WO2010093790A2

WO2010093790A2 - Modular systems architecture

Info

Publication number: WO2010093790A2
Application number: PCT/US2010/023894
Authority: WO
Inventors: Jim Castelaz; Rob Sweney; Vishal Parikh; Jessica Riley; Marvin E. Bush
Original assignee: ADURA SYSTEMS Inc
Current assignee: ADURA SYSTEMS Inc
Priority date: 2009-02-11
Filing date: 2010-02-11
Publication date: 2010-08-19
Anticipated expiration: 2011-08-11
Also published as: WO2010093790A3

Abstract

This invention provides modular systems architecture that can be used for hybrid-electric and electric vehicles. The system may consist of one or more modules (each of which may have a power regulator circuit), a shared power bus, a communications channel between modules, and a method of controlling the power flowing between modules.

Description

MODULAR SYSTEMS ARCHITECTURE CROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 61/151786, filed February 11, 2009, which application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] In conventional DC power systems, components are connected with a DC link, which may or may not be shared between more than 2 components. Typically, the link voltage is fixed. The amount of current that flows between components is regulated by just one of the components. For example, a motor inverter may use PWM control to regulate how much current it draws from a fixed-voltage DC link. Alternatively, one component may be responsible for holding the DC link voltage while other components source or sink a specific amount of current to the DC link. This method is typically used if one component is a battery, for example in the conventional powertrain of FIGURE 1. Here, the battery will hold the DC link voltage at the battery voltage while a motor and a step-down DC/DC converter each draw current from the DC link. The battery is recharged through a separate DC link. Examples of previous power systems may be provided by U.S. Patent Publication No. 2008/0281480, U.S. Patent Publication No. 2008/0243325, U.S. Patent Publication No. 2007/0247003, U.S. Patent Publication 2008/0296971, and U.S. Patent Publication 2006/0065451, which are hereby incorporated by reference in their entirety.

[0003] As the battery drains, the DC link voltage may decrease. If the DC link voltage decreases, the motor and DC/DC converter may need to compensate by drawing more current. Thus, the coupling of the DC link voltage to the battery voltage in conventional systems results in inefficiencies. [0004] Also, if one component on the DC link fails to regulate the amount of power it is drawing, it is possible that the batteries will continue sourcing power, which may result in dangerously high levels of power.

[0005] Therefore a need exists for an improved powertrain system that may uncouple the DC link voltage from the battery voltage so that system performance need not be affected by battery state of charge. A further need exists for a powertrain system that may separably control power moving into and out of each component.

SUMMARY OF THE INVENTION

[0006] The following summary of the invention and description of preferred embodiments of the invention are not intended to limit the invention to these descriptions, but rather to enable any person skilled in the art to make and use this invention.

[0007] The invention provides systems and methods for modular systems architecture. Various aspects of the invention described herein may be applied to any of the particular applications set forth below or for other types of energy control systems. The invention may be applied as a standalone system or method, or as part of an application, such as hybrid-electric or electric vehicles. It shall be understood that different aspects of the invention can be appreciated individually, collectively, or in combination with each other.

[0008] In accordance with an aspect of the invention, a modular systems architecture may be provided, comprising a plurality of modules connected to a variable voltage shared power bus, a communication channel between the modules, and a power control system for controlling the power flowing between the modules. The shared power bus voltage may advantageously be decoupled from a DC link voltage, or a system battery voltage. Some examples of modules that may be utilized within the architecture may include a battery module, a motor module, a generator module, an engine module, and/or a power converter module. Each module may have a power source or sink, power regulator, a memory, and a communication interface for communicating with other modules or external controllers. The modular systems architecture may be provided for a hybrid-electric or electric vehicle.

[0009] Another aspect of the invention provides for methods of controlling power allocation within a system. The method may include providing a plurality of modules that are connected to a power bus and that are in communication with a controller. The controller may receive data about the state of the various modules. The controller may determine, based on the state data, power allocation constraints for the various modules, and transmit the power allocations to the modules. By allocating power for each of the modules, the power bus voltage may be maintained and/or varied. The system may include an objective function, which may help determine the power allocation constraints.

[0010] A method of controlling power allocation within a module may be provided in accordance with another aspect of the invention. The method may include estimating a present state of the module, determining possible electrical power source/sink levels based on the estimated state of the module, transmitting state maps to a controller external to the module, receiving power allocation instructions from the controller, and controlling a power regulator to source/sink power according to the allocation instructions. The method may also include receiving a system objective, and estimating system objective values for given electrical power source/sink levels based on the system objectives. The state map may be a function estimated for each system objective that inputs a power source/sink level and outputs a system objective value.

