Phase Balancing for Aircraft Electrical Distribution Systems

The aircraft of the future will use several new concepts to improve its electrical power supply system, transforming it into a small smart distribution grid. Among these concepts, power management systems, increase in the main bus voltage, integration of high-voltage direct current grids, phase balancing, and power feeder balancing have been suggested. All these methods aim to reduce the overall weight of the aircraft. In order to analyze the weight-saving potential of aircraft through the phase-balancing method, simulations have been built based on the electrical load analysis of an actual passenger aircraft. The simulations reproduce the electrical power supply grid of an aircraft and the asymmetric utilization of the phases of the power feeders. Within the simulations, phase balancing is tested with different objective functions in order to achieve a more symmetric load of the feeder main line and the feeder branches and to minimize the return current. The new proposed concept suggests that loads be shifted depending on the ground/flight phases based on a fixed switching scheme, which is calculated before the first flight of the aircraft. As a result, only the nonflight-relevant commercial loads have been made switchable. Additionally, based on former publications, the local distribution of the loads and the load power factor have thereby been taken into account. Based on the simulation results, the weight benefit for the actual aircraft has been calculated. To validate the new concept, a switching box containing several multiplex switches has been built, and experimental results are presented.