The Low-Voltage DC Power System is composed of a DC excitation motor, voltage regulator, reverse current cutoff, and overvoltage protector. The rated voltage is 28.5 volts, with power ratings available in 3, 6, 9, 12, and 18 kilowatts. The low-voltage DC power is converted into AC power for secondary power supply by an inverter or a static inverter.
2. Constant Speed Constant Frequency AC Power System: A 400Hz, 115/200V three-phase AC power system composed of a constant speed transmission device and an AC generator. It is rated for 20, 30, 40, 60, 90, 120, and 150 kilovolt-amperes. The secondary power source is provided by a transformer rectifier, with an emergency power source consisting of aircraft batteries and an emergency AC generator.
3. Variable Frequency Constant Frequency AC Power System: A 400Hz three-phase AC power system composed of brushless AC motors directly driven by aviation engines and inverters. The secondary power, emergency power, and auxiliary power are the same as those of the constant speed constant frequency AC power system. Aviation ground power 2, 36V aviation power 1, 400Hz inverter power 7, 115/200V power 2, 27V DC power 5, 400Hz power 12, aviation power
4. Hybrid Power System: The main power source consists of a low-voltage DC power supply and a variable-frequency AC or constant-frequency AC power supply. The battery serves as an emergency power source, with an inverter or a static inverter used for the secondary power supply. For example, aircraft and helicopters equipped with heating and de-icing systems consume a significant amount of power, which can be powered by variable-frequency AC. It is composed of a variable-frequency AC generator driven by an aircraft engine and a voltage regulator, which is relatively simple.
5. High-Voltage Direct Current (HVDC) Power System: Research and development of a HVDC power system with a rated voltage of 270 volts commenced in the 1970s. This system combines the advantages of both low-voltage DC and AC power systems: high efficiency, lightweight, simple parallel distribution, easy to maintain uninterrupted power supply, strong anti-interference capability, and no need for a constant-speed transmission device. However, the circuit switches, power conversion devices, and brushless DC motors are relatively complex.
