International Journal of Applied Electromagnetics and Mechanics - Volume 44, issue 2

Authors: Dughiero, F. | Forzan, M. | Pozza, C. | Pastore, C. | Zerbetto, M.

Article Type: Research Article

Abstract: Induction cooktops are more and more used in the houses with increasing market in comparison with gas cooktops and resistance or halogen cooktops. The main reasons for this are the higher energy efficiency, the low heating times, the controllability of the power delivered to the pot, the safety with reference to the low temperature of the glass, the superior cleanability. The main core of the Induction Hob (IH) is constituted by the power electronics board and …the inductor which are strictly correlated in the sense that the frequency converter (the frequency operating range is 20–100 kHz) must be designed in order to correctly resonate with the coil in order to achieve its optimum efficiency over the broadest possible operation range; this means that the inductor must be designed in order to fulfill the Zero Voltage switching condition of the frequency converter over the whole range of operation. These requirements are much more important in the quasi resonant converters for the limitations in the controllability of soft switch mode of solid state switching. In the paper a design procedure based on a fully 3D FEM model of the inductor coupled with the frequency converter circuit is presented. The simulation results will be discussed and compared with experimental data. Show more

Keywords: Induction cooktops, finite element analysis, quasi-resonant converter

DOI: 10.3233/JAE-141761

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 44, no. 2, pp. 209-215, 2014

Authors: Frogner, Kenneth | Cedell, Tord | Andersson, Mats

Article Type: Research Article

Abstract: A laboratory implementation of a two-phase travelling wave induction heating setup is described. The focus is the development of a versatile power control system for multi-coil experiments and parameter studies. The drive system features high temporal accuracy, full real-time controllability, and integrated measurement technology, analyzed step wise. The performance was tested using a full pitch travelling wave inductor based on litz wire with a flux concentrator from a powder material. Thermographic images from the …experiments are presented and the results are compared with simulations. The challenges related to multi-coil configurations are explained, many of which are difficult to predict from simulations. Show more

Keywords: Induction heating, travelling wave, TWIH

DOI: 10.3233/JAE-141762

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 44, no. 2, pp. 217-226, 2014

Authors: Aono, Hiromichi | Naohara, Takashi | Maehara, Tsunehiro | Hirazawa, Hideyuki

Article Type: Research Article

Abstract: Nano-sized superparamagnetic Y_{3} Fe_{5} O_{12} ferrite having a high heat generation ability in an AC magnetic field was prepared by physical bead milling. The highest heat ability in the AC magnetic field was for the fine Y_{3} Fe_{5} O_{12} powder with a 16-nm crystallite size (the samples were milled for 4 h using 0.1 mm� beads). The main reason for the high heat generation …property of the milled samples was ascribed to an increase in the Néel relaxation of the superparamagnetic material. For the samples milled for 4 h using 0.1 mm� beads, the heat generation ability (W·g^{-1} ) was estimated using a 3.58 × 10^{-4} · f· H^{2} frequency (f/kHz) and the magnetic field (H/kA·m^{-1} ), which is the highest reported value of superparamagnetic materials. Furthermore, Y_{3} Fe_{5} O_{12} microspheres having a 20–32 μm diameter range were prepared by a spray dryer using the bead-milled nano-sized particles. Show more

Keywords: Y_{3}Fe_{5}O_{12} , AC magnetic field, thermal coagulation therapy, nano particle, bead milling

DOI: 10.3233/JAE-141763

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 44, no. 2, pp. 227-234, 2014

Authors: Więckowski, A. | Korpas, P. | Krysicki, M. | Dughiero, F. | Bullo, M. | Bressan, F. | Fager, C.

Article Type: Research Article

Abstract: A solid-state microwave generators system is considered as an alternative to the magnetron, in order to inject electromagnetic energy into the cavity of a microwave oven for domestic use. Over current devices, the use of solid state technology allows one to control the frequency and phase of the electromagnetic field generated. Considering a simplified cavity with 2 solid state sources, the influence of the electrical parameters on maximum efficiency obtainable in the process of microwave …heating is investigated. By varying the frequency, different values of optimal phases and different values of maximum efficiency are detected. Moreover, the procedure is repeated with varying the position of one source port and the influence of geometry on the system performance is evaluated. Our results demonstrate that the ability to control the electrical quantities of a microwave heating process makes it possible to obtain better results in terms of energy efficiency over the current poorly controllable systems. Show more

Keywords: Efficiency optimization, microwave oven, solid-state technology, phase control

DOI: 10.3233/JAE-141764

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 44, no. 2, pp. 235-241, 2014