WO2016053786A1

WO2016053786A1 - Multi-mode hybrid control for range-extended plug-in vehicles

Info

Publication number: WO2016053786A1
Application number: PCT/US2015/052232
Authority: WO
Inventors: Paul L. Paterson
Original assignee: Ballard Power Systems Inc; Siemens VDO Electric Drives Inc; Ballard Material Products Inc
Current assignee: Ballard Power Systems Inc; Siemens VDO Electric Drives Inc; Avcarb Material Solutions Inc
Priority date: 2014-10-01
Filing date: 2015-09-25
Publication date: 2016-04-07
Anticipated expiration: 2017-04-01

Abstract

Multi-mode control systems and methods for range-extended plug-in electric vehicles. The plug-in electric vehicle principally utilizes a battery as an energy source and employs a secondary power source, such as a fuel cell subsystem, as a battery charger to extend the range of the vehicle. A control subsystem operates the secondary power source to minimize fuel consumption near an end of a trip. In some operating modes, the secondary power source operates at full rated power to reduce the required run time of the secondary power source, thereby increasing its lifetime. The secondary power source may also operate more efficiently at full rated power as compared to operating in a part power or load-following mode.

Description

MULTI-MODE HYBRID CONTROL FOR RANGE-EXTENDED

PLUG-IN VEHICLES

BACKGROUND Technical Field

The present disclosure relates to power management for range- extended plug-in electric vehicles.

Description of the Related Art

P!ug-ίη hybrid electric vehicles (PHEV) are an extension of existing hybrid electric vehicle (HEV) technology, in which a primary battery pack is supplemented with a secondary power source (e.g. , an internal combustion engine, a fuel ceil system) to gain increased mileage and reduced vehicle emissions. A PHEV adds the capability of recharging the battery pack from a standard electrical outlet or other external power source. Because the battery pack has a large capacity, the PHEV can be operated primarily by electric propulsion for a substantial distance, for example, a battery operation range of 10-40 miles, after a full battery recharge. The secondary power source is only started to assist vehicle propulsion in limited circumstances such as high speed and/or high power demand operations due to system constraints. After the usable battery electricity is depleted, the secondary power source takes over the primary role in vehicle propulsion by consuming fuel energy {e.g., gasoline, diesel, hydrogen). By relying on electrical energy from the grid to charge the battery and then using that energy for a significant fraction of vehicle travel, the amount of fuel consumed by the PHEV is greatly reduced, especially when the traveling distance is close to the battery operation range.

While conventional HEVs are operated to maintain the battery state of charge (SOC) at a nearly constant level, a PHEV generally uses as much pre-saved battery electric ("grid") energy as possible before the next battery charge event due to the relatively lower cost of grid-supplied electric energy. After the battery's SOC decreases to a desired charge-sustaining level or a lowest conservative level, the PHEV resumes operation as a conventional HEV, in order to ensure that the grid-supplied electric energy is expended, the base PHEV control mode largely uses up the electric energy first and the secondary power source takes over the leading role in vehicle propulsion only when the battery is substantially discharged.

Figure 1 shows a plot 10 of a state of charge 12 for a battery of a PHEV in the aforementioned two operation modes, namely a discharging mode (DM) and a charge-sustaining mode (CSfvl). In the example shown, a mostly charged PHEV is driven in the discharging mode for the first part of the trip, where the battery's SOC exhibits a net decrease between points 14 and 16. Due to the lower cost of electricity compared to fuel, the available battery electric energy is used for vehicle usage function before the next PHEV plug-in recharge event to largely displace fuel consumption. Since knowledge of the occurrence of the next battery recharge event is usually unknown, by default, the PHEV operation starts in the discharging mode to maximize the likelihood of battery depletion before the end of the trip.

During the discharging mode, the battery's electric energy is used primarily to propel the vehicle, thereby maximally or near maximally depleting the electric energy stored in the battery. In the discharging mode, the secondary power source is kept in an off state or at a very low power level. By primarily utilizing the battery energy to propel the vehicie early in the trip, the PHEV fuel consumption is minimized when the trip distance is close to the battery operation range. Once the battery's SOC decreases to a predetermined sustaining level (e.g., 20% SOC), the vehicle switches to the charge-sustaining mode at point 16, where the battery's SOC is kept within a certain range close to the desired sustaining SOC level. In the charge-sustaining mode, the vehicle is mainly powered by the secondary power source {i.e., fuel energy). At point 18, the trip has ended and the vehicle is proximate an external power source, such as an electrical outlet. The battery may then be recharged to the fully charged condition via the external power source. BRIEF SUMMARY

A hybrid vehicle may be summarized as including; an electric machine coupled to provide propulsion power for the hybrid vehicle; an energy storage subsystem electrically coupled to the electric machine to provide at least one of; a source of electrical energy to the electrical machine, and a sink of electrical energ from the electrical machine; a fuel cell subsystem

electrically coupled to the energy storage subsystem to charge the energy storage subsystem; and a control subsystem electrically coupled to the electric machine, the energy storage subsystem, and the fuel cell subsystem, the control subsystem receives next charging opportunity information, the next charging opportunity information at least partially indicative of an anticipated next opportunity to charge the energy storage subsystem via a power source other than the fuel cell subsystem, the control system monitors a state of charge of the energy storage subsystem and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem according to a normal control mode or an approaching next charging opportunity control mode based at least on part on the received next charging opportunity information, wherein in the normal control mode the control subsystem repeatedly; permits depletion of the energy storage subsystem to a first state of charge; and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge; and in the approaching next charging opportunity control mode the control subsystem: permits depletion of the energy storage subsystem to a third state of charge, the third state of charge lower than the second state of charge: and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem proximate the third state of charge.

The next charging opportunity information may include at least one of: an anticipated distance until a next opportunity to charge the energy storage subsystem via a power source other than the fuel cell subsystem: an anticipated time of operation until a next opportunity to charge the energy storage subsystem via a power source other than the fuel ceil subsystem; and an anticipated energy output requirement for the energy storage subsystem untii a next opportunity to charge the energy storage subsystem via a power source other than the fuel ceil subsystem. The anticipated energy output requirement may be based at least in part on at least one of route information, terrain information, speed limit information, traffic information, temperature information, and vehicle ioad information. The next charging opportunity information may be based at least in part on an input to the control subsystem via a human-machine interface. The next charging opportunity information may be based at least in part on data coliected by the coniroi subsystem concerning a driving pattern of the hybrid vehicle or a driving pattern of a driver of the hybrid vehicle. The hybrid vehicle may further include: a giobai positioning system (GPS) navigation system coupled to the controi subsystem, wherein the next charging opportunity information is based at least in part on signals from the GPS navigation subsystem. The energy storage subsystem may include at least one of an electrochemical battery cell and an ultra-capacitor cell, the hybrid vehicle further comprising: a charger interface coupled to the hybrid vehicle and to an external power source to charge the energy storage subsystem. The first state of charge may be less than 25% of ful! charge for the energy storage subsystem and the second state of charge may be greater than 70% of full charge for the energy storage subsystem. The first state of charge and the third state of charge may be approximately equal to each other. The fuel cell subsystem may include a plurality of fuel ceils electrically coupied in series to form a fuel cell stack.

