Overview
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An inductive power supply system is a device which transmits power by electromagnetic
induction without physical contact. The system can be used for various
applications, such as moving devices, rotating devices, and devices placed
in closed spaces.
Because the primary side and the secondary side of a transformer are separated
by a gap, and the flux leakage and efficiency vary with the position of
the two sides, obtaining the position of each characteristic is advantageous.
This example presents the use of a magnetic field analysis to obtain the
transmission characteristics of an inductive power supply system when the
position of the primary and secondary sides changes. |
Vertical Distance versus Power Transmission Efficiency
| The magnetic flux density distribution when the vertical distance between
the primary side and secondary side is varied is indicated in Fig. 1. The
vertical distance versus power transmission efficiency is indicated in
Fig. 2.The leakage flux increases depending on the vertical position, and
the magnetic flux inside of the secondary side core reduces as indicated
in Fig. 1. Approximately 80% of the maximum efficiency can be achieved
when the vertical distance is 2 mm as indicated in Fig. 2. The efficiency
is mostly reduced linearly because the reduction in flux linkage in the
secondary coil is caused simply by the increase of the vertical distance. |
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Horizontal Distance versus Power Transmission Efficiency
| The magnetic flux density distribution when the horizontal distance is
varied is indicated in Fig. 3 and The horizontal distance versus power
transmission efficiency is indicated in Fig. 4 when vertical distance between
the primary and secondary sides is fixed at 2 mm.The flux linkage is not
produced in the secondary coil when the horizontal distance is 10 mm because
the magnetic flux on the left side of the secondary core decreases depending
on the horizontal distance, as indicated in Fig. 3. The efficiency is reduced
nonlinearly as indicated in Fig. 4. The cause of the reduction in the flux
linkage of the secondary coil is not only distance, but also the variations
in the flow of the magnetic flux. |
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