Battery state of charge compensation

Abstract

The power source includes a battery defining a state of charge, a converter in electrical communication with the battery, and a controller in operable communication with the converter, the controller including a compensation trigger circuit configured to provide a compensation trigger value based on a power output of the battery, a dynamic droop control circuit configured to receive the compensation trigger value and switch an output droop value of the dynamic droop control circuit from an upper output droop measurement to a lower output droop measurement, wherein the lower output droop measurement is based on the state of charge of the battery.

Description

TECHNICAL FIELD

[0001] The present subject matter relates generally to a state of charge compensator for batteries of an electric power system, such as a battery system of a hybrid-electric aircraft propulsion system. BACKGROUND

[0002] Certain aircraft utilize electric power to drive or supplement propulsion devices of the aircraft, various aircraft loads, or both. It is not uncommon for an aircraft to include a plurality of batteries to provide such electric power, or to supplement such electric power. It is also not uncommon for the state of charge of the various batteries to be different during operation due to uneven charging, age of the batteries, usage of the batteries, and the like.

[0003] Unevenness in the state of charge of the batteries can result in a loss of system performance. A system and / or method that reduces unevenness in the state of charge between batteries would be useful. SUMMARY

[0004] Aspects and advantages of the application will be set forth in part in the following description, or can be obvious from the description, or can be learned through practice of the application.

[0005] In one example embodiment of the present disclosure, a power source is provided. The power source includes a battery defining a state of charge, a converter in electrical communication with the battery, and a controller in operable communication with the converter, the controller including a compensation trigger circuit configured to provide a compensation trigger value based on an electric power output of the battery, and a dynamic droop control circuit configured to receive the compensation trigger value and switch an output droop value of the dynamic droop control circuit from an upper output droop measurement to a lower output droop measurement, wherein the lower output droop measurement is based on the state of charge of the battery.

[0006] These and other features, aspects, and advantages of the present application will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0007] The detailed description set forth below in connection with the appended drawings describes exemplary embodiments of the application and is not intended to represent the only embodiments in which the present application might be practiced, the entire disclosure of which is incorporated herein by reference and which is intended to fully and completely describe various embodiments of the application.

[0008] Figure 1 is a top view of an aircraft in accordance with various example embodiments of the present disclosure.

[0009] Figure 2 is a schematic cross-sectional view of a gas turbine engine in accordance with example embodiments of the present disclosure, the gas turbine engine being mountable on an example aircraft of Figure 1 .

[0010] Figure 3 is a schematic cross-sectional view of an electric fan assembly according to an example embodiment of the disclosure, which can be installed on an example aircraft of Figure 1

[0011] Figure 4 is a top view of an aircraft including a propulsion system according to another example embodiment of the disclosure.

[0012] Figure 5 is a close-up view of a power source according to an example embodiment of the disclosure.

[0013] Figure 6 is a schematic view of a power source according to an example embodiment of the disclosure.

[0014] Figure 7 is a close-up view of a first controller of a power source of Figure 6

[0015] Figure 8 is a lookup table according to an example embodiment of the disclosure.

[0016] Figure 9 is a flowchart of a method of operating a power source. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to present embodiments of the application, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations

[0018] As used herein, the terms "first", "second", and "third" can be used interchangeably to distinguish one component from another and do not necessarily indicate location or importance of the individual components.

[0019] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0020] ​​As used herein throughout the specification and claims, approximate language is applied to modify any quantitative representation that can be permitted to vary without resulting in a change in the basic function to which it is related. Thus, a value modified by one or more terms, such as "about," "approximately," and "substantially," is not limited to the precise value specified. At least in some cases, approximate language can correspond to the precision of an instrument for measuring a value, or the precision of a method or machine for constructing or manufacturing a component and / or system. For example, approximate language can refer to within a margin of 1, 2, 4, 5, 10, 15, or 20% of an endpoint of a single value, a range of values, and / or a range of values. Here and throughout the specification and claims, range limitations are combined and interchanged, and such ranges are identified and include all subranges contained therein unless the context or language indicates otherwise.

[0021] As used herein, the terms "processor" and "computer," as well as related terms such as "processing device," "computing device," and "controller," are not limited to those integrated circuits commonly referred to in the art as computers, but rather refer generally to one or more processing devices, including one or more of a microcontroller, a microcomputer, a programmable logic controller (PLC), an application-specific integrated circuit, and other programmable circuits, and these terms are used interchangeably herein. In the embodiments described herein, a computer or controller may additionally include memory. This memory may include, but is not limited to, computer-readable media such as random access memory (RAM) and computer-readable non-volatile media such as flash memory. Alternatively, a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), and / or a digital versatile disc (DVD) may be used. Furthermore, in the embodiments described herein, a computer or controller may include one or more input channels and / or one or more output channels. Input channels may include, but are not limited to, computer peripherals associated with an operator interface, such as a mouse and keyboard, or sensors, such as engine sensors associated with an engine (e.g., a gas turbine engine) for determining engine operating parameters. Furthermore, in exemplary embodiments, output channels may include, but are not limited to, an operator interface display. Additionally, the memory may store software or other instructions that, when executed by a controller or processor, allow the controller to perform certain operations or functions. The term "software" may include any computer program stored in the memory or accessible by the memory for execution by, for example, a controller, processor, client, or server.

[0022] Referring now to the drawings, wherein like numerals refer to like elements throughout, Figure 1 A top view of an exemplary aircraft 10 is provided, which may incorporate various embodiments of the present disclosure. Figure 1As shown, the aircraft 10 defines a longitudinal centerline 14 extending through the aircraft 10, a lateral direction L, a forward end 16, and an aft end 18. In addition, the aircraft 10 includes a fuselage 12 extending longitudinally from the forward end 16 of the aircraft 10 to the aft end 18 of the aircraft 10, and a wing assembly including a port side and a starboard side. More specifically, the port side of the wing assembly is a first, port wing 20, while the starboard side of the wing assembly is a second, starboard wing 22. The first wing 20 and the second wing 22 each extend laterally outward relative to the longitudinal centerline 14. The first wing 20 and a portion of the fuselage 12 collectively define a first side 24 of the aircraft 10, while the second wing 22 and another portion of the fuselage 12 collectively define a second side 26 of the aircraft 10. For the embodiment being described, the first side 24 of the aircraft 10 is configured as the port side of the aircraft 10, while the second side 26 of the aircraft 10 is configured as the starboard side of the aircraft 10.

