The aircraft DC power system consists of the main power supply, emergency power supply, and auxiliary power supply, sometimes including additional power sources. The main power supply is composed of generators driven by the aircraft engine, power control and protection equipment, and supplies power during flight. In the event of a failure in the main power supply during flight, the battery or emergency generator becomes the emergency power supply.
The aircraft power system has evolved through the stages of low-voltage DC, AC, and high-voltage DC, with the AC power system experiencing constant-speed constant-frequency, variable-speed constant-frequency, and variable-speed variable-frequency developments.
The aircraft power system consists of the main power, emergency power, and secondary power, and sometimes includes auxiliary power. The main power is composed of generators driven by the aircraft engine and power control and protection equipment, which supply power during flight.
When the aircraft engine is not operational (such as during ground tests), the main power supply is also inactive, and it is powered by the auxiliary power supply. The aircraft battery or auxiliary power unit (a power unit consisting of a small on-board engine, generator, and hydraulic pump, etc.) is commonly used as the auxiliary power source. In the event of a main power supply failure during flight, the battery or emergency generator becomes the emergency power source.
Aircraft electrical equipment demands high-quality power supply, including technical standards for voltage adjustment accuracy, frequency adjustment accuracy, AC voltage waveform sine wave purity, voltage surges, and spikes, etc.
Aircraft power system with the main power supply in the form of direct current.
Two types: 28V Low-Voltage DC Power Supply; 270V High-Voltage DC Power Supply: The power supply in a high-voltage DC power supply system is mainly composed of brushless DC generators and generator controllers. The brushless DC generator is essentially a combination of a brushless AC generator and a rectifier and filter circuit, with two types of combinations: one is the combination of a brushless AC generator with an uncontrolled rectifier and filter circuit, as the F-22 uses this approach; the other is the combination of a brushless AC generator with a controllable rectifier and filter circuit, which is a new development. The advantage of the latter is that it has both starting and power generation functions, and can also absorb the energy feedback from the system during power generation.
The system is composed of the main power supply, auxiliary power supply, emergency power supply, and secondary power supply, etc. The power generation unit of the main power supply is typically a direct current generator directly driven by an aircraft engine.
Most auxiliary power sources utilize aviation batteries, with some employing auxiliary power units to drive generators.
Emergency power sources are predominantly aviation batteries, but there are also a few cases that utilize emergency generators.
Secondary power sources in aircraft DC power systems were predominantly rotary converters in the early days, which are now gradually being replaced by static inverters.
