various home and industrial applications. Despite of many advantages of this type of motors, such as simple structure, low cost, and high reliability, the main disadvantage of them is the generation of high torque ...
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Nowadays the use of the Switched Reluctance Motors (SRMs) has been considerably increased in various home and industrial applications. Despite of many advantages of this type of motors, such as simple structure, low cost, and high reliability, the main disadvantage of them is the generation of high torque pulsation. This paper presents a novel method to optimize a typical SRM such that the torque ripple reaches its minimum value. Meanwhile, the torque average and the motor efficiency become maximum. It is shown that the pole width to the pole pitch ratio, for both stator and rotor poles, have a great impact on the torque ripple and torque average. Finite Element Method (FEM) is used to obtain the torque ripple, the torque average and the motor efficiency for a large number of ratios. A functional relationship is developed between the input and the output parameters. Normalized summation of the torque ripple minus the torque average and the efficiency is considered to be the cost function, which must be minimized. Then, the Particle Swarm Optimization (PSO) is used to find the optimum ratio of pole width to pole pitch, for both stator and rotor. The optimum design is verified by FEM.