[0011] Other goals and advantages of the invention will be further appreciated and understood when considered in conjunction with the following description and accompanying drawings. While the following description may contain specific details describing particular embodiments of the invention, this should not be construed as limitations to the scope of the invention but rather as an exemplification of preferable embodiments. For each aspect of the invention, many variations are possible as suggested herein that are known to those of ordinary skill in the art. A variety of changes and modifications can be made within the scope of the invention without departing from the spirit thereof.

INCORPORATION BY REFERENCE

[0012] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. BRIEF DESCRIPTION OF THE FIGURES

[0013] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0014] FIGURE 1 provides an overview of an embodiment of the invention compared to conventional systems.

[0015] FIGURE 2 is a block diagram of a modular system architecture in accordance with an embodiment of the invention.

[0016] FIGURE 3 is a circuit schematic for a possible regulator circuit on an energy storage module.

[0017] FIGURE 4 is a functional block diagram of one system embodiment.

[0018] FIGURE 5 shows an example of an embedded controller's process flow.

[0019] FIGURE 6 is an example of the system controller process flow

DETAILED DESCRIPTION OF THE INVENTION

[0020] While preferable embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention.

[0021] One aspect of the invention may provide a modular systems architecture that can be used for hybrid-electric and electric vehicles. The system may comprise at least two modules, each of which may have a power regulator circuit, a shared power bus, a communications channel between modules, and a method of controlling the power flowing between modules. FIGURE 4 shows an example of a functional block diagram in accordance with an embodiment of the invention.

[0022] FIGURE 1 shows a comparison between a proposed powertrain to a conventional power train. An example of a proposed powertrain is provided in accordance with an embodiment of the invention. One, two, three, four, five, six or more modules may be provided. The modules may include a battery module 101, 105, a motor module 102, an accessory module 103, a charging module 104, or any other module that may contribute or use power within the powertrain system.

[0023] The modules may all be connected to a variable voltage power bus 106. Alternatively, not all modules need to be connected to the variable voltage power bus. In some embodiments, one, two, or more modules need not be connected to the power bus. In some embodiments, the modules may be connected to the power bus so to enable bidirectional energy flow between the modules and the variable voltage power bus. In some alternate embodiments of the invention, one or more modules may enable unidirectional energy flow from the module to the power bus, or vice versa. Any combination of bidirectional energy flow or unidirectional energy flow connections between the modules and the power bus may be utilized. In some embodiments, the modules may be directly connected to the power bus. In some instances, the modules may be connected to the power bus without any intervening modules. The modules may be connected to the power bus in parallel. Alternatively, the modules may be connected to the power bus in series or in any combination of parallel or series connections. The modules may be physically connected to the power bus and/or in electrical communication with the power bus. [0024] The modules may all be in communication with a communications channel 107. Alternatively, not all modules need to be in communication with the communications channel. In some embodiments, one, two, or more modules need not be communicating with the communications channel. In some embodiments, the modules may be connected to the communications channel so to enable bidirectional communications between the modules and the communications channel. In some alternate embodiments of the invention, one or more modules may enable unidirectional communications from the module to the communication channel, or vice versa. Any combination of bidirectional communications, or unidirectional communications between the modules and the communications channel may be utilized. The modules may or may not be physically connected to the communications channel. The modules may or may not directly communicate with one another via the communications channel or any other communications interface.

[0025] A controller 108 may be in communication with the communications channel. The controller may preferably communicate with the communications channel in a bidirectional manner. Alternatively, the controller may communicate with the communications channel in a unidirectional manner. The controller may be communicating with one, two, or more modules through the communications channel. The controller may be communicating with all of the modules through the communications channel. Preferably, the communications between the controller and the modules may be bidirectional, although as previously described, one or more such communications may be unidirectional. [0026] The proposed powertrain may provide advantages over a conventional electric powertrain, as described elsewhere herein. The conventional electric powertrain may include batteries 110 in electrical communication with a motor 111. The electrical connection between the batteries and the motor may be a DC link that is fixed to the battery voltage. Wall power may be provided to a rectifier 112 which may form a DC link with the batteries.

[0027] In accordance with an embodiment of the invention, all components (e.g., modules) in the proposed powertrain (e.g., as shown in FIGURE 1) may be connected to a shared power bus (e.g., a DC link). If each component can regulate the current it sources/sinks on the power bus, then the power bus voltage can be de-coupled from the DC link voltage (and thus, a battery voltage). In some embodiments, all components connected to the power bus may regulate the power it sources/sinks to the power bus. In other embodiments, none, one, or some of the components may be divided into groups or subgroups that may regulate the power sourced or sunk at that level.

[0028] Then, the DC power bus voltage need not be fixed at any voltage level, but may instead be determined by its capacitance and the imbalance in the amount of current sourced and sunk on the bus. Sinking more current than is sourced from the power bus can increase its voltage. Conversely, if more current is sourced than sank, the power bus voltage will fall. The power bus voltage can be varied to allow more efficient power transfer between modules. Preferably, one, two, or more, or all of the components may regulate the current it sources/sinks on the power bus. Thus, the voltage on the power bus can be varied or maintained in accordance with the current regulation of the components. The voltage of the power bus may be varied or maintained depending on relative current balances (or imbalances) between the components. Different types of batteries and/or batteries at different states of charge may be used.

