Number Of Poles Research Articles

Design and harmonic analysis of single winding bearingless PM synchronous motor with high winding coefficient

Compared with double-winding bearingless permanent magnet synchronous motor, single-winding bearingless permanent magnet synchronous motor (SBPMSM) has the advantages of low copper loss and low failure rate. However, if the slot-pole combination of SBPMSM is not reasonably selected, the winding coefficient will be reduced, and even many advantages of the single-winding structure will be offset. In this paper, a single-winding design method based on magnetomotive force (MMF) star diagram is proposed, which can ensure high winding coefficient. The design process of the proposed single winding structure is introduced. This method can match the appropriate number of stator slots according to the number of rotor poles, and the winding phase separation design can be realized by reversing the slot number transposition. The mathematical models of the suspension force and torque of the bearingless permanent magnet synchronous motor are derived considering the magnetic field harmonics, and the 6-slot/2-pole SBPMSM and 18-slot/8-pole SBPMSM are taken as examples to analyze the magnetic field. The finite element simulation models of 6-slot/2-pole SBPMSM and 18-slot/8-pole SBPMSM are built and analyzed. Through the analysis of electromagnetic torque, suspension force and air-gap magnetic field under different magnetic fields, the general rules of main torque fluctuation and suspension force fluctuation are summarized.

Analysis The Effect Of Magnet Structure On The Unbalance Magnetic Pull Of Fractional Slot Number Type In Permanent Magnet Machine

Within this study, the effect of magnet structure on the unbalanced magnetic draw (UMP) of fractional slot number permanent magnet machines (PMMs) was methodically investigated. The literature revealed that fractional slot number PMMs use a variety of magnet structure configurations, including radial, parallel, and hybrid arrangements. Different magnet configurations were discovered to affect the distribution of magnetic flux density, thereby impacting UMP concentrations. The effect of various magnet geometries, including arc, rectangular, and trapezoidal, on UMP was examined. Moreover, the selection of magnet materials, such as ferrite, neodymium-iron-boron, and samarium-cobalt, influenced the magnetic field distribution and UMP characteristics. Due to their particular slot and pole combinations, fractional slot number PMMs were found to be more susceptible to UMP than other PMM varieties. Unbalanced forces caused by UMP resulted in unwanted vibrations, increased noise levels, and possible machine durability issues. Numerous factors influence UMP in fractional slot number PMMs, including the number of slots and poles, the length of the stator-rotor air gap, the magnet pole breadth, and the magnet thickness. The level of UMP was affected by the interaction of these factors with magnet structure configurations.

Field-Oriented Control of a Nine-Phase Cage Induction Generator with Large Speed Changes and Variable Load

This paper presents a voltage control system for multiphase squirrel-cage induction generators operating at a high variability of speed and variable load. Field-oriented vector control was used with a change in the sequence of the stator phase currents what changes the number of poles of the magnetic field produced by nine-phase stator winding. At low speeds, the current sequence is changed so that the number of poles increases allowing for the desired voltage to be obtained with greater efficiency. The task of the automatic control system was to control the DC voltage to a desired value at the output of the multiphase PWM converter. This is an alternative control method to the scalar control of voltage and frequency presented in a previous work. The control method and parameters of the automatic control system result from the mathematical model of the multiphase induction machine. The results of the laboratory tests were compared with the effects of the operation of the same nine-phase scalar controlled generator.

A pole-changing flux reversal permanent magnet motor

In this paper, a pole-changing (PC) flux reversal permanent magnet (FRPM) motor is proposed for obtaining a wide speed range. According to the general air-gap field modulation theory, the permanent magnet (PM) magnetic field is modulated into a series of harmonics with different pole numbers by rotor teeth. By introducing an especial PM arrangement, two groups of working harmonics with different pole-pair numbers are generated in the proposed 12-7 PC-FRPM motor due to the modulation of rotor teeth. Based on the calculated slot pitch angles of these harmonics, two winding connections can be obtained for PC operation to achieve two operating modes. The electromagnetic performance of PC-FRPM motor before and after PC are analyzed using finite element analysis and verified by the experimental test results.

Different Rotor Segmented Approaches for Electromagnetic Vibration and Acoustic Noise Mitigation in Permanent Magnet Drive Motor: A Comparative Study

Stator slot skewing and rotor step-skewing methods are the most commonly used methods to reduce the torque ripple and electromagnetic vibration in the electric vehicle (EV) drive motor industry. However, these two methods have limitations on the suppression of the 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order vibration component and multiples of rotor magnetic pole number order vibration components. This article presents a novel rotor-segmented motor with different pole widths to reduce electromagnetic vibration for EVs. The principle of the presented new rotor segmented motor to mitigate the 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order and the multiples of rotor magnetic pole number orders vibration components are analytically analyzed and illustrated. Three multi-physics field models, i. e., conventional motor, rotor step-skewing motor, and the presented motor, were established. The electromagnetic vibration properties related performances, including air-gap flux density, radial force, torsional force, and vibration response, are extensively compared. Finally, the rotor step-skewing motor and the presented motor were prototyped, and extensive tests were conducted. The results show that the presented motor has a specific mitigating effect on electromagnetic vibration, with a significant decrease in the 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order vibration amplitude and the overall vibration level is the same as that of the rotor step-skewing motor.

