Whether it's American civilian aircraft or European civilian aircraft, inTraditional aircraft power distribution systemIn terms of system design concepts, they are still quite similar. This system will be indispensableAviation contactorSwitching andAviation circuit breakerThe protection of these two types of devices constitutes the basic power distribution system. The traditional aircraft power system typically consists of two or more engines driving generators to provide AC load for the entire aircraft. In some civil aircraft configurations, engine driven generators are separately connected to the distribution bus (i.e. each generator is responsible for a specific number of bus bars), and almost all American and European airlines mandate the use of parallel connection configurations. In this configuration, the busbars of the main generator are connected together through a busbar circuit breaker (BTB). If a generator malfunctions, it will automatically isolate itself from its respective busbar and then shut down all busbar loads to be taken over by the running generator.

However, if both generators fail, unnecessary loads will no longer be able to supply power, but the battery will automatically provide the necessary power and maintain its scheduled operating time and battery charging status according to load requirements. In traditional aircraft systems, synchronous generators provide a constant frequency of AC voltage to the AC load in the aircraft power system. The AC/DC rectifier is used to convert the fixed frequency AC voltage on the main AC bus into a multi-level DC voltage on the secondary bus that supplies power to the DC load, as shown in the above figure. The disadvantage of this system is that the power cannot be too high. It can be imagined that if it is a 28V system or a 90KVA system, it will impose very strict requirements on the relevant components of the power distribution, such as contactors and circuit breakers. Only by developing more devices with higher current carrying capacity or breaking away from traditional system concepts can we meet the increasingly high requirements of load systems.

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