[0029] Additionally, a shared power bus with modules that may all regulate power allows for multiple batteries to be connected to the power bus. Typically, in conventional systems, different types of batteries cannot be connected to the same DC link because they would both source/sink current necessary to hold the DC link voltage at different voltage levels. They would source and sink uncontrolled amounts of power, which can cause battery performance and lifetime degradation. However, as illustrated in the proposed powertrain, when each battery or battery module has a regulator circuit to control the power it sources and sinks, multiple batteries (or battery modules) can be connected to the same power bus with no fear of performance or lifetime degradation.

[0030] For the preferred method of control, there may be one or more systems objectives. In preferable embodiments of the invention, each module can have an embedded controller and memory. In some alternate embodiments, a group of modules can have a controller and memory. This controller may determine and communicate state maps to a control algorithm. The control algorithm can use state maps from all modules to maximize or minimize a function of system objectives.

[0031] FIGURE 2 illustrates the components and sub-components of the invention in accordance with an embodiment of the invention. For example, one, two, three, four, or more modules 201, 202, 203, 204 may be provided. In some embodiments, any number of modules may be used. In a preferable embodiment, each module may include an electricity source or sink 205, 206, 207, 208, a controller 209, 210, 211, 212, and a regulator circuit 213, 214, 215, 216. In alternate embodiments, modules may share an electricity source or sink, a controller and/or a regulator circuit. In some examples, a module may have an electricity storage or sink, such as but not limited to: electricity storage, and electricity source, an electricity sink, and/or an electricity sink/storage. Any combination of modules may have any combination of types of electricity storage or sink.

[0032] Communication channels may be provided within a module and between two or more modules. For example, a sensor/switching communications channel may be provided. The sensor/switching communications may be unidirectional or bidirectional. In one example, within a module, an electricity storage or sink may unilaterally provide communications to a controller, which may unilaterally provide communications to a regulator circuit. Alternatively, the communications may be provided in the opposite direction, or bidirectionally. Also, bidirectional communications channels may be provided between modules. FIGURE 2 shows an example of a bidirectional communications channel. Alternatively, the communications channels between modules may be unidirectional, providing communications to or from the modules. Any combination of communication channels may be used. [0033] Power may flow between one or more module and a power bus 217. Such power flow may be a bidirectional electrical power flow or a unidirectional electrical power flow. Unidirectional electrical power flow may be from a module or to a module. Any number or combination of modules may be provided such that any combination of unidirectional or bidirectional power flows may occur (e.g., all modules may use bidirectional power flow, all modules may use unidirectional power flow, some modules may use bidirectional power flow while other modules may use unidirectional power flow, etc.). [0034] Power may also flow within a module. For example, power may flow between an electricity source or sink and a regulator circuit, as well as between the regulator circuit and the power bus. Any of these power flows may be bidirectional, unidirectional, or any combination thereof. In one example, bidirectional power flow may be provided between an electricity storage or an electricity sink/source and a regulator circuit, and between the regulator circuit and the power bus. In another example, unidirectional power flow may be provided from an electricity source to a regulator circuit, and from the regulator circuit to the power bus. Unidirectional power flow may be provided from a power bus to a regulator circuit, and from the regulator circuit to an electricity sink.

[0035J FIGURE 4 shows a functional block diagram in accordance with an embodiment of the invention. A plurality of modules 401, 402, 403, 404, 405 may be connected to a power bus 410. A module 405 may include an embedded controller 406, memory 407, electricity sink/store/source 408, and a power regulator 409. The modules may also be in communication with a controller 412 via a communications channel 411. Such components may be described in greater detail elsewhere herein. System Objectives

[0036] System objectives may be measures of system performance, status, or degradation. These could include global system efficiency, some measure of remaining performance lifetime of system components, or some measure of system power production or consumption. Other objectives could be measures of system usefulness or how well it is accomplishing some task. For example, a system objective may be the level of mechanical torque output from an electrical motor module. For example, producing a desired level of torque under certain conditions may be a system objective.

[0037) In some implementations, system objectives may relate to the performance of a hybrid-electric or electric vehicle, or any other environment or application that may use the system. For instance, a system may relate to preserving the lifetime of one or more vehicle batteries, increasing system efficiency, decreasing power consumption, or to obtain a desired level of mechanical torque output from a vehicle motor, or any other possible objective that may be a measure of system usefulness or how well it's accomplishing a task.

