Analysis and design of a modular, high power converter with high efficiency for electrical power distribution systems

The analysis and design of a modular high power converter is presented, suitable to replace a typical power distribution transformer in future. The novel converter consists of three simple converter cells, each containing a high frequency transformer with high insulation capability. The converter allows a redundant operation in case of a failure of one converter cell. In addition, the modular structure of the converter guarantees an easy and fast adaptation of different voltage systems with different power frequency ratings. The operation principle of the converter is discussed and general mathematical expressions are derived to estimate the stress of all components of the power train. In addition, a simple low loss snubber is introduced to reduce the switching losses of the primary sided switches and therefore to improve the efficiency of the converter. With the snubber circuitry an overall efficiency of 98% is achieved. Experimental results of a prototype with an output power of 105 kW demonstrate the suitability of the topology selected. Measurements were compared with calculations to confirm the theoretical investigations performed.