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This paper aims to propose an effective modeling method of dynamic hysteresis properties for soft magnetic composite (SMC) core using an equivalent circuit representation. Because the eddy currents flowing inside iron powder particles should be considered, it is well known that an accurate magnetic field analysis of the SMC core in a wide range of excitation frequency is not easy. To overcome this difficulty, a dynamic hysteresis modeling based on the standard Cauer circuit is investigated.

In the proposed method, the first inductance represents the static magnetic property of the SMC, and the latter part represents the dynamic effect because of the eddy currents. The values of the circuit elements were determined by an optimization method based on symmetric loops measured at several frequencies. To verify the validity of the proposed modeling method, finite-element analyses of a ring core inductor and an alternating current reactor were performed.

By comparing the simulated and measured magnetic properties, the necessity to consider magnetic hysteresis in the equivalent circuit model is clarified. Furthermore, the frequency-dependent inductances of practical reactors can be obtained from the finite-element analysis combined with the proposed method.

This paper demonstrates the significance of determining the circuit parameters in the equivalent circuit for dynamic hysteresis modeling based on the measured magnetic properties. The effectiveness of the proposed method is verified by comparing frequency-dependent inductances of two kinds of reactors between the simulation and measurement.

The purpose of this paper is to examine the relationships between processing conditions and magnetic properties of cores made of Soft Magnetic Composite (SMC) Somaloy 500.

The effects of compaction pressure and hardening temperature may be combined considering SMC density. This quantity may be chosen for optimization of properties of ready-made cores. In order to describe hysteresis loops the phenomenological model based on hyperbolic tangent transformation is applied.

SMC density affects substantially the shape of hysteresis loop. The paper provides a number of charts useful for checking how the parameters of the hysteresis model are affected.

The present study considers just one composition of the SMC and one type of lubricant. Future research shall be devoted to verification of the approach on a wider class of SMCs.

Material density may be a relevant quantity in optimization of magnetic properties of ready-made SMC cores. The simple hysteresis model based on the, “effective field” concept and Takács’ idea of hyperbolic tangent transformation may be useful for description of hysteresis curves of SMC cores. Model parameters are sensitive against variations of material density.

The results of the analysis may be useful for designers of magnetic circuits made of SMCs.

The purpose of this paper is to examine the effect of varying compaction pressure on magnetic properties of self-developed soft magnetic composite (SMC) cores. The change in shape of ferromagnetic hysteresis curves has – in turn – the impact on the values of hysteresis model parameters. The phenomenological GRUCAD model is chosen for description of hysteresis curves.

Several cylinder-shaped cores have been made from a mixture of iron powder and suspense polyvinyl chloride using a hydraulic press with a form and a band with a thermocouple for controlling heat treatment conditions. The only varying parameter in the study is the compaction pressure. The magnetic properties of developed cores have been measured using a computer-acquisition card and LabView software. The obtained hysteresis curves are fitted to the equations of the phenomenological GRUCAD model. This description is compliant with the laws of irreversible thermodynamics. The variations of model parameters are presented as functions of compacting pressure.

The compaction pressure has a significant impact on magnetic properties of self-developed SMC cores. The paper provides a number of charts useful for checking how the parameters of the hysteresis model are affected.

The present paper is limited to modelling symmetrical loops only. Description of more complex magnetization cycles is postponed to another, forthcoming paper.

The GRUCAD hysteresis model may be a useful tool for the designers of magnetic circuits. Its parameters depend on the processing conditions (in this study – the compaction pressure) of the SMC cores.

Modelling of magnetic properties of SMC cores has been carried so far using some well-known description like Preisach, Takács and Jiles–Atherton proposals. The GRUCAD model has a number of advantages, and it may be a useful alternative to the latter formalism. So far it has been used for description of hysteresis curves in conventional materials like non-oriented and grain-oriented electrical steels. In the present work, it is applied to novel SMC materials.

The purpose of this paper is to examine scaling algorithms in the description and modelling of power loss in soft magnetic composites (SMCs).

