Enhanced short circuit detection and protection for circuits

Abstract

Energy storage systems are configured to operate with enhanced short circuit detection and protection features. Energy storage systems are configured to selectively manage inrush current within modules of the energy storage system. Techniques that detect and prevent transistor switching faults, sometimes referred to as shoot through, within power converters of the modules are described. Seamless transitions for an energy system switching between modes in an environment having a utility grid and a load, such as a microgrid, are described. Seamless transitions can include an adjustment of control loads that enables grid voltage managing to alleviate inrush current when the system is connected to the utility grid. The seamless transitions can also include the capability to detect a loss of less than all phases and continue operation of the energy system to form the lost phases such that power to the microgrid load is not interrupted.

Description

ENHANCED SHORT CIRCUIT DETECTION AND PROTECTION FOR CIRCUITSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of, and priority to, U.S. Provisional Application Serial No. 63 / 634,898, filed on April 16, 2024, which is incorporated by reference herein in its entirety for all purposes.FIELD

[0002] The subject matter described herein relates generally to systems, devices, and methods for modular energy storage systems.BACKGROUND

[0003] Energy storage systems are becoming more prevalent due to the growing popularity of electric vehicles, the desire to buffer energy from renewable energy generation sources, and the integration of storage systems in residential, commercial, and industrial environments. In electrical engineering, power engineering, and the electric power industry, power conversion is converting electric energy from one form to another, e.g., converting between alternating current (AC) and direct current (DC), adjusting the voltage or frequency, or some combination of these. A power converter is an electrical or electro-mechanical device for converting electrical energy. A power converter can be as simple as a transformer to change the voltage of AC power, but can also be implemented using far more complex systems. The term “power converter” can also refer to a class of electrical machinery that is used to convert one frequency of alternating current into another frequency. Power conversion systems often incorporate redundancy and voltage regulation. An example of a power converter is an inverter that converts DC into AC.

[0004] In power engineering, inverters are part of a class of devices called power electronics that regulate the flow of electrical power. An inverter is an electrical assembly that can facilitate power delivery to the grid or a microgrid load from a power source. Some inverters may accomplish DC-to-AC conversion by controlling switches in a prescribed manner. As a result, a DC input becomes an AC output. Two example types of inverters are stand-alone inverters and grid-connected inverters.

[0005] Safe operation of power converters, including grid support utility interactive inverters, can involve ceasing operation of the inverter during an overcurrent event, e.g., from a short circuit, overload, ground fault, or other reason. In addition, the converters should produce a voltage or current with low total harmonic distortion and low emissions of individual harmonics. For these and other reasons, needs exist for systems, devices, and methods to facilitate safe operation of power converters and to improve power quality of the power converters.SUMMARY

[0006] The example embodiments described herein provide for energy storage systems that are configured to operate with enhanced short circuit detection and protection features. Example embodiments are also described that allow energy storage systems to selectively manage inrush current within modules of the energy storage system. Example embodiments are also described that detect and prevent transistor switching faults, sometimes referred to as shoot through, within power converters of the modules. Example embodiments are described that enable seamless transitions for an energy system switching between modes in an environment having a utility grid and a load, such as a microgrid. Seamless transitions can include an adjustment of control loads that enables grid voltage managing to alleviate inrush current when the system is connected to the utility grid. The seamless transitions can also include the capability to detect a loss of less than all phases, sometimes referred to as a partial island condition, and continue operation of the energy system to form the lost phases such that power to the microgrid load is not interrupted.

[0007] Other systems, devices, methods, features and advantages of the subject matter described herein will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the subject matter described herein, and be protected by the accompanying claims. In no way should the features of the examples be construed as limiting the appended claims, absent express recitation of those features in the claims.BRIEF DESCRIPTION OF FIGURES

[0008] The details of the subject matter set forth herein, both as to its structure and operation, may be apparent by study of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead beingplaced upon illustrating the principles of the subject matter. Moreover, all illustrations are intended to convey concepts, where relative sizes, shapes and other detailed attributes may be illustrated schematically rather than literally or precisely.

[0009] FIGs. 1 A-1C are block diagrams depicting example implementations of a modular energy system.

[0010] FIGs. 1D-1E are block diagrams depicting example implementations of control devices for an energy system.

[0011] FIGs. 1F-1G are block diagrams depicting example implementations of modular energy systems coupled with a load and a charge source.

[0012] FIGs. 2A-2B are block diagrams depicting example implementations of a module and control system within an energy system.

[0013] FIG. 2C is a block diagram depicting an example implementation of a physical configuration of a module.

[0014] FIG. 2D is a block diagram depicting an example implementation of a physical configuration of a modular energy system.

[0015] FIGs. 3A-3C are block diagrams depicting example implementations of modules having various electrical configurations.

[0016] FIGs. 4A-4F are schematic views depicting example implementations of energy sources.

[0017] FIGs. 5A-5C are schematic views depicting example implementations of energy buffers.

[0018] FIGs. 6A-6C are schematic views depicting example implementations of converters.

[0019] FIGs. 7A-7E are block diagrams depicting example implementations of modular energy systems having various topologies.

[0020] FIG. 8A is a plot depicting an example output voltage of a module.

[0021] FIG. 8B is a plot depicting an example multilevel output voltage of an array of modules.

[0022] FIG. 8C is a plot depicting an example reference signal and carrier signals usable in a pulse width modulation control technique.

[0023] FIG. 8D is a plot depicting example reference signals and carrier signals usable in a pulse width modulation control technique.

[0024] FIG. 8E is a plot depicting example switch signals generated according to a pulse width modulation control technique.

[0025] FIG. 8F as a plot depicting an example multilevel output voltage generated by superposition of output voltages from an array of modules under a pulse width modulation control technique.

[0026] FIGs. 9A-9B are block diagrams depicting example implementations of controllers for a modular energy system.

[0027] FIG. 10A is a block diagram depicting an example implementation of a multiphase modular energy system having interconnection module.

[0028] FIG. 10B is a schematic diagram depicting an example implementation of an interconnection module in the multiphase embodiment of FIG. 10A.

[0029] FIG. 10C is a block diagram depicting an example implementation of a modular energy system having two subsystems connected together by interconnection modules.

[0030] FIG. 10D is a block diagram depicting an example implementation of a three-phase modular energy system having interconnection modules supplying auxiliary loads.

[0031] FIG. 10E is a schematic view depicting an example implementation of the interconnection modules in the multiphase embodiment of FIG. 10D.

[0032] FIG. 1 OF is a block diagram depicting another example implementation of a three- phase modular energy system having interconnection modules supplying auxiliary loads.

[0033] FIG. 11 A is a block diagram depicting an example embodiment of an energy storage system.

[0034] FIG. 1 IB is a block diagram depicting an example embodiment of a current manager.

[0035] FIG. 11C is a block diagram depicting an example embodiment of a current limiter.

[0036] FIG. 1 ID is a block diagram depicting an example embodiment of a current sensor and measurement circuit.

[0037] FIG. 1 IE is a schematic diagram depicting an example embodiment of a rapid short detector.