[0023] Each wing 20, 22 of the example embodiment being described includes one or more leading edge flaps 28 and one or more trailing edge flaps 30. The aircraft 10 further includes a vertical stabilizer 32 having rudder flaps (not shown) for yaw control, and a pair of horizontal stabilizers 34 each having elevator flaps 36 for pitch control. The fuselage 12 additionally includes an outer surface or skin 38. It should be appreciated, however, that in other example embodiments of the present disclosure, the aircraft 10 can additionally or alternatively include any other suitable configuration. For example, in other embodiments, the aircraft 10 can include stabilizers of any other configuration.

[0024] Reference is now also made to Figure 2 and Figure 3 , Figure 1 The example aircraft 10 also includes a propulsion system 50 having a first propulsor assembly 52 and a second propulsor assembly 54. Figure 2 A schematic cross-sectional view of the first propulsor assembly 52 is provided, and Figure 3 A schematic cross-sectional view of the second propulsor assembly 54 is provided. As shown, each of the first propulsor assembly 52 and the second propulsor assembly 54 is configured as an underwing mounted propulsor assembly.

[0025] With particular reference to Figure 1 and Figure 2 The first propulsor assembly 52 is mounted or configured to be mounted on the first side 24 of the aircraft 10, or more specifically, on the first wing 20 of the aircraft 10. The first propulsor assembly 52 generally includes a turbomachine 102 and a main fan (see Figure 2More specifically, for the depicted embodiment, first propeller assembly 52 is configured as a turbofan engine 100 (ie, turbine 102 and fan 104 are configured as part of turbofan 100 ).

[0026] like Figure 2 As shown, the turbofan 100 defines an axial direction A1 (extending parallel to a longitudinal centerline 101 provided for reference) and a radial direction R1 . As previously mentioned, the turbofan 100 includes a fan 104 and a turbine 102 disposed downstream of the fan 104 .

[0027] The depicted exemplary turbomachine 102 generally includes a substantially tubular outer casing 106 defining an annular inlet 108. The outer casing 106 encloses, in serial flow relationship, a compressor section, including a boost or low-pressure (LP) compressor 110 and a high-pressure (HP) compressor 112; a combustion section 114; a turbine section, including a first, low-pressure (LP) turbine 118 and a second, high-pressure (HP) turbine 116; and an exhaust gas ejection nozzle section 120.

[0028] The exemplary turbine 102 of the turbofan 100 also includes one or more shafts that are rotatable with at least a portion of the turbine section, and for the depicted embodiment, one or more shafts that are rotatable with at least a portion of the compressor section. More particularly, for the depicted embodiment, the turbofan 100 includes a high-pressure (HP) shaft or spool 122 that drivingly connects the high-pressure turbine 116 to the high-pressure compressor 112. Additionally, the exemplary turbofan 100 includes a low-pressure (LP) shaft or spool 124 that drivingly connects the low-pressure turbine 118 to the low-pressure compressor 110.

[0029] Furthermore, the depicted exemplary fan 104 is configured as a variable pitch fan having a plurality of fan blades 128 coupled in a spaced-apart manner to a disk 130. As can be appreciated, the fan 104 includes a total number (i.e., count) of fan blades 128 and defines a fan diameter 126. The fan diameter 126 refers to a measurement equal to twice the radius of the fan blade 128, where the radius of the fan blade 128 is measured from the tip of the fan blade 128 to the longitudinal centerline axis 101 along the radial direction R1.

[0030] The fan blades 128 extend generally in a radial direction Rl outwardly from the disk 130. Each fan blade 128 is rotatable about a respective pitch axis Pl relative to the disk 130, as the fan blades 128 are operably coupled to appropriate actuation members 132 that are configured to collectively change the pitch of the fan blades 128. The fan 104 is mechanically coupled to the low pressure shaft 124, such that the fan 104 is mechanically driven by the first, low pressure turbine 118. More particularly, the fan 104, including the fan blades 128, the disk 130, and the actuation members 132, is mechanically coupled to the LP shaft 124 through a power gear box 134, and is rotatable about the longitudinal axis 101 by the LP shaft 124 through the power gear box 134. The power gear box 134 includes a plurality of gears for reducing the rotational speed of the LP shaft 124 to a more efficient fan rotational speed. Thus, the fan 104 is powered by the LP system of the turbine engine 102, including the LP turbine 118.

[0031] Still referring to the exemplary embodiment of Figure 2 , the disk 130 is covered by a rotatable front hub 136 that has an aerodynamic profile to facilitate airflow through the plurality of fan blades 128. Further, the turbofan 100 also includes an annular fan casing or outer nacelle 138 that circumferentially surrounds at least a portion of the fan 104 and / or the turbine engine 102. Thus, the exemplary turbofan 100 described can be referred to as a "ducted" turbofan engine. Further, the nacelle 138 is supported relative to the turbine engine 102 by a plurality of circumferentially spaced apart outlet guide vanes 140. A downstream section 142 of the nacelle 138 extends to an exterior of the turbine engine 102 so as to define a bypass airflow passage 144 therebetween.

[0032] Still referring to the exemplary embodiment of Figure 2 , the propulsion system 50 also includes an electric machine, which for the described embodiment is configured as a generator 56. In the described embodiment, the generator 56 is positioned within the turbine engine 102 of the turbofan engine 100, and is in mechanical communication with one of the shafts of the turbofan engine 100. More particularly, for the described embodiment, the generator is driven by the first, low pressure turbine 118 through the low pressure shaft 124. The generator 56 is configured to convert the mechanical power of the low pressure shaft 124 to electrical power. Thus, the generator 56 is also powered by the low pressure system of the turbine engine 102, including the low pressure turbine 118.