A system to control the operation of a hybrid machine may be summarized as including an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a fuel cell subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, the system comprising: a processor operatively coupled to the electric machine, the energy storage subsystem, and the fuel celi subsystem, the processor: receives next charging opportunity information, the next charging opportunity information at least partially indicative of an anticipated next opportunity to charge the energy storage subsystem via a power source other than the fuel ceii subsystem; monitors a state of charge of the energy storage subsystem; and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem according to a normal control mode or an approaching next charging opportunity control mode based at least on part on the received next charging opportunity information, wherein: in the normal control mode the processor permits depletion of the energy storage subsystem to a fi rst state of charge, and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge; and in the approaching next charging opportunity control mode the processor permits depletion of the energy storage subsystem to a third state of charge, the third state of charge lower than the second state of charge, and causes the fuel ceil subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem proximate the third state of charge.

The next charging opportunity information may be based at least in part on an input via a human-machine interface. The hybrid machine may include a hybrid vehicle, and the next charging opportunity information may be based at least in part on data collected concerning a driving pattern of the hybrid vehicle or a driving pattern of a driver of the hybrid vehicle. The processor may receive the next charging opportunity information from a global positioning system (GPS) navigation subsystem. The energy storage subsystem may include at least one of an electrochemical battery cell and an ultra-capacitor cell. The first state of charge may be less than 25% of the fully charged state of charge for the energy storage subsystem and the second state of charge may be greater than 70% of the fully charged state of charge for the energy storage subsystem. The first state of charge and the third state of charge may be approximately equal to each other. The fuel cell subsystem may include a plurality of^' fuel cells electrically coupied in series to form a fuei ceil stack.

A method to control a hybrid machine having an electric machine, an energy storage subsystem eiectrscaSly coupled to the eleciric machine, and a secondary electrical power delivery subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, may be summarized as including: receiving charging opportunity information in a processor-readable medium, the next charging opportunity information at least partially indicative of an anticipated next opportunity to charge the energy storage subsystem via a power source other than the secondary electrical power delivery subsystem; monitoring a state of charge for the energy storage subsystem; autonomously causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem according to a normal control mode or an approaching next charging opportunity control mode based at least on part on the received next charging opportunity information, wherein the normal control mode comprises: permitting depletion of the energy storage subsystem to a first state of charge; and causing the secondary electrical power delivery subsystem to operate at full rated power to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge: and the approaching next charging opportunity control mode comprises: causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at or below a third state of charge.

Causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at or below a third state of charge may include repeatedly: permitting depletion of the energy storage subsystem to fourth state of charge, the fourth state of charge lower than the third state of charge; and causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the fourth state of charge to the third state of charge. Causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at or below a third state of charge may include causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at a charge-sustaining state of charge, the charge-sustaining charge at or below the third state of charge. Receiving next charging opportunity information may include receiving an input via a human-machine interface. The hybrid machine may include a hybrid vehicle, and receiving next charging opportunity information may include receiving data concerning a driving pattern of the hybrid vehicle or a driving pattern of a driver of the hybrid vehicle. Receiving next charging opportunity information may include receiving signals from a global positioning system (GPS) navigation system. Causing the secondary electrical power delivery subsystem to operate at full rated power to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to the second state of charge higher than the first state of charge may include causing the secondary electrical power delivery subsystem to charge the energy storage subsystem from a state of charge less than 25% of the fully charged state of charge for the energy storage subsystem to a state of charge greater than 70% of the fully charged state of charge for the energy storage subsystem. Permitting depletion of the energy storage subsystem to a first state of charge may include permitting depletion of the energy storage subsystem to the charge-sustaining state of charge.

A method to control a hybrid vehicle during a trip, the hybrid vehicle having an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a secondary electrical power delivery subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, may be summarized as including: detecting a state of charge for the energy storage subsystem; operating the secondary electrical power delivery subsystem at fuii rated power to charge the energy storage subsystem from a first state of charge to a second state of charge higher than the first state of charge when the state of charge for the energy storage subsystem is detected to be at or below the first state of charge; receiving an indication at feast partially indicative of an anticipated upcoming end of the trip; permitting depletion of the energ storage subsystem to the first state of charge: and operating the secondary eiectricai power delivery subsystem to provide eiectricai energy to the energy storage subsystem to maintain the energy storage subsystem at a charge-sustaining state of charge.

Operating the secondary eiectricai power delivery subsystem to provide eiectricai energy to the energy storage subsystem to maintain the energy storage subsystem at a charge-sustaining state of charge may include operating the secondary eiectricai power delivery subsystem to provide eiectricai energy to the energy storage subsystem to maintain the energy storage subsystem at a state of charge that is less than 50% of the state of charge of the energy storage subsystem when fuiiy charged.

A method to control a hybrid machine, the hybrid machine having an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a secondary eiectricai power delivery subsystem eiectricaliy coupled to the energy storage subsystem to charge the energy storage subsystem, may be summarized as including: for a duration time when the hybrid machine is eiectricaliy decoupled from an externa! power source: detecting a state of charge for the energy storage subsystem; repetitively permitting depletion of the energy storage subsystem to a first state of charge; and repetitively causing the secondary eiectricai power deiivery subsystem to operate at full rated power to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge when the state of charge for the energy storage subsystem is detected to be at or beiow the first state of charge, the second state of charge less than 50% of the state of charge of the energy storage subsystem when fully charged. Repetitiveiy causing trie secondary electrical power delivery subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge may include causing the secondary electrical power delivery subsystem to charge the energy storage subsystem from a state of charge less than 25% of the state of charge of the energy storage subsystem when fully charged to a state of charge less than 30% of the state of charge of the energy storage subsystem when fully charged.

