Power system and method

Abstract

To provide a vehicle system and method having an electric power system.SOLUTION: An electric power system 350 includes an inverter device 310 coupled with a motor 304. The inverter device receives from the motor electric energy generated by dynamic braking of the motor. An energy storage device 312 is coupled with the inverter device, and a variable resistive component 320 is disposed between the inverter device and the energy storage device. The variable resistive component controls a direction of conduction of the electric energy from the inverter device toward the energy storage device, a resistive grid, or a system load. The variable resistive component controls the direction of conduction of the electric energy from the inverter device based on a first amount of the electric energy conducted from the inverter device, a transfer rate of the electric energy conducted from the inverter device, or one or more characteristics of the energy storage device.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The subject matter described herein relates to vehicle systems having electrical power systems and related methods. [Background technology]

[0002] Technology Considerations In some battery electric systems (e.g., vehicles, stationary systems, etc.), the battery may have limited power absorption capabilities in various instances due to various factors. Such factors may include state of charge level, allowable transfer rate of power, etc. In systems that generate electrical energy during dynamic braking of the system, a portion of the generated braking power may need to be dissipated in a resistive grid or may be directed to the system load (e.g., propulsion loads, non-propulsion loads, etc.). In power systems with fixed resistance values, a certain amount of power loss may occur in the battery voltage, and the remaining power may be used to charge the battery. For example, there may be no control over the battery charging power. Additionally, in systems where the power system is not connected to a resistive grid, the power system may have no control over the power provided to the battery (e.g., regardless of the battery's state of charge).

[0003] For example, Figure 1 shows a schematic diagram of an existing power system 100 for a vehicle system. The power system includes a motor 102, such as a traction motor, electrically coupled to an inverter 104. The power system further includes a resistive component 112 electrically coupled to and disposed between the inverter, an energy storage device 110 (e.g., a battery, etc.) and a vehicle load or resistive grid 106. The resistive component may be a fixed resistive component such that the resistive component can direct electrical energy in a single direction.

[0004] The motor can generate electrical energy (e.g., braking power) that is generated by dynamic braking of the motor of the vehicle system. As the speed of movement of the vehicle system increases, the amount of electrical energy required to brake or slow the movement of the vehicle system decreases, and the excess electrical energy is directed from the motor through the inverter to the resistive component. The resistive component includes a switch 114 that controls the direction of conduction (e.g., flow, movement, etc.) of electrical energy from the motor. The electrical energy may be directed in a first direction 116 toward the energy storage device while the switch is in an open position, or the electrical energy may be directed in a second direction 118 toward the vehicle load or grid while the switch is in a closed position. Optionally, the power system may lack a resistive component and a vehicle load or resistive grid, whereby all electrical energy from the motor may be directed to the energy storage device.

[0005] The position of the switch between the open and closed positions is based on the voltage of the energy storage device 122 relative to the DC link voltage 120. When the vehicle load or grid is connected to the DC link (e.g., as shown in FIG. 1), the grid power is a function of the voltage of the energy storage device and the grid resistance, and the energy storage charging power is based on the electric energy of the vehicle system (e.g., braking power) and the grid power. For example, since the grid power cannot be controlled, the energy storage charging power is the remaining power after grid dissipation. Alternatively, when the vehicle load or grid is not connected to the DC link, all the electric energy (e.g., braking power) is directed to the energy storage device, regardless of the state of charge of the energy storage device.

[0006] Figure 2 shows a graph 130 illustrating the operation of the power system shown in Figure 1. In the illustrated embodiment of Figure 2, a vehicle load or grid is connected with a DC link. The graph includes a vertical axis 132 representing power (e.g., volts) and a horizontal axis 134 representing the speed of travel of the vehicle system (e.g., miles per hour). Data line 136 represents the DC link voltage of the electrical energy from the motor, data line 138 represents the amount of available electrical energy (e.g., braking power) generated by dynamic braking of the motor of the vehicle system, data line 140 represents the amount of electrical energy directed to the vehicle load or resistive grid, and data line 142 represents the amount of electrical energy directed to an energy storage device of the vehicle system.

[0007] While the voltage of the energy storage device is greater than the DC link voltage, the switch is in a closed position and electrical energy is directed to the vehicle load or to the grid. As the speed of travel of the vehicle system increases, the braking power generated by the vehicle system and the corresponding DC link voltage increases. The position of the switch moves to an open position in response to the DC link voltage increasing to a level substantially equal to or greater than the voltage of the energy storage device.

[0008] For example, as the speed of the vehicle system increases, the amount of power coming from the motor through the inverter changes. From speed S0 to speed S1, the voltage across the DC link is less than the voltage across the energy storage device, so the switch of the resistive component remains in a closed position and electrical energy is directed to the vehicle load or the grid (e.g., data line 140). As the moving speed of the vehicle system increases, the voltage across the DC link changes. At moving speed S1, the voltage across the DC link changes such that the voltage across the DC link is greater than the voltage across the energy storage device, and the switch of the resistive component shown in FIG. 1 changes from a closed position to an open position and electrical energy is directed to the energy storage device.

[0009] However, the energy storage device may be capable of absorbing greater electrical energy than is directed to the energy storage device. For example, electrical energy may only be directed to the energy storage device after grid or load dissipation, and thus the amount of power from the motor directed to the energy storage device may not be optimized. Alternatively, if the vehicle load or grid is not connected to the DC link, the electrical energy from the motor to the energy storage device may not be controlled. For example, the energy storage device may receive a constant amount of electrical energy regardless of the state of charge of the energy storage device, or the energy storage device may receive electrical energy at a rate greater than the rate the energy storage device can receive it. It would be desirable to have a system and method different from those currently available. Summary of the Invention

[0010] In one or more embodiments of the subject matter described herein, a power system includes an inverter device coupled to a motor. The inverter device receives electrical energy from the motor generated by dynamic braking of the motor. An energy storage device is coupled to the inverter device, and a variable resistance component is disposed between the inverter device and the energy storage device. The variable resistance component controls a conduction direction of electrical energy from the inverter device toward one or more of an energy storage device, a resistive grid, or a system load. The variable resistance component controls the conduction direction of electrical energy from the inverter device based on one or more of a first amount of electrical energy conducted from the inverter device, a transmission rate of electrical energy conducted from the inverter device, or one or more characteristics of the energy storage device.