[0033] It should be appreciated, however, that in other example embodiments, the generator 56 can instead be positioned anywhere else within the turbine 102 or elsewhere and can be powered, for example, in any other suitable manner. For example, in other embodiments, the generator 56 can be mounted coaxially with the low pressure shaft 124 within the turbine section, or can be offset from the low pressure shaft 124 and driven through a suitable gear set. Additionally, or instead, in other example embodiments, the generator 56 can be powered by the high pressure system, i.e., by the high pressure turbine 116 through the high pressure shaft 122, or by both the low pressure system (e.g., the low pressure shaft 124) and the high pressure system (e.g., the high pressure shaft 122) via a dual drive system.

[0034] It should be further appreciated that, Figure 2 The example turbofan engine 100 described in the Background section can have any other suitable configuration in other example embodiments. For example, in other example embodiments, the fan 104 can not be a variable pitch fan, and further, in other example embodiments, the LP shaft 124 can be directly mechanically coupled to the fan 104 (i.e., the turbofan engine 100 can not include a gearbox 134). Moreover, it should be appreciated that in other example embodiments, the turbofan engine 100 can instead be configured as any other suitable aircraft engine, including a turbine mechanically coupled to a main fan. For example, in other embodiments, the turbofan engine 100 can instead be configured as a turboprop engine (i.e., the main fan can be configured as a propeller), a non- ducted turbofan engine (i.e., the gas turbine engine can not include an outer nacelle 138), and so forth.

[0035] Still referring to Figure 1 and Figure 2The described propulsion system 50 also includes an electrical power bus 58 to allow the generator 56 to be in electrical communication with the propulsion system 50 and / or one or more other components of the aircraft 10. For the described embodiment, the electrical power bus 58 includes one or more electrical wires 60 connected to the generator 56, and for the described embodiment, the one or more electrical wires 60 extend through the one or more exit guide vanes 140. In addition, the described propulsion system 50 further includes one or more energy storage devices 55, such as one or more batteries or other electrical energy storage devices, that are in electrical connection with the electrical power bus 58 for providing electrical power to, for example, the electric fan assembly 54 and / or receiving electrical power from the generator 56. In certain example embodiments, the one or more energy storage devices 55 can be positioned proximate to the electric fan assembly 54 for weight distribution purposes. The inclusion of the one or more energy storage devices 55 can provide performance gains and can increase the propulsion capabilities of the propulsion system 50 during, for example, transient operations. More specifically, the propulsion system 50 including the one or more energy storage devices 55 can respond more quickly to speed change demands.

[0036] Referring now particularly to Figure 1 and Figure 3 The example propulsion system 50 also includes a second propulsor assembly 54 that is positioned or configured to be positioned at a location spaced apart from the first propulsor assembly 52, including, for example, the turbine and the main fan. More specifically, for the described embodiment, the second propulsor assembly 54 is mounted at a location that is distanced from the first propulsor assembly 52 along the lateral direction L such that they ingest different airflows along the lateral direction L. However, in other embodiments, the first propulsor assembly 52 and the second propulsor assembly 54 can each be mounted to the aircraft 10 using a common pylon. However, with such a configuration, the first propulsor assembly 52 and the second propulsor assembly 54 can still be positioned on the pylon spaced apart from each other along the lateral direction L, such as to ingest different airflows along the lateral direction L.

[0037] Still referring to the example embodiment of Figure 1 and Figure 3 The second propulsor assembly 54 is mounted on the second side 26 of the aircraft 10, or in other words, on the second wing 22 of the aircraft 10. Referring particularly to Figure 3The second propulsor assembly 54 is generally configured as an electric fan assembly, which includes an electric fan 200. The electric fan 200 defines an axial direction A2 extending along a longitudinal centerline axis 202, which extends through for reference, and a radial direction R2. Further, the electric fan 200 generally includes a fan 204 and an electric machine, which is configured as an electric motor 206 for the described embodiment. The fan 204 is rotatable about the centerline axis 202 for the described embodiment.

[0038] The fan 204 includes a plurality of fan blades 208 and a fan shaft 210. The plurality of fan blades 208 are attached to / rotatable with the fan shaft 210 and are spaced generally along a circumferential direction of the electric fan 200 (not shown). More specifically, the fan 204 of the electric fan 200 generally includes a total number of fan blades 208 and defines a fan diameter 211. The fan diameter 211 refers to a measurement of twice the radius of the fan blades 208, which refers to a measurement along the radial direction R2 from a tip of the fan blades 208 to the longitudinal centerline axis 22.

[0039] In certain example embodiments, the plurality of fan blades 208 can be attached to the fan shaft 210 in a fixed manner, or alternatively, the plurality of fan blades 208 can be rotatable relative to the fan shaft 210, such as in the described embodiment. For example, the plurality of fan blades 208 each define a respective pitch axis P2, and for the described embodiment, are attached to the fan shaft 210 such that the pitch of each of the plurality of fan blades 208 can be uniformly changed, such as by a pitch changing mechanism 211. Changing the pitch of the plurality of fan blades 208 can improve the efficiency of the second propulsor assembly 54 and / or can allow the second propulsor assembly 54 to achieve a desired thrust profile. With such example embodiments, the fan 204 can be referred to as a variable pitch fan.

[0040] Further, for the described embodiment, the described electric fan 200 also includes a fan housing or outer nacelle 212, which is attached to a core 214 of the electric fan 200 by one or more struts or outlet guide vanes 216. For the described embodiment, the outer nacelle 212 substantially completely encloses the fan 204, particularly the plurality of fan blades 208. Thus, for the described embodiment, the electric fan 200 can be referred to as a ducted electric fan.

[0041] Still referring in particular to Figure 3The fan shaft 210 is mechanically coupled to the motor 206 within the core 214 such that the motor 206 drives the fan 204 through the fan shaft 210. For the described embodiment, the motor 206 is configured as a variable speed motor such that the motor 206 can drive the fan 204 at various rotational speeds regardless of the amount of electrical power provided thereto. Further, for the described embodiment, the electric fan 200 also includes a gear box 215 that allows the rotational speed of the fan shaft 210 to be further increased or decreased relative to the rotational speed of the motor 206. Thus, for the described embodiment, the motor 206 further drives the fan 204 through the gear box 215 and through the fan shaft 210.

