Browsing by Subject "Coil arrays"

Now showing 1 - 2 of 2

Open Access
High-efficiency arrays of inductive coils
(2014) Gönendik, Erdal
Inductive heating is widely exploited in industrial operations including metal hardening, forging and brazing. Recently, as a promising alternative to traditional heating, inductive heating has attracted substantial commercial interest for domestic cookers. This is because inductive heating o ers fast, precise and e cient heating compared to traditional methods that make use of either convection or conduction as a means of heat transfer. To introduce full exibility in using the cooking space, a strong demand is currently directed toward all-surface induction ovens, with the capability to heat a vessel placed arbitrarily anywhere on the surface of the induction cook top. For this purpose, inductive coils of tens of mm in diameter are required to be designed and stacked together to form coil arrays. However, this typically comes at the cost of reduced e ciency. To address this problem, this thesis work focuses on high-e ciency coil arrays designed for all-surface induction with optimum ferrite placement. Here analytical, numerical and experimental electromagnetic analyses of sample coils are performed. Effects of di erent ferrite placements are investigated and, contrary to the general intuition of placing ferrite bars only under the coil, an e ective way of ferrite placement is proposed and shown. These results indicate that the proposed highe ciency arrays of inductive coils are highly promising for all-surface inductive heating.
Open Access
Innovative modular and arrayed coil systems for ultrahigh efficiency in inductive heating and automated metal detection
(2016-12) Kılıç, Veli Tayfun
Induction systems have become increasingly more important and popular in our modern world and their application areas have widely expanded because of their high levels of safety and controllability. Today one important application of these induction systems is the inductive heating, which now finds use not only in conventional applications of point-source heating but also in new areas including all-surface heating with some degree of exibility in localization. The efficiency of such emerging systems, especially in planar structures across an entire surface, however, has thus far been limited compared to conventional inductive heating. In this thesis, to address these problems, we show a new class of strongly coupled planar coils that enhance magnetic coupling in square lattice stacking by design and with phase difference application in operation. These coils can be tiled in two-dimensional arrays in a modular fashion or to cover an arbitrarily large continuous surface. In a proof-of-concept realization, we experimentally demonstrated that these proposed outer squircle-inner circular coils outperform the conventional coils of circular shape. Using square-arrayed coil architecture, here we also present all-surface induction systems achieving uniform and enhanced heating speed for all loading positions no matter what the misalignment of the heated vessel with respect to the coils is. In addition, to solve the problems of automatically detecting metals over the whole surface together with determining their exact positions, we introduce a new method that relies on simultaneous wireless measurement and tracking of inductance-resistance of the coils at multiple frequencies to identify those coupled with the metal targets to be detected in the system. While pinpointing the location of the targeted metals, the proposed technique also identifies their material types. For future ubiquitous all-surface systems, this approach allows for automated sensing of metal vessels and powering the loaded coils for the highest possible performance independent of the specific location of each vessel with respect to coils. These findings indicate that the proposed innovative modular and arrayed coils enable, for the first time, full degree of exibility in localized inductive heating with space-invariance in all-surface heating.