Parallel Operation of Direct Current Transformers

Abstract:
This paper analyses the impact of the parameters variation on the current sharing unbalance of direct current transformers after paralleling several units. In order to allow scalability and ensure the same operational principles of a single unit, the critical parameters are identified and the switching frequency as the only available degree of freedom is used to enhance the current sharing. The analysis relies on the input impedance of the small signal model. The performance of the parallel arrangement is assessed and corrections with the switching frequency are evaluated. Modeling and predictions are verified by means of simulation and experimental investigations.