[0042] The fan shaft 210 is supported by one or more bearings 218, such as one or more roller bearings, ball bearings, or any other suitable bearing. Further, the motor 206 can be an internal rotor motor (i.e., including a rotor radially inward of a stator) or can also be an external rotor motor (i.e., including a stator radially inward of a rotor). As briefly described above, the generator 56 of the propulsion system 50 is in electrical communication with the electric fan 200 in order to power the electric fan 200. More particularly, the motor 206 of the electric fan 200 is in electrical communication with the power bus 58, which, for the described embodiment, includes one or more electrical wires 60 electrically connected to the motor 206. Thus, the motor 206 is more particularly in electrical communication with the power bus 58 through the one or more electrical wires 60 of the power bus 58, and the power bus 58 can deliver electrical power to the motor 206 to drive the motor 206, and in turn, the fan 204.

[0043] Referring again briefly to Figure 1 The described propulsion system 50, or more particularly, the described power bus 58, also includes an electrical controller 62. The described exemplary generator 56 is in electrical communication with the electric fan 200 through the electrical controller 62 of the power bus 58. The electrical controller 62 can be operably connected to one or more additional controllers of the aircraft to control the amount of electrical power provided to the electric fan assembly.

[0044] Further, it should be appreciated that, in certain example embodiments, the fan 204 of the electric fan 200 can be different from the fan 104 of the turbofan engine 100. More specifically, at least one of the fan diameter 126 or the total number of fan blades 128 of the fan 104 of the turbofan engine 100 can be different from the fan diameter 211 or the total number of fan blades 208 of the fan 204 of the electric fan assembly. Further, or alternatively, in other example embodiments, the fan 104 of the turbofan engine can define a different fan pressure ratio than the fan 204 of the electric fan 200 during operation of the respective fans at a rated speed. As used herein, the term "fan pressure ratio" refers to the ratio of the air pressure immediately downstream of the fan to the air pressure immediately upstream of the respective fan. Further, the term "rated speed", as used herein with respect to the electric fan 200 and the turbofan engine 100, refers to the maximum rotational speed that the electric fan 200 and the turbofan engine 100 can achieve during normal operation. For example, the electric fan 200 and the turbofan engine 100 can operate at their respective rated speeds during maximum load operations, such as during takeoff operations.

[0045] In view of the first propulsor assembly being configured to be mounted to a turbofan engine of a first side of the aircraft and the second propulsor assembly being configured to be mounted to an electrically driven fan of a second side of the aircraft, the propulsion system according to one or more embodiments described above can be referred to as a gas-electric, or hybrid, propulsion system. Such a configuration can allow a single relatively large engine to power two or more propulsors (which can be configured as, for example, fans, propellers, etc.). Thus, the propulsion system according to one or more embodiments of the present disclosure can allow for inclusion of a relatively large engine, which in turn can allow for the engine to have increased efficiency (as compared to a relatively small engine).

[0046] However, it should be appreciated that, in other embodiments, the electric fan assembly can include an electric fan 200 having any other suitable configuration. For example, in other embodiments, the electric fan 200 can be configured without the outer nacelle 212 (i.e., configured as a non-ducted electric fan). Thus, it should be appreciated that, in certain example embodiments, the electric fan assembly can include a non-ducted electric fan.

[0047] Further, in other embodiments, the example propulsion system can be integrated into the aircraft 10 in any other suitable manner. For example, referring now to Figure 4 , an aircraft 10 and propulsion system 50 according to another example embodiment of the present disclosure are described. Figure 4 The example aircraft 10 and propulsion system 50 of Figure 1 to Figure 3The exemplary aircraft 10 and propulsion system 50 are constructed in substantially the same manner, and thus, the same or similar numbers may refer to the same or similar parts.

[0048] For example, Figure 4 The exemplary aircraft 10 generally includes a fuselage 12 and a wing assembly including a port wing 20 and a starboard wing 22. In addition, the propulsion system 50 includes a first propulsion system 52 including a turbine and a fan, for example, configured as part of a turbofan engine. The propulsion system 50 also includes a generator 56 mechanically driven by the turbine (see Figure 2 ). In addition, the propulsion system 50 includes a second propulsion assembly 54, which is an electric fan assembly. A generator 56 is electrically connected to the electric fan assembly for powering the electric fan assembly.

[0049] However, it is worth noting that for Figure 4 In the embodiment, the electric fan assembly includes a plurality of electric fans 200. More specifically, Figure 4 The electric fan assembly includes a first electric fan 200A mounted on the port wing 20 of the aircraft 10 , which is located laterally outside the fuselage 12 relative to the turbofan engine 100 . Figure 4 The electric fan assembly further includes a second electric fan 200B mounted on the starboard wing 22 and a third electric fan 200C also mounted on the starboard wing 22. The second electric fan 200B and the third electric fan 200C are spaced apart along the lateral direction L of the aircraft 10. Figure 4 In the exemplary embodiment, the electric fan assembly includes a plurality of electric fans 200, the plurality of electric fans 200 including at least two electric fans 200, and more specifically, for the depicted embodiment, at least three electric fans 200. However, it is noted that in other exemplary embodiments, the electric fan assembly may include any other suitable number of electric fans 200. For example, in other exemplary embodiments, the electric fan assembly may include two electric fans 200, four electric fans 200, or any other suitable number of electric fans 200. Furthermore, the plurality of electric fans 200 may be arranged in any other suitable manner and attached to the aircraft 10 (including a tail-mounted configuration) in any suitable location.

[0050] Furthermore, for the described embodiment, the plurality of electric fans 200 may be at least partially powered by a power supply. The power supply may include a plurality of batteries 55, the plurality of batteries 55 being connected to a plurality of batteries 55. Figure 4The power bus 58 described above in connection with FIG. 1 is in electrical communication with, and further in electrical communication with, a generator 56 (not shown) of the first propeller 52. The generator 56 can be provided to power / charge the battery, to provide power directly to one or more electric fans 200 via the power bus 58, or both. In addition, the power source includes a plurality of controllers 62.

