Method of controlling an electric power system of a fuel cell electric vehicle

1 . A computer implemented method of controlling an electric power system of a fuel cell electric vehicle (FCEV), the electric power system comprising a fuel cell and an energy storage system electrically connected to each other, wherein the FCEV comprises an electric traction motor connected to the electric power system, the electric power system being configured to feed electric power to the electric traction motor at a propulsion power level range during propulsion, and to receive electric power, generated by the electric traction motor, during braking, the electric power system being operable to assume a low load operation mode, in which electric power is fed to an energy consumer of the FCEV at a power level below the propulsion power level range, the energy consumer being different from the electric traction motor, and processing circuitry operatively coupled to the energy storage system, the method comprising:

determining, by the processing circuitry, an upcoming position at which the electric power system will assume the low load operation mode;

determining, by the processing circuitry, a current state of charge level of the energy storage system;

determining, by the processing circuitry, a desired state of charge level of the energy storage system when ending the low load operation mode;

determining, by the processing circuitry, an energy consumption level of the energy consumer during the low load operation mode;

determining, by the processing circuitry, a charging level of the energy storage system by the fuel cell during the low load operation mode;

determining, by the processing circuitry, a power distribution scheme between the electric power system and the electric traction motor for arriving at the upcoming position with a state of charge level of the energy storage system below a predetermined threshold level, wherein the predetermined threshold level of the energy storage system when arriving at the upcoming position is based on the desired state of charge level and a difference between the charging level of the energy storage system and the energy consumption level of the energy consumer;

controlling, by the processing circuitry, the electric power system based on the power distribution scheme; and

controlling, by the processing circuitry, the electric power system to feed electric power from the fuel cell at least to the energy consumer when the electric power system assumes the low load operation mode at the upcoming position.

2 . The computer implemented method according to claim 1 , wherein the desired state of charge level of the energy storage system is based on topology data of a road path operable by the FCEV after the low load operation mode has ended.

3 . The computer implemented method according to claim 1 , further comprising:

determining, by the processing circuitry, an electric energy consumption of the electric traction motor for arriving at the upcoming position;

wherein the power distribution scheme is based on the determined electric energy consumption.

4 . The computer implemented method according to claim 3 , wherein the determined electric energy consumption is based on scheduled operational information of the electric traction motor for propelling the FCEV from a present position to the upcoming position.

5 . The computer implemented method according to claim 3 , further comprising:

determining, by the processing circuitry, a road topology for a road path from a present position to the upcoming position to be operated by the FCEV; and

wherein the determined electric energy consumption is based on the road topology from the present position to the upcoming position.

6 . The computer implemented method according to claim 3 , further comprising:

dividing, by the processing circuitry, an upcoming road path from a current position to the upcoming position into a plurality of road path sections, each road path section being associated with individual road topology data;

wherein the electric energy consumption of the electric traction motor is determined for each road path section.

7 . The computer implemented method according to claim 6 , further comprising:

setting, by the processing circuitry, a desired state of charge level of the energy storage system at the upcoming position, the desired state of charge level being below the predetermined threshold level;

determining, by the processing circuitry, a desired electric energy capacity of the electric power system for each road path sections to arrive at the upcoming position with the desired state of charge level of the energy storage system, the desired electric energy capacity for each road path section being based on its next coming road path section; and

controlling, by the processing circuitry, the electric power system based on the desired electric energy capacity of each road path section.

8 . The computer implemented method according to claim 1 , further comprising:

controlling, by the processing circuitry, the electric power system to feed electric power solely from the energy storage system to the electric traction motor during at least a portion of a travelling distance from a present position to the upcoming position when the current state of charge level of the energy storage system is above an upper threshold level.

9 . The computer implemented method according to claim 1 , wherein the fuel cell is operable to assume an idle mode in which the fuel cell generates electric power at a first power level, and a power mode in which the fuel cell generates electric power at a second power level, the second power level being higher than the first power level.

10 . The computer implemented method according to claim 9 , wherein the fuel cell assumes the idle mode when the electric power system assumes the low load operation mode.

11 . The computer implemented method according to claim 9 , wherein the fuel cell assumes the idle mode when the electric power system is controlled to feed electric power from the energy storage system to the electric traction motor for arriving at the upcoming position.

12 . The computer implemented method according to claim 1 , wherein the FCEV is arranged in a stand-still operating mode when the electric power system assumes the low load operation mode.

13 . The computer implemented method according to claim 1 , wherein the energy consumer is a vehicle auxiliary system electrically connected to the electric power system.

14 . The computer implemented method according to claim 1 , wherein the energy consumer consumes electric power at a power level below the power level generated by the fuel cell when the electric power system assumes the low load operation mode, wherein a difference between electric power generated by the fuel cell and the electric power consumed by the energy consumer is fed from the fuel cell to the energy storage system when the electric power system assumes the low load operation mode.

15 . The computer implemented method according to claim 1 , the method further comprising:

determining, by the processing circuitry, the upcoming position at which the electric power system will assume the low load operation mode based on previous vehicle usage.

16 . The computer implemented method according to claim 1 , the method further comprising:

determining, by the processing circuitry, the upcoming position at which the electric power system will assume the low load operation mode based on map data.

17 . An electric power system of a fuel cell electric vehicle (FCEV), the electric power system comprising a fuel cell, an energy storage system electrically connected to the fuel cell, and a control unit connected to the fuel cell, the electric power system being configured to feed electric power to an electric traction motor of the FCEV during propulsion at a propulsion power level range, and to assume a low load operation mode in which the electric power system feeds electric power to an energy consumer of the FCEV at a power level below the propulsion power level range, the energy consumer being different from the electric traction motor, the control unit being configured to:

determine an upcoming position in which the electric power system will assume the low load operation mode;

determine a current state of charge level of the energy storage system;

determine a desired state of charge level of the energy storage system when ending the low load operation mode;

determine an energy consumption level of the energy consumer during the low load operation mode;

determine a charging level of the energy storage system by the fuel cell during the low load operation mode;

determine a power distribution scheme between the electric power system and the electric traction motor for arriving at the upcoming position with a state of charge level of the energy storage system below a predetermined threshold level, wherein the predetermined threshold level of the energy storage system when arriving at the upcoming position is based on the desired state of charge level and a difference between the charging level of the energy storage system and the energy consumption level of the energy consumer;

control the electric power system based on the power distribution scheme; and

control the electric power system to feed electric power from the fuel cell at least to the energy consumer when the electric power system assumes the low load operation mode at the upcoming position.

18 . A fuel cell electric vehicle (FCEV) comprising an electric power system according to claim 17 .

19 . A non-transitory computer readable medium carrying a computer program comprising program code for performing the method of claim 1 when the program product is run on a control unit.

20 . A control unit for controlling an auxiliary system of a transportation vehicle, the control unit being configured to perform the method according to claim 1 .