[0011] In one or more embodiments of the subject matter described herein, a method includes receiving electrical energy generated by dynamic braking of a motor from an inverter device and controlling a direction of conduction of the electrical energy from the inverter device to one or more of an energy storage device, a resistive grid, or a system load, the direction of conduction of the electrical energy being based on one or more of a first amount of electrical energy conducted from the inverter device, a transmission rate of the electrical energy conducted from the inverter device, or one or more characteristics of the energy storage device.

[0012] In one or more embodiments of the subject matter described herein, a method includes receiving electrical energy generated by dynamic braking of a motor from an inverter device, determining a state of charge of an energy storage device, and operating a variable resistance component in a first operating mode or a second operating mode, where in the first operating mode, the variable resistance component directs a first amount of electrical energy from the inverter device toward the energy storage device, and in the second operating mode, the variable resistance component directs a second amount of electrical energy from the inverter device toward the energy storage device. [Brief description of the drawings]

[0013] The subject matter of the invention can be understood from reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0014] [Figure 1] FIG. 1 illustrates an example schematic diagram of a power system for a vehicle system. [Diagram 2] 2 shows a graph of the schematic diagram shown in FIG. 1. [Diagram 3] 1 illustrates a vehicle system according to one embodiment. [Figure 4] 1 shows a schematic diagram of a power system according to one embodiment. [Diagram 5] 5 illustrates a graph of the schematic diagram shown in FIG. 4 according to one embodiment. [Figure 6]2 shows a bar graph illustrating operation of the power system shown in FIG. 1 under a first operating condition. [Figure 7] 5 shows a bar graph illustrating operation of the power system shown in FIG. 4 under a first operating condition. [Figure 8] 2 shows a bar graph illustrating operation of the power system shown in FIG. 1 under second operating conditions. [Figure 9] 5 shows a bar graph illustrating operation of the power system shown in FIG. 4 under second operating conditions. [Figure 10] 1 shows a schematic diagram of a power system according to one embodiment. [Figure 11] 1 illustrates an example flow chart for controlling the conduction of electrical energy generated by dynamic braking of a vehicle system, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Embodiments of the subject matter described herein relate to a power system and a method of operation. The power system may include an inverter device coupled to a motor of an electric system and an energy storage device coupled to the inverter device, and a variable resistance component may be disposed between the inverter device and the energy storage device. In one embodiment, the electric system may include the motor and may be part of a vehicle system. A suitable motor may be a traction motor that propels a vehicle in one operating mode and generates electric energy in another operating mode. The traction motor may generate electricity by dynamically braking the vehicle system. The variable resistance component may control the direction of conduction of electric energy from the motor through the inverter device to one or more of an energy storage device and / or a resistive grid or a vehicle load. An embodiment of the power system described herein may prioritize directing electric energy toward the energy storage device over directing electric energy toward a resistive grid for dissipation and / or vehicle load.

[0016] The variable resistance component may control the operation of the power system to operate in one or more different operating modes. The different operating modes may control the direction of electrical energy conduction or flow and the amount of electrical energy that may be directed toward an energy storage device, a resistive grid, or a system load (e.g., a vehicle system load). In one embodiment, in a first operating mode, the variable resistance component may direct all of the electrical energy to the energy storage device. In another embodiment, in a second operating mode, the variable resistance component may direct a portion of the electrical energy to the energy storage device and a portion of the electrical energy to either or both of the resistive grid or the system load. In another embodiment, in a third operating mode, the variable resistance component may direct all of the electrical energy to either the resistive grid or the system load, or a portion of the electrical energy to the resistive grid and another portion of the electrical energy to the system load.

[0017] In one or more embodiments, the direction of conduction of the electrical energy from the inverter device may be based on the amount of electrical energy from the inverter device, the transfer rate of the electrical energy from the inverter device, or a characteristic of the energy storage device. The characteristic of the energy storage device may be and / or may include the total amount of electrical energy that the energy storage device is capable of receiving, the transfer rate of the energy storage device, the type of energy storage device (e.g., make, model, etc.), the age of the energy storage device, the length of time the energy storage device has been in operation (e.g., the cumulative number of hours the energy storage device has been in operation, the length of time the energy storage device has been in operation in one or more operations of the power system), and the like. In one example, the variable resistance component may direct all of the electrical energy to the energy storage device. In another example, the variable resistance component may direct a portion of the electrical energy to the energy storage device and another portion of the electrical energy to the resistive grid and / or the vehicle loads (e.g., the propulsion loads of the vehicle system and / or the non-propulsion loads of the vehicle system). The amount of electrical energy directed to the resistive grid and / or the vehicle loads may be the remaining portion of the total amount of electrical energy from the inverter device.

[0018] The amount of electrical energy directed to the energy storage device may vary based on changes in dynamic braking of the vehicle system. Optionally, the amount of electrical energy directed to the energy storage device may vary based on a state of charge of the energy storage device. In one or more embodiments, the state of charge of the energy storage device may change during operation of the vehicle system. Optionally, the amount of electrical energy directed to the energy storage device may vary based on a classification (e.g., type, make, model, age, etc.) of the energy storage device.

[0019] In one or more embodiments, the amount of electrical energy from the inverter device may change in response to a change in dynamic braking of the vehicle system. The variable resistance component may change the direction of conduction of the electrical energy based on the new amount of electrical energy from the inverter device. Optionally, the variable resistance component may change the amount of the first portion of the electrical energy directed to the energy storage device. Changing the amount of the first portion of the electrical energy changes the amount of the second portion of the electrical energy directed to the resistive grid and / or the vehicle load. For example, a portion of the electrical energy may be directed to the energy storage device and a remaining portion of the total amount of electrical energy may be directed to one or both of the resistive grid or the vehicle load.

[0020] In one embodiment, the electrical system may be a vehicle system. A suitable vehicle system may be a thrust-producing vehicle. Examples of suitable vehicle systems may include rail vehicles, automobiles, trucks, buses, mining vehicles, marine vessels, aircraft (manned or unmanned aerial vehicles such as drones), agricultural vehicles, industrial equipment, or another off-highway vehicle. Suitable rail vehicles may include locomotives, switchers, shunters, and the like. Optionally, the vehicle system may be a marine vessel or aircraft and may be wheelless. For example, the vehicle system may also move along waterways, flight paths, and the like. In one embodiment, the vehicle system is a single vehicle. In other embodiments, the vehicle system may include two or more vehicles that may travel together. Group movement may be achieved by the vehicles being mechanically coupled together, such as in a train, convoy, formation, group, flotilla, platoon, fleet, and the like, or by the vehicles being mechanically separated but logically or virtually coupled and communicating with each other to travel together. At least one vehicle of the vehicle system may be a thrust-producing vehicle, and optionally, the vehicle system may include one or more non-thrust-producing vehicles.