[0051] Referring now to Figure 5 , a close-up view of a power source 300 in accordance with example embodiments of the present disclosure is provided. For example, in certain example embodiments, Figure 5 the power source 300 can be constructed in a manner similar to the power source 300 described above in connection with Figure 4 .

[0052] As shown, the power source 300 includes a battery 302 and a power regulator 304, the power regulator 304 including a converter 306 in electrical communication with the battery 302 and a controller 308 in operable communication with the converter 306. More specifically, for the illustrated embodiment, the power source 300 includes a plurality of batteries 302 and a corresponding plurality of power regulators 304. More specifically, and again for the illustrated embodiment, the battery 302 is a first battery 302A and the power regulator 304 is a first power regulator 304A (as such, the converter 306 is a first converter 306A and the controller 308 is a first controller 308A). Further to the described embodiment, the power source 300 further includes a second battery 302B and a second power regulator 304B having a second converter 306B in electrical communication with the second battery 302B and a second controller 308B in operable communication with the second converter 306B.

[0053] For the illustrated embodiment, the first battery 302A and the first power regulator 304A are in electrical communication with a power bus 310 (similar to the bus 58), and likewise, the second battery 302B and the second power regulator 304B are also in electrical communication with the power bus 310. In this manner, the first battery 302A and the second battery 302B can provide power to a load 312 via the power bus 310, can receive power from the power bus 310, charge the first battery 302A and the second battery 302B, or both.

[0054] In certain example embodiments, the load 312 can be an electric or hybrid electric propeller (such as in the embodiments described above in connection with Figure 1 to Figure 4 , can be an aircraft system load, etc.

[0055] It can be appreciated that, while in Figure 5A single load 312 is described in the drawings, but in other exemplary embodiments, the power supply 300 can provide power to any suitable number and type of loads. For example, the power supply 300 can be configured to provide power to Figure 1 The second propeller assembly 54 described in Figure 4 The plurality of electric fans 200 described in the above embodiment provide electric power.

[0056] In this manner, it can be appreciated that the battery 302 can be a relatively powerful battery 302 capable of providing a relatively large amount of power to the load 312 (or multiple loads 312). For example, in certain exemplary embodiments, each battery 302 can define a maximum power output of at least 200 volts (V). Alternatively, in other embodiments, each battery 302 can define a maximum power output of at least 250 volts, at least 300 volts, at least 400 volts, at least 500 volts, and up to, for example, 5000 volts. Each battery 302 can define substantially the same maximum power output.

[0057] However, it is worth noting that each of the plurality of batteries 302, and more specifically, the first battery 302A and the second battery 302B, can define a different state of charge (i.e., a charge level of the battery). For example, the first battery 302A can define a first state of charge that is different from the second state of charge defined by the second battery 302B. When two batteries defining different states of charge are electrically connected to the load 312, the battery 302 with the lower state of charge may draw a higher current and, therefore, may be drained faster than the battery 302 with the higher state of charge. Generally speaking, it is desirable to maintain the batteries 302 with substantially the same state of charge to ensure desired system performance. This is particularly true in propulsion systems, such as in aviation propulsion systems.

[0058] Now refer to Figure 6 , depicts a schematic diagram of a power supply 300 having one or more features for normalizing the state of charge of a plurality of batteries 302, according to an exemplary embodiment of the present disclosure. In certain embodiments, Figure 6 The power supply 300 depicted in FIG. 1 may be similar to the power supply 300 described above with reference to FIG Figure 5 The exemplary power supply 300 described in FIG. Figure 6 The power supply 300 generally includes a first battery 302A and a second battery 302B, and a first power conditioner 304A and a second power conditioner 304B. For the embodiment shown, the first battery 302A and the second battery 302B are in electrical communication with a load 312 in a parallel electrical communication arrangement.

[0059] The first power conditioner 304A generally includes a first converter 306A in electrical communication with the first battery 302A and a first controller 308A in operable communication with the first converter 306A. Likewise, the second power conditioner 304B generally includes a second converter 306B in electrical communication with the second battery 302B and a second controller 308B in operable communication with the second converter 306B. The first controller 308A is structured to instruct the first converter 306A to modify the power provided from the first battery 302A to the load 312 in a manner that normalizes the state of charge of the first battery 302A using the state of charge of the second battery 302B. Likewise, the second controller 308B is structured to instruct the second converter 306B to modify the power provided from the second battery 302B to the load 312 in a manner that normalizes the state of charge of the second battery 302B using the state of charge of the first battery 302A.

[0060] For example, as will be explained in detail below, the controllers 308A, 308B are each structured to, in at least some cases, draw more power from the battery 302 having a higher state of charge than the battery 302 having a lower state of charge. This concept is referred to herein as dynamic droop control. Droop control systems can control the power output of a battery by applying a droop resistance in a droop control circuit to provide a more consistent power output over a range of states of charge of the battery. The present disclosure further dynamically controls the droop resistance in certain cases (e.g., below high power demand cases) to normalize the states of charge of the multiple batteries.

[0061] Notably, in the illustrated embodiment, the first controller 308A and the second controller 308B are communicatively isolated from one another. In this manner, it can be appreciated that the normalization of the state of charge of the first battery 302A in the second battery 302B is accomplished without communication between the first controller 308A and the second controller 308B and / or the first converter 306A and the second converter 306B, but rather based on locally sensed quantities. As used herein, the term "locally sensed" with respect to a particular controller 308 and / or converter 306 refers to quantities / parameters sensed in the circuit including the respective battery, upstream of the circuit encountering the power bus 310.

[0062] The operation of this exemplary system will now be described in more detail with respect to the first battery 302A and the first power conditioner 304A. Still referring to Figure 6It will be appreciated that the power source 300 includes various sensors for sensing current and voltage throughout the respective circuits. For example, the power source 300 includes a first battery current sensor 314 for sensing current from the first battery 302A, a first battery voltage sensor 316 for sensing voltage of power provided from the first battery 302A, a first load current sensor 318 for sensing current to the load 312, and a first load voltage sensor 320 for sensing voltage of power provided to the load 312. In addition, the power source 300 includes a first state of charge circuit 322 for determining a first state of charge of the first battery 302A based on data sensed from the first battery current sensor 314 and the first battery voltage sensor 316. It will be appreciated that, although not labeled, the power source 300 includes similar sensors for the second battery 302B circuit, for the example power source 300 described.

