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Interior permanent magnet synchronous motors (IPMSMs) exhibit significant nonlinear electromagnetic behaviour due to the effects of saturation, cross-coupling, spatial harmonics, temperature, and iron losses. In order to effectively capture the actual electromagnetic behaviour of IPMSMs, this paper proposes an improved IPMSM nonlinear model. The proposed model is based on the nonlinear flux-linkage model and progressively incorporates the effects of spatial harmonics, temperature, and iron losses. In this paper, the discrete-time form of the improved nonlinear model is established directly. It is suitable not only for embedding into the Matlab/Simulink environment as an alternative to field circuit coupling simulation but also for deployment into field programmable gate arrays (FPGA) as the model basis for hardware-in-the-loop testing. The effectiveness and feasibility of the improved model are verified by experimental results. [ABSTRACT FROM AUTHOR]

Nowadays, there is considerable research interest in proposing modern permanent magnet (PM) electric machine structures for applications such as electric vehicles. Several radial and axial topologies with different arrangements of PM in the stator and rotor have been introduced for PM Vernier motors (PMVM) with the aim of increasing the performance characteristics such as power factor, efficiency, rotational torque, torque density and wider constant torque-speed region. Meanwhile, the spoke PM arrangement has provided higher torque density than the surface and V-shaped arrangement. But in contrast, the V-shaped arrangement has a more sinusoidal flux and less cogging torque. In this paper, a 620 W, 12-slot 16-pole Vernier PM motor with a fractional slot arrangement. Consequent K-shaped pole is introduced, which has the advantages of spoke and V-shaped magnetic arrangements. After presenting and confirming the concept of the proposed structure based on functional comparison with conventional structures, an analytical modeling based on the harmonic analysis method is introduced to accurately predict the performance of the machine, and finally the proposed structure is prototyped and the experimental results are simulated and modeling are compared.

For permanent magnet synchronous machines (PMSMs), accurate machine model is critical for high performance maximum torque per ampere (MTPA) control. However, as motor speed increases, the nonlinearity such as core loss effect will affect the accuracy of machine model and thus the performance of online MTPA control. This paper firstly investigates the performance of the model based MTPA control under different motor speeds through modeling, simulation and experiments, which indicates that the accuracy of MTPA control is greatly reduced especially under high-speeds due to machine nonlinearity. Hence, this paper proposes an efficient nonlinearity compensation model based on polynomial fitting to model and compensate the MTPA error as motor speed increases. Considering both core loss and magnetic saturation effects, the compensation model is a nonlinear polynomial of speed and stator current. To obtain the fitting data, a derivative modeling method is proposed to compute the actual and detected MTPA angles under different speeds, in which the derivative model of torque to current ratio is fitted and the MTPA angle is obtained by setting the derivative model to zero. The proposed compensation model is both computation effective and easy to use for MTPA control, as it computes the compensation term that can be directly combined to other model-based methods. The proposed model is evaluated with experiments and comparisons on a test motor to show the performance improvement.

Abstract Accurate magnetic field calculation is the premise of electromagnetic performance prediction. Conventional subdomain (SD) techniques assume that the iron’s relative permeability is infinite, leading to falsely overestimated flux density. We propose an accurate magnetic field analytical model for permanent magnet (PM) in-wheel machines considering iron’s magnetization nonlinearity and saturation. Specifically, according to the excitation source and topology, the entire solution domain of the machine is divided into sub-regions such as stator slots/teeth, stator slot-openings/tooth-tips, air-gap, and rotor slots/teeth, etc. Poisson’s or Laplace’s magnetic vector potential (MVP) equations are solved using Maxwell’s electromagnetic theory and complex Fourier series methods in each sub-region. Specifically, in our approach, The Cauchy product theorem addresses the discontinuous magnetic permeability change at the slot and tooth interface. The machine’s magnetic saturation effect is considered by combining the actual magnetization characteristics of iron with an iterative algorithm. The general solution for the MVP is solved using the boundary conditions between adjacent subregions. Subsequently, electromagnetic properties such as air-gap flux density, back electromotive force (EMF), and electromagnetic torque are obtained. The accuracy of the analytical model is verified by finite element analysis (FEA) and prototype tests, which proved that the proposed analytical model can consider the iron’s nonlinearity and the magnetic saturation. In addition, the inaccurate overestimation of electromagnetic torque and air-gap magnetic flux density by the conventional SD techniques has also been proven.

Accurate magnetic field calculation is the premise of electromagnetic performance prediction. Conventional subdomain (SD) techniques assume that the iron's relative permeability is infinite, leading to falsely overestimated flux density. We propose an accurate magnetic field analytical model for permanent magnet (PM) in-wheel machines considering iron's magnetization nonlinearity and saturation. Specifically, according to the excitation source and topology, the entire solution domain of the machine is divided into sub-regions such as stator slots/teeth, stator slot-openings/tooth-tips, air-gap, and rotor slots/teeth, etc. Poisson's or Laplace's magnetic vector potential (MVP) equations are solved using Maxwell's electromagnetic theory and complex Fourier series methods in each sub-region. Specifically, in our approach, The Cauchy product theorem addresses the discontinuous magnetic permeability change at the slot and tooth interface. The machine's magnetic saturation effect is considered by combining the actual magnetization characteristics of iron with an iterative algorithm. The general solution for the MVP is solved using the boundary conditions between adjacent subregions. Subsequently, electromagnetic properties such as air-gap flux density, back electromotive force (EMF), and electromagnetic torque are obtained. The accuracy of the analytical model is verified by finite element analysis (FEA) and prototype tests, which proved that the proposed analytical model can consider the iron's nonlinearity and the magnetic saturation. In addition, the inaccurate overestimation of electromagnetic torque and air-gap magnetic flux density by the conventional SD techniques has also been proven. [ABSTRACT FROM AUTHOR]