A system to control the operation of a hybrid machine, the hybrid machine comprising an electric machine, an energy storage subsystem eiectricatiy coupled to the electric machine, and a secondary electrical power delivery subsystem electricaiiy coupled to the energy storage subsystem to charge the energy storage subsystem, may be summarized as including: a processor operative!y coupled to the electric machine, the energy storage subsystem, and the fuel cell subsystem, wherein for a duration time when the hybrid machine is electrically decoupled from an external power source, the processor: detects a state of charge for the energy storage subsystem;

repetitively permits depletion of the energy storage subsystem to a first state of charge; and repetitively causes the secondary electrical power delivery subsystem to operate at full rated power to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge when the state of charge for the energy storage subsystem is detected to be at or below the first state of charge, the second state of charge less than 50% of the state of charge of the energy storage subsystem when fully charged.

The first state of charge may be less than 25% of the state of charge of the energy storage subsystem when fully charged, and the second state of charge may be less than 30% of the state of charge of the energy storage subsystem when fully charged. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings.

Figure 1 is an example plot of a battery state of charge (SOC) versus trip distance for a conventional control strategy for a plug-in hybrid electric vehicle to complete a trip that is longer than the operation range for a battery of the vehicle.

Figure 2 is a schematic diagram illustrating a hybrid piug-in electric vehicle, according to at least one illustrated embodiment.

Figure 3 is a flow diagram depicting a power management process for a range-extended plug-in electric vehicle, according to at least one illustrated embodiment.

Figure 4 is a plot of a battery SOC versus trip distance for a control strategy for a plug-in hybrid electric vehicle to complete a trip that is longer than the operation range for a battery of the vehicle, according to at least one illustrated embodiment.

Figure 5 is a plot of a power level for a secondary power source versus trip distance for the control strategy of Figure 4, according to at least one illustrated embodiment.

Figure 6 is a plot of a battery SOC versus trip distance for a control strategy for a plug-in hybrid electric vehicle to complete a trip that is longer than the operation range for a battery of the vehicle, according to at least one illustrated embodiment. Figure 7 is a plot of a power level for a secondary power source versus trip distance for the control strategy of Figure 6, according to at ieast one illustrated embodiment.

Figure 8 is a plot of a battery SOC versus trip distance for a control strategy for a plug-in hybrid electric vehicle to complete a tri that is longer than the operation range for a battery of the veliide, according to at feast one illustrated embodiment.

Figure 9 is a plot of a power level for a secondary power source versus trip distance for the control strateg of Figure 8, according to at least one illustrated embodiment.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. in other instances, weii-known structures associated with power or control systems for electric vehicles have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments.

Unless the context requires otherwise, throughout the specification and claims that follow, the word "comprise" and variations thereof, such as, "comprises" and "comprising" are to be construed in an open, indusive sense, that is as "including, but not limited to."

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at Ieast one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily aii referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitabie manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms ¾^* "an," and "the" include plural referents unless the content cleariy dictates otherwise, it should also be noted that the term ^aor" is generally employed in is broadest sense, that is, as meaning "and/or" unless the content clearly dictates otherwise.

The headings and Abstract of the Disclosure provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.

Embodiments of the present disclosure are directed to multi-mode control or power management systems and methods for range-extended plug-in electric vehicles and other electrical machines. The plug-in electric vehicles principally utilize a primary energy storage subsystem (e.g., one or more electrochemical battery ceils and/or super- or ultra-capacitor cells) as a rechargeable energy source and empioy a secondary power source, such as a fuel cell subsystem or an internal combustion engine, as a source of energy to charge the primary energy storage subsystem to extend the range of the vehicle. In some operating modes, the secondary power source operates at full rated power to reduce the required run-time of the secondary power source, thereby increasing the lifetime of the secondary power source. The secondary power source may also operate more efficiently at full rated power as compared to operating in a part power or load-following mode.

Figure 2 shows a range extended plug-in hybrid electrical machine or vehicle 200, according to one or more embodiments. The vehicle 200 may include a ground-based vehicle (e.g., car, bus), an aircraft, an aquatic vehicle, or can even take non-vehicle forms. For example, the vehicle or machine 200 may be implemented as a backup power system for various power applications, such as cell phone base stations power applications, building power applications, etc. in the discussion below, examples may be provided in the context of ground-based vehicles for the purpose of explanation. The vehicle 200 includes art energy storage subsystem 202 and at least one electrical machine such as a motor-generator 204 that converts the stored energy into motion, such as rotary motion. The energy storage subsystem 202 ma comprise one or more electrochemical battery ceils {/^'.e._; batteries). For example, the energy storage subsystem 202 may include one or more lithium ion eels coupled in parallel and/or coupied in series. In some embodiments, the energy storage subsystem 202 is capable of delivering a peak power of approximately 150-250 kW, delivering an operational power of approximately 130-180 kW. and providing a DC bus output voltage of 500 - 750. The energy storage subsystem 202 may be capable of delivering more or less power and may be capable of operating at higher or lower output voltages as suits the particular application, in some embodiments, the energy storage subsystem 202 may utilize one or more lithium ion nano-iron-phosphate ceils, for example.

The vehicle 200 may also include an electrical power converter

206 to convert energy from the energy storage subsystem 202 into energy usable by the motor-generator 204. In some embodiments, the motor- generator 204 may generate energy that is transmitted to the power converter 206, which converts the energy into a form that may be stored by the energy storage subsystem 202. Thus, in addition to converting energy into motion, the motor-generator 204 can aiso capture energy from regenerative processes, such as braking.

The power converter 206 may include one or more transistors, such as metal-oxide semiconductor field effect transistors ( OSFETs), insulated gate bipolar transistors (IGBTs), etc. In some embodiments, the power converter 206 may include a switch bank or bridge that receives direct current (DC) from the energy storage subsystem 202 and outputs alternating current (AC) to the motor-generator 204 (e.g., alternator). For example, the alternating current may be three-phase alternating current, in some

embodiments, such as during a regenerative braking process, the power converter 206 converts {e.g., rectifies) an alternating current signal into direct current power to be stored in the energy storage subsystem 202. The power converter 206 may also convert energy from the energy storage subsystem 202 into energy usable by electrical loads other than the motor-generator 204, such as lights, power windows, power seats, windshield wipers, etc. For example, the power converter 206 may step a voltage up or down {e.g., a switch-mode DC-DC converter). The motor-generator 204 may, for example, be a three- phase alternating current motor-generator. The motor-generator 204 may include a plurality of electrical motors.

