Topic
Epstein frame
About: Epstein frame is a research topic. Over the lifetime, 226 publications have been published within this topic receiving 2073 citations. The topic is also known as: Epstein square.
Papers published on a yearly basis
Papers
TL;DR: Experimental results show that the proposed model can significantly improve the calculation accuracy of core losses of the SSRM, and the accuracy is better than the conventional Epstein frame method.
Abstract: In this paper, a new nonlinear lumped parameter equivalent circuit model is proposed to calculate the core losses of a novel 16/10 segmented rotor switched reluctance motor (SSRM) for belt-driven starter generators. The model investigates the hysteresis, eddy current and anomalous losses by using the method of energy conservation. Four parameters are introduced in the proposed model to consider the effects of saturation and leakage flux in SSRM. They are the incremental leakage inductance, the incremental equivalent winding resistance, the incremental magnetizing inductance, and the incremental equivalent core-loss resistance. This model can overcome the hysteresis effects of winding resistance and leakage inductance on the current, and improve the accuracy of the parameters. To illustrate the advantages of the proposed model, an experiment platform is developed. Experimental results show that the proposed model can significantly improve the calculation accuracy of core losses of the SSRM. The accuracy is better than the conventional Epstein frame method. The proposed core-loss model and analysis method can be applied to other kinds of switched reluctance motors.
147 citations
TL;DR: In this paper, core loss characteristics of stator permanent-magnet (PM) machines are analyzed and calculated, in which the unique dc-biased magnetic induction is taken into account.
Abstract: In this paper, core loss characteristics of stator permanent-magnet (PM) machines are analyzed and calculated, in which the unique dc-biased magnetic induction is taken into account. The flux density variation patterns in some key points in a doubly salient PM (DSPM) machine are analyzed by the two-dimensional time-stepping finite-element method. To calculate the core loss of stator and other minor hysteresis loops under dc magnetic bias, core loss characteristics of silicon steel sheet under dc-biased induction condition are first tested by a simple test system based on traditional Epstein frame and a functional relationship between the change of dc-biased induction and hysteresis loss is proposed. Two core loss calculation methods considering rotational magnetization based on flux density waveform are improved to take the influence of dc-biased magnetic induction into consideration. The calculation results are verified by experiments on a prototype DSPM machine. The conclusions are also applicable to other kinds of stator PM machines.
131 citations
TL;DR: In this paper, a computerized automated adaptive digital feedback system built for measuring magnetic properties of soft magnetic materials under fully controlled nonsinusoidal flux density waveforms is presented. But the system is limited to the frequency range of 0.5 Hz to 2 kHz and the peak flux density up to 90% of saturation.
Abstract: There are increasing calls to employ conventional magnetic testers, such as the Epstein frame and single sheet tester, for the accurate measurements of magnetic properties of soft magnetic materials under fully controlled nonsinusoidal flux density waveforms. This paper presents a computerized automated adaptive digital feedback system built for that purpose. We present several examples of the ability of the system to control an arbitrary shape of the flux density waveforms over the frequency range of the data acquisition system (0.5 Hz to 2 kHz) and for peak flux density up to 90% of saturation. The control algorithm is capable of magnetizing magnetic material under controlled sinusoidal, triangular, trapezoidal, and pulsewidth-modulated magnetizing conditions as well as other arbitrary waveforms that do not contain dc components. We provide a full description of the adaptive digital feedback technique together with measurements showing the B-H loops for several magnetic materials under various controlled excitation conditions.
110 citations
12 Oct 2003
TL;DR: In this article, a comparison of the Epstein frame and toroid test results for annealed and unannealed steel was presented for core loss under nonsinusoidal supplies, and the combination of the improved loss separation algorithm and the form factor concept was found to yield results close to the measured losses under high frequency supplies such as pulse width modulated waveforms.
Abstract: This paper first reviews three internationally standardized core loss measurement methods: Epstein frame, toroids and single sheet testers. A comparison of the Epstein frame and toroid test results is presented for annealed and unannealed steel. Two methods are used to predict core losses under nonsinusoidal supplies. The first method uses the Fourier series and an improved loss separation algorithm to predict core losses under equivalent brushless DC motor flux waveform with known spectrum. For lower harmonics, superposition yielded results close to the measured values. The second method uses the form factor concept and an improved loss separation algorithm to predict core loss. The combination of the improved loss separation algorithm and the form factor concept was found to yield results close to the measured losses under high frequency supplies, such as pulse width modulated waveforms. An Epstein frame with commercial 0.0140-inch electrical steel was used for direct core loss measurements; the methods and test bench used are detailed in the paper, along with test results.
83 citations
TL;DR: The magnetic characteristics of a magnetic core is simulated and the core loss distribution within the core obtained by the dynamic hysteresis model and FEM.
Abstract: For accurate computation of core losses, the Jiles–Atherton ( $J$ – $A$ ) dynamic hysteresis model accounting for hysteresis, eddy current and excess losses is incorporated into the finite-element method (FEM). The $J$ – $A$ dynamic hysteresis model is constructed by combining the traditional $J$ – $A$ hysteresis model with the models of instantaneous eddy current and excess losses. The $J$ – $A$ model parameters and dynamic loss coefficients are determined by fitting the models to the measurement data of a single sheet tester (SST 500) and Epstein frame tester. To find the robust best fit, the particle swarm optimization algorithm is employed. By using the proposed $J$ – $A$ dynamic hysteresis model and FEM, the magnetic characteristics of a magnetic core is simulated and the core loss distribution within the core obtained. The calculated and measured results are compared to show the accuracy and effectiveness of the proposed model.
74 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 7 |
| 2020 | 17 |
| 2019 | 16 |
| 2018 | 14 |
| 2017 | 12 |
| 2016 | 14 |