Iron Loss Characteristics Research Articles

磁気ヒステリシスを考慮したスイッチトリラクタンスモータのＲＮＡモデル

This paper presents a method for calculating the iron loss characteristics of a switched reluctance (SR) motor based on reluctance network analysis (RNA). The RNA model of the SR motor consists of a multiple number of nonlinear reluctances and magnetomotive forces (MMFs) exerted by a winding current. In addition to these elements, magnetic inductances that express the magnetic hysteresis are incorporated into the model. The RNA model of the SR motor is combined with its drive circuit and motion calculation circuits in SPICE, which is a general-purpose circuit simulator. Using the electromagnetic and motion-coupled models, we can calculate dynamic characteristics, including iron loss, quickly and accurately. We evaluate the validity of the proposed method by comparing the result with measured values.

田形磁心のＲＮＡモデルにおける渦電流のモデリング手法

Variable inductors can control the inductance of ac winding by dc excitation from a control circuit. For a large-capacity variable inductor, an EIE core is suitable because it is made of laminated iron and has no gaps for harmonic current reduction. EIE cores are expected to have practical applications to power control apparatuses in electric power systems. For optimum design of an EIE core, we previously proposed a reluctance network analysis (RNA). However, it is necessary to improve the accuracy of the iron loss calculation. This paper presents a method for modeling the eddy current caused by leakage flux in the laminated direction. We predict the paths of the eddy current, and express them in an electric circuit model. The eddy current circuit model is combined with the RNA model of an EIE core. We calculate the iron loss characteristics of the EIE core variable inductor, and evaluate the validity of the proposed method by comparing the calculated results with measured values.

A study of the loss characteristics of the amorphous magnetic material under nonsinusoidal wave magnetic flux

This paper presents a study on iron loss characteristics of an amorphous magnetic material under nonsinusoidal wave magnetic flux. The iron loss characteristics of the amorphous magnetic material have been compared to those of grain-oriented magnetic steel sheets. Measurements of the iron loss have been carried out by means of an SST. It was found that the ratio of the iron loss increase of the amorphous magnetic material under the excitation by distorted waveforms and symmetric PWM waveforms is lower than that of grain-oriented magnetic steel sheets. On the other hand, the ratio of the iron loss increase of the amorphous magnetic material under the excitation by asymmetric PWM waveforms is higher than that of grain-oriented magnetic steel sheets. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(3): 11–18, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20004

ＳＰＩＣＥ用非線形磁気抵抗におけるヒステリシスの一表現法

Magnetic circuit methods make it possible to analyze characteristics of various magnetic devices by simple calculations. Furthermore, we can use general-purpose tools, such as a SPICE circuit simulator, for calculation. In a previous paper, we proposed a method for calculating iron loss characteristics based on a magnetic circuit model considering iron loss. However, since this method treats hysteresis loss and eddy-current loss collectively, it is necessary to vary the parameters of the magnetic circuit model when frequency is varied. In this paper, we propose a method for calculating iron loss for each frequency without varying the parameters of the magnetic circuit.

A Study of the Loss Characteristics of the Amorphous Magnetic Material under the Non-sinusoidal Wave Magnetic Flux

This paper has investigated iron loss characteristics of amorphous magnetic materials under the non-sinusoidal wave magnetic flux. The iron loss characteristics of amorphous magnetic materials have been compared with grain-oriented magnetic steel sheet. The measurement of the iron loss has been carried out with SST. As a result, it is found that the increase ratio of the iron loss of the amorphous magnetic material under the excitation of distorted waveforms and symmetric PWM-waveforms is less than that of the grain-oriented magnetic steel sheet. On the other hand, it is found that the increase ratio of the iron loss of the amorphous magnetic material under the excitation of asymmetric PWM-waveforms is larger than that of the grain-oriented magnetic steel sheet.

A study of the loss characteristics of the amorphous magnetic material under the distorted wave magnetic flux

In this paper, iron loss characteristics of amorphous magnetic material under distorted waveforms have been described. The loss characteristics of amorphous magnetic materials have been compared with grain-oriented silicon steel sheet. The measurement of the iron loss has been carried out with SST. In the result, it is found that amorphous magnetic materials have better characteristics under the distorted waveforms than grain-oriented silicon steel sheet.

Iron losses of silicon steel under square wave voltage excitation

Iron loss characteristics under square wave voltage excitation are investigated in detail. It is shown that iron losses under square wave voltage excitation are increased or decreased compared with losses under sinusoidal excitation, according to the shape of the square wave voltage.

Iron Loss of Silicon Steel Under Square Wave Voltage Excitation

The iron loss characteristics of silicon steel were studied using the iron loss estimation method previously proposed by the authors. The rate of increase of the square wave iron loss with respect to the sine wave iron loss was only slightly greater than predicted. It was found that this iron loss estimation method provides adequate precision for widespread application to excitation due to square wave voltages, such as occur in inverter transformers.