The motor-generator 204 may be coupled to wheels 208 of the vehide 200 via an optional drive unit 210 (e.g., transmission, gearset, transaxle, etc.). in some implementations, rotary motion may be transferred from the drive unit 2 0 to the wheels 208 via one or more axles (not shown).

The vehicle 200 also includes a secondary power source, which is illustrated as a fuel ceil subsystem 212, electrically coupled to the energy storage subsystem 202 to provide energy thereto to charge the energy storage subsystem 202. The fuel cell subsystem 212 may be a polymer electrolyte membrane (PEM) fuel cell system, a solid oxide fuel eel! system, a molten carbonate fuel cell system, or any other type of fuel ceil system. The fuel cell subsystem 212 can include a plurality of individual fuel cells arranged in any configuration known to those of skill in the art. For example, the fuel cell subsysiem 212 may include one or more fuel cell stacks 214, one or more fuel cell columns, etc. The fuel cell subsystem 212 may include a fuel storage 2 6 that stores a consumable and replenishable fuel, such as liquid or gaseous hydrogen. The fuel cell subsystem 212 may also include one or more power converters (not shown). A non-limiting example of a suitable fuel cell subsystem 212 is the FCvelocity-HD6 fuel cell module offered by Ballard Power Systems, Inc. of Bu naby, British Columbia, Canada.

The secondary power source may be a power source other than a fuel cell subsystem 212. Generally, the secondary power source may also be any fuel-burning engine that consumes or bums any of a variety of fuels, such as fossil fuels, synthetic fuels, and bio fuels. In some implementations, a power converter (e.g., a DC/DC converter, an AC/DC converter, etc.) may be coupled between the secondary power source and the energy storage subsystem 202 so that energy from the secondary power source may be provided to the energy storage subsystem in a form suitable for storage by the energy storage subsystem.

The vehicle 200 also includes a control subsystem 218 operatively coupled to the energy storage subsystem 202, the fuel cell subsystem 212, the motor-generator 204, and the transmission 210. As discussed in further detail below, the control subsystem 218 may also be coupled to a human-machine interface 220, a global positioning system (GPS) navigation system 222, and a wired and/or wireless communications interface 224.

The control subsystem 218 may include one or more computing devices, such as one or more processors, microcontrollers, microprocessors, digital signal processors (DSPs), graphical processing units (GPUs), or application specific integrated circuits (ASICs), and associated software or hardware constructs, and/or one or more processor-readable media to carry out certain functions and methods. The computing devices may be embodied in a single centra! processing unit, or may be distributed such that a subsystem or function has its own dedicated processor. Moreover, some embodiments of subsystems may be provided as a computer program product including

nontransitory processor-readable medium having stored thereon instructions that may be used to program a computer (or other electronic device) to perform processes or methods described herein. The nontransitory processor-readable medium may include, but is not limited to, hard drives, floppy diskettes, optical disks, CD-ROMs, DVDs, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPRO s, flash memory, magnetic or optical cards, solid-state memory devices, or other types of machine-readable media suitable for storing electronic instructions.

The control subsystem 218 is operative to control the operation of the fuel ceil subsystem 212 which in turn controls the amount of energy provided to charge the energy storage subsystem 202. For example, the control subsystem 218 may command or cause the fuel cell subsystem 212 to be in an OFF mode wherei substantially no power is delivered to the energy storage subsystem 202, in a fully ON mode wherein full or near full rated power (e,g., 75 kW, 150 kW, etc.) is delivered to the energy storage subsystem, or a "part power'' or "load following mode wherein a power level less than full rated power is delivered to the energy storage subsystem. Specific examples of control methods are discussed below with reference to Figures 4-9.

The control subsystem 218 is also operative to detect or monitor the state of charge (SOC) of the energy storage subsystem 202. The control subsystem 218 may detect coulombs, watt-hours, or other measure indicative of how much energy is in the energy storage subsystem 202. In some embodiments, the energy storage subsystem 202 includes components or circuitry that provides the SOC information to the control subsystem 218.

The vehicle 200 also includes an external power interface 226 that facilitates selective coupling with an external power source 228. For example, the external power source 228 may be a charging station coupled to a municipal or other power grid. The external power source 228 may be positioned in any location, such as near a highway, in a parking lot, in a garage, at a fueling station, etc. in some embodiments, the external power source 228 may convert alternating current power into power storable by the energy storage subsystem 202. In some embodiments, the externa! power interface 226 may provide suitable energy conversion circuitry to convert power from the external power source 228 into a form storable by the energy storage subsystem 202. Such energy conversion circuitry may be integrated within the vehicle 200, or may be separate therefrom.

As noted above, the vehicle 200 may include a human-machine interface (H I) 220 coupled to the control subsystem 218. The H1V11 220 may receive input regarding operational preferences or trip information (e.g., distance or time until the end of a trip or until the vehicle 200 reaches a charging station), as well as other types of input. The HMI 220 may include one or more buttons, keys, touch screens, voice capturing devices, image-capturing devices, or any other type of device capable of capturing input from a user, directly or indirectly. The HSvll 220 may also inciude one or more output devices such as displays, illumination sources, speakers, etc.

The vehicle 200 may also include the GPS navigation system 222 coupled to the control subsystem 218. The GPS navigation system 222 receives GPS signals to determine the location of the vehicle 200, and provides positioning data to the control subsystem 218. The positioning data may indicate the location of the vehicle 200, the location of a trip destination (e.g., home, work, etc.), the location of an external power source 228, or other positioning information.

The vehicle 200 may also include the wired and/or wireless communications interface 224 coupled to the control subsystem 218. The communications interface 224 may allow the control subsystem 218 to communicate with one or more external devices. For example, the

communications interface 224 may facilitate communication between the control subsystem 218 and a computing device of a user, such as a smart phone. As another example, the communications interface 224 may facilitate communication between the control subsystem 218 and a remote server over a network (e.g., the Internet).

Utilizing the HM\ 220, the GPS system 222, the communications interface 224, an electronic odometer, and/or wireless information from fleet operations, the control subsystem 218 may be able identify or predict when the vehicle 200 will arrive at an external power source 228. Such information may be provided directly by the user or may be derived from various data, such as previous driving patterns, user inputs, user profiles, GPS data, map data, odometer data, fleet operations data, third-party data, etc. As discussed below, the control subsystem 218 utilizes the identified distance or time to the next charging station information to control the operation of the fuel cell subsystem 212 to charge the energy storage subsystem 202. Generally, the control subsystem 218 may command or cause the fuel cell subsystem 212 to selectively operate at full rated power to reduce the required run-time of the fuel cell subsystem, thereby allowing the fuel cell subsystem to operate more efficiently while simultaneously increasing its lifetime, Moreover, utilizing the determined or identified distance or time until the next charging station,, the control subsystem 218 controls the fuel cell subsystem 2 to allow the vehicle 200 to use as much energy from the energy storage subsystem 202 as possible before the next charging event so that use of the fuel cell subsystem is minimized. This is advantageous because of the relatively lower cost of grid- supplied electric energy compared to fuel costs. Thus, since the occurrence of the next recharge event is known in the embodiments disclosed herein, the control subsystem 218 is able to maximize the likelihood of depletion of the energy storage subsystem 202 before the end of the trip, thereby achieving significant fuel savings.

