Magnetic Circuit Research Articles

Linearity Range Extension of Magnetostrictive Current Sensors Through Magnetic Circuit Optimization

Linearity Range Extension of Magnetostrictive Current Sensors Through Magnetic Circuit Optimization

Research on Electromagnetic Sensing Detection Technology for Non-Destructive Testing Applications

Abstract Nondestructive testing technology, as an indispensable part of modern industrial production, is of great significance for guaranteeing product quality, improving production efficiency, and ensuring production safety. This paper is based on nondestructive testing and electromagnetic sensing detection technology research. The study first adopts ACFM detection to analyze the sensitivity of the surface defect parameters of the material to be detected, and based on the analysis of the magnetic circuit of the electromagnetic sensing structure, to build a mathematical model of ACFM and electromagnetic coupling probe, and then through the magnetic method of non-destructive testing on the material cracks in the detection of the signal effect of the study. The results show that the amplitude of the response signal increases with the increase of the defect angle from 0 to 7 ms, reaching a maximum value of 0.24–0.26 around 6 ms. The amplitude of the response signal decreases with the decrease of the defect angle from 7 to 14 ms and reaches a minimum value of −0.16–0.18 around 14.5 ms. The amplitude of the detection signal is related to the depth of the crack and the length of the surface defect of the steel sheet specimen. The crack depth and surface defect length of the steel plate specimen influence the detection signal’s magnitude. When the defect depth and surface length of the steel plate specimen are 1.5 mm, the detection signal value is weak, and the noise on the surface of the steel plate specimen has a significant effect on the detection signal. Promoting the development and application of NDT technology is greatly aided by the results of this paper.

A Novel Vector Magnetic Circuit Based Position Observer for IPMSM Drives Using High-Frequency Signal Injection

A Novel Vector Magnetic Circuit Based Position Observer for IPMSM Drives Using High-Frequency Signal Injection

IMPROVEMENT OF THE METHOD OF CALCULATINGTHE PARAMETERS OF THE INDUCTION MOTORS REPLACEMENT SCHEME

The optimization of the equivalent circuit parameters of a three-phase induction motor with an equivalent double-circuit rotor is presented. The initial parameters of the equivalent circuit are estimated using a method known as engineering, based on the data provided in the manufacturer’s data sheet. The purpose of the work is aimed at increasing the accuracy of calculating currents and torques when using a double-circuit equivalent circuit of an induction motor by improving the method for determining the parameters of the equivalent circuit. A procedure for optimizing parameters has been developed to reduce errors between the calculated and actual values of the motor torque and current. Achieving the goal is ensured through the use of the author’s method of taking into account the nonlinearities of the motor, namely saturation of the magnetic circuit along the main path and scattering paths. To analyze the characteristics of an induction motor and predict its behavior in the event of faults and various operating modes, it is necessary to create a mathematical model of this motor. To ensure the adequacy of model calculations, it is necessary to take into account various nonlinearities of an induction motor, such as the effects of current displacement and machine saturation, steel losses, and others. The choice of a specific nonlinearity to take into account, as well as the methodology for taking it into account, are determined by the complexity of the tasks posed to the model. The depth of taking into account the nonlinear parameters of an induction motor depend on the requirements for the accuracy of the analysis and necessarily includes taking into account the most significant factors affecting the performance of the machine. A universal mathematical model has been created that describes an induction motor in a coordinate system that is stationary relative to the stator and takes into account the nonlinearity of its parameters. The parameters of the equivalent circuit of twelve industrial induction motors without and with optimization were assessed. A comparison was made of the results obtained from the engineering method and the actual data of the manufacturer to verify the effectiveness of the proposed method. Keywords: induction motor, nonlinearity of IM parameters, manufacturer’s data, optimization, parameter estimation, squirrel cage, mathematical modeling, experimental studies

Dynamic Model of an External Rotor Hub-motor Based on an Improved Magnetic Circuit Method

Dynamic Model of an External Rotor Hub-motor Based on an Improved Magnetic Circuit Method

Design and Optimization of a High Thrust Density Voice Coil Motor with Auxiliary Enhanced Magnetic Circuits

Design and Optimization of a High Thrust Density Voice Coil Motor with Auxiliary Enhanced Magnetic Circuits