[0038] FIG. 12A is a schematic diagram depicting an example embodiment of a module having a shoot through detection circuit.

[0039] FIG. 12B is a schematic diagram depicting an example embodiment of a shoot through detection circuit configured to operate without a latch.

[0040] FIG. 12C is a schematic diagram depicting an example embodiment of shoot through detection circuit 1202 configured to operate with a latch.

[0041] FIG. 12D is a schematic view depicting an embodiment of a latch having a delay circuit.

[0042] FIG. 13 is a block diagram depicting an example of grid-connected system in which an energy storage system is connected to a load and a grid using circuit contactors.

[0043] FIG. 14A is an electrical equivalence diagram depicting the example of the grid- connected system in which the energy system is connected to the micro-grid load and the grid.

[0044] FIG. 14B is a flow diagram depicting an example embodiment of a method of operating an energy storage system connected to a grid and microgrid load.DETAILED DESCRIPTION

[0045] Before describing the example implementations pertaining to energy source control, it is first useful to describe these underlying systems in greater detail. With reference to FIGs. 1 A through 10F, the following sections describe various applications in which the modular energy systems can be implemented, implementations of control systems or devices for the modular energy systems, configurations of the modular energy systems with respect to charging sources and loads, implementations of individual modules, implementations of topologies for arrangement of the modules within the systems, implementations of control methodologies, implementations of balancing operating characteristics of modules within the systems, and implementations of the use of interconnection modules.Examples of Applications

[0046] Stationary applications are those in which the modular energy system is located in a fixed location during use, although it may be capable of being transported to alternative locations when not in use. The module-based energy system resides in a static location while providing electrical energy for consumption by one or more other entities, or storing or buffering energy for later consumption. Examples of stationary applications in which the implementations disclosed herein can be used include, but are not limited to: energy systems for use by or within one or more residential structures or locales, energy systems for use by or within one or more industrial structures or locales, energy systems for use by or within one or more commercial structures or locales, energy systems for use by or within one or more governmental structures orlocales, including both military and non-military uses, energy systems for charging the mobile applications described below, e.g., a charge source or a charging station, and systems that convert solar power, wind, geothermal energy, fossil fuels, or nuclear reactions into electricity for storage. Stationary applications often supply loads such as grids and microgrids, motors, and data centers. A stationary energy system can be used in either a storage or non-storage role.

[0047] Mobile applications, sometimes referred to as traction applications, are generally ones where a module-based energy system is located on or within an entity, and stores and provides electrical energy for conversion into motive force by a motor to move or assist in moving that entity. Examples of mobile entities with which the embodiments disclosed herein can be used include, but are not limited to, electric and / or hybrid entities that move over or under land, over or under sea, above and out of contact with land or sea, e.g., flying or hovering in the air, or through outer space. Examples of mobile entities with which the embodiments disclosed herein can be used include, but are not limited to, vehicles, trains, trams, ships, e.g., both surface ships and submarines, vessels, aircraft, and spacecraft. Examples of mobile vehicles with which the implementations disclosed herein can be used include, but are not limited to, those having only one wheel or track, those having only two-wheels or tracks, those having only three wheels or tracks, those having only four wheels or tracks, and those having five or more wheels or tracks. Examples of mobile entities with which the implementations disclosed herein can be used include, but are not limited to, a car, a bus, a truck, a motorcycle, a scooter, an industrial vehicle, a mining vehicle, construction and utility vehicles, a flying vehicle, e.g., a plane, a helicopter, a drone, etc., a maritime vessel, e.g., commercial shipping vessels, ships, yachts, boats, container ships, ferries, barges, or other watercraft, a submarine, a locomotive or rail-based vehicle, e.g., a train, a tram, etc., a military vehicles including land, sea and air craft, a spacecraft, and a satellite.

[0048] In some mobile applications for mobile entities, the systems described herein can provide power for a single engine that provides power to one or multiple wheels or tracks of land based vehicles, or one or multiple propellers on surface ships and submarines, or one or multiple propellers or rotors on aircraft. In some mobile applications for mobile entities, the systems herein can provide power for multiple engines, where each engine of the multiple engines provides power to one or more individual tracks or wheels of a multi-tracked or multi-wheeled land based vehicle, one or more individual propellers on a multi-propeller surface ship or multi-propeller submarine, and one or more individual propellers or individual rotors on a multipropeller or multi-rotor aircraft. The systems described herein can provide power for other types of land, sea and air propulsions systems not listed above.

[0049] In some mobile applications for mobile entities, the systems described herein can provide power for auxiliary systems in land based vehicles, surface ships and submarines, and aircraft. The power can, in some embodiments, be provided in addition to the power provided to the propulsion systems as described above.

[0050] The mobile applications described above include mobile applications for private mobile entities, commercial mobile entities, and military / government mobile entities. Examples of private mobile entities include personal conveyances, pleasure crafts, campers, planes, helicopters, utility vehicles, and other privately owned mobile entities. Examples of commercial mobile entities include vehicles for hire, fleet assets including land, sea and air capable mobile entities, and other commercial mobile entities. Such commercial mobile entities may be used for passenger conveyance, cargo conveyance, passenger and cargo conveyance, construction, mining, etc. Examples of construction and mining vehicles include dump trucks, excavators, cranes, graders, forklifts, bulldozers, loaders, backhoes, compactors, mixers, e.g., concrete mixers, tractors, haul trucks, mining transport trucks, and the like. Examples of military or government mobile entities government agency fleet assets including land, sea and air mobile entities of all classes, military fleet assets including land, sea and air mobile entities of all classes), and other govemment / military mobile entities. Such government / military mobile entities can be used for passenger conveyance, cargo conveyance, passenger and cargo conveyance, construction, first response activities, law enforcement activities, military activities, etc.

[0051] In describing implementations herein, reference may be made to a particular stationary application, e.g., grid, micro-grid, data centers, cloud computing environments, or mobile application, e.g., an electric car. Such references are made for ease of explanation and do not mean that a particular embodiment is limited for use to only that particular mobile or stationary application. Implementations of systems providing power to a motor can be used in both mobile and stationary applications. While certain configurations may be more suitable to some applications over others, all example implementations disclosed herein are capable of use in both mobile and stationary applications unless otherwise noted.Module-based Energy System Examples

[0052] FIG. 1 A is a block diagram depicts an example embodiment of a module-based energy system 100. Here, the system 100 includes a control system 102 communicatively coupled with N converter-source modules 108-1 through 108-N, over communication paths or links 106-1 through 106-N, respectively. The modules 108 are configured to store energy and output the energy as needed to a load 101 or other modules 108. In these implementations, any number of two or more modules 108 can be used, e.g., N is greater than or equal to two. The modules 108 can be connected to each other in a variety of manners as will be described in more detail with respect to FIGs. 7A-7E. For ease of illustration, in FIGs. 1 A-1C, the modules 108 are shown connected in series, or as a one dimensional array, where the Nth module is coupled to a load 101.