[0021] FIG. 3 illustrates a vehicle system 300 according to one embodiment. In the illustrated embodiment, the vehicle system may be a single vehicle including multiple wheels 302 that contact a path along which the vehicle system travels. The vehicle system may include a controller 308 disposed on the vehicle system. The controller may represent a control module and may include one or more processors, microcontrollers, or other logic-based devices, and / or associated software or instructions for performing one or more operations described herein. The controller controls the operation of the vehicle system, such as by controlling traction and / or braking forces provided by a propulsion system, such as a motor 304 (e.g., traction motor, engine, etc.) and a braking system 306. The controller may be operated manually by receiving command signals from an input device (e.g., a device that receives input from an operator, such as, but not limited to, a touch screen, joystick, keyboard, switch, wheel, microphone, etc.) based on manual input from an operator at an input device (not shown). An output device (not shown) may provide information to the operator such as the current operational settings of the vehicle systems, the specified operational settings of the trip plan, the current amount of electrical energy stored on the vehicle systems, and the current storage capacity of the on-board energy storage device 312.

[0022] In one or more embodiments, the controller may be automatically operated to autonomously control the operation of the vehicle systems. For example, the trip plan may be provided by an energy management system (not shown) and / or may be stored in a tangible and non-transitory computer-readable storage medium, or memory (not shown) accessible by the controller. The controller and the energy management system may represent two or more control modules in one or more embodiments. The trip plan may specify operational settings of the vehicle systems as a function of time or distance along a route of travel to a destination of the vehicle system. The specified operational settings of the trip plan may be established to reduce one or more of fuel consumed by the vehicle systems for the trip, emissions generated, or time spent traveling. The energy management system may include one or more processors, microcontrollers, or other logic-based devices, and / or associated software or instructions for performing one or more operations described herein.

[0023] Traction components operably coupled with the propulsion and / or braking systems (e.g., traction motors, brakes such as air brakes, etc.) may control the movement of the wheels 302 (and / or axles coupled to the wheels, not shown) of the vehicle system to generate traction to propel the vehicle system along a path. In addition to providing propulsion to propel the vehicle system, the propulsion system and / or braking system may act to slow or stop movement of the vehicle system using dynamic braking.

[0024] The propulsion system and / or braking system may be electrically powered by electrical energy (e.g., electrical current) provided by one or more on-board and / or off-board power sources. For example, the vehicle system may be referred to as a hybrid vehicle system, such that the vehicle system is powered by an off-board external power source, an on-board power source, or a combination of an external power source and an on-board power source. With respect to an on-board power source, the vehicle system may include an on-board energy storage device 312 and / or one or more fuel cells, batteries, or other power sources (not shown). The on-board power source may additionally or alternatively include one or more on-board energy sources (not shown) that generate electrical current on the vehicle. For example, the on-board energy source may include a generator and / or an alternator, which may be connected by a shaft to the motor 304. Rotation of the shaft by the motor rotates a rotor of the generator to generate electrical energy (e.g., electrical current).

[0025] In one or more embodiments, the on-board energy source may include another type of device that generates or stores electrical energy on the vehicle, such as one or more solar cells, wind turbines, etc. In another example, the on-board energy source may include a traction motor of the propulsion system when the traction motor operates in a dynamic braking mode, in which electrical energy is generated by the traction motor during deceleration of the vehicle system. At least a portion of the electrical energy generated by the dynamic braking may be provided to an on-board energy storage device for storage. Additionally or alternatively, at least a portion of the electrical energy generated by the dynamic braking may be provided to a system load (e.g., a vehicle load) and / or a resistive grid 314. In one or more embodiments, the vehicle load may be an auxiliary load of the vehicle system (e.g., a non-propulsion load, such as air conditioning, coach lighting, passenger power outlets, etc.) and / or another vehicle operably coupled to the vehicle system. Optionally, the vehicle load may be a propulsion load of the vehicle system and / or another vehicle operably coupled to the vehicle system.

[0026] Although the on-board energy storage device is shown disposed on the vehicle system and operably coupled to the propulsion system and braking system via the inverter device 310, alternatively, the on-board energy storage device may be disposed on another vehicle that is coupled to the vehicle system 300. For example, the energy storage device may be disposed on an energy resupply vehicle that is connected to the vehicle system 300 by one or more mechanical connections such that movement of the vehicle system also moves the resupply vehicle. Such an energy storage device may be connected to the propulsion system of the vehicle system by one or more electrical conductors (e.g., a bus, a cable, a wire, etc.).

[0027] The energy storage device may directly supply current to the traction motor(s) of the propulsion system by being directly coupled to the traction motor(s) (e.g., without an intermediate conductive bus, transformer, etc. between the energy storage device and the motor). Alternatively or additionally, the energy storage device may indirectly supply current to the traction motor(s) by transmitting the current to the motor(s) via one or more conductive buses, transformers, etc. Optionally, the energy storage device may supply current directly and / or indirectly to an inverter device, converter device (not shown), etc. of the vehicle system. Further, optionally, the energy storage device may directly and / or indirectly supply current to one or more different vehicles operatively coupled (e.g., mechanically and / or logically) with the vehicle system to power one or more systems of the different vehicles.

[0028] 4 shows a schematic diagram of a power system 350 according to one embodiment. The power system controls the conduction of electrical energy from the motor generated by dynamic braking of the vehicle system. In one or more embodiments, a portion of the electrical energy generated by dynamic braking may exceed the amount of braking power required to slow or stop the movement of the vehicle system. For example, as the speed of movement of the vehicle system increases, the amount of electrical energy required to brake (e.g., slow or stop) the movement of the vehicle system decreases, and the excess electrical energy (e.g., braking power) may be directed to one or more of the vehicle system's on-board energy storage device or a resistive grid or a vehicle load.

[0029] The resistive grid may represent a device in which electrical energy is dissipated. A portion of the electrical energy may be directed to the resistive grid and another portion of the electrical energy may be directed to the vehicle loads. Optionally, the vehicle system may not include a resistive grid or may be decoupled from the resistive grid and the electrical energy may be directed to the vehicle loads. In one or more embodiments, a portion of the electrical energy may be directed to a number of different vehicle loads (e.g., propulsion and / or non-propulsion loads). Optionally, a portion of the electrical energy may be directed to one or more different vehicle loads and a portion of the electrical energy may be dissipated within the resistive grid.