Photocatalysts that combine with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. A series of Cd 0.4 Co 0.6 Dy X Ce X Fe 2-2X O 4 spinel nano ferrites (nFs) were synthesized by using a highly efficient low-temperature method of citrate sol-gel auto-combustion for Methylene Blue (MB) dye degradation photocatalysts under visible light irradiation that combines with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. The recycled MB is one of the hazardous textile dyes that is used extensively but causes risks for both humans and the environment. The prepared Dy3+ and Ce3+ doped Cd–Co nFs were polycrystalline with cubic structure, and crystalline size was increased from 15.78 to 21.02 nm with higher crystallinity, and the surface morphology changes from a spherical shape to a hexagonal shape with higher doping concentrations. The direct optical band gap values are increased. FTIR spectra reveal the stretching vibrations along the [M↔O] bond tetrahedral (A) and octahedral (B) sites. HRTEM results revealed that the prepared Cd–Co nFs have higher crystalline nature and high porosity. VSM indicates the sample's soft magnetic action and hysteresis loops showed the highest saturation magnetization (Ms) is 12.243 emu/g, and retentivity increases around 6.038 emu/g, decreasing the dielectric tangent loss, dielectric constant and dielectric loss. The AC conductivity raised with applied frequency. The PL gives a blue emission, and photocatalytic has the highest degradation activity 40.93 % of MB would be successful after 120 min irradiation of X = 0.07 Dy3+ and Ce3+ doped Cd–Co nFs. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, the use of permanent magnet synchronous motors has become popular. These engines are cheaper, lighter, and more durable. However, to control these motors, accurate information about the position of the rotor is necessary. For this reason, various methods have been used to improve the motor position estimation performance. One of these methods is estimation by injecting harmonic current into the stator winding. In this paper, using high-frequency currents injected into the stator, the rotor position in IPMSM motors is estimated. However, the response obtained has a DC offset due to the inaccuracy of the current measurement sensors, which causes an error in the estimation of the rotor position. The improved ePLL method was used to solve this problem. This method causes the convergence of the estimated position of the rotor to its real position by removing the noises of the current measurement circuit and the DC offset effect. The efficiency of this method has been proven first by simulation in MATLAB software, then in a Psim environment, and then implemented on the drive of a permanent magnet motor using a TMS320F28034 processor.

In recent years, the use of permanent magnet synchronous motors has become popular. These engines are cheaper, lighter, and more durable. However, to control these motors, accurate information about the position of the rotor is necessary. For this reason, various methods have been used to improve the motor position estimation performance. One of these methods is estimation by injecting harmonic current into the stator winding. In this paper, using high-frequency currents injected into the stator, the rotor position in IPMSM motors is estimated. However, the response obtained has a DC offset due to the inaccuracy of the current measurement sensors, which causes an error in the estimation of the rotor position. The improved ePLL method was used to solve this problem. This method causes the convergence of the estimated position of the rotor to its real position by removing the noises of the current measurement circuit and the DC offset effect. The efficiency of this method has been proven first by simulation in MATLAB software, then in a Psim environment, and then implemented on the drive of a permanent magnet motor using a TMS320F28034 processor. [ABSTRACT FROM AUTHOR]

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Electric scooters are increasingly gaining popularity in India owing to rising global crude oil prices and rising levels of vehicular pollution. Most of them are currently powered by expensive in-wheel (IW) permanent magnet (PM) brushless DC motors. Owing to their simplicity, and ruggedness while being cost-effective (since they do not employ PMs), switched reluctance motors (SRMs) are a viable alternative. Despite these benefits, SRMs possess drawbacks such as low torque density and inferior efficiency. Recently, a multi-teeth (MT) SRM with an improved performance was reported. However, the design of MTSRM topologies and their electromagnetic performance have not been explored sufficiently. In this paper, a design formula governing the selection of the number of MT and rotor poles for MTSRMs has been proposed. Using this, a novel four-phase 8/18 IW-MTSRM is derived and proposed for an E-scooter. The characteristics of the proposed SRM are numerically compared with a conventional 8/10 SRM based on magnetic characteristics, efficiencies and steady-state operation for the complete torque-speed range. Results indicate that the proposed 8/18 MTSRM has a higher peak torque capacity, torque density, superior drive cycle efficiency and reduced torque ripple. Further, the FEA model is validated experimentally on a downsized 8/18 MTSRM prototype. [ABSTRACT FROM AUTHOR]

