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This paper presents a subharmonic-based brushless wound rotor synchronous machine (BL-WRSM) topology with permanent magnet-assisted (PMA) and consequent-pole (CP) rotor structures to achieve better torque characteristics as compared to the conventional subharmonic-based brushless WRSM. The proposed topologies use the conventional high-efficient subharmonic field excitation technique to achieve a brushless operation and a lower volume of permanent magnet (PM) to achieve better average, starting, maximum, and minimum torques and lower torque ripple. A four-pole, twenty-four-slot (4-pole/24-slot) machine with conventional, PM-assisted (PMA), and consequent-pole (CP) rotor structures are developed in a JMAG-Designer 20.1 environment to carry out two-dimensional finite element analysis (2D-FEA). The developed machines are used to validate the operation and achieve electromagnetic and electromechanical performances of the proposed subharmonic-based BL-WRSM topologies with better torque attributes. [ABSTRACT FROM AUTHOR]

This paper studies the effect of permanent magnet shape on the performance and efficiency of coreless axial flux permanent magnet synchronous generator (AFPMSG) for low-speed applications. The objective of this study was to come up with an optimal magnet shape among the studied cases that will lead to the highest value of induced EMF, eventually leading to the better output power of the machine. According to the obtained results, a coreless AFPMSG with a triangular magnet shape has higher induced EMF as compared to trapezoidal or skewed-shaped magnets. Also, a topology with rounded-triangular magnets is analyzed to investigate the effect of the rounded edges on the performance of the generator. 3D-finite element analysis (FEA) is used to analyze and compare the back-EMF and output power of all the investigated coreless AFPMSG topologies. This analysis is carried out using JMAG-Designer 19. 1. [ABSTRACT FROM AUTHOR]

Summary: In this paper, an interior permanent magnet synchronous motor with a D‐type rotor configuration is presented. The performance of the proposed motor is compared with that of the widely used V‐type interior permanent magnet synchronous motor. For a fair comparison, all the motor parameters are identical. With the advent of different rotor topologies, multilayered and multisegmented permanent magnets are extensively used; however, an analytical modeling of D‐type interior permanent magnet synchronous motor has not yet been conducted. Furthermore, its analysis using the finite element method is considerably time‐consuming. To resolve this problem, an analytical method based on a magnetic equivalent circuit is proposed for the slotless D‐type interior permanent magnet synchronous motor. It is then compared with the finite element method at different pole arc–pole pitch ratios to demonstrate the effectiveness of the proposed method. Additionally, Schwarz‐Christoffel mapping is employed to maintain the slot shape and include the effect of adjacent slots by considering the slotting effect in the slotless air‐gap flux density. Finally, the presented motors are optimized based on the pole arc–pole pitch ratio to maximize the fundamental air‐gap flux density and minimize the total harmonic distortion. [ABSTRACT FROM AUTHOR]

Due to the intermittent nature of wind, there exists a major disparity between the power generation from the wind and the demand of electricity. Hence, a sophisticated maximum power point tracking (MPPT) control paradigm must be formulated for maximizing the power extraction from the wind. This research article focuses on the formulation of a nonlinear fast dynamic terminal sliding mode control (FDTSMC)-based MPPT strategy for optimizing the power extraction from a 3kW, variable speed, fixed-pitch wind energy conversion system equipped with a permanent magnet synchronous generator. The proposed MPPT strategy is compared with the benchmark fast terminal sliding mode control, conventional sliding mode control, feedback linearization control and proportional integral derivative control-based MPPT strategies under a stochastic wind speed profile. The proposed paradigm has been found superior in its tracking performance by converging the output tracking error to zero in a finite time, realizing a high precision performance, offering fast dynamic response, reducing the chattering to a minute level and guaranteeing global robustness. The superior performance and effectiveness of the proposed FDTSMC-based MPPT control paradigm is tested and validated through extensive MATLAB/Simulink simulations. [ABSTRACT FROM AUTHOR]

This paper reports an energy-efficient permanent magnet (PM) zero-holding-energy magnetic contactor (ZMC) that consumes no energy while maintaining an open or closed state. Conventional solenoid magnetic contactor (MC) technology has several critical drawbacks, including high continuous energy consumption, continuous vibration, and low reliability. The proposed ZMC substantially reduces energy consumption and heat generation, produces no vibration, and provides increased reliability. Traditional MC analysis typically requires computationally expensive finite element analysis (FEA). To reduce the analysis costs, a recently proposed fast and accurate nonlinear transient path energy method (NT-PEM) is utilized to significantly reduce analysis time and costs. Analysis accuracy was verified experimentally using a fabricated ZMC prototype. The economic and environmental benefits of the proposed ZMC confirm its significant potential as an energy-efficient eco-friendly alternative to traditional MC technology. ZMC is particularly promising for vehicular micro-grids due to the prolongation of the lifetime of batteries owing to reduced energy consumption. [ABSTRACT FROM AUTHOR]

To optimize an interior permanent magnet synchronous motor (IPMSM) design for a fuel cell electric vehicle, a new surrogate-assisted multi-objective optimization (MOO) algorithm is proposed in this paper. The proposed algorithm is a multi-objective algorithm (MOO) that can account for three kinds of objectives such as the torque amplitude, torque ripple, and magnet usage simultaneously to improve the power transmission and to reduce the noise, vibration, and cost for various design variables. While the conventional MOO algorithms have a series that requires many function evaluations, especially considering many objectives and design variables, the proposed algorithm can create an accurate and well-distributed Pareto front set with few function evaluations. In comparison with the conventional MOO algorithms, the outstanding performance of the proposed algorithm is verified. Finally, the proposed algorithm is applied to an optimal design process of an IPMSM. [ABSTRACT FROM AUTHOR]

