Controlling hybrid-electric or all-electric powertrains and propulsion systems
A hybrid-electric or all-electric powertrain may include a power control unit electrically coupled to an energy storage system. The power control unit may determine a power level command based at least in part on a power level request for the powertrain, and a power level-UCL and/or a power level-LCL. The power level-UCL and/or the power level-LCL may be based at least in part on an aggregate obverse power level request representing a requested power level for one or more obverse powertrains electrically coupled to the energy storage system. The power level commands may be limited by the power level-UCL and/or the power level-LCL. The power level-UCL may be set equal to either an available discharge power capacity or an apportionate discharge power capacity. The power level-LCL may be set equal to either an available storage power capacity or an apportionate storage power capacity.
1 . A powertrain for an aircraft, the powertrain comprising:
an electric machine;
an energy storage system; and
a power control unit, the power control unit electrically coupling the electric machine to the energy storage system;
wherein the power control unit comprises an electronic controller, the electronic controller comprising a non-transitory computer-readable medium comprising computer-executable instructions, which when executed by a processor associated with the electronic controller, cause the power control unit to perform a method comprising:
determining a power level-upper control limit (power level-UCL) for the powertrain, wherein the power level-UCL corresponds to a difference between an aggregate obverse power level request and a power discharge threshold;
determining a power level-lower control limit (power level-LCL) for the powertrain by determining an available storage power capacity, the available storage power capacity comprising a difference resulting from subtracting (i) the aggregate obverse power level request from (ii) a charging threshold, the charging threshold comprising a threshold level for supplying electrical power to the energy storage system; and
determining a power level command for the powertrain, the power level command determined based at least in part on one of the power level-UCL or the power level-LCL, wherein determining the power level command for the powertrain comprises limiting the power level command by the one of the power level-UCL or the power level-LCL.
2 . The powertrain of claim 1 , wherein determining the power level-UCL comprises:
determining an available discharge power capacity, the available discharge power capacity comprising a difference resulting from subtracting (i) the aggregate obverse power level request from (ii) the power discharge threshold, the aggregate obverse power level request comprising a requested power level for one or more obverse powertrains electrically coupled to the energy storage system, and the power discharge threshold comprising a threshold level for discharging electrical power from the energy storage system; and
setting the power level-UCL equal to the available discharge power capacity.
3 . The powertrain of claim 2 , wherein the powertrain, the one or more obverse powertrains, and the energy storage system are electrically coupled to a distribution bus.
4 . The powertrain of claim 2 , wherein the requested power level for the one or more obverse powertrains is provided by an input apparatus, the input apparatus comprising at least one of: a thrust lever, a power lever, or an automatic throttle system.
5 . The powertrain of claim 1 , wherein the powertrain comprises a series configuration, a parallel configuration, or a series-parallel configuration.
6 . The powertrain of claim 1 , comprising:
a combustion engine; and
one or more propulsors configured to receive mechanical power from the combustion engine and the electric machine, individually or simultaneously.
7 . The powertrain of claim 1 , wherein the power control unit comprises one or more power management devices, the one or more power management devices comprising at least one of: an inverter, a converter, a rectifier, a synchronous converter, a synchronous buck converter, a bidirectional interleave converter, an autotransformer rectifier, or a matrix converter.
8 . A method of controlling a powertrain of an aircraft, the method comprising:
determining a power level-upper control limit (power level-UCL) for the powertrain, the powertrain electrically coupled to an energy storage system;
determining a power level-lower control limit (power level-LCL) for the powertrain by determining an available storage power capacity, the available storage power capacity comprising a difference resulting from subtracting (i) an aggregate obverse power level request from (ii) a charging threshold, the charging threshold comprising a threshold level for supplying electrical power to the energy storage system; and
determining a power level command for the powertrain, the power level command determined based at least in part on one of the power level-UCL or the power level-LCL;
wherein the power level-UCL corresponds to a difference between the aggregate obverse power level request and a power discharge threshold; and
wherein determining the power level command for the powertrain comprises limiting the power level command by the one of the power level-UCL or the power level-LCL.