[0038] System objectives may be known from the time of system design. In some embodiments, the system objectives may be fixed and/or predefined. In other embodiments, the system objectives may be variable. In some instances, the system objectives may be user defined. For example, a driver of a hybrid-electric or electric vehicle utilizing the system may be able to define a goal, which may determine a system objective. In other examples, the system objectives may be automatically determined by the system based on one or more factors or parameters. Such factors or parameters may depend on the state of one or more module. Modules

[0039] A module may be a self-regulating power source and/or sink connected to a power bus shared with at least one other module. Modules may include energy storage systems like batteries, and energy transformation systems like electrical machines and voltage level converters. Some examples of types of modules may include battery modules (which may include one or more battery), motor modules (which may include one or more electrical machines operating as a motor), accessory modules (which may include various vehicle accessories, such as but not limited to air conditioning, lights, radio, etc.), or charging module (which may include one or more electrical machines operating as a generator). In some embodiments, power may be provided from a battery module, or to a battery module to charge the battery. Similarly, power may be powered to a motor module to power the motor, although in other embodiments, power may be provided from the motor. Similarly, power may be provided to power various accessories, while in some instances, power may be provided from the accessory module. Power may be provided from a charging module, although in some events power may be provided to the charging module. [0040] Modules may have at least three components: a power source or sink, a power regulator, and a means of communicating with other modules or external controllers. A preferable means of communication may use an embedded controller and memory in each module. Power Source/Sink

[0041] This component may be the part of the module that can transform power moving to or from the power bus and use or store that power. Examples include a chemical battery, an ultra-capacitor, an electric machine, or a combustion engine electrical power generator. Battery chemistries can include lead-acid, nickel, or lithium based chemistries. Some examples of batteries may include but are not limited to: lead-acid batteries, nickel-cadmium batteries, nickel metal hydride (NiMH) batteries, nickel- zinc (NiZn) batteries, lithium ion batteries, zinc-carbon batteries, zinc chloride batteries, alkaline batteries, oxy nickel hydroxide batteries, lithium based batteries (e.g., lithium-copper oxide, lithium-iron disulfide, lithium-manganese dioxide), mercury oxide batteries, or silver-oxide batteries. Other examples of power sources or sinks may include Re Motors, AC induction, Permanent Magnet or Switch Reluctance Motors. [0042] For example, a battery may be used as a power source, and an electrical motor generating torque output may be a power sink. An electricity sink/store/source may include batteries, a motor, electrical generator, or electrical heating coils, as provided in FIGURE 4. Power Regulator

[0043) Each module may have an integral power regulating circuit that connects it to the power bus and controls the amount of power moving in and out of the module. In some instances, the power regulating circuit may control the amount of power flow using pulse width modulation (PWM), or any other technique. This regulator circuit can ensure that when that module is not connected to a communications channel and in fault-free operation, no power can be sourced from or sunk to that module. The physical connection on the module that connects to the power bus is effectively dead (i.e. not 'hot') in this instance. Modules can be designed with physical connectors that may simultaneously connect and disconnect the power bus and the communications channel from the module. [0044] Some examples of power regulators may include a bidirectional current-controlled buck-boost converter or a current controlled 3-phase inverter. An example of a power regulator circuit for a battery module is provided in FIGURE 3. A plurality of switches (e.g., SWl, SW2, SW3, SW4) may be provided, with an inductor therebetween. The circuit may include HV to battery cells, HV to a power bus, and a return to battery cells or return to power bus (ground). Switches may be controlled to control power flow between the battery and power bus. Embedded Controller

[0045] In a preferable control method for this system, an embedded controller in the module may have various functions. Such functions may include but are not limited to functions discussed herein. [0046] First, it may receive the power source/sink request from a control algorithm via a communications channel and operate the regulator circuit such that each module may source or sink a controlled amount of power to or from the power bus. Such control allocations may be provided from the controller via a communications channel. In fault-free operation, the regulator circuit and embedded controller in a module may be responsible for controlling the amount of power sourced from or sunk to that module. [0047] Second, the controller may estimate functional mappings from power level to system objectives. These mappings, or functions, are called 'state maps'. A state map may predict how the system objectives for that module will be affected by the power level that module sources or sinks. For example, an efficiency state map may describe what that module's efficiency may be as a function of the power sourced to or sunk from the power bus. A remaining lifetime state map may describe what the remaining lifetime of the module may be as a function of power sourced to or sunk from the module. A torque output state map of an electric machine module may describe how much torque that machine may output as a function of power sunk from the power bus.

[0048] Third, the embedded controller may transmit these state maps via the communications channel to a controller running a control algorithm.

[0049] The embedded controller may also use sensors to monitor the module. Monitoring the module may assist with determining a present state of the module. After receiving the power allocation, the module may control the regulator circuit to meet power allocation. The embedded controller may also report errors.