[0053] The system 100 is configured to supply power to a load 101. The load 101 can be any type of load such as a motor or a grid. The system 100 is also configured to store power received from a charge source. FIG. IF is a block diagram depicting an example embodiment of the system 100 with a power input interface 151 for receiving power from a charge source 150 and a power output interface for outputting power to a load 101. In this example implementation, the system 100 can receive and store power over the interface 151 at the same time as outputting power over interface 152. FIG. 1G is a block diagram depicting another example implementation of the system 100 with a switchable interface 154. In this example implementation, the system 100 can select, or be instructed to select, between receiving power from a charge source 150 and outputting power to a load 101. The system 100 can be configured to supply multiple loads 101, including both primary and auxiliary loads, and / or receive power from multiple charge sources 150, e.g., a utility-operated power grid and a local renewable energy source, e.g., solar.

[0054] FIG. IB depicts another example implementation of a system 100. Here, the control system 102 is implemented as a main control device (MCD) 112 communicatively coupled with N different local control devices (LCDs) 114-1 through 114-N over communication paths or links 115-1 through 115-N, respectively. Each LCD 114-1 through 114-N is communicatively coupled with one module 108-1 through 108-N over communication paths or links 116-1 through 116-N, respectively, such that there is a 1 : 1 relationship between LCDs 114 and modules 108.

[0055] FIG. 1 C depicts another example implementation of a system 100. Here, the MCD 112 is communicatively coupled with M different LCDs 114-1 to 114-M over communication paths or links 115-1 to 115-M, respectively. Each LCD 114 can be coupled with and control two or more modules 108. In the example shown here, each LCD 114 is communicatively coupled with two modules 108, such that M LCDs 114-1 to 114-M are coupled with 2M modules 108-1 through 108-2M over communication paths or links 116-1 to 116-2M, respectively.

[0056] The control system 102 can be configured as a single device, e.g., FIG. 1A, for the entire system 100 or can be distributed across or implemented as multiple devices, e.g., FIGs. 1B-1C. In some implementations, control subsystem can be distributed between LCDs 114 associated with the modules 108, such that no MCD 112 is necessary and can be omitted from system 100.

[0057] The control system 102 can be configured to execute control using software, e.g., instructions stored in memory that are executable by processing circuitry, hardware, or a combination thereof. The one or more devices of the control system 102 can each include processing circuitry 120 and memory 122 as shown here. Example implementations of processing circuitry and memory are described further below.

[0058] The control system 102 can have a communicative interface for communicating with devices 104 external to the system 100 over a communication link or path 105. For example, the control system 102, e.g., MCD 112, can output data or information about system 100 to another control device 104, e.g., the Electronic Control Unit (ECU) or Motor Control Unit (MCU) of a vehicle in a mobile application, grid controller in a stationary application, etc.

[0059] The communication paths or links 105, 106, 115, 116, and 118 (FIG. 2B) can each be wired, e.g., electrical and / or optical, or wireless communication paths that communicate data or information bidirectionally, in parallel or series fashion. Data can be communicated in a standardized, e.g., IEEE, ANSI, or custom, e.g., proprietary, format. In automotive applications, the communication paths 115 can be configured to communicate according to FlexRay or CAN protocols. The communication paths 106, 115, 116, and 118 can also provide wired power to directly supply the operating power for the control system 102 from one or more modules 108. For example, the operating power for each LCD 114 can be supplied only by the one or more modules 108 to which that LCD 114 is connected and the operating power for MCD 112 can besupplied indirectly from one or more of modules 108, e.g., such as through a car’s power network.

[0060] The control system 102 is configured to control one or more modules 108 based on status information received from the same or different one or more of modules 108. Control can also be based on one or more other factors, such as requirements of load 101. Controllable aspects include, but are not limited to, one or more of voltage, current, phase, and / or output power of each module 108.

[0061] Status information of every module 108 in system 100 can be communicated to the control system 102, from which the control system 102 can independently control every module 108-1. . . 108-N. Other variations are possible. For example, a particular module 108 or subset of modules 108 can be controlled based on status information of that particular module 108 or subset, based on status information of a different module 108 that is not that particular module 108 or subset, based on status information of all modules 108 other than that particular module 108 or subset based on status information of that particular module 108 or subset and status information of at least one other module 108 that is not that particular module 108(or subset, or based on status information of all modules 108 in system 100.

[0062] The status information can be information about one or more aspects, characteristics, or parameters of each module 108. Types of status information include, but are not limited to, the following aspects of a module 108 or one or more components thereof, e.g., energy source, energy buffer, converter, monitor circuitry: State of Charge (SOC), e.g., the level of available charge of an energy source relative to its capacity, such as a fraction or percent, of the one or more energy sources of the module 108, State of Health (SOH), e.g., a figure of merit of the physical condition, such as age, of an energy source compared to its ideal conditions, of the one or more energy sources of the module 108, temperature of the one or more energy sources or other components of the module 108, capacity of the one or more energy sources of the module 108, voltage of the one or more energy sources and / or other components of the module 108, current of the one or more energy sources and / or other components of the module 108, State of Power (SOP) (e.g., the available power limitation of the energy source during discharge and / or charge), State of Energy (SOE), e.g., the present level of available energy of an energy source relative to the maximum available energy of the source, and / or the presence of absence of a fault in any one or more of the components of the module 108.

[0063] The LCDs 114 can be configured to receive the status information from each module 108, or determine the status information from monitored signals or data received from or within each module 108, and communicate that information to the MCD 112. In some implementations, each LCD 114 can communicate raw collected data to the MCD 112, which then algorithmically determines the status information on the basis of that raw data. The MCD 112 can then use the status information of the modules 108 to make control determinations accordingly. The determinations may take the form of instructions, commands, or other information, such as a modulation index described herein, that can be utilized by LCDs 114 to either maintain or adjust the operation of each module 108.

[0064] For example, the MCD 112 may receive status information and assess that information to determine a difference between at least one module 108, e.g., a component thereof, and at least one or more other modules 108, e.g., comparable components thereof. For example, the MDC 112 may determine that a particular module 108 is operating with one of the following conditions as compared to one or more other modules 108: with a relatively lower or higher SOC, with a relatively lower or higher SOH, with a relatively lower or higher capacity, with a relatively lower or higher voltage, with a relatively lower or higher current, with a relatively lower or higher temperature, or with or without a fault. In such examples, the MCD 112 can output control information that causes the relevant aspect, e.g., output voltage, current, power, temperature, of that particular module 108 to be reduced or increased, e.g., depending on the condition. In this manner, the utilization of an outlier module 108, e.g., operating with a relatively lower SOC or higher temperature, can be reduced so as to cause the relevant parameter of that module 108, e.g., SOC or temperature, to converge towards that of one or more other modules 108.