[0030] The power system may include a motor 304 (e.g., a traction motor) and an inverter device 310 (corresponding to the motor and inverter device shown in FIG. 3). The inverter device receives electrical energy from the motor generated by dynamic braking of the vehicle system. The power system may include an energy storage device 312, a resistive grid and / or vehicle load 314, and an auxiliary inverter 318 electrically coupled to the resistive grid and / or vehicle load.

[0031] The power system may include a variable resistance component 320 disposed between the inverter device, the energy storage device, and the resistive grid and / or the vehicle load. In one or more embodiments, the variable resistance component may be referred to as a chopper or chopper circuit. The variable resistance component controls the direction of conduction of electrical energy from the inverter device to one or both of the energy storage device or the resistive grid and / or the vehicle load. For example, the variable resistance component may direct a first portion 352 of the electrical energy to the energy storage device and / or a second portion 354 of the electrical energy to the resistive grid and / or the vehicle load. The variable resistance component may operate in one or more different operating modes to control the direction of conduction of electrical energy from the inverter device. The operating mode of the variable resistance component, and the resulting direction of electrical energy conduction, may be based on the amount of electrical energy from the inverter device, the rate of electrical energy transfer from the inverter device (e.g., the rate at which electrical energy is induced from the inverter device), or one or more characteristics of the energy storage device (e.g., the state of charge of the energy storage device, the total amount of energy the energy storage device can hold, the make and / or model of the energy storage device, the age of the energy storage device, the rate at which the energy storage device can receive electrical energy, etc.).

[0032] In one or more embodiments, the power system may include a banking device (not shown) electrically coupled to the energy storage device. The banking device may be a fuel cell, a capacitor bank, or other storage device that may temporarily receive and hold electrical energy directed to the energy storage device. For example, the banking device may be disposed between the variable resistance component and the energy storage device. The banking device may receive electrical energy from the variable resistance component and store, hold, maintain, etc., the electrical energy intended for the energy storage device. The banking device may direct at least a portion of the electrical energy to the energy storage device in response to a state of charge of the energy storage device reaching a predetermined threshold. For example, the energy storage device may have a state of charge and / or an amount of energy that prohibits further receipt of electrical energy. The banking device may temporarily hold or maintain a portion of the electrical energy until the state of charge of the energy storage device drops to a predetermined threshold to indicate that the energy storage device is capable and / or permitted to receive more electrical energy.

[0033] 5 illustrates a graph 500 of the schematic diagram of the power system shown in FIG. 4 according to one embodiment. The graph illustrates the distribution of electrical energy between the energy storage device and / or resistive grid / vehicle loads based on one or more operating conditions of the vehicle system. The graph may include a horizontal axis 504 representing the locomotive's travel speed (e.g., miles per hour), a first vertical axis 502 representing increasing power, and a second vertical axis 506 representing increasing percentage of the duty cycle of the variable resistive component.

[0034] Data line 520 represents the duty cycle of the variable resistive component. The duty cycle may be used to determine the amount of electrical energy directed to the resistive grid and / or the vehicle load. The controller may calculate the duty cycle of the variable resistive component based on multiple factors. First, the estimated power dissipated in the resistive grid and / or the vehicle load may be based on the amount of power generated by the vehicle system through dynamic braking, the charging current of the energy storage device, and the voltage of the energy storage device. The duty cycle may be based on the estimated power dissipated in the grid, the charging current of the energy storage device, the voltage of the energy storage device, the grid resistance, the internal resistance of the energy storage device, and any additional stray resistance of the power system.

[0035] Data line 536 represents the battery voltage level and the DC link voltage, with the battery voltage being substantially equal to (within 5% of) the power system DC link voltage. Data line 538 represents the electrical energy generated by dynamic braking of the vehicle system (e.g., braking power). Data line 542 represents the amount of electrical energy directed to an energy storage device (e.g., energy storage device charging power). Data line 540 represents the amount of electrical energy directed to the resistive grid of the vehicle system and / or the vehicle load.

[0036] The power system shown in FIG. 4 prioritizes the energy storage device over the resistive grid and / or the vehicle load. For example, the power system may first direct all electrical energy to the energy storage device and then, in response to the state of charge of the energy storage device reaching a predetermined threshold, direct a portion of the electrical energy to the resistive grid and / or the vehicle load. For example, in the illustrated embodiment, from travel speed S2 to speed S3, the variable resistance component operates in a first operating mode and the power system directs all electrical energy to the energy storage device. At speeds increasing from speed S3, the variable resistance component changes operating mode from the first operating mode to operate in a second operating mode and the power system directs a first portion of the electrical energy to the energy storage device and simultaneously directs a second portion of the electrical energy to the resistive grid and / or the vehicle load. The amount of electrical energy in the first and / or second portions may be based on one or more factors and / or characteristics of the vehicle system, the energy storage device, the resistive grid and / or the vehicle load, etc.

[0037] With respect to the duty cycle, this ratio may determine, or at least contribute to, the amount of the first portion of electrical energy directed to the energy storage device, as well as the amount of electrical energy directed to the resistive grid and / or the vehicle load. The amount of the first portion of electrical energy (e.g., directed to the energy storage device) may be based on changes in dynamic braking of the vehicle system (e.g., the amount of power generated by the vehicle system by dynamic braking), the state of charge of the energy storage device (e.g., the charging current of the energy storage device), the type or classification of the energy storage device (e.g., one model of the energy storage device may have a larger charge capacity than another model of another energy storage device, one model may have a transfer rate of electrical energy that the model may receive that is different from the transfer rate of another model of the energy storage device, etc.). In one or more embodiments, the total amount and / or transfer rate of the energy storage device may be based on the state of charge of the energy storage device, which may change during operation of the vehicle system. For example, the state of charge (e.g., the amount of current stored in the energy storage device) may decrease as a portion of the current stored in the energy storage device is used in one or more systems (propulsion and / or non-propulsion systems) of the vehicle system.

[0038] In one embodiment, the controller may determine and / or calculate the amount of electrical energy directed to the resistive grid and / or the vehicle loads based on the following equation: P g =P ブレーキ -P b (P ブレーキ >P b In the case of Eq..1

[0039] In Equation 1, P g represents the resistive grid power, P ブレーキ represents the total electrical energy (e.g., braking power) represented by data line 538, and P brepresents the energy storage device (e.g., battery) power. Using Equation 1, b ) allowable capacity of brake power (P ブレーキ ), the amount of electrical energy directed to a resistive grid of the vehicle system and / or to the vehicle loads can be determined. For example, the energy storage device can contain or hold a predetermined amount of electrical energy used to power one or more systems on the vehicle system (e.g., propulsion system and / or non-propulsion system, etc.).