Figure 3 is a flow diagram of a method 300 of operation for controlling the power delivered by the fuel cell subsystem 212 to the energy storage subsystem 202 of the vehicle 200. The method 300 starts at 302 when a user starts the vehicle 200 and begins a trip, for example, after the energy storage subsystem 202 has been fully charged at the external power source 228.

At 304, the control subsystem 218 detects or monitors the state of charge for the energy storage subsystem 202. The hardware utilized to implement detection and monitoring of the state of charge may be associated with the control subsystem 218, with the energy storage subsystem 202, or with an independent state of charge monitoring subsystem.

At 306, the control subsystem 21 S commands or causes the fuel cell subsystem 212 to charge the energy storage subsystem 202 according to a norma! trip operational mode control strategy. Examples of control strategies for the normal trip operational mode are discussed below with reference to Figures 4-9.

At 308, the control subsystem 218 receives distance to next charge information or other anticipated next charging opportunity information (e,g., anticipated time until the next charging opportunity, anticipated energy output requirements untiS the next charging opportunity). The control subsystem 218 may receive the anticipated next charging opportunity informatio at any time. For example, in some impiementatfons, the anticipated next charging opportunity information may be received prior to the beginning of operation, or the information may be received while the energy storage subsystem 202 is operated according to a normal trip operational mode control strategy. In implementations where the next charging opportunity information includes anticipated energy requirements until the next charging opportunity, the control subsystem 218 may utilize any suitable data that may impact anticipated energy requirements, such as route information, terrain, speed limits, traffic, temperature, vehicle load, etc. The control subsystem 218 may utilize a combination of information, such as the energy requirement for the energy storage subsystem 202 until the next charging opportunity and the time until the next charging opportunity. The control subsystem 218 may store the received distance to next charge information in a processor-readable medium. The distance to next charge information provides an indication of the distance until the vehicle 200 next reaches a charging station.

For example, a user may input a destination address into the GPS navigation system 222 of the vehicle 200. The destination address and location information from the GPS navigation system 222 may be used by the control subsystem 218 to identify the distance to next charge information. As another example, the user may input into the HMl 220 that he or she plans to stop at a charging station that is 20 miles away. As another example, the control subsystem 218 may predict the route of the vehicle 200 based at least in part on previous driving patterns for the vehicle or the driver of the vehicle. For instance, the control subsystem 218 may recognize that the vehicle 200 is traveling to the user's place of work by recognizing a particular route, day, and time normally traveled by the user.

At 310, the control subsystem 218 determines that the distance to the next charging event is near (e.g., the vehicle 200 is approaching a charging station, a battery swapping station, etc.). For example, utilizing trie distance to next charge information and optionally other data (e.g., GPS data, odometer data, velocity data, elapsed time data), the control subsystem 218 determines that the vehicle 200 will arrive at a charging station within a certai distance (e.g., 0-20 miles, etc.). This determination may be made at any time, including before a trip has begun or while the trip is in progress. For example, prior to the beginning of a trip, the control subsystem 218 may detect that the vehicle will follow a predicabie route (e.g., a daily commute) during the trip, and the control subsystem may use this information prior to the beginning of the trip to determine when the next charging opportunity is expected.

In response to determining the end of a trip is near, the control subsystem 218 commands or causes the fuel cell subsystem 212 to charge the energy storage subsystem 202 according to an end-of-trip operational mode or approaching next charging opportunity operational mode at 312. Generally, the control subsystem 218 may control the fuel ceil subsystem 212 in a way that the energy storage subsystem 202 is substantially depleted when the vehicle 200 arrives at the charging station to minimize fuel expended by the fuel cell subsystem. More specifically, the control subsystem 218 may minimize or terminate operation of the fuel cell subsystem 212 to utilize the energy that remains in the energy storage subsystem 202 to propel the electric vehicle 200 to the charging destination. Examples of control strategies for the end-of-trip operational mode are discussed below with reference to Figures 4-9.

The method 300 ends at 314. For example, the method may end when the vehicle 200 arrives at a charging station and the energy storage subsystem 202 is charged via the external power source 228. The method 300 may begin again once the vehicle 200 begins a new trip {e.g., departs from a charging station).

Figures 4 and 5 illustrate two control modes for the control subsystem 218, according to one embodiment. Specifically, Figure 4 shows a state of charge (SOC) 400 for the energy storage subsystem 202 of Figure 2 during a trip that spans between a beginning point 402 and an end point 404. Figure 5 shows an output power level 500 of a secondary power source, such as the feel celi subsystem 212, during the trip. Figures 4 and 5 show the SOC 400 and the output power level 500, respectively, during a norma! operational mode ( M) and an end-of-trip operational mode (ΒΟΎΜ).

in the normal operational mode, the control subsystem 218 permits the SOC 400 of the energy storage subsystem 202 to be depleted to a specified first state of charge at point 406. The control subsystem 21 S then commands or causes the fuel ceil subsystem 212 to operate at fuil rated power or substantially full rated power to charge the energy storage subsystem 202 to a higher second state of charge, achieved at point 408. As an example, the first state of charge may be approximately 20% of the state of charge of the energy control subsystem 218 when fully charged (i.e., 100% SOC, or "full charge"), and the second SOC may be approximately 80% SOC. These percentages are provided as examples, although other percentages or ranges of percentages are contemplated. In some embodiments, the second state of charge is less than 100% SOC to allow for charging the energy storage subsystem 202 through regenerative processes, as discussed above.

Once the fuel ceil subsystem 212 has charged the energy storage subsystem 202 to the second state of charge at point 408, the control subsystem 218 may shut off or disengage the fuel celi subsystem 212 to permit the SOC 400 of the energy storage subsystem 202 to again be depleted to the first state of charge at point 410. This cycle may continue while the control subsystem 218 operates in the normal operational mode during the trip.