Modeling and Predictive Control of PMSM Considering Eddy-Current Reaction by Vector Magnetic Circuit Theory

Modeling and Predictive Control of PMSM Considering Eddy-Current Reaction by Vector Magnetic Circuit Theory

Fault Current Limiter Principle by Switching Magnetic Circuit

Fault Current Limiter Principle by Switching Magnetic Circuit

D-Q-axis magnetic field design and investigation of asymmetrical multi-layer flux barriers PM motor for speed regulation enhancement

In this paper, an asymmetrical multi-layer flux barriers permanent magnet (AMFB-PM) motor is proposed. The key of this study is to design the d-q-axis magnetic field reasonably. Firstly, the influence of d-axis inductance on the constant power speed range is analyzed. To optimize the constant power speed regulation performance, an asymmetric flux barrier is employed to adjust the saturation degree of the d-axis magnetic circuit under flux-weakening state. Additionally, the introduction of the asymmetrical flux barrier enables directional deflection of reluctance torque, thereby enhancing the output torque. The analysis results verify the effectiveness of the asymmetrical flux barrier design, which provide a wide speed regulation with constant power operation and high torque density for PM motors.

Analysis and Calculation for a Novel Transverse Flux Linear Synchronous Motor With 3-D Magnetic Circuit Method

Analysis and Calculation for a Novel Transverse Flux Linear Synchronous Motor With 3-D Magnetic Circuit Method

Analysis of Magnetic Properties of Soft Magnetic Composite Using Magnetic Circuits Generated by Discrete Element Method

Analysis of Magnetic Properties of Soft Magnetic Composite Using Magnetic Circuits Generated by Discrete Element Method

Design and analysis of a hybrid permanent magnet variable leakage flux motor for low core loss and wide speed range

In this paper, a new hybrid permanent magnet variable leakage flux (VLF-HPM) motor is proposed. In order to enhance motor speed range, short arc-shaped and elliptical-shaped magnetic barriers are placed on the q-axis magnet circuit, realizing the so-called leakage flux effect. In addition, ferrite PMs are artfully designed, so self-leakage flux can be reduced while main flux is enhanced. The relationship among PM topology, flux barrier and flux-regulation capability are also investigated in detail. Finally, the electromagnetic performance of VLF-HPM motor is evaluated by the finite element analysis and compared with a conventional V-typed PM motor. It is noted that, compared with conventional V-typed PM motor, the VLF-HPM motor possesses lower core losses and a wider speed range, which offers a new research path for high-performance PM motor.

Analytical Loss Model for Magnetic Cores Based on Vector Magnetic Circuit Theory

Analytical Loss Model for Magnetic Cores Based on Vector Magnetic Circuit Theory

Developing adjustable stiffness for smart material of magnetorheological elastomer to diminish vibration

Many vibration isolators, such as passive vehicle mounting devices, have an inflexible stiffness. This article presents the development of a smart material vibration isolator based on magnetorheological elastomer (MRE), which has adjustable stiffness to minimize unwanted vibrations. The objective of this research is to first create a design for the vibration isolator, and then simulate a magnetic circuit. The Finite Element Method Magnetics (FEMM) software was employed to simulate the effectiveness of the electromagnetic circuit in generating a magnetic field through the vibration isolator by employing MRE samples. Pure iron was chosen as the material for the housing of the vibration isolator test rig. To attain an optimal magnetic field, an inventive design of the magnetic circuit, including examination of the wire type, size, and coil turn number, along with the housing material of the test rig, was performed. The study analyzed the performance of the MRE vibration isolator concerning different current inputs in the coil. The results indicate that the stiffness value of the MRE-based isolator system can be more effectively modified by increasing the current inputs. Therefore, a larger current input leads to a greater change in stiffness.