[0040] Alternatively, the controller may change the operating mode of the variable resistance component to change the conduction direction or amount of electrical energy directed to one or both of the energy storage device or resistive grid and / or vehicle loads based on the total amount of electrical energy the variable resistance component receives from the inverter device and the total amount of electrical energy that changes in response to changes in dynamic braking of the vehicle system. For example, if the total amount of electrical energy is less than the allowable capacity of the energy storage device, the amount of electrical energy directed to the resistive grid and / or vehicle loads may be based on the following formula: P g =D*V バッテリ 2 / R グリッド (P ブレーキ <P b In the case of Eq..2

[0041] In Equation 2, D represents the duty cycle of a variable resistance component (e.g., a chopper in a power system), and V バッテリ represents the voltage of the energy storage device, and R グリッドrepresents the resistance of the resistive grid and / or vehicle load. For example, unlike the graph shown in FIG. 2, the power system shown in FIG. 4 prioritizes directing electrical energy to the energy storage device and then directs a portion of the electrical energy to the resistive grid and / or vehicle load of the vehicle system. Additionally, as the percentage of the duty cycle increases (e.g., with an increase in the speed of travel of the vehicle system), the amount or portion of the electrical energy directed to the resistive grid and / or vehicle load increases. For example, the amount of electrical energy directed to the resistive grid and / or vehicle load may change in response to the amount of electrical energy directed to the energy storage device changing.

[0042] In one or more embodiments, a controller of the vehicle system may monitor the total amount of electrical energy generated by dynamic braking of the vehicle system and / or the state of charge of the energy storage device. Optionally, the controller may automatically (e.g., without operator input) control the operation of the variable resistance component to change the operating mode of the variable resistance component. Changing the operating mode of the variable resistance component changes the direction of electrical energy conduction, changes the amount of electrical energy directed to the energy storage device, and / or changes the amount of electrical energy directed to the resistive grid of the vehicle system and / or the vehicle load.

[0043] In one embodiment, the controller may control the operation of the variable resistance component to operate in a first mode of operation to direct all of the electrical energy to the energy storage device. In another embodiment, the controller may control the operation of the variable resistance component to operate in a second mode of operation to direct at least a portion of the electrical energy to the energy storage device and at least a portion of the electrical energy to one or both of the resistive grid or the vehicle load. While the variable resistance component operates in the second mode of operation, the amount of electrical energy directed to the energy storage device may also vary based on the state of charge of the energy storage device, the amount of electrical energy from the inverter device, etc. In another embodiment, the controller may control the operation of the variable resistance component to operate in a third mode of operation to direct all of the electrical energy to the resistive grid or the vehicle load, or to direct a portion of the electrical energy to the resistive grid and a portion of the electrical energy to the vehicle load.

[0044] The controller may change the operating mode of the variable resistance component in response to the total amount of electrical energy changing, exceeding a predetermined threshold, or falling below a predetermined lower threshold. Optionally, the controller may indicate to an operator of a vehicle system (e.g., an on-board and / or off-board vehicle system) that the operating mode of the variable resistance component should be changed. Optionally, the controller may instruct the operator how to manually change the operating mode of the variable resistance component.

[0045] FIG. 6 illustrates a bar graph 600 responsive to operating the power system shown in FIG. 1 under a first operating condition. FIG. 7 illustrates a bar graph 700 responsive to operating the power system shown in FIG. 4 under the same first operating condition. As an example, the first operating condition of the vehicle system may include operating the vehicle system to generate approximately 1050 horsepower (hp) per axle of the vehicle system. Graphs 600 and 700 include a vertical axis 602 representing increasing power. Data line 604 represents the axle power limit and data line 606 represents the nominal electrical energy (e.g., braking power) generated by dynamic braking per axle. In the illustrated embodiments of FIGS. 6 and 7, a resistive grid and / or vehicle loads are electrically connected with the power systems shown in FIGS. 1 and 4, respectively.

[0046] Bars 610 and 710 represent axle 1 of the vehicle system, bars 612 and 712 represent axle 2 of the vehicle system, bars 614 and 714 represent axle 3 of the vehicle system, and bars 616 and 716 represent axle 4 of the vehicle system. Bar A of each axle represents the amount of electrical energy required by the energy storage device, bar B of each axle represents the amount of electrical energy directed to the resistive grid due to dissipation (e.g., resistive grid losses), and bar C of each axle represents the actual amount of electrical energy received by the energy storage device.

[0047] As shown in graph 600, line 620 indicates that substantially the same amount of electrical energy generated by each axle 610, 612, 614, and 616 is directed to and dissipated within the resistive grid. Additionally, as shown in FIG. 6, each axle is unable to achieve the power requirement of the energy storage device compared to the actual amount of power directed to the energy storage device. For example, rod A of axle 610, 612, 614, and 616 is greater in amount than or greater than rod C of axle 610, 612, 614, and 616. The actual amount of electrical energy (e.g., power) generated by each axle 610-616 is less than the electrical energy (e.g., power) requirement of the energy storage device. For example, the energy storage device may receive more electrical energy than the energy storage device is actually receiving. The power system shown in FIG. 1 may selectively prioritize the resistive grid ahead of the energy storage device.

[0048] Alternatively, as shown in graph 700, the power system shown in FIG. 4 prioritizes the energy storage device over the resistive grid and / or vehicle load. For example, pole A of axles 710, 712, 714, and 716 is substantially the same as pole C of axles 710, 712, 714, and 716. The energy storage device receives substantially the same amount of electrical energy as the amount of electrical energy required by the energy storage device. For example, the energy storage device receives the same or substantially the same amount of electrical energy as the amount of electrical energy the energy storage device can receive. Additionally, the amount of electrical energy directed to the resistive grid and / or vehicle load is varying between axles 710, 712, 714, and 716. For example, a variable resistance component controls the amount of electrical energy directed to the energy storage device and the amount of electrical energy directed to the resistive grid and / or vehicle load, prioritizing the energy storage device over the resistive grid and / or vehicle load.