This paper presents a design and analysis method for a novel hybrid flux permanent-magnet (PM) machine for a high-power density. By combining radial and axial flux machines with integrated windings, the air-gap flux density is increased, and an overhang structure of the PM and additional magnetic cores are applied to increase the power density. For the analysis and design of the proposed motor, a time-consuming 3-D finite-element analysis (FEA) is required owing to its unique structure. To address this problem, a correct and rapid novel analysis method is proposed using an equivalent 2-D conversion method. The accuracy of the proposed analysis method and the usefulness of the proposed motor are confirmed via the 3-D FEA and experimental results. [ABSTRACT FROM PUBLISHER]

This paper presents a magnetic field analysis of a surface-mounted permanent magnet machine with an overhang structure wherein the rotor axial length exceeds that of the stator. A 2-D analytic method using a lumped magnetic circuit model (LMCM) is proposed for more rapid computation of the overhang effect compared with a conventional 3-D or quasi-3-D finite element analysis (FEA). In the LMCM, the effective overhang length is calculated, and a leakage flux generated in the overhang region is estimated. The accuracy and usefulness of the proposed analytic method is confirmed through the 3-D FEA and the experimental results according to the diverse overhang length, the number of slot/pole, and stator core length. [ABSTRACT FROM PUBLISHER]

For a permanent magnet machine, temperature rise due to the losses in the rotor can affect the performance of the permanent magnet. This is a critical problem for the designers of electric machine. These losses, especially eddy current losses in the conductive part of the rotor, cause heat which cannot easily be mitigate due to the mechanical structure. Therefore, it is very important to consider the losses in the designing step to ensure that the machine operates stably. The most common technique of reducing the eddy current losses is to divide them into smaller parts. The analysis for this segmentation structure is only possible in 3D-FEM (Finite Element Method) and though this requires a considerable amount of time during design step. Therefore, it is necessary to calculate the eddy current losses rapidly and accurately. In this paper, an eddy current loss analysis method in the retainer of the permanent magnet machine which has a high power density is proposed. First, the concept of effective conductivity is introduced to solve the segmentation problems not to use 3D-FEM. Also, in order to improve the accuracy of the proposed method, the skin effect which occurs in high speed driving region is considered and a FFT analysis is also performed on the harmonic components of air gap flux density. Finally the thermal analysis result which is based on the loss analysis result is also demonstrated and it is verified to compare with the thermal experimental results. [ABSTRACT FROM AUTHOR]

Due to the continuous energy consumption in a closing coil for the maintenance of a closed state, the conventional solenoid type MC has serious problems such as inefficient energy consumption, welding in contacts, vibration, and noise. To address these problems, an advanced MC using a permanent magnet, an inter-locking system, and a guiding structure is proposed and named the MCPIG (magnetic contactor using permanent magnet, inter-locking system, and guiding structure) in this paper. Analysis method and design strategy are proposed for the MCPIG in this research. Through examining the experimental data of a prototype, the practicality of the proposed analysis and design method as well as the usefulness of the MCPIG for 220 V 85 AF MC are verified. [ABSTRACT FROM PUBLISHER]

In the two-dimensional (2-D) finite-element (FE) analysis, the overhang effect can be considered through an increase in the remanence flux density of the permanent magnet in order to reflect the increment of the air-gap flux density due to the overhang structure. However, a repetitive 2-D FE analysis was performed in order to match the air-gap flux density with it in the three-dimensional (3-D) FE analysis. The proposed method accurately accounts for the overhang effect without trial and error. From the results of the 3-D FE analysis, the validity of the proposed method is verified. [ABSTRACT FROM PUBLISHER]

The solenoid magnetic actuator has been widely used as an actuator for MS (magnetic switch). Thus, conventional MSs continuously consume electrical power to maintain a closed state. To address this problem, an innovative structure which uses a permanent magnet to generate holding force in the closed state without electrical power is suggested in this paper. Further, the permanent magnet is dedicated to the opening operation and the closing operation by means of its magnetic force. In other words, an eco-friendly MS is proposed in this research. However, this structure has a critical problem in that, if unexpected external force is applied to the MS when in the open state, the MS returns to the closed state by the force of the permanent magnet and remains in the closed state, causing an unintended operation of the load. To solve this problem, a novel inter-locking mechanism is proposed. Hence, we termed the proposed novel MS the MSPI (magnetic switch using a permanent magnet and an inter-locking system). In addition, analysis and design methods for the MSPI are proposed in this paper. The usefulness of the MSPI and the accuracy of the analysis and design methods are confirmed through an experiment. [ABSTRACT FROM AUTHOR]

In this paper, a hexagonal magnet shape is proposed to have an arc profile capable of reducing torque ripples resulting from cogging torque in a single-sided axial flux permanent magnet (AFPM) machine. The arc-shaped permanent magnet increases the air-gap length effectively and makes the flux of the air-gap more sinusoidal, which decreases air-gap flux density and hence causes a reduction in cogging torque. Cogging torque is the basic source of vibration, along with the noise in PM machines, since it is the main cause of torque ripples. Cogging torque is independent of the load current and is proportional to the air-gap flux and the reluctance variation. Three-dimensional finite element analysis (FEA) is used in the JMAG-Designer to analyze the performance of the conventional and proposed hexagonal-shaped PM AFPM machines. The proposed shape is designed to reduce cogging torque, and the voltage remains the same as compared to the conventional hexagonal-shaped PM machine. Further, optimization is performed by utilizing an asymmetric overhang. Latin hypercube sampling (LHS) is used to create samples, the kriging method is applied to approximate the model, and a genetic algorithm is applied to obtain the optimum parameters of the machine. [ABSTRACT FROM AUTHOR]