This work aims to study the effect of Zr-Ni dopant on the structure and traits of M-type barium calcium hexaferrites (BaCaM). For the first time, Ba0.8Ca0.2ZrxNixFe12–2xO19 (0.0 ≤ x ≤ 1.0) samples are synthesized employing the SGACM (sol-gel auto-combustion method). The pure phase formation of BaCaM was established by XRD data Rietveld refinement. An augmentation in both the lattice parameters (‘a’ as well as ‘c’) owing to the higher ionic radii of dopant ions as compared to Fe3+ shows that Ni2+and Zr4+ions were successfully swapped with Fe3⁺. The ''c/a'' ratio lies between 3.93–3.96 disclosing that the synthesized materials possess an M-type hexagonal ferrite structure. The reduction in crystallite with an increase in doping level might be due to lattice strain generated by the larger size of Ni2+ and Zr4+ dopant ions. The presence of two bands in the wavenumber range of 400 to 880 cm-1 in FTIR spectra corresponds to the Fe–O stretching in octahedral and tetrahedral locations. The Raman peaks widen without any shifting of the peak with an increment in Ni2+-Zr4+ ions contents revealing that Ni2+-Zr4+ are incorporated into BaCaM without changing its crystal structure. According to the M-H plots Ms value enhance from 24.94 (x = 0.00) to 36.84 emu/g (x = 0.60) and beyond x = 0.60, Ms values drop with an increment in Ni2+-Zr4+substitution level. A broad coercivity range lies between 4858 Oe (x = 0.0) to 653 Oe (x = 1.0), decreasing monotonically with substitution in Ni2+-Zr4+. All the synthesized material exhibits a reduction in dielectric constant value as frequency increases. Ni-Zr-doped BaCaM materials could be a suitable candidate for magnetic recording media and microwave absorber applications.

Interior permanent magnet synchronous motors (IPMSMs) exhibit significant nonlinear electromagnetic behaviour due to the effects of saturation, cross-coupling, spatial harmonics, temperature, and iron losses. In order to effectively capture the actual electromagnetic behaviour of IPMSMs, this paper proposes an improved IPMSM nonlinear model. The proposed model is based on the nonlinear flux-linkage model and progressively incorporates the effects of spatial harmonics, temperature, and iron losses. In this paper, the discrete-time form of the improved nonlinear model is established directly. It is suitable not only for embedding into the Matlab/Simulink environment as an alternative to field circuit coupling simulation but also for deployment into field programmable gate arrays (FPGA) as the model basis for hardware-in-the-loop testing. The effectiveness and feasibility of the improved model are verified by experimental results.

When magnetic saturation occurs during the operation of a permanent magnet (PM) slotless brushless DC motor, the material permeability will no longer be a constant value, and the neglected magnetic saturation model used for motor optimization will no longer be applicable. And considering that the increase in motor torque will lead to a high temperature rise of the winding, therefore, an electromagnetic heat coupling model applicable to the occurrence of magnetic saturation in the motor is established, and the model is utilized in combination with the particle swarm algorithm to enhance the maximum output torque of the motor. Firstly, a 100 W, 16,400 r/min high-speed PM slotless DC brushless motor is taken as the object of study, and its electromagnetic–thermal coupling model is established to derive the analytical equations for the electromagnetic torque with respect to the split ratio, the thickness of the stator yoke, the PM thickness, and the copper loss. Secondly, based on the modeling, the motor was optimized using a particle swarm algorithm to maximize the output torque and minimize the copper loss. Finally, a prototype was fabricated and verified with the prototype through no-load and load experiments. The difference between the theoretical maximum output torque and the experimental maximum output torque is less than 8%. The results show that this method can effectively predict the maximum output torque of the motor in the case of magnetic saturation, and the model is suitable for increasing the maximum output torque of slotless brushless DC motors under space constraints. [ABSTRACT FROM AUTHOR]

In permanent magnet synchronous motor (PMSM) sensorless drive systems, the motor inductance is a crucial parameter for rotor position estimation. Variations in the motor current induce changes in the inductance, leading to core magnetic saturation and degradation in the accuracy of rotor position estimation. In systems with constant load torque, the saturated inductance remains constant. This inductance error causes a consistent error in rotor position estimation and some performance degradation, but it does not result in speed estimation errors. However, in systems with periodic load torque, the error in the saturated inductance varies, consequently causing fluctuations in both the estimated position and speed errors. Periodic speed errors complicate speed control and degrade the torque compensation performance. In this paper, we propose a wavelet denoising-group method of data handling (GMDH) based method for accurate inductance estimation in PMSM sensorless control systems with periodic load torque compensation. We present a method to analyze and filter the collected three-phase current signals of the PMSM using wavelet transformation and utilize the filtered results as inputs to GMDH for training. Additionally, a method for magnetic saturation compensation using the inductance parameter estimator is proposed to minimize periodic speed fluctuations and improve control accuracy. To replicate the load conditions and parameter variations equivalent to the actual system, experiments were conducted to measure the speed ripples, inductance variations, and torque component of the current. Finally, software simulation was performed to confirm the inductance estimation results and verify the proposed method by simulating load conditions equivalent to the experimental results. [ABSTRACT FROM AUTHOR]

This work involves an efficient approach for the modeling and discrimination of the stator asymmetries and magnetic saturation in the self-excited induction generators. For this purpose, an improved model considering magnetic saturation has been developed for the self-excited induction generators operating under asymmetrical load conditions. Magnetic saturation must be considered for the modeling and analysis of the self-excited induction generators. This is because linear modeling with fixed parameters never makes it possible to analyze the performances of such machines. Due to fact that the magnetic saturation and stator asymmetries both cases generate similar harmonic components through the stator voltages and currents, we have to elaborate an improved model to evaluate the electromagnetic performances and to clearly discriminate the stator asymmetries and magnetic saturation. The contribution of this work is that a state model has been developed considering the increase of the common point voltage during asymmetrical conditions and the derivation of the machine inductances due to magnetic saturation. Various electromagnetic characteristics have been extracted such as stator voltages, currents and common point voltage. It will be deduced that the common point voltage can be considered as an interesting signal for the discrimination of the stator asymmetries and magnetic saturation. The concordance between simulation and experimental results shows the consistency of this approach for the modeling and discrimination of the stator asymmetries and magnetic saturation in the self-excited induction generators. [ABSTRACT FROM AUTHOR]