[0065] The determination of whether to adjust the operation of a particular module 108 can be made by comparison of the status information to predetermined thresholds, limits, or conditions, and not necessarily by comparison to statuses of other modules 108. The predetermined thresholds, limits, or conditions can be static thresholds, limits, or conditions, such as those set by the manufacturer that do not change during use. The predetermined thresholds, limits, or conditions can be dynamic thresholds, limits, or conditions, that are permitted to change, or that do change, during use. For example, the MCD 112 can adjust the operation of a module 108 if the status information for that module 108 indicates it to beoperating in violation of, e.g., above or below, a predetermined threshold or limit, or outside of a predetermined range of acceptable operating conditions. Similarly, the MCD 112 can adjust the operation of a module 108 if the status information for that module 108 indicates the presence of an actual or potential fault, e.g., an alarm, or warning, or indicates the absence or removal of an actual or potential fault. Examples of a fault include, but are not limited to, an actual failure of a component, a potential failure of a component, a short circuit or other excessive current condition, an open circuit, an excessive voltage condition, a failure to receive a communication, the receipt of corrupted data, and the like. Depending on the type and severity of the fault, the faulty module’s utilization can be decreased to avoid damaging the module, or the module’s utilization can be ceased altogether.

[0066] The MCD 112 can control modules 108 within the system 100 to achieve or converge towards a desired target. The target can be, for example, operation of all modules 108 at the same or similar levels with respect to each other, or within predetermined thresholds limits, or conditions. This process is also referred to as balancing or seeking to achieve balance in the operation or operating characteristics of modules 108. The term “balance” as used herein does not require absolute equality between modules 108 or components thereof, but rather is used in a broad sense to convey that operation of system 100 can be used to actively reduce or otherwise manage disparities in operation, or operative state, between modules 108 that would otherwise exist. For example, as described below, the disparities can be managed based on the distance from the system 100 to a charge source 150. In such cases, the disparities between the operating parameters of modules 108 or sources of a module 108 may be increased based on the distance to reduce the time required to charge the sources of the system 100.

[0067] The MCD 112 can communicate control information to an LCD 114 for the purpose of controlling the modules 108 associated with the LCD 114. The control information can be, e.g., a modulation index and a reference signal as described herein, a modulated reference signal, or otherwise. Each LCD 114 can use, e.g., receive and process, the control information to generate switch signals that control operation of one or more components, e.g., a converter, within the associated module(s) 108. In some implementations, the MCD 112 generates the switch signals directly and outputs them to the LCD 114, which relays the switch signals to the intended module component.

[0068] All or a portion of the control system 102 can be combined with a system external control device 104 that controls one or more other aspects of the mobile or stationary application. When integrated in this shared or common control device or subsystem, control of the system 100 can be implemented in any desired fashion, such as one or more software applications executed by processing circuitry of the shared device, with hardware of the shared device, or a combination thereof. Non-exhaustive examples of external control devices 104 include: a vehicular ECU or MCU having control capability for one or more other vehicular functions, e.g., motor control, driver interface control, traction control, etc.; a grid or micro-grid controller having responsibility for one or more other power management functions, e.g., load interfacing, load power requirement forecasting, transmission and switching, interface with charge sources, e.g., diesel, solar, wind, charge source power forecasting, back up source monitoring, asset dispatch, etc.; and a data center control subsystem, e g., environmental control, network control, backup control, etc..

[0069] FIGs. ID and IE are block diagrams depicting example implementations of a shared or common control device or system 132 in which control system 102 can be implemented. In FIG. ID, a common control device 132 includes an MCD 112 and external control device 104. The MCD 112 includes an interface 141 for communication with LCDs 114 over path 115, as well as an interface 142 for communication with external control device 104 over internal communication bus 136. The external control device 104 includes an interface 143 for communication with main control device 112 over bus 136, and an interface 144 for communication with other entities, e.g., components of the vehicle or grid, of the overall application over communication path 136. In some implementations, the common control device 132 can be integrated as a common housing or package with devices 112 and 104 implemented as discrete integrated circuit (IC) chips or packages contained therein.

[0070] In FIG. IE, the external control device 104 acts as common control device 132, with the main control functionality implemented as a component within device 104. This component 112 can be or include software or other program instructions stored and / or hardcoded within memory of device 104 and executed by processing circuitry thereof. The component can also contain dedicated hardware. The component can be a self-contained module or core, with one or more internal hardware and / or software interfaces, e.g., application program interface (API) for communication with the operating software of external control device 104. The external controldevice 104 can manage communication with LCDs 1 14 over interface 141 and other devices over interface 144. In various implementations, device 104 / 132 can be integrated as a single IC chip, can be integrated into multiple IC chips in a single package, or integrated as multiple semiconductor packages within a common housing.

[0071] In the implementations of FIGs. ID and IE, the main control functionality of the control system 102 is shared in common device 132, however, other divisions of shared control or permitted. For example, part of the main control functionality can be distributed between common device 132 and a dedicated MCD 112. In another example, both the main control functionality and at least part of the local control functionality can be implemented in common device 132, e.g., with remaining local control functionality implemented in LCDs 114. In some implementations, all of control system 102 is implemented in common device or subsystem 132. In some implementations, local control functionality is implemented within a device shared with another component of each module 108, such as a Battery Management System (BMS).Modules within Cascaded Energy System Examples

[0072] A module 108 can include one or more energy sources and a power electronics converter and, if desired, an energy buffer. FIGs. 2A-2B are block diagrams depicting additional example implementations of a system 100 with module 108 having a power converter 202, an energy buffer 204, and an energy source 206. The converter 202 can be a voltage converter or a current converter. The implementations are described herein with reference to voltage converters, although the implementations are not limited to such. The converter 202 can be configured to convert a direct current (DC) signal from energy source 204 into an alternating current (AC) signal and output it over power connection 110, e.g., an inverter. The converter 202 can also receive an AC or DC signal over connection 110 and apply it to energy source 204 with either polarity in a continuous or pulsed form. The converter 202 can be or include an arrangement of switches, e.g., power transistors, such as a half bridge of full bridge (H-bridge). In some implementations, the converter 202 includes only switches and the converter, and the module as a whole, does not include a transformer.

[0073] The converter 202 can be also, or alternatively be, configured to perform AC to DC conversion, e.g., a rectifier, such as to charge a DC energy source from an AC source, DC to DC conversion, and / or AC to AC conversion, e.g., in combination with an AC-DC converter. In some implementations, such as to perform AC-AC conversion, the converter 202 can include atransformer, either alone or in combination with one or more power semiconductors, e.g., switches, diodes, thyristors, and the like. In other implementations, such as those where weight and cost is a significant factor, the converter 202 can be configured to perform the conversions with only power switches, power diodes, or other semiconductor devices and without a transformer.