[0050] FIGURE 5 provides and example of a module embedded controller flow in accordance with an embodiment of the invention. This will be discussed in further detail elsewhere herein. Memory

[0051] In a preferable control method for this system, some component of memory on each module may be provided for storing the state maps and the algorithm used for determining and updating the state maps. In alternate embodiments, a memory may be provided to store state maps and/or an algorithm to determine and update state maps, wherein the memory may or may not be on a module. For example, one or more modules may share or access such a memory.

[0052] Some examples of memory may include flash memories, EEPROM, or magnetic memory storage. State maps and algorithms may be stored in any format. In some embodiments, tangible computer readable media, which may contain instructions, logic, data, or code may be stored in persistent or temporary memory of the module and/or may somehow affect or initiate action by a module. Shared Power Bus

[0053] A shared power bus may connect to each module and allow power to flow between all of the different modules. The power bus may provide a physical connection for power transfer between modules. In one implementation, the shared power bus could be a pair of high-power cables with some associated capacitance. Some other examples may include capacitance on high voltage DC cables, 3- phase AC cables, or 5 phase AC cables. The power bus may form a DC connection or an AC connection. Any other power bus structure as known or later developed in the art may be used, including but not limited to a bar structure, any arrangement of wires, or any other structure that may allow signals (e.g., power or information) to be transferred between one or more modules. Connections with one or more modules and a power bus may be provided by any way known or later developed in the art. See, e.g., U.S. Patent Publication No. 2007/0241614, which is hereby incorporated by reference in its entirety. [0054] In a preferable embodiment, the power bus may have enough capacitance to tolerate small imbalances in current being sourced and sunk on the power bus. A power bus may have any capacitance value, which may include but are not limited to capacitance values or the order of capacitance values provided as examples herein. In some embodiments, the power bus may have a capacitance on the order of 1 pF or higher, 10 pF or higher, 100 pF or higher, 500 pF or higher, 1 nF or higher, 10 nF or higher, 100 nF or higher, 1 μF or higher, 5 μF or higher, 10 μF or higher, 50 μF or higher, 100 μF or higher, 500 μF or higher, 1 mF or higher, 5 mF or higher, 10 mF, 50 rnF, 100 mF or higher, 200 mF or higher, 500 mF or higher, IF or higher, or 10 F or higher. This may enable the power bus to buffer slight power imbalances between modules. In some embodiments, a variable capacitance value may be selected, which may vary with voltage.

[0055] If slightly more current is sourced to the power bus than is sunk from it, the capacitance of the power bus may allow this charge to accumulate and increase the voltage of the power bus. Likewise, if more current is sunk than sourced, the power bus voltage will decrease. If the control algorithm prescribes slight current imbalances between modules, the power bus voltage can be intentionally varied. In some embodiments, the voltage may be varied between 50 V and 1.5 kV. In other examples, the voltage may be varied between 10 V and 5 kV, 30 V and 2.5 kV, 40 V and 2 kV, 60 V and 1 kV, 80 V and 500 V, or any other voltage. In some embodiments, the voltage variation of the power bus may be of about 10 V or greater, 30 V or greater, 50 V or greater, 75 V or greater, 100 V or greater, 200 V or greater, 300 V or greater, 500 V or greater, 750 V or greater, 1 kV or greater, 1.25 kV or greater, 1.5 kV or greater, 2 kV or greater, 5 kV or greater, or 10 kV or greater. Thus, the power bus voltage can be maintained or varied based on current distribution of the modules. The control algorithm can then adjust or maintain the power bus voltage to increase or maximize an objective function, which may be discussed in further detail below. Communications Channel

[0056] Some channel for communications between modules and any external controllers must be present. An external controller may be attached to one or more modules via a communications channel but need not be connected to the power bus. The communication channel may provide bidirectional or unidirectional communications between modules or with a controller.

[0057] A communications channel could be an RS-232 connection, an Ethernet connection, controller- area-network (CAN) connection, FlexRay, TCP/IP connection or any other wired connection, or a wireless network protocol with transceivers on each module, or any other communication means or connection known or later developed in the art. Similarly, one or more modules may communicate with one or more external controller across a network, and may transmit instructions, logic, or data residing in memory. The network, for example, can include a wired or wireless network for connecting one or more modules to one or more external controller. The network may be a local area network or a wide area network, such as the Internet. Any communication system or arrangement known or later developed in the art may be used. See, e.g., U.S. Patent Publication No. 2009/0021919, which is hereby incorporated by reference in its entirety.

[0058] In a preferable embodiment, the communications channel may also serve to time-synchronize all modules. This time synchronization may ensure that there is no unknown time interval between different modules' sourcing and sinking of power. Control Algorithm

[0059] A controller may be in communication with a communications channel. A control algorithm or other distributed program may run on module embedded controllers, a standalone embedded controller, or

PC.