Structure optimization design and magneto-mechanical characteristics analysis of amorphous alloy with oriented silicon steel composite wound core

Three-dimensional wound cores are widely used in three-phase distribution transformer due to the symmetrical magnetic circuit structure. Amorphous alloy and oriented silicon steel are two kinds of ferromagnetic materials commonly used to make distribution transformer cores, each has own advantages and disadvantages in magnetic and mechanical characteristics. The amorphous alloy and oriented silicon steel composite core can synthesize the advantages of both. In this paper, a double-layer composite wound core (DCWC) structure is proposed and the corresponding dual nonlinear electric circuit and magnetic circuit coupling model is established. A structure optimization design method for the DCWC based on the free parameter scanning method is proposed by taking the percentage of oriented silicon steel in the composite core and the structure parameters as free variables. Based on the proposed optimization design method, a DCWC is designed and the experimental prototypes are manufactured. Further, the flux density distribution, core loss and mechanical vibration displacement of the DCWC are analyzed, and the effectiveness of the proposed method is verified by comparing with the measured results.

Study of the electromagnetic system of holding the mine in the barrel channel of the gas detonation mortar

The paper presents the results of the study of the electromagnetic system of holding the mine in the bore of the gas detonation mortar. To reduce the time from the detection of the target to its destruction, the use of a gas detonation mortar with a semi-automatic guidance system in the direct line of sight of the target is proposed. This type of mortar will reduce the total time of hitting the target to 2-3 minutes. An analysis of the influence of the magnetic holding of the mine on the operation of the gas detonation mortar was carried out. Holding the mine in the bore during the formation of the gaseous propellant charge allows you to fix the volume of the charge. The electromagnetic mine holding system consists of an electromagnetic coil, a magnetic circuit, a DC source with a commutator. The switch on of the electromagnetic system is carried out immediately before the shot to reduce the heating of the coil. The mine holding force was calculated, on the basis of which the parameters of the mine holding electromagnetic system were substantiated. Based on the results of experimental studies, the dependence of the holding force of the mine on the power supply current of the electromagnetic system was determined. The developed dynamometric measurement system consisted of a piezoelectric force meter with a spring, an electric cylinder and a cable clutch. The pressure when the mine detaches from the electromagnet in the barrel of the gas detonation mortar is estimated. It was found that the power consumed by the electromagnetic system is about 15 W, and with holding forces of 930-980 N, mine extraction will begin at the overpressure of the compressed gas charge, equal to 0.15-0.2 MPa.

CALCULATION OF POWER TRANSFORMER INDUCTANCE MATRIX

Practical calculations of electric equipment and electric networks are performed using equivalent circuits. Without taking into account saturation phenomena, electromagnetic processes in a power transformer are described by a system of linear equations, which can be represented in matrix form. The transformer inductance matrix contains self and mutual winding inductances, whose values for one phase are determined directly from the passport data containing the results of no-load and short circuit experiments. Mutual inductances between phases depending on the type and size of the magnetic core are not usually given in the transformer documentation. It does not allow to simulate the operating modes that differ from the steady state with uniform phase load.
 
 The purpose of the work is to develop an algorithm for calculating elements of the power transformer inductance matrix according to its passport data and magnetic circuit parameters.
 
 The scientific novelty lies in use of information about magnetic circuit type and size to determine elements of the inductance matrix.
 
 Materials and methods. Methods of linear electric and magnetic circuit theory are used in the work.
 
 Results. The proposed algorithm for calculation of power transformer inductance matrix includes three stages: calculation of self and mutual inductances for one phase; construction of an equivalent circuit for a magnetic circuit and calculation of magnetic fluxes in order to take into account the mutual influence of windings on various phases; assembly of the inductance matrix of three-phase transformer. A method is proposed for constructing the transformer inductance matrix with an arbitrary type of magnetic circuit, phases and windings quantity. The method involves preliminary calculation of the coefficient matrix that characterizes the magnetic circuit and depends mainly on its type and, to a less, on the ratio of geometric dimensions in rods and yokes. The coefficient matrix can be calculated in advance and used to determine the inductance matrix of a wide range of transformers.
 
 Conclusions. 1. The passport data of the transformer do not allow to model transformer operation at unbalanced load validly. 2. An algorithm for determining the inductance matrix of transformers has been developed. 3. A method for compilation of a transformer inductance matrix with an arbitrary type of magnetic circuit, the number of phases and windings is introduced. The practical significance of the algorithm is determined by the simplicity of algorithmizing, as well as by the possibility of using it in computer simulation of electrical circuits with transformers, for example, using the modified nodal analysis method.