[0074] The energy source 206 is preferably a robust energy storage device capable of outputting direct current and having an energy density suitable for energy storage applications for electrically powered devices. The energy source 206 can be an electrochemical battery, such as a single battery cell or multiple battery cells connected together in a battery module or array, or any combination thereof. FIGs. 4A-4D are schematic diagrams depicting example implementations of an energy source 206 configured as a single battery cell 402 (FIG. 4A), a battery module with a series connection of four cells 402 (FIG. 4B), a battery module with a parallel connection of single cells 402 (FIG. 4C), and a battery module with a parallel connection with legs having two cells 402 each (FIG. 4D). A non-exhaustive list of examples of battery types suitable for use with the present subject matter include solid state batteries, liquid electrotype based batteries, liquid phase batteries as well as flow batteries such as lithium (Li) metal batteries, Li ion batteries, Li air batteries, sodium ion batteries, potassium ion batteries, magnesium ion batteries, alkaline batteries, nickel metal hydride batteries, nickel sulfate batteries, lead acid batteries, zinc-air batteries, and others. Some examples of Li ion battery types include Li cobalt oxide (LCO), Li manganese oxide (LMO), Li nickel manganese cobalt oxide (NMC), Li iron phosphate (LFP), Li nickel cobalt aluminum oxide (NCA), and Li titanate (LTO).

[0075] The energy source 206 can also be a high energy density (HED) capacitor, such as an ultracapacitor or supercapacitor. An HED capacitor can be configured as a double layer capacitor (electrostatic charge storage), pseudocapacitor (electrochemical charge storage), hybrid capacitor (electrostatic and electrochemical), or otherwise, as opposed to a solid dielectric type of a typical electrolytic capacitor. The HED capacitor can have an energy density of 10 to 100 times or higher than that of an electrolytic capacitor, in addition to a higher capacity. For example, HED capacitors can have a specific energy greater than 1.0 watt hours per kilogram (Wh / kg), and a capacitance greater than 10-100 farads (F). As with the batteries described with respect to FIGs. 4A-4D, energy source 206 can be configured as a single HED capacitor ormultiple HED capacitors connected together in an array, e.g., series, parallel, or a combination thereof.

[0076] The energy source 206 can also be a fuel cell. The fuel cell can be a single fuel cell, multiple fuel cells connected in series or parallel, or a fuel cell module. Examples of fuel cell types include proton-exchange membrane fuel cells (PEMFC), phosphoric acid fuel cells (PAFC), solid acid fuel cells, alkaline fuel cells, high temperature fuel cells, solid oxide fuel cells, molten electrolyte fuel cells, and others. As with the batteries described with respect to FIGs. 4A-4D, the energy source 206 can be configured as a single fuel cell or multiple fuel cells connected together in an array, e.g., series, parallel, or a combination thereof. The aforementioned examples of source classes, e.g., batteries, capacitors, and fuel cells, and types, e.g., chemistries and / or structural configurations within each class, are not intended to form an exhaustive list, and those of ordinary skill in the art will recognize other variants that fall within the scope of the present subject matter.

[0077] The energy buffer 204 can dampen or filter fluctuations in current across the DC line or link (e.g., +VDCL and -VDCL as described below), to assist in maintaining stability in the DC link voltage. These fluctuations can be relatively low (e.g., kilohertz) or high (e.g., megahertz) frequency fluctuations or harmonics caused by the switching of the converter 202, or other transients. These fluctuations can be absorbed by the buffer 204 instead of being passed to source 206 or to ports IO3 and IO4 of converter 202.

[0078] The power connection 110 is a connection for transferring energy or power to, from and through the module 108. The module 108 can output energy from energy source 206 to the power connection 110, where it can be transferred to other modules 108 of the system or to a load. The module 108 can also receive energy from other modules 108 or a charging source (DC charger, single phase charger, multi-phase charger). Signals can also be passed through the module 108 bypassing the energy source 206. The routing of energy or power into and out of module 108 is performed by the converter 202 under the control of the LCD 114 or another entity of the control system 102.

[0079] In the implementation of FIG. 2A, the LCD 114 is implemented as a component separate from module 108, e.g., not within a shared module housing, and is connected to and capable of communication with the converter 202 via communication path 116. In the implementation of FIG. 2B, the LCD 114 is included as a component of the module 108 and isconnected to and capable of communication with the converter 202 via an internal communication path 118 e.g., a shared bus or discrete connections. The LCD 114 can also be capable of receiving signals from, and transmitting signals to, the energy buffer 204 and / or the energy source 206 over paths 116 or 118.

[0080] The module 108 can also include monitor circuitry 208 configured to monitor, e g., collect, sense, measure, and / or determine, one or more aspects of the module 108 and / or the components thereof, such as voltage, current, temperature or other operating parameters that constitute status information, or can be used to determine status information by, e.g., the LCD 114. A main function of the status information is to describe the state of the one or more energy sources 206 of the module 108 to enable determinations as to how much to utilize the energy source in comparison to other sources in system 100, although status information describing the state of other components, e.g., voltage, temperature, and / or presence of a fault in buffer 204, temperature and / or presence of a fault in converter 202, presence of a fault elsewhere in module 108, etc., can be used in the utilization determination as well. The monitor circuitry 208 can include one or more sensors, shunts, dividers, fault detectors, Coulomb counters, controllers or other hardware and / or software configured to monitor such aspects. The monitor circuitry 208 can be separate from the various components 202, 204, and 206, or can be integrated with each component 202, 204, and 206, as shown in FIGs. 2A-2B, or any combination thereof. In some implementations, the monitor circuitry 208 can be part of or shared with a Battery Management System (BMS) for a battery energy source 204. Discrete circuitry is not needed to monitor each type of status information, as more than one type of status information can be monitored with a single circuit or device, or otherwise algorithmically determined without the need for additional circuits.

[0081] The LCD 114 can receive status information or raw data about the module components over communication paths 116, 118. The LCD 114 can also transmit information to module components over paths 116, 118. The paths 116 and 118 can include diagnostics, measurement, protection, and / or control signal lines. The transmitted information can be control signals for one or more module components. The control signals can be switch signals for the converter 202 and / or one or more signals that request the status information from module components. For example, the LCD 114 can cause the status information to be transmitted over the paths 116, 118 by requesting the status information directly, or by applying a stimulus, e.g., voltage, to cause thestatus information to be generated, in some cases in combination with switch signals that place the converter 202 in a particular state.

[0082] The physical configuration or layout of the module 108 can take various forms. In some implementations, the module 108 can include a common housing in which all module components, e.g., converter 202, buffer 204, and source 206, are housed, along with other optional components such as an integrated LCD 114. In other implementations, the various components can be separated in discrete housings that are secured together. FIG. 2C is a block diagram depicting an example implementation of a module 108 having a first housing 220 that holds an energy source 206 of the module and accompanying electronics such as monitor circuitry, a second housing 222 that holds module electronics such as the converter 202, energy the buffer 204, and other accompany electronics such as monitor circuitry, and a third housing 224 that holds the LCD 114 for the module 108. Electrical connections between the various module components can proceed through the housings 220, 222, 224 and can be exposed on any of the housing exteriors for connection with other devices such as other modules 108 or the MCD 112.

[0083] The modules 108 of the system 100 can be physically arranged with respect to each other in various configurations that depend on the needs of the application and the number of loads. For example, in a stationary application where the system 100 provides power for a microgrid, the modules 108 can be placed in one or more racks or other frameworks. Such configurations may be suitable for larger mobile applications as well, such as maritime vessels. Alternatively, the modules 108 can be secured together and located within a common housing, referred to as a pack. A rack or a pack may have its own dedicated cooling system shared across all modules. Pack configurations are useful for smaller mobile applications such as electric cars. The system 100 can be implemented with one or more racks, e.g., for parallel supply to a microgrid, or one or more packs, e.g., serving different motors of the vehicle, or combination thereof. FIG. 2D is a block diagram depicting an example implementation of system 100 configured as a pack with nine modules 108 electrically and physically coupled together within a common housing 230.