Three scaling algorithms are examined to determine the most appropriate description of power loss in magnetic composites. The scaling coefficients are estimated in such a way that all measurement data should be collapsed onto a single curve, given in the scaled coordinates. The coefficient estimation is based on a non-linear optimization using the generalized reduced gradient method. The obtained formulae are then used in the power loss modelling.

It is revealed that only two-component formulae are suitable for the scaling analysis of power loss because these allow obtaining of the collapse of measurement data.

This study considers just one type of SMC (Somaloy 700). Further research will be devoted to the verification of the scaling approach to the power loss modelling for other types of magnetic composites.

The power loss is a basic property of soft magnetic materials, which determines their practical applications. The scaling approach to the power loss modelling gives quite simple models that require a reduced number of measurement data to estimate coefficients.

The scaling algorithms can be a useful tool in the analysis and designing of magnetic circuits made of SMCs.

To analyze the Jiles and Atherton hysteresis model used for hysteresis losses estimation in soft magnetic composite (SMC) material.

The Jiles and Atherton hysteresis model parameters are optimized with genetic algorithms (GAs) according to measured symmetric hysteresis loop of soft magnetic composite material. To overcome the uncertainty, finding the best‐optimized parameters in a wide predefined searching area is done with the proposed new approach. These parameters are then used to calculate the hysteresis losses for the modeled hysteresis. The asymmetric hysteresis loops are also investigated.

The classical GAs are good optimization methods when a pre‐defined possible set of solutions is known. If no assumption on solutions is present and a wide searching area range for parameter estimation is selected then the use of the new approach with nested GAs gives good results for symmetric hysteresis loops and further for the estimation of hysteresis losses.

The use of the Jiles and Atherton hysteresis model for asymmetric hysteresis must be explored further. Only one set of optimized Jiles and Atherton hysteresis model parameters used for estimation of hysteresis losses gives good results for only symmetric hysteresis loops. These parameters have limitations for asymmetric hysteresis loops.

Nested GAs are a useful method for optimization when a wide searching area is used.

The originality of the paper is in the establishment of nested GAs and their application in Jiles and Atherton hysteresis model parameters optimization. Also, original is the use of the Jiles and Atherton hysteresis model for hysteresis loop description of soft‐magnetic composite material.

The purpose of this paper is to investigate application possibilities of soft magnetic composites (SMC) in the design of high speed permanent motors for home appliances.

The design of high speed permanent magnet motor (HSPM) with core made of SMC has been proposed. The governing information about SMC has been presented. The possible advantages and disadvantages of applying magnetic powder materials in the design of electrical machines have been studied. To solve the partial differential equations describing magnetic vector distribution in considered HSPM, the edge element method (EEM) has been applied. The formulas of permanent magnet and winding descriptions, and electromagnetic torque calculations have been presented and studied. To verify accuracy of methodology and functionality of the elaborated software, a prototype of the considered motor has been built and the experimental setup for testing torque and electromotive force has been elaborated. The comparison between measured and simulated motor characteristics have been presented and discussed.

Comparison between measured and simulated motor characteristics proves the model accuracy. The obtained results show that the designed HSPM motor has sinusoidal electromotive force waveforms, low cogging torque value and the sinusoidal torque versus rotor angle characteristics. Moreover, it has been indicated that the application of SMC materials can reduce power losses in the high speed motors.

The paper describes the development of the numerical method and software for analysis of HSPM with core made of powder materials.

The purpose of the paper is to evaluate theoretically and experimentally the static and dynamic characteristics of a single‐phase claw‐pole motor using soft magnetic composite (SMC) for the stator core.

On the basis of the static characteristics, which are measured and obtained from a series of 3D FE magnetostatic solutions, the dynamic characteristics are simulated according to a proposed control strategy. The same strategy is tested in dSpace control environment. Apart from the evaluation of the prototype SMC motor, some study has been made in order to improve the existing motor design.