This paper presents the results of a comprehensive investigation into the comparative analysis and design optimization of ferrite-based surface permanent magnet vernier machines (SPMVMs). While SPMVMs boast a simple mechanical structure and enhanced torque density attributed to the flux modulation effect, they suffer from a persistent challenge of low power factor. Several factors hinder the adoption of low-cost ferrite magnets in SPMVMs. First, ferrite magnets are prone to irreversible demagnetization, constraining the allowable range of magnet thickness. Second, the reduced residual magnetic flux density of ferrite magnets exacerbates the decrease in power factor and machine efficiency. Thus, achieving optimal performance in ferrite-based SPMVMs necessitates the careful selection of various design parameters. To address these issues, this study employs a surrogate-based metaheuristic optimization algorithm with adaptive sampling to identify the optimal solution. Additionally, the integration of a Halbach array is explored to further enhance the performance of the three-slot/two-pole SPMVM topology. Subsequently, two ferrite-based SPMVM baseline models—one with a conventional SPM structure and another with a Halbach magnet array—are thoroughly designed, optimized, and subjected to detailed performance analysis using the 2D finite element method. [ABSTRACT FROM AUTHOR]

Power transmission lines are equipped with various electronic devices, including power line inspection robots, safety sensors, and monitoring systems. However, providing power to devices installed on these lines often requires extensive construction and poses many challenges. Therefore, to solve such problems, active research is being conducted on Magnetic Energy Harvesters (MEHs) that harness the magnetic field generated by the current in the power lines to harvest electricity. A crucial design objective of the MEH is to maximize harvested power even if the saturated region is partially included, unlike a current transformer (CT), which must maintain an unsaturated state throughout the operating region. In this paper, design considerations of an MEH are discussed in comparison to the CT. Specifically, this paper formulates the relationship of the airgap between core cutting surfaces, the timing of power harvesting, and the amount of harvested power. It was observed that the MEH core should be designed to have a B-H curve close to the step function by minimizing the airgap and selecting magnetic material with high saturation magnetic flux density to achieve high harvesting power. An optimal MEH model for harvesting the maximum power for each given input current condition is presented. Furthermore, experiments were conducted to verify that 28 W of power was harvested under the input current condition of 150 Arms.

Reluctance coil launchers usually use a pulse current formed by capacitive discharge to excite the excitation coil when launching. The pulse current peaks are high, and the projectile usually undergoes deep magnetic saturation, resulting in low launching efficiency. To address this problem, this article proposes using distributed feeder circuit to drive reluctance coil launchers, replacing the traditional single set of large-capacity capacitor discharge scheme with multiple small-capacity capacitors discharged in a time-sequential manner, so as to reduce the peak current and suppress magnetic saturation problems. The study includes two main aspects, one is to study the effect of the driving method on the launch performance and analyze the reasons; the other is to propose the calculation of the time-varying data in the launch process by the time-segmented calculation method. The efficiency of the model described in the paper is only 1.301% when using a single high-capacity capacitor for launching, while the launching efficiency is increased to 3.535% when driven by the distributed feeder circuit, indicating that the method can effectively improve the launching performance.

The analysis of the reluctance coil launcher (RCL) basically relies on the finite element method (FEM), but the method is time-consuming and does not meet the real-time requirements for control, which seriously hampers the expansion of engineering application areas. To address this problem, this study proposes a numerical calculation method dedicated to RCL based on the mathematical equations of electromagnetic coupling, in which the magnetic saturation problem is corrected by the inductance lookup table method, and the inductance in the coupling circuit is updated in real time according to the instantaneous current and the instantaneous position of the projectile. The accuracy of the calculation method is verified and the reasons for the errors are analyzed by establishing finite element simulation model, MATLAB/Simulink model and experimental platform for a single-stage and a three-stage RCL and comparing the obtained data. When the discharge voltage of the capacitor is 300 V, the accuracy of the projectile muzzle velocity in the single-stage and three-stage is 98.42% and 98.20% respectively, which indicates that the calculation method is correct under specific conditions. The time consumed by the method is only about 1/1000 of that of FEM, which even includes the compilation time of the software MATLAB/Simulink, illustrating the advantages of the algorithm and its application prospects.

The inherent complexity leads to intricate equations, making it challenging for design engineers and researchers to model and analyze MCRs effectively. Despite the increasing attention given to MCRs in power systems, the need for simplified theoretical foundations and design models persists. This paper addresses the challenges posed by the complex excitation conditions of magnetic controlled reactors (MCRs), which are subject to both alternating current and direct current excitations by presenting the theoretical basis, ontological structure, working principle, and design model of MCRs in a systematic manner for enhanced comprehension. Graphical and equivalent electric circuit approaches are employed to derive mathematical expressions, while ANSYS simulation is utilized to create a 3D structure model of the MCR. The simulation results, compared with theoretical analyses, demonstrate that the MCR exhibits alternate magnetization and demagnetization between its two core limbs in a cycle. This suggests that the magnetic valves on both sides alternate between saturation and unsaturation in each cycle. Furthermore, the research reveals that the MCR’s entire capacity can be smoothly adjusted by varying the saturation degree of the magnetic valve core. Overall, this research contributes to a deeper understanding of MCRs under actual operating conditions and serves as a crucial foundation for further investigations into their performance design.

