The invention provides a series resonant LLC power converter unit to provide a plurality of power outputs. The power converter unit comprises a plurality of transformers arranged such that at least one primary winding of each transformer is connected in parallel and configured to provide a power output. An inductive element is positioned in parallel with a single primary winding selected from said plurality of transformers, wherein the inductive element and single primary winding restricts variation in inductance for said plurality of transformers and power outputs in operation.