Power converter, generator and architecture for high efficiency auxiliary power unit

1. A power system for an aircraft, comprising:

an auxiliary power unit (APU) having an AC generator; and

a multifunction power converter-controller module electrically connected to the AC generator, the multifunction power converter-controller module including at least one multifunction power converter-controller (MPCC),

wherein the at least one MPCC is configured to control the AC generator to use ground power to run as a motor to provide mechanical power assist for the APU so that the APU provides bleed air for an environmental control system that the APU runs with a reduced fuel burn that is less than a fuel burn that would occur if the APU were to run without the mechanical power assist, and

wherein the ground power is supplied through the at least one MPCC.

2. The system of claim 1 , wherein the at least one MPCC is configured to start the APU using the AC generator powered by the ground power from a ground power network.

3. The system of claim 1 , wherein the multifunction power converter-controller module is configured to receive an AC power input from the AC generator at a first frequency and supply AC power output to an aircraft power distribution system at a second frequency, wherein the first frequency is different from the second frequency.

4. The system of claim 3 , wherein the first frequency is less than 400 Hz and the second frequency is 400 Hz.

5. The system of claim 1 , wherein the AC generator is a controllable frequency generator.

6. The system of claim 5 , wherein the multifunction power converter-controller module further includes a controllable frequency generator controller to control the controllable frequency generator to provide an AC power output at 400 Hz.

7. The system of claim 4 , wherein the at least one MPCC is connected to a filter to filter the AC power output with the second frequency before supplying the filtered AC power output to the aircraft power distribution system, wherein the filter includes a 4-wire transformer.

8. The system of claim 1 , wherein a source of the ground power is an airport power network.

9. The system of claim 1 , wherein the at least one MPCC is configured to start the APU using the AC generator using battery power supplied from an on board battery system, wherein the battery power is supplied directly or via a DC/DC converter.

10. The system of claim 1 , wherein the at least one MPCC is configured to receive AC power from the AC generator to drive traction motors of an electric taxi system.

11. A method of operating an auxiliary power unit (APU) of an aircraft, comprising:

supplying ground power to a multifunction power converter-controller (MPCC) of the aircraft from a ground power network;

converting the ground power with the MPCC to produce a power output;

motoring an AC generator of the APU with the power output from the MPCC; and

driving a bleed air system of the aircraft via the APU with mechanical power assist supplied from the AC generator of the APU so that the APU runs with a reduced fuel burn that is less than a fuel burn that would occur if the APU were to run without motoring the AC generator with the power output from the MPCC.