9 . The method of claim 8 , wherein limiting the power level command by the one of the power level-UCL or the power level-LCL comprises at least one of:
setting the power level command equal to the power level-UCL when a power level request for the powertrain is greater than the power level-UCL; or
setting the power level command equal to the power level request when the power level request is between the power level-UCL and the power level-LCL, and setting the power level command equal to the power level-LCL when the power level request is less than the power level-LCL.
10 . The method of claim 8 , wherein determining the power level-UCL comprises:
determining an available discharge power capacity, the available discharge power capacity comprising a difference resulting from subtracting (i) the aggregate obverse power level request from (ii) the power discharge threshold, the aggregate obverse power level request comprising a requested power level for one or more obverse powertrains electrically coupled to the energy storage system, and the power discharge threshold comprising a threshold level for discharging electrical power from the energy storage system; and
setting the power level-UCL.
11 . The method of claim 10 , comprising:
receiving at an electronic controller, an additional power level request for the powertrain, the electronic controller at least one of incorporated into or communicatively coupled with a power control unit for the powertrain.
12 . The method of claim 11 , comprising:
receiving, at the electronic controller, at least one of the aggregate obverse power level request or the additional power level request for the one or more obverse powertrains.
13 . The method of claim 11 , comprising:
providing the power level command to one or more power management devices, the one or more power management devices defining at least a portion of the power control unit for the powertrain.
14 . The method of claim 10 , wherein determining the power level-UCL comprises:
determining an apportionate discharge power capacity, the apportionate discharge power capacity comprising an apportionment of the power discharge threshold to the powertrain;
wherein setting the power level-UCL comprises:
setting the power level-UCL equal to either (i) the available discharge power capacity or (ii) the apportionate discharge power capacity.
15 . The method of claim 14 , comprising:
setting the power level-UCL equal to either (i) the available discharge power capacity or (ii) the apportionate discharge power capacity using a capacity level operator.
16 . The method of claim 14 , wherein the apportionment of the power discharge threshold to the powertrain comprises applying an apportionment factor to the power discharge threshold.
17 . The method of claim 8 , comprising:
setting the power level-LCL;
wherein determining the power level command for the powertrain comprises limiting the power level command by the power level-LCL.
18 . The method of claim 17 , wherein determining the power level-LCL comprises:
determining an apportionate storage power capacity, the apportionate storage power capacity comprising an apportionment of the charging threshold to the powertrain;
wherein setting the power level-LCL equal to the available storage power capacity comprises:
setting the power level-LCL equal to either (i) the available storage power capacity or (ii) the apportionate storage power capacity.
19 . The method of claim 18 , comprising:
setting the power level-LCL equal to either (i) the available storage power capacity or (ii) the apportionate storage power capacity using a capacity level operator.
20 . A non-transitory computer-readable medium comprising computer-executable instructions, which when executed by a processor associated with an electronic controller for a powertrain for an aircraft, cause the electronic controller to perform a method comprising:
determining a power level-upper control limit (power level-UCL) for the powertrain, the powertrain electrically coupled to an energy storage system;
determining a power level-lower control limit (power level-LCL) for the powertrain by determining an available storage power capacity, the available storage power capacity comprising a difference resulting from subtracting (i) an aggregate obverse power level request from (ii) a charging threshold, the charging threshold comprising a threshold level for supplying electrical power to the energy storage system; and
determining a power level command for the powertrain, the power level command determined based at least in part on one of the power level-UCL or the power level-LCL;
wherein the power level-UCL corresponds to a difference between the aggregate obverse power level request and a power discharge threshold; and
wherein determining the power level command for the powertrain comprises limiting the power level command by the one of the power level-UCL or the power level-LCL.