The static characteristics of the single‐phase claw‐pole motor have been modelled in 3D FE magnetostatic solver, where the rotor position and stator current have been changed. The characteristics compare well with the measurements, while the discrepancy with the cogging torque waveform needs further analyses and experiments to explain the real magnetization pattern of the plastic bounded ferrite magnet‐ring and the influence of magnetic hysteresis. The 3D FE magnetostatic optimization routine shows the maximum quantities for magnetic coupling and static core loss. Furthermore it is used to obtain the improved pole distribution so that the resting position of the unexcited motor co‐aligns at the position of the maximum electromagnetical torque. This is achieved by changing the angular width of claw‐poles. The specific output of the maximum coupling torque from the single‐phase claw‐pole motor can be increased from the recent 0.1 to 0.6 Nm/kg at a temperature rise of 60°. The simulations of dynamical characteristics show a good correlation with the experiments where the same control system in Simulink is applied to the prototype via dSpace. It is practically easier to implement a simple control strategy for the direct current controlled voltage source inverter. A more advantageous control system needs to be applied for the sampled current controller.

The influence of the magnetization of a multi‐pole magnet ring is not considered while computing the static characteristics in 3D FE magnetostatic solver.

The evaluation of the realistic magnetization pattern in the magnet aggravates the proper theoretical evaluation of static characteristics.

The design of a small size powder core motor is faced with the complexity of evaluating properly the static characteristics, while the magnetization pattern is not exactly known. The broad search here is for an efficient tool to visualize the output of the 3D FE optimization for an improved design.

This paper aims to demonstrate the benefits of using different impeder materials for induction tube welding systems.

To show the difference in using various impeder materials, a new approach was taken to model tube welding systems in two and three dimensions. Three-dimensional (3-D) electromagnetic models were used to determine the current distribution along the weld vee as well as the permeability of the tube along the length of the welding system. Two-dimensional (2-D) coupled electromagnetic plus thermal models with rotational movement were used to determine the temperature distribution in the heat-affected zone.

Simulation results suggest upwards of 25 per cent system power savings when using a soft magnetic composite (SMC) impeder rather than the traditional ferrites.

There is currently a lack of experimental data to validate the models, but future work will include comparison of models to real-world trials.

When dealing with tube welding systems, there are possibilities to improve process efficiency or increase production quality and output by improving the impeder material.

While simulations of tube welding systems have been done previously, studies on improving impeder materials are rarely carried out. This paper brings to light possible improvements to be made to induction tube welding systems.

In this communication, the Preisach and Jiles‐Atherton models are studied to take hysteresis phenomenon into account in finite element analysis. First, the models and their identification procedure are briefly developed. Then, their implementation in the finite element code is presented. Finally, their performances are compared with an electromagnetic system made of soft magnetic composite. Current and iron losses are calculated and compared with the experimental results.

The purpose of this paper is to investigate the impact of the stator core design for a surface permanent magnet motor (SPMM) on the cogging torque profile. The objective is to show how the cogging torque of this type of motor can be significantly reduced by implementing an original compound technique by skewing stator slots and inserting wedges in the slot openings.

At the beginning generic model of a SPMM is studied. By using FEA, for this idealised assembly, characteristics of cogging and electromagnetic torque are simulated and determined for one period of their change. Afterwards, actual stator design of the original SPMM is described. It is thoroughly investigated and the torque characteristics are compared with the generic ones. While the static torque is slightly decreased, the peak cogging torque is almost doubled and the curve exhibits an uneven profile. The first method for cogging torque reduction is skewing the stator stack. The second technique is to insert wedges of SMC in the slot openings. By using 2D and 2 1/2D numerical experiment cogging curves are calculated and compared. The best results are achieved by combining the two techniques. The comparative analyses of the motor models show the advantages of the proposed novel stator topology.

It is presented how the peak cogging torque can be substantially decreased due to changes in the stator topology. The constraint is to keep the same stator lamination. By skewing stator stack for one slot pitch 10° the peak cogging torque is threefold reduced. The SMC wedges in slot opening decrease the peak cogging almost four times. The novel stator topology, a combination of the former ones, leads to peak cogging of respectable 0.182 Nm, which is reduced for 7.45 times.

The paper presents an original compound technique for cogging torque reduction, by combining the stator stack skewing and inserting SMC wedges in the slot openings.