Eddy-Current Losses in Rectifier Transformers

Two methods are developed for evaluating the eddy- current losses occurring in a rectifier transformer during operation, i.e., when carrying pulsating currents. The first is based on the analysis of the whole waveshape; the second starts from the harmonic composition of current curves. Each system is useful from a different point of view, and both achieve the same results. Experimental measurements confirm the theoretical assumption, i.e., that eddy-current losses with pulsating currents can be some multiples higher than those evaluated by the tests prescribed by standards. Eddy-current loss evaluation is made for two-, six-, and twelve-pulse systems.