scholarly journals Application of Wedges for the Reduction of the Space and Time-Dependent Harmonic Content in Squirrel-Cage Induction Motors

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Konstantinos N. Gyftakis ◽  
Panagiotis A. Panagiotou ◽  
Joya C. Kappatou
Keyword(s):  
Magnetic Flux ◽  
Induction Motor ◽  
Flux Density ◽  
High Harmonic ◽  
Air Gap ◽  
Time Dependent ◽  
Magnetic Flux Density ◽  
Iron Core ◽  
Harmonic Content ◽  
Electromagnetic Characteristics

The influence of the semimagnetic stator wedges of different sizes on the electromagnetic characteristics and the behavior of the induction motor is investigated. The study will be carried out with both analytical calculations and FEM analysis. The analytical calculations will take into account the stator and rotor slots, as well as the iron core saturation in order to study the spatial and time-dependent harmonic content of the air-gap magnetic flux density and electromagnetic torque. The size of the wedge plays an important role as it determines the tooth tips saturation, the high harmonic content of the air-gap magnetic flux density, and the electromagnetic characteristics of the induction motor.

scholarly journals The Impact of the Rotor Slot Number on the Behaviour of the Induction Motor

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Konstantinos N. Gyftakis ◽  
Joya Kappatou
Keyword(s):  
Magnetic Flux ◽  
Induction Motor ◽  
Flux Density ◽  
Magnetic Flux Density ◽  
Strong Impact ◽  
Stator Current ◽  
Time Harmonic ◽  
Geometrical Features ◽  
Electromagnetic Characteristics ◽  
The Impact

The impact of the rotor slot number selection on the induction motors is investigated. Firstly, analytical equations will reveal the spatial harmonic index of the air gap magnetic flux density, connected to the geometrical features and the saturation of the induction motor. Then, six motors with different rotor slot numbers are simulated and studied with FEM. The stator is identical in all motors. The motors are examined under time-harmonic analysis at starting and at 1440 rpm. Their electromagnetic characteristics, such as electromagnetic torque, stator current, and magnetic flux density, are extracted and compared to each other. The analysis will reveal that the proper rotor slot number selection has a strong impact on the induction motor performance.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

scholarly journals DESIGN OF A SINGLE-PHASE RADIAL FLUX PERMANENT MAGNET GENERATOR WITH VARIATION OF THE STATOR DIAMETER

2019 ◽  
Vol 81 (4) ◽  
Author(s):  
Hari Prasetijo ◽  
Winasis Winasis ◽  
Priswanto Priswanto ◽  
Dadan Hermawan
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Single Phase ◽  
Air Gap ◽  
Wire Diameter ◽  
Terminal Phase ◽  
Magnetic Flux Density ◽  
Phase Voltage ◽  
Radial Flux

This study aims to observe the influence of the changing stator dimension on the air gap magnetic flux density (Bg) in the design of a single-phase radial flux permanent magnet generator (RFPMG). The changes in stator dimension were carried out by using three different wire diameters as stator wire, namely, AWG 14 (d = 1.63 mm), AWG 15 (d = 1.45 mm) and AWG 16 (d = 1.29 mm). The dimension of the width of the stator teeth (Wts) was fixed such that a larger stator wire diameter will require a larger stator outside diameter (Dso). By fixing the dimensions of the rotor, permanent magnet, air gap (lg) and stator inner diameter, the magnitude of the magnetic flux density in the air gap (Bg) can be determined. This flux density was used to calculate the phase back electromotive force (Eph). The terminal phase voltage (V∅) was determined after calculating the stator wire impedance (Z) with a constant current of 3.63 A. The study method was conducted by determining the design parameters, calculating the design variables, designing the generator dimensions using AutoCad and determining the magnetic flux density using FEMM simulation.  The results show that the magnetic flux density in the air gap and the phase back emf Eph slightly decrease with increasing stator dimension because of increasing reluctance. However, the voltage drop is more dominant when the stator coil wire diameter is smaller. Thus, a larger diameter of the stator wire would allow terminal phase voltage (V∅) to become slightly larger. With a stator wire diameter of 1.29, 1.45 and 1.63 mm, the impedance values of the stator wire (Z) were 9.52746, 9.23581 and 9.06421 Ω and the terminal phase voltages (V∅) were 220.73, 221.57 and 222.80 V, respectively. Increasing the power capacity (S) in the RFPMG design by increasing the diameter (d) of the stator wire will cause a significant increase in the percentage of the stator maximum current carrying capacity wire but the decrease in stator wire impedance is not significant. Thus, it will reduce the phase terminal voltage (V∅) from its nominal value.

Control for Optimized Air-Gap Magnetic Field of Five-Phase Induction Motor through Dual-Plane Asynchronous Rotation Transformation

2013 ◽  
Vol 347-350 ◽  
pp. 486-490
Author(s):  
Mu Yi Yin ◽  
Ling Zhang ◽  
Peng Zhu ◽  
Fei Guan
Keyword(s):  
Magnetic Field ◽  
Induction Motor ◽  
Flux Density ◽  
Mechanical Load ◽  
Air Gap ◽  
Linear Functions ◽  
Magnetic Flux Density ◽  
Third Harmonic ◽  
The Third ◽  
Air Gap Magnetic Field

This paper presents a control scheme with an optimized air-gap magnetic field for five-phase induction motor, the control objective is to generate a quasi-square magnetic flux density by the control of excitation and torque currents in the two planes. In this paper, the decoupling vector control model of five-phase induction motor in d1-q1-d3-q3 coordinate system is analyzed, and the direct and quadrature current components in the third harmonic plane as non-linear functions of the fundamental are built, which guarantee the air-gap magnetic to be a constant quasi-square waveform irrespective of the mechanical load, and then the third harmonic current injected method for improved air-gap magnetic field is proposed. Finally, the simulations by Matlab/Simulink and experiments are implanted on a 5.5 kW, five-phase concentrated full-pitch windings induction motor. The results indicate that the proposed method can satisfy the requirement of a quasi-square air-gap flux density, and the air-gap magnetic field gets improved.

Influence of slot geometry on air gap magnetic flux density of rotating machines

2016 ◽  
Author(s):  
Rodrigo Alves de Lima ◽  
A. C. Paulo Coimbra ◽  
Tony Almeida ◽  
Viviane Margarida Gomes ◽  
Thiago Martins Pereira ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Rotating Machines

Rotor Power Losses in Planar Radial Magnetic Bearings — Effects of Number of Stator Poles, Air Gap Thickness, and Magnetic Flux Density

1998 ◽  
Author(s):  
P. E. Allaire ◽  
M. E. F. Kasarda ◽  
L. K. Fujita
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Power Loss ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Power Losses ◽  
Loss Mechanism

Rotor power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with 8 pole and 16 pole stators and two laminated rotors. Two different air gaps were tested. The rotor power losses were determined by measuring the rundown speed of the rotor after the rotor was spun up to speeds of approximately 30,000 rpm, DN = 2,670,000 mm-rpm, in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. Given past publications and the opinions of researchers in the field, the results were quite unexpected. The measured power losses were found to be nearly independent of the number of poles in the bearing. Also, the overall measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased. A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis, for large clearance bearings. Hysteresis and windage effects did not change much from one configuration to the other.

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