Electrical Machines
S. Nasr; B. Ganji; M. Moallem
Abstract
Background and Objectives: Due to exclusive advantages of the permanent magnet synchronous motors (PMSMs) such as large torque/power density, high efficiency and wide speed range in constant power region, special attention has been paid to these motors especially for electric vehicle (EV) application. ...
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Background and Objectives: Due to exclusive advantages of the permanent magnet synchronous motors (PMSMs) such as large torque/power density, high efficiency and wide speed range in constant power region, special attention has been paid to these motors especially for electric vehicle (EV) application. A conventional type of PMSMs which is more suitable for EV application is the interior permanent magnet synchronous motors (IPMSM). The main objective of the present paper is design optimization of this type of PMSM to increase efficiency and reduce torque ripple which are important for EV application. Methods: Using different shape design optimization methods including rotor notch, flux barrier and skewed rotor, design optimization of the delta-shape IPMSM is done and an optimized design is suggested first. One of the most important factors affecting the performance of the IPMSM is the magnet arrangement in the rotor structure. Based on the the design of experiments (DOE) algorithm, optimal values of some design parameters related to magnet are then determined to improve more the motor performance of the suggested structure.Results: The simulation results based on finite element method (FEM) are provided for a typical high-power IPMSM to evaluate the effectiveness of the proposed technique. In comparison to the initial design, 7% increase of average torque, 50% reduction of torque ripple and 1.4% increase of efficiency are resulted for the optimized motor. Conclusion: Using the proposed hybrid design optimization procedure (shape design optimization with optimum design parameters), significant improvement of some characteristics related to the delta-shape IPMSM including efficiency, average torque and torque ripple is resulted and this conclusion is desirable for EV application.
Power
E. Limuchi; A. Taher; B. Ganji
Abstract
Background and Objectives: The microgrid voltage and frequency are strongly affected by active and reactive load fluctuations. Load change in microgrid may result in the lack of balance among generation and consumption and as a result change in output voltage and frequency. If load change is great enough, ...
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Background and Objectives: The microgrid voltage and frequency are strongly affected by active and reactive load fluctuations. Load change in microgrid may result in the lack of balance among generation and consumption and as a result change in output voltage and frequency. If load change is great enough, distribution generation cannot stabilize the microgrid. The main objective of this article is to control the distribution of active and reactive power related to an inverter-based distributed generation (DG) in the microgrid using intelligent methods. Methods: In this study, frequency and voltage of an active generator connected to the microgrid is also controlled with applying adaptive the fuzzy sliding mode control (AFSMC) and the droop control Methods To solve the problems related to design of the sliding mode controller, a compensator control system is suggested. A rule based on the Lyapunov stability theory is also introduced to ensure the stability of closed loop system.Results: Using MATLAB/SIMULINIK software, simulation results are provided for the proposed controller and its performance under different conditions for a typical power system is evaluated. Simulation of the considered power system is done to track different values of active and reactive power.Conclusion: The provided simulation results show the effectiveness of suggested method to regulate active and reactive power and to control voltage and frequency of the microgrid.
Power
P. Vahedi; B. Ganji
Abstract
Background and Objectives: One of the main drawbacks of switched reluctance motors (SRM) is high acoustic noise and significant research has been done to reduce it. In addition, reduction of temperature rise within the machine is usually considered as one of the most important goals of design. Therefore, ...
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Background and Objectives: One of the main drawbacks of switched reluctance motors (SRM) is high acoustic noise and significant research has been done to reduce it. In addition, reduction of temperature rise within the machine is usually considered as one of the most important goals of design. Therefore, a shape design method is introduced in the present paper for the SRM by which both heat transfer and acoustic noise are improved. Methods: For evaluation of the proposed shape design method, a simulation model based on finite element method (FEM) is also developed to predict both the temperature rise within the machine and the produced noise. The simulation model is created using ANSYS finite element (FE) package and it is build up totally as a parametric model in ANSYS parametric design language. Since the convection heat transfer coefficients depend on the temperature rise, they are determined in the developed thermal model based on an iterative algorithm. Results: The proposed shape design method is applied to a typical 8/6 SRM and simulation results including temperature distribution in various sections of the machine, displacement of stator and sound pressure level (SPL) are presented. Conclusion: Based on the obtained simulation results, it is illustrated that the temperature rise and the noise of the SRM could be improved significantly using the introduced shape design method.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
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.