As discussed above, the control subsystem 218 receives next charging opportunity information, which is at least partially indicative of an anticipated {e.g. , predicted, estimated, expected, identified) next opportunity to charge the vehicle 200. When the control subsystem 218 determines the vehicle 200 has reached a specified distance Di to the next charging station, the control subsystem 218 transitions into the end-of-trip operational mode at point 412. In the end-of-trip operationai mode, the control subsystem 218 permits the SOC 400 of the energy storage subsystem 202 to be depleted to a third state of charge at point 414. in some embodiments, the third state of charge may be the same as the first state of charge (e.g. , 20 SOC), Once the energy storage subsystem 202 has reached the third state of charge, the control subsystem 218 engages the fuei ceil subsystem 212 at part power or in a load-following mode to maintai a relatively constant state of charge of the energy storage subsystem. This mode may be referred to as a charge-neutral or a charge-sustaining mode.

The control subsystem 2 8 continues to operate in the end-of-trip operational mode until the vehicle 200 reaches the charging station at the end point 404. Note that since the energy storag subsystem 202 is maintained at a reiativety low SOC du ing the end portion of the tri , use of the fuel cell subsystem 212 is minimized so that the external power source 228, rather than the fuei ceii subsystem, can be used to charge the energy storage subsystem from the Sow third state of charge onc the vehicle 200 has reached the charging station. A benefit of the end-of-tri operational mode is illustrated by a dashed line 416, which shows the additional fuel that would be required if the control subsystem 218 continued to operate in the normal operational mode without switching into the end-of-trip operational mode.

it is noted that although the i!lustrated embodiment shows the control subsystem 218 activating the end-of-trip operational mode at point 412 after receiving the next charging opportunity information, it should be appreciated that the control subsystem may activate the end-of-trip operational mode at any time. For example, the control subsystem 218 may activate the end-of-trip operational mode at any time before the end of a discharge cycle and after the end of a preceding charging cycle. Thus, the determination of the next charging opportunity information need not be precise to obtain the advantages disclosed herein (e.g., maximizing fuel economy while minimizing run time of the fuel cell subsystem).

Figures 6 and 7 illustrate another implementation of a normal operational mode (NM) and an end-of-trip operational mode (EOTM) for the control subsystem 2 8. Figure 6 shows a state of charge 600 for the energy storage subsystem 202 of Figure 2 during a trip that spans between a beginning point 802 and an end point 604, and Figure 7 shows an output power level 700 of a secondary power source, such as the fuel cell subsystem 212, during the trip,

in the implementation shown in Figures 6 and 7, the norma! operational mode is substantially the same as the normal operational mode illustrated in Figures 4 and 5. As with the previous example, when the control subsystem 218 determines the vehicle 200 has reached a specified distance D2 to the next charging station at point 606, the control subsystem 218 transitions into an end-of-trip operational mode. In this implementation, rather than engaging the fuel celi subsystem 212 in a part power mode or ioad-foilowing mode to maintain a relatively constant state of charge at the energy storage subsystem 202, the control subsystem 218 first permits the SOC 600 of the energy storage subsystem to be depleted to the relatively iow third state of charge (e.g., 20% SOC) at point 608, then cycles the fuel cell subsystem 212 between the full rated power mode and the OFF mode to maintain the SOC within a relatively low range. For example, the control subsystem 218 may command or cause the fuel ceil subsystem 212 to deliver full rated power to charge the energy storage subsystem 202 from the lower third state of charge (e.g., 15% SOC, 20% SOC) to a slightly higher fourth state of charge (e.g., 25% SOC, 30% SOC), then disengage the fuei cell subsystem to permit the SOC to be depleted back to the third state of charge. This cycle may be repeated until the vehicle 200 reaches a charging station at the end point 604.

In the implementation of Figures 6 and 7, the fuel celi subsystem 212 is operated at full rated power rather than part power, which minimizes its time of operation and improves its efficiency. Further, since in the end-of-trip operational mode the energy storage subsystem 202 is maintained at a relatively low SOC 600, the vehicle 200 arrives at the external power source 228 with the energy storage subsystem having a low SOC so that the relatively low cost external power source may be used to charge the energy storage subsystem. in addition to monitoring the SOC §00 of the energy storage subsystem 202, the control subsystem 218 may also utilize other variables to control the operation of the fuel eel! subsystem 212 in the end-of-trip

operationai mode. For example, the control subsystem 218 may set a time duration to alternatively operate the fuel ceil subsystem 212 in the full rated power mode and the OFF mode (e.g., a 50% dut cycle with a period of 10 minutes, a 70% duty cycie with a period of five minutes, etc.).

The range of SOC ievels may be chosen to provide a suitable ON/OFF switching rate for the fuel celi subsystem 212 during the end-of-trip operationai mode. As can be appreciated, if the range is sma!i {e.g., 20-22% SOC), the fuei ceil subsystem 212 wii! be cycie much more rapid!y that if the range is iarger (e.g., 15-30% SOC). The SOC range and/or switching rate may be selected to provide a desired balance between fuei savings and the wear imposed on one or more components of the vehicle 200 due to repeatedly switching the fuel celi subsystem 212 between the ON state and the OFF state.

Figures 8 and 9 illustrate another example of a control strategy for the vehicle 200. Figure 8 shows a state of charge 800 for the energy storage subsystem 202 of Figure 2 during a trip that spans between a beginning point 802 and an end point 804, and Figure 9 shows an output power level 900 of a secondary power source, such as the fuel celi subsystem 212, during the trip.

in this implementation, the control subsystem 218 operates in a charge depletion operational mode (COM) and an end-of-trip operational mode (EOTM). in the charge depletion mode, the control subsystem 218 permits the SOC 800 of the energy storage subsystem 202 to be depleted to a specified first state of charge (e.g., 15% SOC, 25% SOC, etc.) at point 806. The control subsystem 218 then switches into the end-of-trip operational mode, in which the control subsystem cycles the fuel cell subsystem 212 between a full rated power state and an OFF state to maintain the SOC of the energy storage subsystem 202 at a relatively iow range of SOC. For example, the control subsystem 218 may maintain the SOC of the energy storage subsystem 202 between 20-25% SOC, between 15-30% SOC, and the like. in the implementation of Figures 8 and 9, since the distance and/or time until the next charging station may not be known, the control subsystem 218 starts in the charge depletion operational mode to maximize the li kelihood of depietion of the energy storage subsystem 202 before the end of the trip. During the charge depletion operational mode, the fuel cell subsystem 212 may be kept in the OFF state or at a ver low power level By primarily utilizing the energy of the energy storage subsystem 202 to propel the vehicle 200 early in the trip, the fuel consumption of the fuel ceil subsystem 212 is minimized when the trip distance is close to the operating range of the energy storage subsystem. Once the SOC 800 of the energy storage subsystem 202 decreases to a relatively low state (shown as point 806), the vehicle 200 switches to the end-of-trip operational mode, where the SOC of the energy storage subsystem is kept within a certain relatively low range (e.g., close to a desired charge-sustaining SOC level). In the end-of-trip operational mode, the fuei ceil subsystem 212 is cycled between the full rated power mode and the OFF mode, which minimizes the run time for the fuel cell subsystem and improves its efficiency. At the end point 804, the trip has ended and the vehicle 200 is proximate the external power source 228, such as an electrical outlet. The energy storage subsystem 202 may then be recharged to the fuily charged condition via the externa! power source 228.

