A 150kW Medium Frequency Transformer Optimized for Maximum Power Density

In order to shrink mass and/or volume of a 150kW transformer, one idea is to operate at higher frequencies enabled by power electronics. Generally, the transformer volume and weight will decrease if the operating frequency increases. But with higher frequency, there will be increased losses, due to skin- and proximity-effect in the windings, and frequency dependent core losses. Increased losses and shrinking volume result in higher operating temperatures, which will result in higher cooling effort (volume and cost of cooling system). It is a multi-parameter optimization problem to find a transformer design with minimum weight (or, e.g., minimum volume or minimum material cost) for given constraints like maximum possible frequency due to the given power semiconductors, cooling system limitations and/or cost targets. There is a large parameter space, and a lot of different effects, often coupled, to be considered. In this paper, it is not the goal to show maximum possible frequency designs. Instead we show dependencies of specific optimized transformer designs for a 150kW medium frequency transformer with a ratio 1800V:750V.