Selecting Method for Number of Slots and Poles in Brushless Direct Current Motor

Selecting Method for Number of Slots and Poles in Brushless Direct Current Motor

Modelling and analysis of the intersecting axis permanent magnet eddy‐current coupler

AbstractThe permanent magnet eddy‐current coupler (PMEC) is a kind of non‐contact, stepless speed regulation device and has been widely used in transmissions. However, the current PMECs are coaxial and cannot achieve transmission and speed regulation in intersecting axes. An intersecting‐axis permanent magnet (PM) eddy current coupler (IPMEC), which consists of a disk‐type PM rotor and a barrel‐type conductive sheet (CS) rotor arranged with intersecting axes, is proposed. It generates eddy currents through the speed difference between the two rotors and uses the non‐contact electromagnetic force between the eddy currents and permanent magnets to transmit torque. During operation, the speed can be adjusted by altering the coupling area or air gap. A theoretical model of the IPMEC based on the equivalent magnetic circuit method is presented and verified by finite element simulation using ANSYS. Then, the effects of the pole number of the PMs, the radius of the CS rotor and the PM rotor on the performance were analysed, and the design method of the IPMEC was proposed. This study can be used to expand the application range of PMECs.

Design and analysis of a semi-symmetrical double winding with same poles number high-speed permanent magnet generator

Design and analysis of a semi-symmetrical double winding with same poles number high-speed permanent magnet generator

The effect of winding topologies on the performance of flux-switching permanent magnet machine having different number of rotor poles

The effect of winding topologies on the performance of flux-switching permanent magnet machine having different number of rotor poles

Design and Optimization of a Novel Permanent Magnet Linear Motor with the Same Number of Poles and Slots

Design and Optimization of a Novel Permanent Magnet Linear Motor with the Same Number of Poles and Slots

Research on Torque Characteristics of the PMSM with the Same Number of Poles and Slots

Research on Torque Characteristics of the PMSM with the Same Number of Poles and Slots

Design of a Novel PMSM Topology with the Same Number of Poles and Slots

Design of a Novel PMSM Topology with the Same Number of Poles and Slots

A General Approach to the Design of Multi-Layer Fractional-Slot Concentrated Windings With Arbitrary Number of Slots, Poles, and Phases

A General Approach to the Design of Multi-Layer Fractional-Slot Concentrated Windings With Arbitrary Number of Slots, Poles, and Phases

DETERMINATION OF THE CHARACTERISTICS OF THE ELECTROMECHANICAL EQUIPMENT OF THE MICRO HYDROELECTRIC POWER PLANT AT THE GUEENI SITE ON THE KOKOULO RIVER

When setting up a small hydroelectric power plant in isolated sites, the choice of electromechanical equipment remains a very important factor. This study is part of this dynamic. Its main objective is the determination of characteristics and the choice of electromechanical equipment for the micro hydroelectric power plant at the Gueeni site on the Kokoulo River in Pita in Guinea, with a variable hydrological regime. The methodology adopted is based on knowledge of the hydraulic parameters and the hydroenergetic characteristics of the site (hydraulic power, net power). Based on these elements, we determined with great precision; the type of turbine (Kaplan), with a rotation speed (586.58 rpm); the specific speed (47 rpm); the number of generator poles (10); the electrical power of the plant (2160 kW), the apparent power of the transformer (2700 kVA) and valve closing time (1.1 s). This study is part of the dynamic of evaluating the hydroenergetic potential of small developable waterfalls in isolated areas of Guinea

Determining the optimal steps of the number of fields with variable windings

In the article, the issue of saving electricity and natural resources by applying two-speed motors with a variable number of poles to electric drives, together with the measures to meet the need for electricity and water resources in the world, is considered in the article. Together with the analysis of the electromagnetic properties of the circuit of the chulgam with the ratio of poles 6/8, the exact values were obtained by using the formulas, and suggestions and recommendations were given for determining the optimal step of the chulgam.

Excitation Control of Brushless Induction Excited Synchronous Motor with Induction Machine Operating in Deep-Plugging Mode

Abstract The popularity of electrified transportation is rising at a sharp pace due to environmental concerns over internal combustion (IC) engines. Researchers are nowadays looking for a brushless and permanent magnet (PM)-less solution for electric vehicle (EV) motors. Wound-field synchronous motor (WFSM) is a potential solution for EVs and is being used in Renault Zoe EV and BMW iX3 e-Drive models. A Brushless Induction excited Synchronous Motor (BINSYM) is a WFSM where the exciter, an induction machine (IM), is embedded inside the synchronous machine (SM) frame. Two machines (SM and IM) are configured for different numbers of poles to achieve magnetic decoupling, which facilitates independent control of both machines. The purpose of IM is to maintain the excitation requirement of SM. The IM is controlled in deep-plugging mode at a constant slip frequency over the entire speed range to minimise its reactive power demand. The maximum torque per ampere (MTPA) and root mean square (rms) current minimisation algorithms are used to control the SM. Simulation of the BINSYM-based system under dynamic conditions (MTPA with varying field current and load transient) has been carried out in MATLAB/Simulink to validate the control strategies. Experimental findings from the laboratory prototype machine closely match the simulation results.