The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, schematics, and examples. Insofar as such block diagrams, schematics, and examples contain one or more functions and/or operations, it will be understood by those skilled in the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, the present subject matter may be implemented via Application Specific integrated Circuits (ASICs). However, those skilled in the art will recognize that the embodiments disclosed herein, in whole or in part, can be equivalently implemented in standard integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more controllers (e.g.,

microcontrollers) as one or more programs running on one or more processors (e,g., microprocessors}, as firmware, or as virtua!ly any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware wouid be well within the skill of one of ordinary skill in the art in tight of this disciosure.

Those of skill in the art will recognize that many of the methods or algorithms set out herein may empioy additional acts, may omit some acts, and/or may execute acts in a different order than specified.

in addition, those skilled in the art will appreciate that the mechanisms taught herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment applies equally regardless of the particular type of nontransitory signal bearing media used to actually carry out the distribution. Examples of nontransitory signal bearing media include, but are not limited to, the following: recordable type media such as floppy disks, hard disk drives, CD ROMs, digital tape, and computer memory.

The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary, to employ systems, circuits and concepts of the various patents, applications and pubiications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above-detailed description, in general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure. Th s application also eiaims the benefit of U.S. Provisional Patent Application No, 62/058,353, filed October 1, 2014, and is incorporated herein by reference in its entirety.

Claims

1. A hybrid vehicle, comprising;

an electric machine coupled to provide propulsion power for the hybrid vehicle;

an energ storage subsystem electrically coupled to the electric machine to provide at least one of: a source of electrical energy to the electrical machine, and a sink of electrical energy from the electrical machine;

a fuel cell subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem; and

a conirot subsystem electrically coupled to the electric machine, the energy storage subsystem, and the fuel cell subsystem, the control subsystem receives next charging opportunity information, the next charging opportunity information at least partially indicative of an anticipated next opportunity to charge the energy storage subsystem via a power source other than the fuel cell subsystem, the control system monitors a state of charge of the energy storage subsystem and causes the fue! cell subsystem to provide electrical energy to the energy storage subsystem according to a norma! control mode or an approaching next charging opportunity control mode based at least on part on the received next charging opportunity information, wherein in the norma! control mode the control subsystem repeatedly:

permits depletion of the energy storage subsystem to a first state of charge; and

causes the fue! cell subsystem to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge;

and in the approaching next charging opportunity control mode the control subsystem: permits depletion of the energy storage subsystem to a third state of charge, the third state of charge !ower than the second state of charge; and

causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem proximate the third state of charge.

2. The hybrid vehicle of ciaim 1 wherein the next charging opportunity information comprises at least one of;

an anticipated distance until a next opportunity to charge the energy storage subsystem via a power source other than the fuel ceil subsystem;

an anticipated time of operation until a next opportunity to charge the energy storage subsystem via a power source other than the fuel celS subsystem and

an anticipated energy output requirement for the energy storage subsystem untii a next opportunity to charge the energy storage subsystem via a power source other than the fuel cell subsystem.

3. The hybrid vehicle of claim 2 wherein the anticipated energy output requirement is based at ieast in part on at least one of route information, terrain information, speed limit information, traffic information, temperature information, and vehicle load information.

4. The hybrid vehicle of ciaim 1 wherein the next charging opportunity information is based at Ieast in part on an input to the control subsystem via a human-machine interface.

5. The hybrid vehicle of ciaim 1 wherein the next charging opportunity information is based at Ieast in part on data coliected by the contro! subsystem concerning a driving pattern of the hybrid vehicle or a driving pattern of a driver of the hybrid vehicle.

6, The hybrid vehicle of claim 1 , further comprising;

a global positioning system (GPS) navigation system coupled to the control subsystem, wherein the next charging opportunity information is based at !east in part on signals from the GPS navigation subsystem.

7. The hybrid vehicle of claim 1 wherein the energy storage subsystem comprises at !east one of an electrochemical battery cell and an uitra-capacitor ceil, the hybrid vehicle further comprising:

a charger interface coupled to the hybrid vehicle and to an external power source to charge the energy storage subsystem.

8. The hybrid vehicle of claim 1 wherein the first state of charge is less than 25% of full charge for the energy storage subsystem and the second state of charge is greater than 70% of full charge for the energy storage subsystem.

9. The hybrid vehicle of ciaim 1 wherein the first state of charge and the third state of charge are approximately equal to each other.

10. The hybrid vehicle of ciaim 1 wherein the fuel cell subsystem comprises a plurality of fuel cells electrically coupled in series to form a fuel cell stack.

11. A system to control the operation of a hybrid machine, the hybrid machine comprising an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a fuel cell subsystem

electrically coupled to the energy storage subsystem to charge the energy storage subsystem, the system comprising;

a processor aperatively coupled to the electric machine, the energy storage subsystem, and the fuel cell subsystem, the processor:

receives next charging opportunity information, the next charging opportunity information at least partially indicative of an anticipated next opportunity to charge the energy storage subsystem via a power source other than the fuel celt subsystem;

monitors a state of charge of the energy storage subsystem; and

causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem according to a norma! control mode or an approaching next charging opportunity control mode based at least on part on the received next charging opportunity information, wherein:

in the normal control mode the processor permits depletion of the energy storage subsystem to a first state of charge, and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge; and in the approaching next charging opportunity control mode the processor permits depletion of the energy storage subsystem to a third state of charge, the third state of charge lower than the second state of charge, and causes the fuel cell subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem proximate the third state of charge.

12. The system of claim 11 wherein the next charging opportunity information is based at least in part on an input via a human- machine interface.