[0049] FIG. 8 illustrates a bar graph 800 responsive to operating the power system shown in FIG. 1 under a second operating condition. FIG. 9 illustrates a bar graph 900 responsive to operating the power system shown in FIG. 4 under the same second operating condition. As an example, the second operating condition of the vehicle system may include operating the vehicle system to generate approximately 750 horsepower (hp) per axle of the vehicle system. Similar to graphs 600 and 700, graphs 800 and 900 include a vertical axis 602 representing increasing power. Data line 804 represents the axle power limit and data line 806 represents the nominal electrical energy (e.g., braking power) generated by dynamic braking per axle. In the illustrated embodiments of FIGS. 8 and 9, a resistive grid and / or vehicle loads are electrically connected with the power systems shown in FIGS. 1 and 4, respectively.

[0050] Bars 810 and 910 represent axle 1 of the vehicle system, bars 812 and 912 represent axle 2 of the vehicle system, bars 814 and 914 represent axle 3 of the vehicle system, and bars 816 and 916 represent axle 4 of the vehicle system. Bar A of each axle represents the amount of electrical energy required by the energy storage device, bar B of each axle represents the amount of electrical energy directed to the resistive grid due to dissipation (e.g., resistive grid losses), and bar C of each axle represents the actual amount of electrical energy received by the energy storage device.

[0051] Similar to graph 600, graph 800 may include line 820 indicating that substantially the same amount of electrical energy generated by each axle 810, 812, 814, and 816 is directed to and dissipated within the resistive grid. Additionally, each axle is unable to achieve the power requirements of the energy storage device compared to the actual amount of power directed to the energy storage device. For example, rod A of axle 810, 812, 814, and 816 is greater than rod C of axle 810, 812, 814, and 816. The actual amount of electrical energy generated at each axle is less than the electrical energy requirements of the energy storage device. For example, the energy storage device may receive more electrical energy than the energy storage device is actually receiving. The power system shown in FIG. 1 prioritizes the resistive grid before the energy storage device.

[0052] Alternatively, similar to graph 700, graph 900 illustrates that the power system illustrated in FIG. 4 prioritizes the energy storage device over the resistive grid and / or vehicle loads. For example, bar A of axles 910, 912, 914, and 916 is substantially the same as bar C of axles 910, 912, 914, and 916. The energy storage device receives substantially the same amount of electrical energy as the amount of electrical energy required by the energy storage device. Additionally, the amount of electrical energy directed to the resistive grid and / or vehicle loads varies as illustrated by bar B of axles 910, 912, 914, and 916. For example, a variable resistance component controls the amount of electrical energy directed to the energy storage device, as well as the amount of electrical energy directed to the resistive grid and / or vehicle loads, prioritizing the energy storage device over the resistive grid and / or vehicle loads.

[0053] In one or more embodiments, the vehicle system may include one or more axles, and each axle may be connected to an energy storage device. For example, a first axle may be connected to a first energy storage device, and a second axle may be connected to a second energy storage device. The first energy storage device may receive electrical power generated by dynamic braking of the first axle, and the second energy storage device may receive electrical power generated by dynamic braking of the second axle. Optionally, the vehicle system may include multiple axles, and each axle may be connected to a single energy storage device. For example, a single energy storage device may receive electrical energy from each of the multiple axles of the vehicle system.

[0054] FIG. 10 illustrates a schematic diagram of a power system 1000 according to an embodiment. Similar to the power system illustrated in FIG. 4, the power system 1000 may include a motor 1004 (e.g., a traction motor) and an inverter device 1010. The inverter device receives electrical energy from the motor, generated by dynamic braking of the vehicle system. The power system may further include an energy storage device 1012, a resistive grid and / or a vehicle load 1016, and an auxiliary inverter 1018 electrically coupled to the resistive grid and / or the vehicle load. The power system may include a variable resistance component 1020 disposed between the inverter device, the energy storage device, and the resistive grid and / or the vehicle load to control the conduction direction of electrical energy from the inverter device toward one or both of the energy storage device or the resistive grid and / or the auxiliary load. For example, a first portion 1052 of the electrical energy may be directed to the energy storage device and / or a second portion 1054 of the electrical energy may be directed to the resistive grid and / or the vehicle load (or may be directed to the vehicle load if the vehicle system is disconnected from the resistive grid).

[0055] The power system may further include a boost circuit 1022 disposed between the variable resistance component and the energy storage device. In one embodiment, the boost circuit may modify a voltage of a portion of the electrical energy directed to the energy storage device. For example, the portion of the electrical energy directed to the resistive grid and / or the vehicle load may have a first voltage or a first voltage level, and the portion of the electrical energy directed to the energy storage device may have a different second voltage or a second voltage level.

[0056] 11 shows an example flowchart 1100 of controlling conduction of electrical energy generated by dynamic braking of a vehicle system, according to one embodiment. In step 1102, electrical energy may be received and induced through a variable resistance component of the power system from a motor (e.g., a traction motor) via an inverter device. The electrical energy may be generated by dynamic braking of the vehicle system. In step 1104, the variable resistance component controls the direction of conduction of the electrical energy toward one or both of an energy storage device or a resistive grid and / or a vehicle load.

[0057] As an example, a controller of the vehicle system may determine that the variable resistance component operates in one mode of operation to direct all of the electrical energy to the energy storage device. In one embodiment, the controller may determine that the variable resistance component operates in another mode of operation to direct a first portion of the electrical energy to the energy storage device and a second portion of the electrical energy to the resistive grid and / or the vehicle load. In other embodiments, the amount of electrical energy directed to the energy storage device may be based at least in part on the total amount of electrical energy received from the motor via the inverter device. In one embodiment, the amount of electrical energy directed to the energy storage device may be based on the state of charge of the energy storage device. In one embodiment, the amount of electrical energy directed to the energy storage device may be based on a classification (e.g., type, make, model, age, etc.) of the energy storage device. In one embodiment, the amount of electrical energy directed to the energy storage device may be based on a transmission speed of the energy storage device. In one embodiment, the amount of electrical energy directed to the energy storage device may be based on other characteristics of the vehicle system, the energy storage device, the electrical energy requirements of one or more vehicle loads (e.g., propulsion and / or non-propulsion loads), etc.

[0058] In step 1106, the controller determines whether the amount of electrical energy received by the variable resistance component has changed. Additionally or alternatively, in step 1108, the controller determines whether the amount of electrical energy directed to the energy storage device needs to change. As an example, the amount of electrical energy directed to the energy storage device may need to change based on a current state of charge of the energy storage device, a total amount of electrical energy from the motor, electrical energy requirements of one or more vehicle loads, etc. If the amount of electrical energy from the motor has not changed and / or if the amount of electrical energy directed to the energy storage does not need to change, the method flow returns to step 1102.