[0060] The system may provide some method of control to determine how power may be allocated between modules. This method could use a communications channel to communicate the desired power allocation to each module. In a preferable control method, a control algorithm could run on one or more modules and/or external controllers. A control algorithm may include a computer file residing in memory which may be transmitted between an external controller over a communication channel to one or more module, which may store it in memory. A module and/or external controller may receive computer readable media, which may contain instructions, logic, data, or code that may be stored in persistent or temporary memory of the module and/or external controller, or may somehow affect or initiate action by a module and/or external controller.

[0061] The controller may also stay within allowable power allocations defined by modules. For example, if a module has particular constraints, a control algorithm may take this into account.

[0062] Also, this control algorithm may be able to identify when modules are added and removed from the system and how this addition or subtraction should affect power transfer between the modules. For example, in some implementations, the modules may be added or removed or swapped in or out. For instance, a new battery module may be swapped in to replace a previous battery module. Or an additional battery module may be added. In other implementations, the modules used may be relatively fixed. [0063] In a preferable control method, this control algorithm may determine how to allocate power between modules by maximizing or approaching an objective function using the state maps communicated from the modules. It may also prescribe current imbalances between modules to raise or lower the power bus voltage to maximize or approach an objective function. The objective function may be a function of system objectives and may define optimal or desired system performance.

[0064] For example, the objective function could be to maximize or increase system efficiency while generating at least 100 N-m of torque from an electric machine module. The objective function might also be to maximize or increase the lifetime of a battery module while maintaining at least 85% system efficiency and keeping an electric machine module within 100 rpm of 1500 rpm. Notice that this objective function may include constraints as above, such as maintaining a minimum or decreased torque or maintaining a rotational speed. A more complex objective may be to minimize or reduce lifetime cost of the system, factoring in both operating costs due to low efficiency and future module operating and replacement costs as modules degrade.

[0065] The objective function may be altered over time depending on the goals of the system's operation.

For instance, the speed or torque constraints may change, or efficiency may become more or less important over time. In some embodiments, a user of a system may define an objective function. For example, in an implementation for hybrid-electric or electric vehicles, a vehicle operator may select or define an objective function. Alternatively, the objective function may be determined by the system in view of a system operation goal. In some embodiments, the objective function may be fixed and predefined.

[0066] Without the proper state maps, the control algorithm may make power allocation less than optimal, but a preferable control method could still approach the objective function with the data it has from the state maps.

[0067] The control algorithm may reside on computer readable medium or any memory or storage. Any computer readable media with logic, code, data, instructions, may be used to implement any software, algorithm, steps or methodology.

[0068] FIGURE 6 shows an example of controller flow in accordance with an embodiment of the invention. This will be discussed in further detail elsewhere herein.

Module embedded controller flow

[0069] FIGURE 5 provides and example of a module embedded controller flow in accordance with an embodiment of the invention. A previous state 501 of the module and/or collected sensor information 502 of the module may be used to estimate a present state 503 of the module. Collected sensor information can be used to detect conditions within a module. For example, for a battery module, a state of charge of a battery or change in the state of charge of a battery may be detected. Other features such as temperature, current flow, voltage or any other characteristic of a module may be detected. In some embodiments, the present state of the module may be determined based on the previous state of the module alone, the collected sensor information alone, or any combination of the two. The present state of the module may be saved 504. The saved present state of the module may become the previous state for a subsequent iteration. In preferable embodiments, the module state information may be stored in a memory of the module. Alternatively, the state information may be stored on a memory of the system which may be external to the module.

[0070] Based on the present state, the module may determine possible electrical power source/sink levels for the module 505. This may or may not incorporate constraints of the module. Based on the possible electrical power source/sink levels and/or system objectives 506, the module may estimate system objective values for any given electrical power sources/sink level 507. This may be done within an acceptable range for the system objective values or the electrical power source/sink levels. [0071] A function (e.g., a state map) may be estimated for each system objective that inputs a power source/sink levels and outputs a system objective value 508. The state map may be transmitted from the module 509. In some embodiments, the state map may be transmitted to a controller external to the module or that may communicate with the module and other modules. A control cycle process 510 may be provided for the controller, to be discussed in greater detail elsewhere herein. In some instances, the control cycle process illustrated in FIGURE 6 or any other control cycle process may be used. [0072] The module may receive a power allocation 511. In some embodiments, the power allocation may be provided from the controller. A control regulator of the module may source/sink the allocated power 512. Such sourcing/sinking may be detected by sensors and used to estimate a state of the module in a subsequent iteration.

[0073] Any of the steps described herein may be optional, or provided in another order, or may be interchangeable with other steps that perform similar functions. Preferably, the steps described may be provided by a module, but alternatively could be distributed between multiple modules or other components of a system. In some embodiments, the steps may be provided within a power system for a hybrid-electric or electric vehicle. Controller flow

[0074| FIGURE 6 shows an example of controller flow in accordance with an embodiment of the invention. A state map may be provided 601. In some embodiments, the state map may be provided to a controller. The controller may be external to a module. The controller may be physically separated from any module (a non-module controller), on a module controller, or distributed between module and/or non- module controllers. In some embodiments, if a module is provided as part of a system, such as a hybrid- electric or electric vehicle, the controller may be provided on the vehicle or external to the vehicle. [0075] Based on the received state maps, power allocation constraints may be determined 602. Based on information received from the module, constraints relating to the module or power allocation between modules may be considered.