Purpose: This paper considers the air gap tracking problem of the levitation control system for medium and low-speed maglev vehicles subject to magnetic nonlinearities and track irregularities. Method: The static and dynamic magnetic field characteristics are investigated, and an improved electromagnetic force model to consider both the magnetic saturation and eddy current effect is developed. By merging neural networks (NNs), a robust adaptive control scheme is proposed, which can deal with the modeling uncertainties and magnetic nonlinearities without requiring precise model information, leading to enhanced levitation performance from the aspects of suspension safety and ride comfort. Based on the Lyapunov method, the continuity of the control signal and uniformly ultimately boundedness(UUB) of all closed-loop signals can be guaranteed. Results and conclusion: With the dynamic model of the whole suspension bogie and random irregularities, numerical simulations under various operation conditions, including constant speed, horizontal curve and vertical curve, validating the developed control scheme improves the suspension safety while maintaining the ride comfortability for passengers. [ABSTRACT FROM AUTHOR]

The synchronous reluctance machine is well-known for its highly nonlinear magnetic saturation and cross-saturation characteristics. For high performance and high-efficiency control, the flux-linkage maps and maximum torque per ampere table are of paramount importance. This study proposes a novel automated online searching method for obtaining accurate flux-linkage and maximum torque per ampere Identification. A limited 6 × 2 dq-axis flux-linkage look-up table is acquired by applying symmetric triangle pulses during the self-commissioning stage. Then, three three-dimensional modified linear cubic spline interpolation methods are applied to extend the flux-linkage map. The proposed golden section searching method can be easily implemented to realize higher maximum torque per ampere accuracy after 11 iterations with a standard drive, which is a proven faster solution with reduced memory sources occupied. The proposed algorithm is verified and tested on a 15-kW SynRM drive. Furthermore, the iterative and execution times are evaluated. [ABSTRACT FROM AUTHOR]

In this research, we investigate the effect of carbon nanotubes (CNTs) as a substrate on the morphology, size, magnetic behavior and band gap energy (Eg ) of nickel ferrite nanoparticles. Synthesis of NiFe2O4 nanoparticles carried out using a direct co-precipitation method in aqueous solution containing carbon nanotubes. The samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible Spectrophotometer and vibrating sample magnetometer (VSM). The results showed that using the CNT as a supporter reduced the size and band gap energy of NiFe2O4 nanoparticles, changed the morphology of the powder from an aggregate state to a filament state and it increased the magnetic saturation properties of nanoparticles. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present a new Hybrid Analytical Model (HAM) based on Winding Function Theory (WFT) for electromagnetic analysis of the performance of one typical Unbalanced Two-Phase Induction Motor (UTPIM). Difierent indexes of electromagnetic modeling, such as winding distribution, slotting efiect, and magnetic saturation, can be accurately considered by using the proposed HAM. To obtain this new hybrid technique, WFT is reformulated to consider magnetic saturation in addition to the inuence of slotting and winding distribution. The Conformal Mappings (CMs) are used to calculate the slotted air-gap length accurately. The Magnetic Equivalent Circuit (MEC) model is used to consider the Magneto-Motive Force (MMF) drop in stator and rotor cores due to the excitation of one phase-winding. The results obtained from CMs and MEC are then utilized in reformulated WFT to calculate the inductances of the respective phase-winding. Transient analysis is then done to calculate the indexes of performance, such as air-gap magnetic field, phase currents, electromagnetic torque, and rotor speed, by using the lookup table of inductances while considering difierent capacitors in the auxiliary phase. In each step, the accuracy of analytical results is confirmed by comparing with corresponding results obtained from the Finite Element Method (FEM). [ABSTRACT FROM AUTHOR]

Fe65Co35 based soft magnetic alloys (SMAs) have been gaining attention for their superior magnetic features and playing significant roles in composite permanent magnets, magnetic storage and automotive electrification technologies. In the present work, the Fe65Co35 alloy were produced by arc melting with subsequent annealing. The effects of arc melting and annealing upon the structural and magnetic properties of the soft magnetic phase of the alloy Fe65Co35 have been investigated. The variation in magnetic and microstructural characteristics with melting and annealing have been observed using the X-ray diffractometer (XRD), scanning electron microscope (SEM), and the vibrating sample magnetometer (VSM). The XRD patterns verified the existence of the Fe65Co35 alloy. After melting and annealing, the alloy surface morphologies were examined using SEM. In this approach, the Fe65Co35 alloy was annealed at 600 °C for 4 h in an argon environment which resulted in the highest saturation magnetization of 237 emu/g and the lowest coercivity of 31 Oe. The rise in saturation magnetization was attributed to the removal of impurities, during the melting and annealing process.