Investigation of Stator/Rotor Pole Number Combinations and PM Numbers on Variable Flux Leakage PM Machine

Investigation of Stator/Rotor Pole Number Combinations and PM Numbers on Variable Flux Leakage PM Machine

Vegetation Dynamics of Coastal Mangrove Forest

In the man-made coastal forest, the vegetation dynamics of protected and unprotected coastal forests have been identified. This study examined and quantified the impacts of grazing on coastal vegetation. The investigation was conducted between January 2013 and December 2020. In a transect line, fifty-two distinct tree, herb, and shrub species were found in unprotected coastal areas, and 36 were found in protected areas. After eight years, the number of saplings (p=0.031), poles (p=0.030), and total (p=0.026) (seedling, sapling, and pole) regeneration were substantially different between protected and unprotected areas. The current study found no significant differences in regeneration and tree density after one and five years of establishing the protected zones. The greatest number of natural poles were found in protected and unprotected areas from 2017 to 2020. The changes in tree density were considerable (p=0.03) after eight years. From 2014 to 2017, the highest rate of seedling recruitment was 36622 to 43439 individuals observed in protected and unprotected areas. In protected areas, Excoecaria agallocha L. and Avicinnia officinalis L. had the most extensive regeneration coverage, and nine species of seedlings, saplings, and poles were seen in 2013 protected areas. After 8 years, E. agallocha had a 47.01% while Phoenix paludosa Roxb. had a 30.81% success rate. In 2020, seedlings of Pongamia pinnata L. (6.6%), Herietiera fomes Buch.-Ham. (5.5%), A. officnalis (5.30%) and the remaining six species were also seen. The species E. agallocha comprised 69.11% of the trees at Soner Char tree density, followed by Sonneratia apetala Buch.-Ham. (23.30%), P. paludosa (8.82%), H. fomes (3.43%), and the remaining two species in 2020. After eight years, the species S. apetala declined by 43.64% and 23.90% in protected and unprotected areas, respectively. The species Phoenix paludosa, H. fomes, A. officinalis, and Dolichandrone spathacea (L.F) Baill. Ex K. Schum. was found to replace S. apetala in protected areas. Grazing affects the natural recruitment stage of saplings and poles and tree stem density in unprotected areas. The observations assume that S. apetala will diminish due to climatic conditions, and E. agallocha will become the main dominating species in coastal areas. J. Asiat. Soc. Bangladesh, Sci. 49(2): 203-224, December 2023

Changes in the provision of ecosystem services based on sidewalk tree-composition scenarios

Cities have been experiencing environmental and social issues due to urban expansion processes, be them planned or not. However, several environmental solutions have been proposed and sidewalk tree planting stands out among them. The aim of the current research is to assess the process to estimate ecosystem services under different sidewalk tree composition scenarios in Irati and Curitiba cities, Paraná State. In order to do so, 10 street segments from neighborhoods sampled in city-wide inventories were selected. Information about sidewalk length, curb ramps’ width, and number of utility poles was collected for each street segment. The number of trees to be fit in each segment and sampled neighborhood was determined based on safety recommendations for these urban structures. Tree dimensions (Diameter at Breast Height - DBH, total height and crown diameter) were projected for the 55th year post-planting, based on using minimum dimensions of seedlings from small, medium and large-sized species. It was done to estimate ecosystem services in i-Tree Eco software. Significant differences among floristic composition scenarios (p&lt;0.05) were observed for all ecosystem services in both cities. Compositions featuring large-sized species have show higher ability to provide ecosystem services, as well as higher monetary valuation, despite fitting a smaller number of trees in the assessed street segments. The herein formulated scenarios have shown the potential to increase the number of planted trees and to select compositions capable of maximizing ecosystem services’ provision and trees’ monetary value.

Design and Comparative Analysis of Axial Flux Permanent Magnet Vernier Motors

This paper analytically investigates both the air gap flux density and the generated power of an Axial Flux Permanent Magnet Vernier Motor (AFPMVM). The AFPMVM has the same operational principle as a magnetic gear. It operates using space harmonics of the air gap flux density due to the magneto-motive force (MMF) and air gap permeance. This paper also examines the effect of various combinations of the rotor magnet pole pairs, stator slots, and winding pole numbers on the power factor and power density using the 3-D finite element method (3D-FEM). It is observed that, although having a higher pole ratio results in low cogging torque and high power density, it makes the machine length longer and has a lower power factor. Therefore, by employing the high pole ratios, the main advantage of the axial flux machines, i.e. having a shorter length, is sacrificed.