[0059] Alternatively, if one or both of the total amounts of electrical energy received from the motor have changed or if the amount of electrical energy directed to the energy storage device needs to change, the method flow proceeds to step 1110. In step 1110, the controller changes the amount of the portion of electrical energy directed to the energy storage device by controlling the variable resistance component to change the operating mode, and changes the amount of the portion of electrical energy directed to the resistive grid and / or the vehicle load. For example, the amount of electrical energy directed to the resistive grid and / or the vehicle load may change in response to the amount of electrical energy directed to the energy storage device changing. The method flow may loop back towards step 1102 and continue to repeat while the vehicle system is operating.

[0060] In one or more embodiments of the subject matter described herein, a power system includes an inverter device coupled to a motor. The inverter device receives electrical energy from the motor generated by dynamic braking of the motor. An energy storage device is coupled to the inverter device, and a variable resistance component is disposed between the inverter device and the energy storage device. The variable resistance component controls a conduction direction of electrical energy from the inverter device toward one or more of the energy storage device, the resistive grid, or a system load. The variable resistance component controls the conduction direction of electrical energy from the inverter device based on one or more of a first amount of electrical energy conducted from the inverter device, a transmission rate of electrical energy conducted from the inverter device, or one or more characteristics of the energy storage device.

[0061] Optionally, the variable resistance component may direct a first portion of the electrical energy to an energy storage device and direct conduction of a second portion of the electrical energy to one or more of a resistive grid or a system load.

[0062] Optionally, the inverter device may receive a second varying amount of electrical energy from the motor based on a change in dynamic braking of the motor.

[0063] Optionally, the variable resistance component may direct a first portion of a varying amount of electrical energy to the energy storage device based on a state of charge of the energy storage device.

[0064] Optionally, the variable resistance component may direct a first portion of a varying amount of electrical energy to the energy storage device based on a classification of the energy storage device.

[0065] Optionally, the one or more characteristics of the energy storage device may include a total amount of electrical energy the energy storage device can receive or a transmission rate of the energy storage device.

[0066] Optionally, the total amount of electrical energy that the energy storage device can receive, or the rate at which the energy storage device can transmit, may be based on the state of charge of the energy storage device.

[0067] Optionally, the variable resistance component may change a direction of electrical energy conduction based on a first amount of electrical energy conducted from the inverter device that varies in response to changes in dynamic braking of the motor.

[0068] Optionally, the power system may include a boost circuit disposed between the variable resistance component and the energy storage device. The boost circuit may modify the voltage of the electrical energy directed to the energy storage device.

[0069] Optionally, an operator may control the operation of the variable resistance component to change one or more of the direction of conduction of electrical energy, the amount of electrical energy directed to the energy storage device, or the amount of electrical energy directed to one or more of the resistive grid or system loads.

[0070] Optionally, the system load may be one or more of an auxiliary load of the vehicle system or a propulsion load of the vehicle system.

[0071] In one or more embodiments of the subject matter described herein, a method includes receiving electrical energy generated by dynamic braking of a motor from an inverter device and controlling a direction of conduction of the electrical energy from the inverter device to one or more of an energy storage device, a resistive grid, or a system load, the direction of conduction of the electrical energy being based on one or more of a first amount of electrical energy conducted from the inverter device, a transmission rate of the electrical energy conducted from the inverter device, or one or more characteristics of the energy storage device.

[0072] Optionally, the method may include controlling a conduction direction of the electrical energy based on an operational mode of the variable resistance component, where a first amount of electrical energy is configured to be conducted toward the energy storage device in response to the variable resistance component operating in the first operational mode, and a second amount of electrical energy is configured to be conducted toward the energy storage device in response to the variable resistance component operating in the second operational mode.

[0073] Optionally, the method may include changing an operating mode of the variable resistance component based on one or more of a change in dynamic braking of the motor, a state of charge of the energy storage device, or a classification of the energy storage device.

[0074] In one or more embodiments of the subject matter described herein, a method includes receiving electrical energy generated by dynamic braking of a motor from an inverter device, determining a state of charge of an energy storage device, and operating a variable resistance component in a first operating mode or a second operating mode, where in the first operating mode, the variable resistance component directs a first amount of electrical energy from the inverter device to the energy storage device and in the second operating mode, the variable resistance component directs a second amount of electrical energy from the inverter device to the energy storage device.

[0075] Optionally, the first amount of electrical energy may be directed to a banking device configured to store the first amount of electrical energy for the energy storage device. The banking device may direct at least a portion of the direct amount of electrical energy to the energy storage device in response to a state of charge of the energy storage device reaching a predetermined threshold.

[0076] Optionally, operating the variable resistance component in the second operating mode includes directing at least a portion of the electrical energy to an energy storage device and directing at least a portion of the electrical energy to one or more of a resistive grid or a system load.

[0077] Optionally, the system load may be one or more of an auxiliary load of the vehicle system or a propulsion load of the vehicle system.

[0078] Optionally, the rate of transmission of electrical energy directed to the energy storage device may be controlled based on one or more of the transmission rate at which the energy storage device can receive electrical energy, the total capacity of the energy storage device, the state of charge of the energy storage device, or one or more characteristics of the energy storage device.

[0079] Optionally, operation of the variable resistance component may be changed from the first mode of operation to the second mode of operation in response to the state of charge of the energy storage device reaching a predetermined threshold.

[0080] As used herein, the terms "processor" and "computer" and related terms, such as "processing device", "computing device", and "controller", may refer to, but are not limited to, integrated circuits referred to in the art as computers, such as microcontrollers, microcomputers, programmable logic controllers (PLCs), field programmable gate arrays, and application specific integrated circuits, as well as other programmable circuits. Suitable memory may include, for example, computer readable media. The computer readable media may be, for example, computer readable non-volatile media, such as random access memory (RAM), flash memory, and the like. The term "non-transitory computer readable media" refers to tangible computer-based devices implemented for short-term and long-term storage of information, such as computer readable instructions, data structures, program modules and sub-modules, or other data within any device. Thus, the methods described herein may be encoded as executable instructions embodied in tangible non-transitory computer readable media, including, but not limited to, storage devices and / or memory devices. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein. The term therefore includes tangible computer-readable media, including but not limited to non-transitory computer storage devices, including but not limited to volatile and non-volatile media, as well as removable and non-removable media such as firmware, physical and virtual memory, CD-ROMs, DVDs, and other digital sources such as a network or the Internet.