[0063] Still referring to Figure 6 and now also referring to Figure 7 a close-up schematic of the first controller 308A is provided. As will be appreciated from the discussion herein, the first power regulator 304 is structured to receive various local sensed quantities from, for example, the first battery sensors 314, 316, 318, 320 and the sub-circuit 322, and to control power output from the first battery 302A to the load 312 to normalize the state of charge of the first battery 302A with other batteries 302 of the power source 300 (i.e., with the battery 302B in the illustrated embodiment).

[0064] In particular, it will be appreciated that, for the illustrated embodiment, the controller 308 generally includes a compensation trigger circuit 324, a dynamic droop control circuit 326, and a voltage regulator droop circuit 328.

[0065] With particular reference to the compensation trigger circuit 324, the compensation trigger circuit 324 is structured to receive data indicative of power output from the first battery 302A to the load 312, and more particularly, to receive data indicative of voltage of power provided to the load 312 and current of power provided to the load 312, each from the first battery 302A. This information can be provided by the first load current sensor 318 and the first load voltage sensor 320. At block 330, this information is received and used to determine data indicative of power provided from the first battery 302A to the load 312.

[0066] The example compensation trigger circuit 324 passes the power output data from block 330 through a power filter 332, and then determines at block 334 whether the power output is above a predetermined upper threshold or at block 334 whether the power output is below a predetermined lower threshold. For the illustrated embodiment, the predetermined upper threshold is 95% of the maximum power output of the first battery 302A, and the predetermined lower threshold is 90% of the maximum power output of the first battery 302A. However, in other embodiments, these upper and lower thresholds can be set to any other suitable values. Moreover, for the described embodiment, a gap is defined between the upper and lower thresholds to ensure that the output does not flip-flop when the power output is right on the border of one of these thresholds.

[0067] The compensation trigger circuit 324 is structured to determine a compensation trigger value based on the power output of the battery 302 at block 338, and provide the compensation trigger value as an output. More specifically, the compensation trigger circuit 324 provides a first compensation trigger value if the power output is above the predetermined upper threshold, and a second compensation trigger value if the power output is below the predetermined lower threshold. The first and second compensation trigger values can be “TRUE” and “FALSE” values, “1” and “0” values, etc.

[0068] The compensation trigger value output from block 338 is then provided to the dynamic droop control circuit 326. The dynamic droop control circuit 326 is structured to receive the compensation trigger value at a switch block 340, and based at least in part on the compensation trigger value, switch the output droop value of the dynamic control circuit from an upper output droop measurement to a lower output droop measurement. For the illustrated embodiment, the upper output droop measurement is based on a baseline droop resistance set at block 342, while the lower output droop measurement is based on the state of charge of the first battery 302A, which is calculated at block 344 using the state of charge of the first battery 302A. More specifically, for the illustrated embodiment, the lower output droop measurement is based on a lookup table at block 344, with the value returned from the lookup table being based on the state of charge of the battery 302. However, it will be appreciated that in certain example aspects, the lower output droop measurement can additionally be based on other parameters, such as the available power margin of a converter (e.g., the first converter 306A, as described below).

[0069] More specifically, with brief reference to Figure 8 An example lookup table of the present disclosure is provided that can be used at block 344. As can be appreciated, this lookup table includes example variations of droop resistance along its Y-axis 346 that are based on the state of charge of the first battery 302A along its X-axis 348. As can be appreciated, the lower output droop measurement (for the illustrated embodiment, a % change in droop resistance measurement) returned from the lookup table is non-linear over the range of state of charge of the first battery 302A.

[0070] Now returning to Figure 7 It will be appreciated that the droop resistance is output at 350 from the dynamic droop control circuit 326. Based on the location in the switching block 340, the droop resistance is either the upper output droop measurement (calculated based on the output of block 342) through filter 352 or the lower output droop measurement (calculated based on the output of block 344) through filter 352. It will be appreciated that the terms "upper" and "lower" as used herein, as used with respect to the upper output droop measurement and the lower output droop measurement, are merely used to distinguish between the two measurements and do not imply any relative value or the like.

[0071] As further described, the droop resistance is output at 350 and provided to the voltage regulator droop circuit 328, which utilizes the output droop value to determine a voltage reference provided from the first battery 302A to the load 312 at 354. More specifically, the voltage regulator droop circuit 328 receives the current provided from the first battery 302A to the load 312 and the output droop value, which is also the droop resistance, at block 356 and sets the reference voltage provided by the first battery 302A to the load 312 through a series of additional blocks, filters, and the like.

[0072] Still again referring to Figure 6 The reference voltage output at 354 from the voltage regulator droop circuit 328 is provided to the first converter 306A, and the first converter 306A is structured to receive power from the first battery 302A and modify the power provided from the first battery 302A to be consistent with the output of the voltage regulator droop circuit 328 to provide the required power to the load 312.

[0073] It will be noted that for the illustrated embodiment, the first converter 306A is a DC-to-DC converter 306 (i.e., a direct current to direct current converter 306).

[0074] It will be appreciated that in other example embodiments, the voltage regulator droop circuit 328 can have other suitable constructions, and similarly, the first converter 306A can have any suitable construction to provide the described functionality.

[0075] In this manner, it can be appreciated that the first controller 308A is generally structured to determine how much power to provide to the load 312. If it is relatively high power (e.g., above an upper threshold), then the dynamic droop control circuit 326 provides an upper output droop measurement, which is based on a baseline droop resistance at block 342, through the filter 352. By contrast, if the power provided to the load 312 is relatively small (e.g., below a lower threshold), then the dynamic droop control circuit 326 provides a lower output droop measurement, which is based on a lookup table at block 344 and the first state of charge, through the droop filter 352. In this manner, if a relatively high amount of power is needed, then the controller 308 does not provide dynamic droop control, but instead prioritizes providing the needed power output. By contrast, if a relatively low power is needed, then the controller 308 provides dynamic droop control that is non-linear across the span of the state of charge of the first battery 302A to allow for standardization of the state of charge of the plurality of batteries 302. More specifically, with such a structure, the dynamic droop control pulls more power from batteries 302 having a higher state of charge than batteries having a lower state of charge.