[0084] Examples of these and further configurations are described in IntT. Appl. No. PCT / US20 / 25366, filed March 27, 2020 and titled Module-Based Energy Systems Capable ofCascaded and Interconnected Configurations, and Methods Related Thereto, which is incorporated by reference herein in its entirety for all purposes.

[0085] FIGs. 3A-3C are block diagrams depicting example implementations of modules 108 having various electrical configurations. These implementations are described as having one LCD 114 per module 108, with the LCD 114 housed within the associated module, but can be configured otherwise as described herein. FIG. 3A depicts a first example configuration of a module 108A within a system 100. The module 108A includes an energy source 206, an energy buffer 204, and a converter 202A. Each component has power connection ports, e.g., terminals and / or connectors, into which power can be input and / or from which power can be output, referred to herein as IO ports. Such ports can also be referred to as input ports or output ports depending on the context.

[0086] The energy source 206 can be configured as any of the energy source classes described herein, e.g., a battery as described with respect to FIGs. 4A-4D, an HED capacitor, a fuel cell, or otherwise. Ports IO1 and IO2 of the energy source 206 can be connected to ports101 and IO2, respectively, of the energy buffer 204. The energy buffer 204 can be configured to buffer or filter high and low frequency energy pulsations arriving at the buffer 204 through the converter 202, which can otherwise degrade the performance of the module 108. The topology and components for the buffer 204 are selected to accommodate the maximum permissible amplitude of these high frequency voltage pulsations. Several non-exhaustive example implementations of the energy buffer 204 are depicted in the schematic diagrams of FIGs. 5A- 5C. In FIG. 5A, the buffer 204 is an electrolytic and / or film capacitor CEB; in FIG. 5B the buffer 204 is a Z-source network 710, formed by two inductors LEBI and LEB2 and two electrolytic and / or film capacitors CEBI and CEB2; and in FIG. 5C, the buffer 204 is a quasi Z-source network 720, formed by two inductors LEBI and LEB2, two electrolytic and / or film capacitors CEBI and CEB2 and a diode DEB.

[0087] Ports IO3 and IO4 of the energy buffer 204 can be connected to ports IO1 and IO2, respectively, of the converter 202A, which can be configured as any of the power converter types described herein. FIG. 6A is a schematic diagram depicting an example implementation of a converter 202A configured as a DC-AC converter that can receive a DC voltage at ports IO1 and102 and switch to generate pulses at ports IO3 and IO4. The converter 202A can include multiple switches, and here converter 202A includes four switches S3, S4, S5, S6 arranged in afull bridge configuration. The control system 102 or LCD 1 14 can independently control each switch via control input lines 118-3 to each gate.

[0088] The switches can be any suitable switch type, such as power semiconductors like the metal-oxide-semi conductor field-effect transistors (MOSFETs) shown here, insulated gate bipolar transistors (IGBTs), or gallium nitride (GaN) transistors. Semiconductor switches can operate at relatively high switching frequencies, thereby permitting the converter 202 to be operated in pulse-width modulated (PWM) mode if desired, and to respond to control commands within a relatively short interval of time. This can provide a high tolerance of output voltage regulation and fast dynamic behavior in transient modes.

[0089] In this implementation, a DC line voltage VDCL can be applied to converter 202 between ports IO1 and IO2. By connecting VDCL to ports IO3 and IO4 by different combinations of switches S3, S4, S5, S6, converter 202 can generate three different voltage outputs at ports IO3 and 104: +VDCL, 0, and -VDCL. A switch signal provided to each switch controls whether the switch is on (closed) or off (open). To obtain +VDCL, switches S3 and S6 are turned on while S4 and S5 are turned off, whereas -VDCL can be obtained by turning on switches S4 and S5 and turning off S3 and S6. The output voltage can be set to zero, including near zero, or a reference voltage by turning on S3 and S5 with S4 and S6 off, or by turning on S4 and S6 with S3 and S5 off. These voltages can be output from the module 108 over the power connection 110. Ports IO3 and 104 of the converter 202 can be connected to or form module IO ports 1 and 2 of the power connection 110, so as to generate the output voltage for use with output voltages from other modules 108.

[0090] The control or switch signals for the implementations of the converter 202 described herein can be generated in different ways depending on the control technique utilized by the system 100 to generate the output voltage of the converter 202. In some implementations, the control technique is a PWM technique such as space vector pulse-width modulation (SVPWM) or sinusoidal pulse-width modulation (SPWM), or variations thereof. FIG. 8A is a graph of voltage versus time depicting an example of an output voltage waveform 802 of a converter 202. For ease of description, the implementations herein will be described in the context of a PWM control technique, although the implementations are not limited to such. Other classes of techniques can be used. One alternative class is based on hysteresis, examples of which aredescribed in Int’l Publ. Nos. WO 2018 / 231810A1, WO 2018 / 232403 Al, and WO 2019 / 183553A1, which are incorporated by reference herein for all purposes.

[0091] Each module 108 can be configured with multiple energy sources 206, e.g., two, three, four, or more. Each energy source 206 of the module 108 can be controllable, e.g., switchable, to supply power to connection 110 or receive power from a charge source independent of the other sources 206 of the module 108. For example, all sources 206 can output power to the connection 110 or be charged at the same time, or only one or a subset of sources 206 can supply power or be charged at any one time. In some implementations, the sources 206 of the module 108 can exchange energy between them, e.g., one source 206 can charge another source 206. Each of the sources 206 can be configured as any energy source described herein, e.g., battery, HED capacitor, fuel cell. Each of the sources 206 can be the same class, e.g., each can be a battery, each can be an HED capacitor, or each can be a fuel cell, or a different class, e g., a first source can be a battery and a second source can be an HED capacitor or fuel cell, or a first source can be an HED capacitor and a second source can be a fuel cell.

[0092] FIG. 3B is a block diagram depicting an example implementation of a module 108B in a dual energy source configuration with a primary energy source 206A and secondary energy source 206B. Ports IO1 and IO2 of the primary source 202 A can be connected to ports IO1 and IO2 of an energy buffer 204. The module 108B includes a converter 202B having an additional IO port. Ports IO3 and IO4 of the buffer 204 can be connected ports IO1 and IO2, respectively, of the converter 202B. Ports IO1 and IO2 of the secondary source 206B can be connected to ports IO5 and IO2, respectively, of the converter 202B, which is also connected to port IO4 of the buffer 204.

[0093] In this example implementation of module 108B, the primary energy source 202A, along with the other modules 108 of system 100, supplies the average power needed by the load. The secondary source 202B can serve the function of assisting the energy source 202A by providing additional power at load power peaks, or absorbing excess power, or otherwise.