[0076] System objectives may be provided 604 as previously discussed. The system objectives may be predefined and fixed. Alternatively, the system objectives may be user defined or automatically determined and/or variable. Also, objective weights may be provided 603. In some embodiments, the objective weights may be user defined and/or variable. Alternatively, they may be predefined or automatically defined. In some instances, the objective weights may be fixed. An objective function may be determined 605 based on the system objectives and/or the objective weights. Optionally, the objective function may be determined based on the system objectives alone, the objective weights alone, or any combination thereof.

[0077] An allowable power allocation that maximizes an objective function may be estimated 606. Preferably, the allowable power allocations may be determined based on the power allocation constraints and the objective function. In some alternate embodiments, the allowable power allocation may be determined based on power allocation constraints alone. In such a situation, an objective function need not be determined. Alternatively, the allowable power allocation may be determined based on the objective function alone, and need not rely on power allocation constraints. In such situations, state maps from one or more modules need not be considered.

[0078) When the allowable power allocations are determined, the power allocations may be transmitted to one or more modules 607. A control cycle process 608 may occur on one or more module. The module control cycle may be the flow process described in FIGURE 5, or may be some variation thereof. [0079] A controller may be in communication with one, two, or more modules. The state maps may be received at the controller from all modules within the system. Alternatively, the state maps from only a subset of the modules may be received. Similarly, the controller may transmit power allocations to all modules within the system. Alternatively, the controller may transmit power allocations to only a subset of the modules within the system. In some embodiments, the subsets of the modules providing the state maps and receiving the power allocations may be the same (i.e. overlap completely), or may include modules in common (i.e. overlap partially), or may have no modules in common (i.e. not overlap at all). [0080] Any of the steps described herein may be optional, or provided in another order, or may be interchangeable with other steps that perform similar functions. Preferably, the steps described may be provided by a module, but alternatively could be distributed between multiple modules or other components of a system. In some embodiments, the steps may be provided within a power system for a hybrid-electric or electric vehicle. In some instances, some or all of the steps may be performed at a hybrid-electric or electric vehicle. In some instances, some of the steps may be performed external to a hybrid-electric or electric vehicle. Example 1

[0081] In a preferable embodiment, the modules may be four battery packs, one 3-phase brushless electric machine capable of motoring and generating, one combustion engine driving a brushless 3-phase electric generator, and one power converter that may output constant 24 volts DC electricity (called the accessory converter). The system objectives may be system efficiency, mechanical torque output from the first electric machine, the RMS deviation from 24 VDC of the output of the accessory converter, and the remaining lifetime of all modules.

[0082] In past conventional systems, the four battery packs may have been connected all in series or parallel to a DC link. This link would be connected to the DC input of a 3-phase inverter for the brushless machine and the DC output of a 3-phase rectifier for the generator. The batteries would hold the DC link at a voltage equal to the sum of the battery voltages if the batteries were connected in series. If the batteries were the same voltage and connected in parallel, they would hold the DC link at their voltage. The accessory converter input may also have been connected to the same DC link. As the batteries source more power, their internal impedance causes the DC link voltage to sag. Also, the battery voltage and DC link voltage will decrease as the battery state of charge decreases. The other components would either receive less power as the DC link voltage was reduced, or they would need to compensate for the lower voltage and draw more current. Additionally, if any component connected to the DC link were to fail and begin drawing too much power, the batteries could continue to source dangerously high power levels. [0083] The invention proposes an alternative method to connect all of the above components that may allow controlled power transfer even if one component fails. This method may also allow power along the power bus voltage to vary for more efficient power transfer that is independent of battery voltage. First, the two modules with brushless electric machines may use 3-phase power inverter circuits as their regulator circuits. The four battery modules may use a bi-directional buck-boost converter connected between the battery cells and the power bus as their regulator circuits. An example of this circuit can be seen in FIGURE 3. The accessory module may use a DC/DC buck converter as its regulator circuit. In alternate embodiments of the invention, other circuits that may be able to provide desired connection or effect may be utilized.