[0081] The singular forms "a," "an," and "the" include plural references unless the context clearly indicates otherwise. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and the description may include cases where the event occurs and does not occur. Approximation language used herein throughout this specification and clauses may be applied to modify any quantitative expression that may be permissibly changed without resulting in a change in the basic function to which it may relate. Thus, values ​​modified by terms such as "about," "substantially," and "approximately" or terms may not be limited to the exact value specified. In at least some cases, approximation language may correspond to the precision of an instrument for measuring the value. Here, and throughout this specification and clauses, range limitations may be combined and / or interchanged, and such ranges may be identified and include all subranges contained therein unless the context or language dictates otherwise.

[0082] This written description uses examples to disclose embodiments, including the best mode, and to enable one of ordinary skill in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The clauses define the patentable scope of the disclosure, and include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the clauses, or if they include equivalent structural elements that differ substantially from the literal language of the claims.

Claims

1. 1. An electric power system comprising: an inverter device coupled to the motor, the inverter device configured to receive electrical energy from the motor generated by dynamic braking of the motor; an energy storage device coupled to the inverter device; a variable resistance component disposed between the inverter device and the energy storage device, the variable resistance component configured to control a direction of conduction of the electrical energy from the inverter device toward one or more of the energy storage device, a resistive grid, or a system load; The variable resistance component is a first amount of the electrical energy conducted from the inverter device; the rate of transmission of the electrical energy conducted from the inverter device; or configured to control the direction of conduction of the electrical energy from the inverter device based on one or more characteristics of the energy storage device; 1. A power system, wherein a transfer rate of electrical energy directed to the energy storage device is controlled based on one or more of: a transfer rate at which the energy storage device can receive electrical energy, a state of charge of the energy storage device, and one or more characteristics of the energy storage device.

2. 2. The power system of claim 1, wherein the variable resistance component is configured to direct conduction of a first portion of the electrical energy to the energy storage device and direct conduction of a second portion of the electrical energy to one or more of the resistive grid or the system load.

3. The power system of claim 2 , wherein the inverter device is configured to receive a second varying amount of the electrical energy from the motor based on a change in the dynamic braking of the motor.

4. 3. The power system of claim 2, wherein the variable resistance component is configured to direct a varying amount of the electrical energy of the first portion to the energy storage device based on a state of charge of the energy storage device.

5. 3. The power system of claim 2, wherein the variable resistance component is configured to direct a varying amount of the electrical energy of the first portion to the energy storage device based on a classification of the energy storage device.

6. The power system of claim 1 , wherein the one or more characteristics of the energy storage device include a total amount of electrical energy the energy storage device can receive or a transmission speed of the energy storage device.

7. 7. The power system of claim 6, wherein one or more of the total amount of electrical energy that the energy storage device can receive or the transfer rate of the energy storage device is based on a state of charge of the energy storage device.

8. 2. The power system of claim 1, wherein the variable resistance component is configured to vary the direction of conduction of the electrical energy based on the first amount of the electrical energy conducted from the inverter device, which varies in response to changes in the dynamic braking of the motor.

9. 10. The power system of claim 1, further comprising a boost circuit disposed between the variable resistance component and the energy storage device, the boost circuit configured to vary a voltage of the electrical energy directed to the energy storage device.

10. 2. The power system of claim 1, wherein an operator is configured to control operation of the variable resistance component to vary one or more of the direction of conduction of the electrical energy, an amount of electrical energy directed to the energy storage device, or an amount of electrical energy directed to one or more of the resistive grid or the system load.

11. The power system of claim 1 , wherein the system load is one or more of an auxiliary load of a vehicle system or a propulsion load of the vehicle system.

12. 1. A method comprising: receiving electrical energy generated by dynamic braking of the motor from an inverter device; and controlling a direction of conduction of the electrical energy from the inverter device toward one or more of an energy storage device, a resistive grid, or a system load, the direction of conduction of the electrical energy being based on one or more of a first amount of the electrical energy conducted from the inverter device, a transmission rate of the electrical energy conducted from the inverter device, or one or more characteristics of the energy storage device, The method comprises: The method further includes controlling a transfer rate of the electrical energy directed to the energy storage device based on one or more of: a transfer rate at which the energy storage device can receive the electrical energy, a state of charge of the energy storage device, and one or more characteristics of the energy storage device.

13. 13. The method of claim 12, further comprising controlling the conduction direction of the electrical energy based on an operational mode of a variable resistance component, wherein a first amount of electrical energy is configured to be conducted toward the energy storage device in response to the variable resistance component operating in a first operational mode, and a second amount of electrical energy is configured to be conducted toward the energy storage device in response to the variable resistance component operating in a second operational mode.

14. 14. The method of claim 13, further comprising changing the operating mode of the variable resistance component based on one or more of a change in the dynamic braking of the motor, a state of charge of the energy storage device, or a classification of the energy storage device.

15. 1. A method comprising: receiving electrical energy generated by dynamic braking of the motor from an inverter device; Determining a state of charge of an energy storage device; operating a variable resistance component in a first mode of operation or a second mode of operation based on the state of charge of the energy storage device; 1. A method of charging an energy storage device, comprising: in the first mode of operation, the variable resistance component directs a first amount of electrical energy to the energy storage device; and in the second mode of operation, the variable resistance component directs a second amount of electrical energy to the energy storage device; The method comprises: controlling a transfer rate of the electrical energy directed to the energy storage device based on one or more of: a transfer rate at which the energy storage device can receive the electrical energy, the state of charge of the energy storage device, and one or more characteristics of the energy storage device.

16. 16. The method of claim 15, further comprising directing the first amount of electrical energy to a banking device, the banking device configured to store the first amount of electrical energy for the energy storage device, and the banking device configured to direct at least a portion of the first amount of electrical energy to the energy storage device in response to the state of charge of the energy storage device reaching a predetermined threshold.

17. 16. The method of claim 15, wherein operating the variable resistance component in the second mode of operation includes directing at least a portion of the electrical energy to the energy storage device and directing at least a portion of the electrical energy to one or more of a resistive grid or a system load.

18. The method of claim 17 , wherein the system load is one or more of an auxiliary load of a vehicle system or a propulsion load of the vehicle system.

19. 16. The method of claim 15, further comprising: changing operation of the variable resistance component from the first mode of operation to the second mode of operation in response to the state of charge of the energy storage device reaching a predetermined threshold.

Images