13. The system of claim 11 wherein the hybrid machine comprises a hybrid vehicle, and the next charging opportunity Information is based at !east in part on data collected concerning a driving pattern of the hybrid vehicle or a driving pattern of a driver of the hybrid vehicle.

14. The system of claim 1 wherein the processor receives the next charging opportunity information from a global positioning system (GPS) navigation subsystem.

15. The system of claim 11 wherein the energy storage subsystem comprises at least one of an electrochemical battery cell and an ultra-capacitor cell.

16. The system of claim 11 wherei the first state of charge is less than 25% of the full charged state of charge for the energy storage subsystem and the second state of charge is greater than 70% of the fully charged state of charge for the energy storage subsystem. 7. The system of claim 11 wherein the first state of charge and the third state of charge are approximately equal to each other.

18. The system of claim 11 wherein the fuel ceil subsystem comprises a plurality of fuel cells eiectricaiiy coupled in series to form a fuel ceil stack.

19. A method to control a hybrid machine having an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a secondary eiectricai power delivery subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, the method comprising:

receiving charging opportunity information in a processor- readable medium, the next charging opportunity information at least partially indicative of an anticipated next opportunity to charge the energ storage subsystem via a power source other than the secondary electrical power delivery subsystem;

monitoring a state of charge for the energy storage subsystem: autonomously causing the secondary eiectricai power delivery subsystem to provide electrical energy to the energy storage subsystem according to a norma! control mode or an approaching next charging opportunity control mode based at least on part on the received next charging opportunity information,

wherein the normal control mode comprises:

permitting depletion of the energy storage subsystem to a first state of charge: and

causing the secondary electrical power delivery subsystem to operate at full rated power to provide eiectricai energy to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge;

and the approaching next charging opportunity control mode comprises:

causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at or below a third state of charge.

20. The method of claim 19 wherein causing the secondary electrical power delivery subsystem to provide electrical energ to the energy storage subsystem to maintain the energy storage subsystem at or beiovv a third state of charge comprises repeatedly:

permitting depletion of the energy storage subsystem to fourth state of charge, the fourt state of charge lower than the third state of charge; and

causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to charge the energy storage subsystem from the fourth state of charge to the third state of charge.

21. The method of claim 19 wherein causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at or beiow a third state of charge comprises causing the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at a charge-sustaining state of charge, the charge-sustaining charge at or below the third state of charge.

22. The method of claim 19 wherein receiving next charging opportunity information comprises receiving an input via a human-machine interface.

23. The method of claim 19 wherein the hybrid machine comprises a hybrid vehicle, and receiving next charging opportunity information comprises receiving data concerning a driving pattern of the hybrid vehicle or a driving pattern of a driver of the hybrid vehicle.

24. The method of claim 19 wherein receiving next charging opportunity information comprises receiving signals from a global positioning system (GPS) navigation system.

25. The method of claim 19 wherein causing the secondary eiectricai power delivery subsystem to operate at full rated power to provide eiectricai energ to the energy storage subsystem to charge the energy storage subsystem from the first state of charge to the second state of charge higher than the first state of charge comprises causing the secondary eiectricai power deliver subsystem to charge the energy storage subsystem from a state of charge less than 25% of the fully charged state of charge for the energy storage subsystem to a state of charge greater than 70% of the fu!iy charged state of charge for the energy storage subsystem.

26. The method of claim 19 wherein permitting depletion of the energy storage subsystem to a first state of charge comprises permitting depletion of the energy storage subsystem to the charge-sustaining state of charge.

27. A method to control a hybrid vehicle during a trip, the hybrid vehicle having an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a secondary eiectricai power delivery subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, the method comprising;

detecting a state of charge for the energy storage subsystem; operating the secondary eiectricai power delivery subsystem at full rated power to charge the energy storage subsystem from a first state of charge to a second state of charge higher than the first state of charge when the state of charge for the energy storage subsystem is detected to be at or beiow the first state of charge;

receiving an indication at ieast partially indicative of an anticipated upcoming end of the trip;

permitting depletion of the energy storage subsystem to the first state of charge; and operating the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at a charge-sustaining state of charge.

28. The method of claim 27 wherei operating the secondary electrical power delivery subsystem to provide electrical energy to the energ storage subsystem to maintain the energy storage subsystem at a charge- sustaining state of charge comprises operating the secondary electrical power delivery subsystem to provide electrical energy to the energy storage subsystem to maintain the energy storage subsystem at a state of charge that is less than 50% of the state of charge of the energy storage subsystem when fuiiy charged.

29. A method to control a hybrid machine, the hybrid machine having an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a secondary electrical power delivery subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, the method comprising;

for a duration time when the hybrid machine is electrically decoupled from an external power source:

detecting a state of charge for the energy storage subsystem;

repetitively permitting depletion of the energy storage subsystem to a first state of charge; and

repetitively causing the secondary electrical power delivery subsystem to operate at ful! rated power to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge when the state of charge for the energy storage subsystem is detected to be at or beiow the first state of charge, the second state of charge less than 50% of the state of charge of the energy storage subsystem when ful!y charged.

30. The method of claim 29 wherein repetitively causing the secondary electrical power delivery subsystem to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge comprises causing the secondary electrical power delivery subsystem to charge the energy storage subsystem from a state of charge less than 25% of the state of charge of the energy storage subsystem when fully charged to a state of charge less than 30% of the state of charge of the energy storage subsystem when fully charged.

31. A system to control the operation of a hybrid machine, the hybrid machine comprising an electric machine, an energy storage subsystem electrically coupled to the electric machine, and a secondary electrical power delivery subsystem electrically coupled to the energy storage subsystem to charge the energy storage subsystem, the system comprising:

a processor operatively coupled to the electric machine, the energy storage subsystem, and the fuel ceil subsystem, wherein for a duration time when the hybrid machine is electrically decoupled from an external power source, the processor:

detects a state of charge for the energy storage

subsystem;

repetitively permits depletion of the energy storage subsystem to a first state of charge; and

repetitively causes the secondary electrical power delivery subsystem to operate at full rated power to charge the energy storage subsystem from the first state of charge to a second state of charge higher than the first state of charge when the state of charge for the energy storage subsystem is detected to be at or below the first state of charge, the second state of charge less than 50% of the state of charge of the energy storage subsystem when fully charged.

32. The system of claim 31 wherein the first state of charge is !ess than 25% of the state of charge of the energy storage subsystein when fully charged, and the second state of charge is less than 30% of the state of charge of the energy storage subsystem when fuliy charged.