General Comparison of Power Loss in Single-Layer and Multi-Layer Windings

This paper systematically and generally addresses the question of when a single-layer winding can have lower loss than a multi-layer winding. Two cases for single-layer windings are investigated. First, when very high frequencies require thinner conductor layers or thinner wire than is practical. Second, when the current waveform contains substantial harmonics. We conclude that multi-layer windings typically provide lower loss except when layer thickness constraints prevent the use of a thickness-to-skin-depth ratio less than 1.45. However, with substantial harmonic content, the advantage of multi-layer windings is typically small and is not always worthwhile in practice