In this study, a generalized torque estimation method is proposed for synchronous motors, including surface permanent magnet synchronous motors (SPMSMs), synchronous reluctance motors (SynRMs), and interior permanent magnet synchronous motors (IPMSMs) for building the analytical motor model. The average motor torque is estimated using the Lorentz force by the generated flux density in the air gap to determine the relationships among torque, flux density, and injected current. In the proposed method, the generated flux density is derived step by step by considering the effects of magnetic flux saturation, the stator slot, the rotor barrier, and permanent magnets (PMs) to ensure that the generated average torque complies with the operating condition of the motor. To verify the proposed method, the output torque of finite element analysis (FEA), Maxwell 2D, is compared to the proposed method in a SPMSM. Moreover, a phasor diagram is plotted to determine the mechanism through which torque is generated in SynRMs and IPMSMs. A SynRM and an IPMSM with ferrites PMs are analyzed using the proposed method, FEA, and the experimental results of this study indicate the effectiveness. [ABSTRACT FROM AUTHOR]

Electromagnetic force is a very important parameter for push-pull solenoids, but it is difficult to calculate analytically due to the nonlinear variation of the magnetic field. Aiming at this problem, To address this problem, the use of magnetic vector potential theory in a columnar coordinate system was investigated to solve the electromagnetic force of a cylindrical push-pull electromagnet. The whole solenoid magnetic field was divided into several sub-domains and the boundary conditions were defined to obtain the sub-domain magnetic vector equations which can be solved numerically, and then the electromagnetic characteristic data such as magnetic vector potential, inductance and electromagnetic force were calculated by MATLAB programming. Comparing the two cases of B-H curves of iron core permeability in finite element with constant value of 10 000 and electric soft iron respectively, the calculation accuracy and error variation trend of this numerical algorithm were illustrated, and the reason for the formation of the error were analyzed. With the increase of current the core will be magnetically saturated, when the magnetic saturation problem is not serious, the calculation result of numerical algorithm has high accuracy. With the increase of current, the error increases rapidly after the core is magnetically saturated. In the experiment, different sizes of excitation currents were applied to the cylindrical push-pull electromagnet, and the output thrust results obtained were consistent with theoretical analysis. [ABSTRACT FROM AUTHOR]

The present work proposes a nonlinear model of a buck–boost DC-DC power converter considering the nonlinear magnetic characteristics of the power inductor and electrical losses of the system. The Euler–Lagrange formalism is used for formulating the proposed model. Previous research works have reported mathematical models to describe power inductor dynamics. However, a gap in the literature remains regarding modeling this kind of element when it operates within power converters. Also, a linear-based controller scheme is proposed to regulate a non-ideal buck–boost DC-DC power converter. A methodology for tuning the proposed controller is presented, which considers the nonlinear model structure of the power converter, the linearization procedure based on an identification process, and a frequency domain analysis based on the approximated linear model. Finally, the tuned control scheme is tested on the nonlinear model of the power converter under several operational conditions showing excellent performance by effectively regulating the output voltage. The results are compared with those derived from alternative control strategies, and a better performance is generally obtained. [ABSTRACT FROM AUTHOR]

In this article, a clear and concise analytical method for predicting the performance of a Liquid-cooling eddy current brake (LC-ECB) is proposed. The LC-ECB has a coolant channel in the rotor to allow direct cooling of the inner surface of the stator. The static air-gap magnetic field distribution is obtained by the dynamic magnetic equivalent circuit (MEC) method, and the magnetic flux leakage and global magnetic saturation effects are fully considered. The magnetic field intensity distribution function of the eddy current reaction magnetic field is derived for the first time based on Ampere circuital theorem. Considering the local magnetic saturation and skin effect, a novel double-iteration algorithm based on the conservation principle of magnetic pressure drop is applied to obtain the transient air-gap flux density distribution, and then the brake torque expression is obtained. The finite element method (FEM) and experimental results show that the proposed method is feasible and effective. The new model is easy to program and can be easily used in the initial design and optimization of LC-ECB. [ABSTRACT FROM AUTHOR]

The study of magnetic saturation modeling is as old as the machines themselves. The existence and importance of magnetic saturation in induction machines have been experimentally verified and well recognized. The conventional model of induction machines is based on linear magnetic properties of the machine. As in any electromagnetic system, the presence of magnetic saturation introduces nonlinearity in the behavior of induction machines also. The cardinal challenge in the modeling of induction machines is that the machine has to be accurately modeled so that realistic performance characteristics can be predicted. Unfortunately, conventional models are not suitable for predicting the dynamic performance of induction machines subjected to physical phenomena such as magnetic saturation. Various modeling techniques have been developed in dealing with the problem of magnetic saturation. This paper provides a review of the effect of magnetic saturation on induction machines as well as the major techniques used to incorporate its effects in the induction machine model. [ABSTRACT FROM AUTHOR]

In this article, an efficient multi-objective optimization strategy for the Halbach array permanent magnet synchronous machine (PMSM) is developed by taking into consideration the nonlinear B-H behavior of soft magnetic materials. Based on the harmonic modeling (HM) technology, the electromagnetic performances (EPs) of the Halbach array PMSM can be computed. To specifically model the local magnetic saturation, the stator teeth are separated into several annular layers, and each tooth is further divided into several regions along the tangential direction. Then, the parameters of the Halbach array PMSM are optimized utilizing combined nonlinear semi-analytical model (SAM) and non-dominated sorting genetic algorithm II (NSGA-II). To validate the effectiveness and accuracy of the developed optimization scheme, a Halbach array prototype is then manufactured in accordance with the optimization results. The multi-objective rapid optimization strategy developed in this article, which includes but is not limited to Halbach array permanent magnet (PM) machines, serves as a reference for the design and optimization of various PM machines. [ABSTRACT FROM AUTHOR]

