System and process for power supply to a railway vehicle, converter, control unit, and air-conditioning unit for the system

1. A power supply system for a railway vehicle having a plurality of cars comprising:

a first electrical converter including a module;

a second electrical converter, the first and second electrical converters transforming a single phase or direct electric voltage received via a catenary into a three-phase electrical voltage delivered to a first three-phase power supply network and a second three-phase power supply network respectively on board the railway vehicle, the first and second electrical converters distributing electrical power to the plurality of cars, the first and second power supply networks being electrically isolatable from one another;

at least one air-conditioning unit installed in each of the plurality of cars, each air-conditioning unit including at least one compressor producing cold air expelled into an interior of the car, the at least one compressor electrically connected to the first three-phase power supply network and receiving three-phase voltage power from the first converter; and

a plurality of auxiliary electrical loads other than the one compressors electrically connected to the second power supply network to be powered with three-phase voltage by the second converter;

a third network for transmitting from each air-conditioning unit to the first electrical converter the respective demands of each air-conditioning unit, each demand indicating the electrical power required by each air-conditioning unit to cool or dehumidify the air within the car of the air-conditioning unit,

the module adjusting both the amplitude of the three-phase voltage and the frequency of the three-phase voltage delivered by the first power supply network in response to the demands transmitted by the air-conditioning units.

2. The system as recited in claim 1 further comprising a set of controllable contactors capable of connecting the plurality of auxiliary loads to the second converter only, so the auxiliary loads are powered from the second converter, and connecting the at least one compressors to the first converter only, so the compressors are powered from the first converter, and alternately connecting the compressors to the second converter only, so the compressors are powered from the second converter.

3. The system as recited in claim 2 further comprising a detector and a unit controlling the set of controllable contactors so that, when the detector detects a fault in the first converter, the unit automatically changes connection of the at least one compressors from the first converter to the second converter.

4. The system as recited in claim 1 further comprising a set of controllable contactors connecting the auxiliary electrical loads other than the compressors to the second converter only so the auxiliary electrical loads are powered from the second converter, and alternately connecting the auxiliary electrical loads to the first converter only so the auxiliary electrical loads are powered only from the first converter.

5. The system as recited in claim 4 further comprising a detector and a unit for controlling the set of controllable contactors so that, when the detector detects a fault in the second converter the unit automatically changes connection of the auxiliary electrical loads from the second converter to the first converter.

6. The system as recited in claim 1 further comprising:

a sensor for ambient temperature in each car including an air-conditioning unit; and

an adjustment module calculating an adjustment parameter for adjusting the three-phase voltage in response to the ambient temperature measured in each car and a reference temperature to be reached;

the adjustment module adjusting both the amplitude voltage and the frequency of the three-phase voltage in the first power supply network in response to the adjustment parameter so one of the compressors takes requiring a greatest amount of electrical power receives the greatest amount of electrical power.

7. The system as recited in claim 1 wherein each air-conditioning unit includes a temperature adjustment mechanism adjusting temperature of the cold air expelled for the three-phase voltage delivered to the at least one compressor and a unit controlling the temperature adjustment mechanism in response to both the amplitude and the frequency of the three-phase voltage delivered to the at least one compressor, the temperature adjustment mechanism adjusting a temperature measured within the car to a reference temperature to be reached.

8. A control unit for an air-conditioning unit in the system as recited in claim 7 , the control unit controlling the temperature adjustment mechanism in response to both the amplitude voltage and the frequency of the three-phase voltage delivered to the at least one compressor, the temperature adjustment mechanism adjusting a temperature measured within the car to a reference temperature to be reached.

9. An air-conditioning unit comprising the control unit as recited in claim 8 .

10. A method of supplying power to a railway vehicle using the power supply system as recited in claim 1 comprising:

adjusting both the amplitude and the frequency of the three-phase voltage delivered by the first power supply network in response to the demands for electrical power transmitted by each air-conditioning unit.

11. The system as recited in claim 1 wherein each demand sent by each air-conditioning unit includes a respective frequency corresponding to the electronic power required by the air conditioning unit.

12. The system as recited in claim 1 wherein the module adjusts the three-phase voltage in such a way as to keep a constant ratio between voltage and frequency.