US Patent 7578136 Integrated power and pressurization system

An integrated power and pressurization management system supplies electrical power and cabin pressurization and cooling air during both airborne and ground operations. The system includes an integral auxiliary power unit (APU) that has a compressor, a motor-generator, and a power turbine all mounted on one shaft. The integral APU can supply compressed air for cabin pressurization and environmental cooling functions, and can generate electrical power for various electrical loads. The system further includes one or more electrically driven compressors.