The paper considers the model predictive current control (MPCC) of an induction motor (IM) drive and evaluates five IM models of different complexities—from conventional to magnetic saturation, iron losses, and stray-load losses—for the MPCC design. The validity of each considered IM model and the corresponding MPCC algorithm is evaluated by comparison of the following performance metrics: the total harmonic distortion of the stator current, the average switching frequency, the rotor flux magnitude error, the rotor flux angle error, and the product of the first two metrics. The metrics' values are determined in wide ranges of the rotor speed (0.1–1 p.u.) and load torque (0–1 p.u.) through simulations performed in the MATLAB Simulink environment. The obtained results allow us to identify the IM model that offers the best tradeoff between the practicability and accuracy. Furthermore, a control effort penalization (CEP) is suggested to reduce the average switching frequency and, hence, the power converter losses. This involves constraining the simultaneous switching to a maximum of two branches of the three-phase power converter, as well as inclusion of the weighted switching penalization term in the cost function. Finally, the performance—both steady-state and dynamic—of the proposed MPCC system with CEP is compared with that of the analogous field-oriented controlled (FOC) IM drive. The inverter switching frequency is reduced more than twice by including the frequency-dependent iron-loss resistance in the MPCC. It is additionally reduced by implementing the proposed CEP strategy without sacrificing many other performance metrics, thus achieving a performance comparable to the FOC IM drive. [ABSTRACT FROM AUTHOR]

Introduction. The active and reactive (inductive) winding resistances of three-phase asynchronous motors (IM) are investigated. These important parameters are determined during design and are the basis for calculating a number of energy parameters and characteristics. Problem. In the classical design of IM, the winding resistances are determined with insufficient accuracy due to a number of assumptions and conventions. Especially it concerns the operation of IM with increased slip and it affects the accuracy of realization of its design data, starting parameters and characteristics. Goal. The paper aims to further develop the IM design system by numerical-field computational analysis of active and reactive resistances of the IM windings in the whole range of changes in its slip and calculation of the mechanical characteristic of IM to confirm the adequacy of the calculations of these resistances. Methodology. Resistances of the IM windings are determined by numerous calculations of the magnetic fields of dispersion with the FEMM program within stator and rotor teeth steps, and with current displacement in a squirrel-cage rotor core. Everything is done in the slip range when operating from start-up to idle with changing currents in the slots and the corresponding magnetic saturation of the core teeth. A Lua script has been created for the calculations, controlling the FEMM program and providing automation of all calculations. Results. The numerical-field method shows that the classical design method gives very large errors in determining the magnetic conductivities of IM slot dispersion, as well as current displacement in the bars of the squirrel-cage rotor winding. This is especially evident with increased slips in the start-up mode. Originality. Numerical estimates of the differences between the classical and numerical-field methods are given and the origin of errors is analyzed: the strong saturation of the teeth of the stator and rotor cores. This leads to a significant decrease in the magnetic conductivities of slot dispersion and the practical absence of current displacement in the rotor bars, on which the main emphasis was previously made. The obtained results made it possible to calculate the mechanical characteristic of the IM according to a transparent formula without the use of correction coefficients and reference graphical functions. Practical value. The provided technique of numerical-field analysis and the obtained results of the calculation of active and reactive winding resistances and mechanical characteristic are recommended as a basis for the improvement of the IM design system.

In order to solve the accurate calculation problem of spoke-type permanent magnet machines with multi-layer winding structure in the magnetic field, based on the two-dimensional subdomain analytical modeling idea, a magnetic density analytical calculation method considering the saturation effect at the rotor magnetic bridge and stator multi-layer winding structure is proposed. In this method, the magnetic vector potential calculation of multi-layer armature winding can be calculated by subdomain division in the stator slot. Then, the saturation effect at the spoke-type rotor core magnetic bridge is equivalent by using an equivalent air gap. To ensure the accuracy of calculation, the error check and cyclic iteration are applied in this method. The key contribution of this method is effectively solving the interior permanent magnet machines′ magnetic field calculation problem in the traditional subdomain modeling method due to the inability to consider the finite magnetic permeability of the core. Taking 8-pole 9-slot and 10-pole 12-slot permanent magnet machines as examples, finite element models with different winding structures are built to validate the validity of the proposed method. The results show that the analytical method achieves a reduction in the computation time while maintaining the calculation accuracy.

The structure of the reluctance electromagnetic launcher (REML) is equivalent to an inductor with a movable iron core. The dynamic current in the launching process is easy to be measured by instruments, but the data such as the position, velocity of the projectile and the equivalent inductance are not only difficult to solve by analytical methods, but also difficult to measure by instruments, which seriously hinders the development of the control technology. To solve this problem, referring to the method of introducing the inductance matrix into the motor algorithm model to realize semi‐analytic calculation, a special algorithm model is proposed to calculate the launch process data of REML based on the current data. According to the working characteristics of the reluctance coil transmitter, it is pointed out that its inductance matrix should be specifically expressed as a three‐dimensional data table rather than a traditional two‐dimensional table. The current can be obtained by closed‐loop calculation according to the proposed algorithm block diagram when the circuit parameters are known, or measured by instruments when the circuit parameters are unknown, and then the launch process data is obtained indirectly through calculation. In this study, an experimental platform was built, and the algorithm model was established using MATLAB/Simulink. The comparison of the dynamic launch process data of the finite element method (FEM) showed that the method was feasible. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