[0084] The regulator circuit of each module may be connected to a shared insulated copper power cable and ground cable that may serve as the power bus. All modules may have on-board embedded controllers and memory. An embedded controller may determine the state maps for all of the modules. The state of charge of the batteries may be estimated and used to determine how much more energy the batteries can source or sink and at what power levels. The embedded controller may also calculate how battery lifetime and efficiency may be affected by battery power level. The controllers in each module may be connected to an external controller via a simple two-wire serial communications channel. [0085] A control algorithm may be run on an external controller. Its objective function may be to maximize efficiency and lifetime, with a defined tradeoff between efficiency and predicted lifetime. The objective function may also include a constraint that the electric machine must produce a minimum mechanical torque output. The control algorithm may use a gradient search method to determine the optimal power allocation plan. Example 2

[0086] As discussed previously, modular systems architecture may be used for various energy control applications. Such energy control applications may include hybrid-electric and electric vehicles. In some embodiments, any of the components described may be located on a vehicle. In some embodiments, some of the components described may be located off a vehicle. For example, in one embodiment, a power bus, one or more modules (e.g., a battery module, motor module, accessory module, and/or charging module), communications channel, and external controller may be part of a vehicle. In another example, a controller may be remotely located, and may communicate with one or more modules over a wireless connection. For any application of the modular systems architecture, the components may be located in any arrangement, and one or more components may or may not be remotely located from one or more other components.

[0087] It should be understood from the foregoing that, while particular implementations have been illustrated and described, various modifications can be made thereto and are contemplated herein. It is also not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the preferable embodiments herein are not meant to be construed in a limiting sense. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. Various modifications in form and detail of the embodiments of the invention will be apparent to a person skilled in the art. It is therefore contemplated that the invention shall also cover any such modifications, variations and equivalents.

[0088] As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the preferred embodiments of the invention without departing from the scope of this invention defined in the following claims.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A modular systems architecture, comprising: a plurality of modules connected to a variable voltage shared power bus; a communication channel between the modules; and a power control system for controlling the power flowing between the modules.

2. The architecture of claim 1 , wherein the shared power bus voltage is decoupled from a battery voltage.

3. The architecture of claim 1, wherein the modules include at least one of the following: a battery module, a motor module, an accessory module, or a charging module.

4. The architecture of claim 1, wherein each module has a power source or sink, a power regulator, a memory, and a means of communicating with other modules or external controllers.

5. The architecture of claim 4, wherein the power regulator connects the module to the shared power bus and controls the amount of power flowing between the module and shared power bus.

6. The architecture of claim 5, wherein the power regulator prevents power from flowing between the module and the shared power bus if the module is not connected to the communication channel.

7. The architecture of claim 1 wherein the power bus utilizes at least one of the following: high voltage DC cables, 3-phase AC cables, or 5-phase AC cables.

8. The architecture of claim 1 wherein the communication channel utilizes at least one of the following: controller-area-network (CAN), FlexRay, TCP/IP, or RS-232.

9. The architecture of claim 1 wherein each module regulates the current it sources/sinks on the shared power bus.

10. The architecture of claim 1 , wherein said architecture is provided for a hybrid-electric or electric vehicle.

1 1. The architecture of claim 10, wherein the power control system includes a controller that is on the hybrid-electric or electric vehicle.

12. The architecture of claim 10, wherein the power control system includes a controller that is external to the hybrid-electric or electric vehicle.

13. A method for controlling power allocation for a hybrid-electric or electric vehicle comprising: providing a plurality of modules connected to a power bus and in communication with a controller; receiving, at the controller, data from the modules about a state of the module; determining, based on the state data, power allocation constraints for the modules; and transmitting power allocations to the modules, thereby maintaining and/or varying the power bus voltage.

14. The method of claim 13 wherein each module has an embedded controller and memory.

15. The method of claim 13 wherein the power bus voltage is controlled by maintaining and/or varying current imbalances between the modules.

16. The method of claim 13 further comprising: providing an objective function, wherein the power allocation constraints are determined based on the objective function.

17. The method of claim 16, wherein the maintaining and/or varying the power bus voltage approaches and/or maintains the objective function.

18. The method of claim 16, wherein the objective function is at least one of the following: generating a desired amount of torque from an electric machine module, increasing battery life, controlling rotational speed, obtaining a desired system efficiency, or increasing remaining lifetime of modules.

19. The method of claim 16, wherein the objective function is defined and fixed.

20. The method of claim 16, wherein the objective function is determined by a user.

21. A method of controlling power allocation within a module of a hybrid-electric or electric vehicle comprising: estimating, at the module, a present state of the module; determining possible electrical power source/sink levels based on the estimated present state; transmitting state maps to an external controller; receiving, from the external controller, power allocation instructions; and controlling a regulator to source/sink the allocated power according to the power allocation instructions.

22. The method of claim 21, wherein said estimation of the present state of the module is based on collected sensor information and previous state information.

23. The method of claim 21, further comprising storing the present state of the module in a memory of the module.

24. The method of claim 21, further comprising: receiving a system objective; and estimating system objective values for given electrical power source/sink levels, based on system objectives.

25. The method of claim 24, wherein a state map is a function estimated for each system objective that inputs a power source/sink level and outputs a system objective value.