Implementation of multiplex-switches for power feeder balancing in aircraft

Multiple approaches are available for designing more flexible and energy-efficient electrical grids on board aircraft in order to lower the weight of aeroplanes. Here, two novel concepts in aviation, dealing with intelligent switching nodes based on power semiconductors, are introduced. The balancing concepts (phase balancing and power feeder balancing) reduce the return currents and allow reduction of the power feeder diameter by symmetrising the load of all phases of the power feeders. The focus of this paper is examination of the feasibility and practical realization of multiplex-switches for implementing the two concepts. That is why a prototype multiplex-switch has been developed and tested. The implementation of the multiplex-switch, which is usable for phase and feeder balancing, is explained in detail in this paper. Different transistor types, possible realisations of bidirectional switches and the suitability of Flexible AC Transmission System (FACTS) for load balancing have been discussed. Additionally, experimental results of the prototype multiplex-switch are shown and discussed. Different switching strategies for shifting loads between different feeders have been implemented in the multiplex-switches and have been tested with different load types on a test bench.