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This paper proposes a stator core design to achieve variable-flux characteristics enhanced by magnetic saturation in fractional-slot concentrated winding (FSCW) permanent-magnet (PM) motors without additional excitation systems, complicated structures, or active controls. Magnetic saturation induced at suitable locations can enhance variable-flux characteristics because the PM flux linkage is variable with the magnetic saturation in cores. In distributed winding configurations, magnetic saturation is induced symmetrically for each rotor pole by the fundamental that is dominant in the spatial distribution of the air-gap flux density. The magnetic saturation at each rotor pole can enhance variable-flux characteristics. In FSCW configurations, magnetic saturation is not induced symmetrically for each rotor pole because of several dominant space harmonics. The magnetic saturation at several rotor poles cannot enhance variable-flux characteristics. In the proposed design, the stator core has thin tooth tips for inducing magnetic saturation. The magnetic saturation in the stator core achieves the variable-flux characteristics that are effective for expanding the operating region or decreasing electromotive force and increasing torque. The efficacy of the proposed design is determined by estimating motor performance through a finite element method analysis and demonstrating the actual motor performance of a prototype. [ABSTRACT FROM AUTHOR]

Increasing the power density in switched mode power supplies is one of the main goals in power electronics. This aim can be achieved by using smaller inductors operating at partial magnetic saturation. In this work, a partially saturating ferrite core inductor is exploited in a switching DC-DC boost converter, regulated through nonlinear model predictive control. A nonlinear behavioral inductor model, identified through experimental measurements, accounts for both magnetic saturation and losses. The simulation results show that the converter output voltage is correctly regulated and the imposed current constraints are fulfilled, even when partial magnetic saturation occurs. Comparisons with traditional control techniques are also presented. [ABSTRACT FROM AUTHOR]

Introduction. The active and reactive (inductive) winding resistances of three-phase inductions motors (IMs) are investigated. These important parameters are determined during design and are the basis for calculating a number of energy parameters and characteristics. Problem. In the classical design of IM, the winding resistances are determined with insufficient accuracy due to a number of assumptions and conventions. Especially it concerns the operation of IM with increased slip and it affects the accuracy of realization of its design data, starting parameters and characteristics. Goal. The paper aims to further develop the IM design system by numerical-field computational analysis of active and reactive resistances of the IM windings in the whole range of changes in its slip and calculation of the mechanical characteristic of IM to confirm the adequacy of the calculations of these resistances. Methodology. Resistances of the IM windings are determined by numerous calculations of the magnetic fields of dispersion with the FEMM program within stator and rotor teeth steps, and with current displacement in a squirrel-cage rotor core. Everything is done in the slip range when operating from start-up to idle with changing currents in the slots and the corresponding magnetic saturation of the core teeth. A Lua script has been created for the calculations, controlling the FEMM program and providing automation of all calculations. Results. The numerical-field method shows that the classical design method gives very large errors in determining the magnetic conductivities of IM slot dispersion, as well as current displacement in the bars of the squirrel-cage rotor winding. This is especially evident with increased slips in the start-up mode. Originality. Numerical estimates of the differences between the classical and numerical-field methods are given and the origin of errors is analyzed: the strong saturation of the teeth of the stator and rotor cores. This leads to a significant decrease in the magnetic conductivities of slot dispersion and the practical absence of current displacement in the rotor bars, on which the main emphasis was previously made. The obtained results made it possible to calculate the mechanical characteristic of the IM according to a transparent formula without the use of correction coefficients and reference graphical functions. Practical value. The provided technique of numerical-field analysis and the obtained results of the calculation of active and reactive winding resistances and mechanical characteristic are recommended as a basis for the improvement of the IM design system. [ABSTRACT FROM AUTHOR]

In permanent magnet synchronous motor (PMSM) sensorless drive systems, the motor inductance is a crucial parameter for rotor position estimation. Variations in the motor current induce changes in the inductance, leading to core magnetic saturation and degradation in the accuracy of rotor position estimation. In systems with constant load torque, the saturated inductance remains constant. This inductance error causes a consistent error in rotor position estimation and some performance degradation, but it does not result in speed estimation errors. However, in systems with periodic load torque, the error in the saturated inductance varies, consequently causing fluctuations in both the estimated position and speed errors. Periodic speed errors complicate speed control and degrade the torque compensation performance. In this paper, we propose a wavelet denoising-group method of data handling (GMDH) based method for accurate inductance estimation in PMSM sensorless control systems with periodic load torque compensation. We present a method to analyze and filter the collected three-phase current signals of the PMSM using wavelet transformation and utilize the filtered results as inputs to GMDH for training. Additionally, a method for magnetic saturation compensation using the inductance parameter estimator is proposed to minimize periodic speed fluctuations and improve control accuracy. To replicate the load conditions and parameter variations equivalent to the actual system, experiments were conducted to measure the speed ripples, inductance variations, and torque component of the current. Finally, software simulation was performed to confirm the inductance estimation results and verify the proposed method by simulating load conditions equivalent to the experimental results.

Abstract A new hybrid analytical model (HAM) based on conformal mapping (CM) method and magnetic equivalent circuit (MEC) model is presented in this paper for electromagnetic modelling of cage rotor induction motors (CRIMs) used in electric submersible pumps (ESPs). For every operating point, the iron parts are modelled with a non‐linear MEC model to calculate the equivalent virtual currents, which represent the influence of magneto motive force (MMF) drops and MMF sources in stator and rotor cores. The effects of the equivalent virtual currents on the air‐gap magnetic field are then considered using the CM method and Hague's solution. This approach for calculating the air‐gap field is also used to prepare a 3‐D lookup table (3‐D LUT) for each element of inductance matrix and derivative of inductance matrix in terms of rotor position. These LUTs are then used for transient modelling and analysis of CRIM under no‐load and loading conditions. The accuracy of proposed HAM is validated by comparing the results obtained through HAM with corresponding results obtained from finite element method and experiment set‐up.