Full circumferential reluctance maglev coupling for 2D proportional flow rate valve: Design, modelling and experimental validation

A novel full circumferential reluctance maglev coupling (FCRMC) is proposed in this paper, which not only meets the requirements of force transmission and valve position feedback of two-dimensional (2D) valve but also has the advantages of closed-loop magnetic circuit and high magnetic energy utilization rate. To investigate the torque-displacement characteristic of FCRMC, a detailed analytical model based on the equivalent magnetic circuit method is formulated, which considers the leakage flux effect, edge effect, and magnetic permeability nonlinearity. The effects of the inclination angle, width, air gap, and number of teeth on the torque are explored by the analytical model, and appropriate structural parameters are selected to design and manufacture the prototype. A dedicated test bench is built and the static/dynamic characteristics of FCRMC are tested. The experimental results show that the FCRMC prototype has a step velocity of 20.8 × 10−3 mm/ms, a torque-volume ratio of 8.47 × 10−3 N m/cm3, a torque-permanent magnets(PMs) volume ratio of 0.050 N m/cm3, and a step velocity-PMs volume ratio of 2.63 × 10−3 mm/ms·cm3. Finally, to verify the feasibility of the FCRMC in real work situations, the FCRMC is applied to a 2D electro-hydraulic proportional flow valve. The experimental results show that, at 15 MPa, the no-load flow of the valve is 82.4L/min, with a hysteresis of 3.8 %, a step velocity of 17.5 × 10−3 mm/ms, and amplitude and phase frequency widths of 22.4 Hz and 26.5 Hz.

Line-Start Permanent Magnet Synchronous Motor Supplied with Voltage Containing Negative-Sequence Subharmonics

In some power systems, the voltage waveform contains frequency components less than fundamental, called subharmonics or subsynchronous interharmonics. Voltage subharmonics can be both positive- and negative-sequence, independent of their frequency (order). Subharmonics exert harmful effects on sundry electrical equipment, especially on rotating machinery; they cause various noxious phenomena, such as a local saturation of the magnetic circuit, increases in power losses and windings temperature, and torque pulsations leading to vibration of unacceptable severity. Notably, previous works reported excessive vibration of rotating machinery only under no-load, while under full load, rather moderate vibration occurred. This study deals with vibration analysis of a line-start permanent magnet synchronous motor (LSPMSM) supplied with the voltage containing negative-sentence subharmonics. Experimental investigations were conducted for a 3 kW, four-pole production LSPMSM for subharmonics of various values and frequencies. Voltage subharmonics of values significantly less than reported in real power systems were found to cause unacceptable vibration, especially under full load.

Comprehensive assessment of the quality of laminated core of electrical machines by the high-frequency induction-vibration method

In this work, the problem of assessing the quality of active parts of electric machines, in particular charged magnetic conductors, is considered. The essential diagnostic indicators of the actual state of the recruitment core were determined, namely specific losses during remagnetization and weakening of package pressing, which are associated with increased losses, decreased efficiency, violation of the thermal regime, etc. induction-measuring module for determining the level of inter-sheet insulation breakdown and the growth of losses in the core. It is recommended when loosening for small-sized magnetic conductors, impregnation of the weakened area with adhesive varnish and subsequent drying with a compressed core. Also, for cores of a small diameter, between the pressure washer and the extreme sheets of the core, drive textolite wedges every 2...4 teeth. When the pressing of the cores of large electric machines, in which the pressing is carried out by tension pins, is weakened, the pins are tightened. A two-dimensional field mathematical model of a charged magnetic core package was developed in order to estimate the distribution of the electromagnetic field and eddy currents and losses at different frequencies from 50 Hz to 10 kHz. It is proposed to use the analysis of the transient process when the magnetic flux changes in the magnetic circuit. To simplify the measuring scheme, it is proposed to use the process of switching the current in the excitation winding. With the help of the developed model, the calculation of transient modes was carried out on the example of the studied magnetic circuit. As an object of research, a mock-up of a stacked magnetic core was used, which is a set package of magnetic steel sheets used in magnetic cores of dry transformers of small and medium power. In order to combine the two methods, an installation was developed that allows checking the quality of pressing and the quality of inter-sheet insulation at the same time.