[0076] Still referring to Figure 6 It will be further appreciated that the illustrative power source 300 includes a similar structure for a second battery circuit (connecting the second battery 302B to the power bus 310 and the load 312). More specifically, as noted above, the power source 300 further includes a second power regulator 304B, which includes a second converter 306B in electrical communication with the second battery 302B and a second controller 308B in operable communication with the second converter 306B. The second controller 308B can be structured in substantially the same manner as the first controller 308A, as described above with reference to, for example Figure 7 More detail. For example, the second controller 308B can include a second compensation trigger circuit (not shown, similar to 324) structured to provide a second compensation trigger value based on a power output of the second battery 302B, and a second dynamic droop control circuit (not shown, similar to 326) structured to receive the second compensation trigger value and switch an output droop value of the second dynamic control circuit from an upper output droop measurement to a lower output droop measurement. The lower output droop measurement of the output droop value of the dynamic droop control circuit can be based on a second state of charge of the second battery 302B. For example, similar to the structure described above with reference to, for example Figure 7 and Figure 8 The lower output droop measurement of the output droop value of the dynamic droop control circuit can be based on a lookup table based on the second state of charge of the second battery 302B. The lookup table for the second dynamic control loop can be the same lookup table as the lookup table for the first dynamic control loop, or, can be a different lookup table.

[0077] Further, the second controller 308B can further include a second voltage regulator droop circuit 328 that utilizes the output droop value of the second dynamic droop control circuit 326.

[0078] In this manner, it can be appreciated that two or more batteries 302 (or each battery 302) can employ selective dynamic droop control to more effectively standardize the state of charge of the batteries 302 without requiring operational communication between the respective controllers 308, converters 306, etc.

[0079] Referring now to Figure 9 , a flowchart of a method 400 of operating a power source is provided. The method 400 can be used with one or more of the example power sources described above with reference to Figure 1 to Figure 8 , among other example embodiments. Figure 9 In other example embodiments, the example method 400 of

[0080] The method 400 includes, at (402), determining a power output of a battery defining a state of charge, and at (404), determining a compensation trigger value based on the power output of the battery determined at (402). In at least certain example aspects, determining the compensation trigger value based on the power output of the battery determined at (404) includes, at (405), determining that the power output of the battery is below a lower power output threshold, and responsively setting the compensation trigger value.

[0081] Further, the method 400 includes, at (406), switching the output droop value from an upper output droop measurement to a lower output droop measurement based on the determined compensation trigger value, wherein the lower output droop measurement is based on the state of charge of the battery.

[0082] As with the above-described embodiments, the upper output droop measurement can be based on a baseline droop resistance.

[0083] Still referring to Figure 9 , for the described example aspects, switching the output droop value from the upper output droop measurement to the lower output droop measurement at (406) includes, at (408), determining the lower output droop measurement based on a lookup table based on the state of charge of the battery. In at least certain aspects of these example aspects, the lower output droop measurement is non-linear over a range of the state of charge of the battery.

[0084] The method 400 further includes determining, at (410), a reference output voltage using a voltage regulator droop circuit of the controller, the voltage regulator droop circuit utilizing the output droop value of the dynamic droop control circuit. The method 400 also includes modifying, at (412), the power output of the battery using the converter in electrical communication with the controller, and more specifically, modifying the power output of the battery using the converter in electrical communication with the controller based on the reference output voltage determined at (410).

[0085] Further, it can be appreciated that, in at least certain example aspects, the method 400 described herein can be utilized with a plurality of batteries. For example, in certain example embodiments, the battery described above can be a first battery, the state of charge can be a first state of charge, and the method 400 can further include: determining, at (414), a second power output of a second battery defining a second state of charge; determining, at (416), a second compensation trigger value based on the second power output of the second battery determined at (414); and switching, at (418), the second output droop value from an upper output droop measurement value to a lower output droop measurement value based on the determined second compensation trigger value. With such example aspects, the lower output droop measurement value can be based on the second state of charge of the battery (e.g., utilizing a lookup table). Notably, steps (414), (416), and (418) can occur in parallel with the preceding method steps.

[0086] This written description uses examples to disclose the application, including the best mode, and also to enable any person skilled in the art to practice the application, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the application is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural

[0087] Further aspects of the disclosure are set forth in the following clauses:

[0088] A power source, comprising: a battery, the battery defining a state of charge; a converter, the converter in electrical communication with the battery; and a controller, the controller in operable communication with the converter, the controller including: a compensation trigger circuit, the compensation trigger circuit configured to provide a compensation trigger value based on a power output of the battery; a dynamic droop control circuit, the dynamic droop control circuit configured to receive the compensation trigger value and switch an output droop value of the dynamic droop control circuit from an upper output droop measurement value to a lower output droop measurement value, wherein the lower output droop measurement value is based on the state of charge of the battery.

[0089] The power source according to one or more of the clauses, wherein the upper output droop measurement is based on a baseline droop resistance.

[0090] The power source according to one or more of the clauses, wherein the lower output droop measurement is based on a lookup table based on the state of charge of the battery.

[0091] The power source according to one or more of the clauses, wherein the lower output droop measurement is non-linear over a range of the state of charge of the battery.

[0092] The power source according to one or more of the clauses, wherein the controller further comprises a voltage regulator droop circuit that utilizes the output droop value of the dynamic droop control circuit.

