Aluminum Windings and Other Strategies for High-Frequency Magnetics Design in an Era of High Copper and Energy Costs

Recent Cu price increases motivate careful examination of approaches to minimize Cu use in high-frequency transformers and inductors. Approaches that can reduce Cu use without increasing losses include careful winding design, trading winding volume for core volume, replacing Cu with Al, and using Cu-clad Al (CCA) windings. Al wire is particularly attractive. The cost of Al is lower than it might appear from the cost per unit mass when the much lower density of Al is also considered, and the disadvantage of higher resistivity becomes less important when high-frequency effects are considered.