[0094] As mentioned both the primary source 206A and the secondary source 206B can be utilized simultaneously or at separate times depending on the switch state of the converter 202B. If at the same time, an electrolytic and / or a film capacitor (CES) can be placed in parallel with the source 206B as depicted in FIG. 4E to act as an energy buffer for the source 206B, or the energysource 206B can be configured to utilize an HED capacitor in parallel with another energy source, e.g., a battery or fuel cell, as depicted in FIG. 4F.

[0095] FIGs. 6B and 6C are schematic views depicting example implementations of converters 202B and 202C, respectively. The converter 202B includes switch circuitry portions 601 and 602A. The portion 601 includes switches S3 through S6 configured as a full bridge in similar manner to the converter 202A, and is configured to selectively couple 101 and IO2 to either of IO3 and 104, thereby changing the output voltages of the module 108B. Portion 602A includes switches SI and S2 configured as a half bridge and coupled between ports 101 and 102. A coupling inductor LB is connected between port 105 and a nodel present between switches SI and S2 such that switch portion 602A is a bidirectional converter that can regulate (boost or buck) voltage (or inversely current). The switch portion 602A can generate two different voltages at nodel, which are +VDCL2 and 0, referenced to port 102, which can be at virtual zero potential. The current drawn from or input to the energy source 202B can be controlled by regulating the voltage on coupling inductor LB, using, for example, a pulse-width modulation technique or a hysteresis control method for commutating switches SI and S2. Other techniques can also be used.

[0096] The converter 202C differs from that of the converter 202B as the switch portion 602B includes switches SI and S2 configured as a half bridge and coupled between ports 105 and 102. A coupling inductor LB is connected between port 101 and a nodel present between switches SI and S2 such that the switch portion 602B is configured to regulate voltage.

[0097] The control system 102 or the LCD 114 can independently control each switch of the converters 202B and 202C via control input lines 118-3 to each gate. In these implementations and that of FIG. 6A, the LCD 114, not MCD 112, generates the switching signals for the converter switches. Alternatively, the MCD 112 can generate the switching signals, which can be communicated directly to the switches, or relayed by the LCD 114.

[0098] In implementations where a module 108 includes three or more energy sources 206, the converters 202B and 202C can be scaled accordingly such that each additional energy source 206B is coupled to an additional IO port leading to an additional switch circuitry portion 602A or 602B, depending on the needs of the particular source. For example a dual source converter 202 can include both switch portions 202A and 202B.

[0099] Modules 108 with multiple energy sources 206 are capable of performing additional functions such as energy sharing between sources 206, energy capture from within the application, e.g., regenerative braking, charging of the primary source by the secondary source even while the overall system is in a state of discharge, and active filtering of the module output. The active filtering function can also be performed by modules 108 having a typical electrolytic capacitor instead of a secondary energy source. Examples of these functions are described in more detail in Int’l. Appl. No. PCT / US20 / 25366, filed March 27, 2020 and titled Module-Based Energy Systems Capable of Cascaded and Interconnected Configurations, and Methods Related Thereto, and Int’l. Publ. No. WO 2019 / 183553, filed March 22, 2019, and titled Systems and Methods for Power Management and Control, both of which are incorporated by reference herein in their entireties for all purposes.

[0100] Each module 108 can be configured to supply one or more auxiliary loads with its one or more energy sources 206. Auxiliary loads are loads that require lower voltages than the primary load 101. Examples of auxiliary loads can be, for example, an on-board electrical network of an electric vehicle, or an HVAC system of an electric vehicle. The load of system 100 can be, for example, one of the phases of the electric vehicle motor or electrical grid. This implementation can allow a complete decoupling between the electrical characteristics (terminal voltage and current) of the energy source and those of the loads.

[0101] FIG. 3C is a block diagram depicting an example implementation of a module 108C configured to supply power to a first auxiliary load 301 and a second auxiliary load 302, where the module 108C includes an energy source 206, an energy buffer 204, and a converter 202B coupled together in a manner similar to that of FIG. 3B. The first auxiliary load 301 requires a voltage equivalent to that supplied from the source 206. The load 301 is coupled to IO ports 3 and 4 of the module 108C, which are in turn coupled to ports IO1 and IO2 of the source 206. The source 206 can output power to both the power connection 110 and the load 301. The second auxiliary load 302 requires a constant voltage lower than that of the source 206. The load 302 is coupled to IO ports 5 and 6 of the module 108C, which are coupled to ports IO5 and IO2, respectively, of the converter 202B. The converter 202B can include a switch portion 602 having coupling inductor LB coupled to port IO5 (FIG. 6B). Energy supplied by the source 206 can be supplied to the load 302 through the switch portion 602 of the converter 202B. It is assumed that the load 302 has an input capacitor, e.g., a capacitor can be added to module 108Cif not, so switches SI and S2 can be commutated to regulate the voltage on and current through coupling inductor B and thus produce a stable constant voltage for the load 302. This regulation can step down the voltage of the source 206 to the lower magnitude voltage is required by the load 302.

[0102] The module 108C can thus be configured to supply one or more first auxiliary loads in the manner described with respect to the load 301, with the one or more first loads coupled to IO ports 3 and 4. The module 108C can also be configured to supply one or more second auxiliary loads in the manner described with respect to the load 302. If multiple second auxiliary loads 302 are present, then for each additional load 302, module 108C can be scaled with additional dedicated module output ports (like 5 and 6), an additional dedicated switch portion 602, and an additional converter IO port coupled to the additional portion 602.

[0103] Energy source 206 can thus supply power for any number of auxiliary loads, e.g., 301 and 30), as well as the corresponding portion of system output power needed by the primary load 101. Power flow from the source 206 to the various loads can be adjusted as desired.

[0104] A module 108 can be configured as needed with two or more energy sources 206 (FIG. 3B) and to supply first and / or second auxiliary loads (FIG. 3C) through the addition of a switch portion 602 and converter port IO5 for each additional source 206B or second auxiliary load 302. Additional module IO ports, e.g., 3, 4, 5, or 6, can be added as needed. A module 108 can also be configured as an interconnection module to exchange energy, e g., for balancing, between two or more arrays, two or more packs, or two or more systems 100 as described further herein. This interconnection functionality can likewise be combined with multiple source and / or multiple auxiliary load supply capabilities.

[0105] The control system 102 can perform various functions with respect to the components of modules 108A, 108B, and 108C. These functions can include management of the utilization, e.g., amount of use, of each energy source 206, protection of the energy buffer 204 from overcurrent, over-voltage and high temperature conditions, and control and protection of the converter 202.