[0093] The power source according to one or more of the clauses, wherein the battery is a first battery, wherein the state of charge is a first state of charge, wherein the converter is a first converter, wherein the controller is a first controller, and wherein the power source further comprises: a second battery, the second battery defining a second state of charge; a second converter, the second converter in electrical communication with the second battery; a second controller, the second controller in operable communication with the second converter, the second controller comprising: a second compensation trigger circuit, the second compensation trigger circuit configured to provide a second compensation trigger based on a power output of the second battery; a second dynamic droop control circuit, the second dynamic droop control circuit configured to receive the second compensation trigger value and switch an output droop value of the second dynamic droop control circuit from an upper output droop measurement to a lower output droop measurement, wherein the lower output droop measurement is based on the second state of charge of the second battery.

[0094] The power source according to one or more of the clauses, wherein the lower output droop measurement of the output droop value of the second dynamic droop control circuit is based on a lookup table based on the second state of charge of the second battery.

[0095] The power source according to one or more of the clauses, wherein the first controller and the second controller are communicatively isolated from each other.

[0096] The power source according to one or more of the clauses, wherein the first controller comprises a first voltage regulator droop circuit that utilizes the output droop value of the first dynamic droop control circuit, and wherein the second controller comprises a second voltage regulator droop circuit that utilizes the output droop value of the second dynamic droop control circuit.

[0097] The power source according to one or more of the clauses, wherein the first battery and the second battery are in electrical communication with a common load.

[0098] The power source according to one or more of these clauses, wherein the compensation trigger circuit is configured to provide the compensation trigger value equal to the first output when the power output is above the upper threshold and equal to the second output when the power output is below the lower threshold.

[0099] The power source according to one or more of these clauses, wherein the dynamic droop control circuit is configured to switch the output droop value of the dynamic droop control circuit from the upper output droop measurement to the lower output droop measurement when the compensation trigger value is equal to the second output.

[0100] The power source according to one or more of these clauses, wherein the power source is for a propulsion system.

[0101] The power source according to one or more of these clauses, wherein the power source is for an aerospace propulsion system.

[0102] The power source according to one or more of these clauses, wherein the first battery defines a maximum power output of at least 250 volts.

[0103] The power source according to one or more of these clauses, wherein the first battery defines a maximum power output of at least 500 volts and up to 5000 volts.

[0104] The power source according to one or more of these clauses, wherein the converter is a DC-to-DC converter.

[0105] A method of operating a power source, comprising: determining a power output of a battery defining a state of charge; determining a compensation trigger value based on the determined power output of the battery; switching an output droop value from an upper output droop measurement to a lower output droop measurement based on the determined compensation trigger value, wherein the lower output droop measurement is based on the state of charge of the battery.

[0106] The method according to one or more of these clauses, wherein the upper output droop measurement is based on a baseline droop resistance.

[0107] The method according to one or more of these clauses, wherein switching the output droop value from the upper output droop measurement to the lower output droop measurement comprises determining the lower output droop measurement based on a lookup table, the lookup table based on the state of charge of the battery.

[0108] The method according to one or more of these clauses, wherein the lower output droop measurement is non-linear over a range of the state of charge of the battery.

[0109] The method according to one or more of these clauses, further comprising determining the reference output voltage using a voltage regulator droop circuit of the controller, the voltage regulator droop circuit utilizing the output droop value of the dynamic droop control circuit; and modifying the power output of the battery using a converter in electrical communication with the controller.

[0110] The method according to one or more of these clauses, wherein the battery is a first battery, wherein the state of charge is a first state of charge, and wherein the method further comprises determining a second power output of a second battery defining a second state of charge; determining a second compensation trigger value based on the determined second power output of the second battery; switching the second output droop value from an upper output droop measurement to a lower output droop measurement according to the determined second compensation trigger value, wherein the lower output droop measurement is based on the second state of charge of the battery.

[0111] The method according to one or more of these clauses, wherein determining the compensation trigger value based on the determined power output of the battery comprises determining that the power output of the battery is below a lower threshold.

Claims

1. An electric power source, characterized in that include: a battery, the battery defining a state of charge; a converter in electrical communication with the battery; and a controller in operative communication with the converter, the controller comprising: a compensation trigger circuit configured to provide a compensation trigger value based on a power output of the battery; and a first dynamic droop control circuit configured to receive the compensation trigger value and switch an output droop value of the first dynamic droop control circuit from an upper output droop measurement value to a lower output droop measurement value based on the compensation trigger value, wherein the lower output droop measurement value is based on the state of charge of the battery.

2. The electric power source according to claim 1, wherein Wherein, the upper output droop measurement value is based on the baseline droop resistance.

3. The electric power source according to claim 1, wherein in, The lower output droop measurement is based on a lookup table that is based on the state of charge of the battery.

4. The electric power source according to claim 3, characterized in that in, The lower output droop measurement is non-linear over the range of states of charge of the battery.

5. The electric power source according to claim 1, wherein The controller further includes a voltage regulator droop circuit that utilizes the output droop value of the first dynamic droop control circuit.

6. The electric power source according to claim 1, wherein in, The battery is a first battery, wherein the state of charge is a first state of charge, wherein the converter is a first converter, wherein the controller is a first controller, and wherein the power source further comprises a second battery defining a second state of charge; a second converter in electrical communication with the second battery; A second controller is in operative communication with the second converter, the second controller comprising a second compensation trigger circuit configured to provide a second compensation trigger value based on the power output of the second battery; a second dynamic droop control circuit configured to receive the second compensation trigger value and switch an output droop value of the second dynamic droop control circuit from an upper output droop measurement value to a lower output droop measurement value, wherein the lower output droop measurement value is based on the second state of charge of the second battery.

7. The electric power source according to claim 6, characterized in that in, The lower output droop measurement of the output droop value of the second dynamic droop control circuit is based on a lookup table that is based on the second state of charge of the second battery.

8. The electric power source according to claim 6, characterized in that in, The first controller and the second controller are communicatively isolated from each other.

9. The electric power source according to claim 6, characterized in that in, The first controller includes a first voltage regulator droop circuit that utilizes the output droop value of the first dynamic droop control circuit, and wherein the second controller includes a second voltage regulator droop circuit that utilizes the output droop value of the second dynamic droop control circuit.

10. The electric power source according to claim 6, characterized in that in, The first battery and the second battery are in electrical communication with a common load.

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