Study on coupling characteristics of contactless power supply system for moving apparatus

New contactless power supply system implements contactless power transmission by the combination of electromagnetic inductive coupling and power electronic technology. For moving apparatus air coil structures have some potential advantages over the iron core structures, such as, lightweight, good coupling stability with horizontal displacement etc. This paper does the calculations of self-inductance for coils with different shape and mutual inductances between coils with displacement by the magnetic flux method and Neumann's formula. Further study has been given on the effect that the coil shape and dimensions have on the coupling change characteristics. Finally the results acquired have been validated by the experimental research. The experimental and calculated results show that the rectangular coil is more effective for stabilizing the coupling in the contactless power supply system for moving apparatus, which is mainly determined by the coil width and the length ratio between the primary and the secondary. The smaller the width and the larger the length ratio, the better the coupling characteristic with displacement.