Reduction in eddy current loss for a power coupler in an electrodeless discharged lamp

Abstract

We investigated reduction in an eddy current loss for a power coupler in an electrodeless discharged lamp with our previously proposed analysis method for plasma in the lamp. We confirmed that a large eddy current flow was observed at the top of an Al stage in the power coupler and the loss was reduced by a decrease in the height of the Al stage. This result suggests that a decrease in the height is effective to reduce wasted power losses and implies the possibility of an improvement in the lamp efficiency. We also confirmed that upward-moving and moderate-elongation of the ferrite core in the power coupler is effective to reduce the wasted loss. In order to verify the result, we evaluated the lamp efficiency of a lamp with a modified power coupler. Resultantly, the lamp efficiency was increased by approximately 3 lm/W (lumen per Watt). Therefore, we can conclude that reducing the eddy current loss in the power coupler is one of the important factors to obtain high lamp efficiency.