[0106] For example, to manage, e.g., adjust by increasing, decreasing, or maintaining, utilization of each energy source 206, the LCD 114 can receive one or more monitored voltages, temperatures, and currents from each energy source 206 or monitor circuitry. The monitored voltages can be at least one of, preferably all, voltages of each elementary componentindependent of the other components, e.g., each individual battery cell, HED capacitor, and / or fuel cell, of the source 206, or the voltages of groups of elementary components as a whole, e.g., voltage of the battery array, HED capacitor array, and / or fuel cell array. Similarly the monitored temperatures and currents can be at least one of, preferably all, temperatures and currents of each elementary component independent of the other components of the source 206, or the temperatures and currents of groups of elementary components as a whole, or any combination thereof. The monitored signals can be status information, with which the LCD 114 can perform one or more of the following: calculation or determination of a real capacity, actual State of Charge (SOC) and / or State of Health (SOH) of the elementary components or groups of elementary components; set or output a warning or alarm indication based on monitored and / or calculated status information; and / or transmission of the status information to the MCD 112. The LCD 114 can receive control information, e g., a modulation index, synchronization signal, from the MCD 112 and use this control information to generate switch signals for the converter 202 that manage the utilization of the source 206.

[0107] To protect energy buffer 204, the LCD 114 can receive one or more monitored voltages, temperatures, and currents from energy buffer 204 or monitor circuitry. The monitored voltages can be at least one of, preferably all, voltages of each elementary component of the buffer 204, e.g., of CEB, CEBI, CEB2, LEBI, LEB2, DEB, independent of the other components, or the voltages of groups of elementary components or buffer 204 as a whole, e.g., between IO1 and IO2 or between IO3 and IO4. Similarly the monitored temperatures and currents can be at least one of, preferably all, temperatures and currents of each elementary component of the buffer 204 independent of the other components, or the temperatures and currents of groups of elementary components or of the buffer 204 as a whole, or any combination thereof. The monitored signals can be status information, with which the LCD 114 can perform one or more of the following: set or output a warning or alarm indication; communicate the status information to the MCD 112; or control the converter 202 to adjust, e.g., increase or decrease, the utilization of the source 206 and the module 108 as a whole for buffer protection.

[0108] To control and protect the converter 202, the LCD 114 can receive the control information from the MCD 112, e.g., a modulated reference signal, or a reference signal and a modulation index, which can be used with a PWM technique in the LCD 114 to generate the control signals for each switch, e.g., SI through S6. The LCD 114 can receive a currentfeedback signal from a current sensor of the converter 202, which can be used for overcurrent protection together with one or more fault status signals from driver circuits (not shown) of the converter switches, which can carry information about fault statuses, e.g., short circuit or open circuit failure modes, of all switches of the converter 202. Based on this data, the LCD 114 can make a decision on which combination of switching signals to be applied to manage utilization of the module 108, and potentially bypass or disconnect the converter 202 and the entire module 108 from the system 100.

[0109] If controlling a module 108C that supplies a second auxiliary load 302, the LCD 114 can receive one or more monitored voltages, e.g., the voltage between IO ports 5 and 6, and one or more monitored currents, e.g., the current in coupling inductor LB, which is a current of load 302, in module 108C. Based on these signals, the LCD 114 can adjust the switching cycles, e.g., by adjustment of modulation index or reference waveform, of SI and S2 to control and stabilize the voltage for the load 302.Cascaded Energy System Topology Examples

[0110] Two or more modules 108 can be coupled together in a cascaded array that outputs a voltage signal formed by a superposition of the discrete voltages generated by each module 108 within the array. FIG. 7A is a block diagram depicting an example implementation of a topology for a system 100 where N modules 108-1, 108-2 . . . 108-N are coupled together in series to form a serial array 700. In this and all implementations described herein, N can be any integer greater than one. The array 700 includes a first system IO port SIO1 and a second system IO port SIO2 across which is generated an array output voltage. The array 700 can be used as a DC or single phase AC energy source for DC or AC single-phase loads, which can be connected to SIO1 and SIO2 of array 700. FIG. 8A is a plot of voltage versus time depicting an example output signal 801 produced by a single module 108 having a 48 volt energy source. FIG. 8B is a plot of voltage versus time depicting an example single phase AC output signal 802 generated by array 700 having six 48V modules 108 coupled in series.

[0111] The system 100 can be arranged in a broad variety of different topologies to meet varying needs of the applications. The system 100 can provide multi-phase power (e.g., two- phase, three-phase, four-phase, five-phase, six-phase, etc.) to a load by use of multiple arrays 700, where each array can generate an AC output signal having a different phase angle.

[0112] FIG. 7B is a block diagram depicting a system 100 with two arrays 700-PA and 700-PB coupled together. Each array 700 is one-dimensional, formed by a series connection of N modules 108. The two arrays 700-PA and 700-PB can each generate a single-phase AC signal, where the two AC signals have different phase angles PA and PB, e.g., 180 degrees apart. IO port 1 of module 108-1 of each array 700-PA and 700-PB can form or be connected to system IO ports SIO1 and SIO2, respectively, which in turn can serve as a first output of each array that can provide two phase power to a load (not shown). Or alternatively ports SIO1 and SIO2 can be connected to provide single phase power from two parallel arrays. IO port 2 of module 108-N of each array 700- PA and 700- PB can serve as a second output for each array 700- PA and 700- PB on the opposite end of the array from system IO ports SIO1 and SIO2, and can be coupled together at a common node and optionally used for an additional system IO port SIO3 if desired, which can serve as a neutral. This common node can be referred to as a rail, and IO port 2 of modules 108-N of each array 700 can be referred to as being on the rail side of the arrays.

[0113] FIG. 7C is a block diagram depicting a system 100 with three arrays 700-PA, 700-PB, and 700-PC coupled together. Each array 700 is one-dimensional, formed by a series connection of N modules 108. The three arrays 700-1 and 700-2 can each generate a single-phase AC signal, where the three AC signals have different phase angles PA, PB, PC , e.g., 120 degrees apart. IO port 1 of module 108-1 of each array 700-PA, 700-PB, and 700-PC can form or be connected to system IO ports SIO1, SIO2, and SIO3, respectively, which in turn can provide three phase power to a load (not shown). IO port 2 of module 108-N of each array 700-PA, 700- PB, and 700-PC can be coupled together at a common node and optionally used for an additional system IO port SIO4 if desired, which can serve as a neutral.

[0114] The concepts described with respect to the two-phase and three-phase implementations of FIGs. 7B and 7C can be extended to systems 100 generating still more phases of power. For example, a non-exhaustive list of additional examples includes: a system 100 having four arrays 700, each of which is configured to generate a single phase AC signal having a different phase angle, e.g., 90 degrees apart; a system 100 having five arrays 700, each of which is configured to generate a single phase AC signal having a different phase angle, e.g., 72 degrees apart; and a system 100 having six arrays 700, each array configured to generate a single phase AC signal having a different phase angle, e.g., 60 degrees apart.

[0115] The system 100 can be configured such that arrays 700 are interconnected at electrical nodes between modules 108 within each array. FIG. 7D is a block diagram depicting a system 100 with three arrays 700-PA, 700-PB, and 700-PC coupled together in a combined series and delta arrangement. Each array 700 includes a first series connection of M modules 108, where M is two or greater, coupled with a second series connection of N modules 108, where N is two or greater. The delta configuration is formed by the interconnections between arrays, which can be placed in any desired location. In this implementation, IO port 2 of module 108-(M+N) of array 700-PC is coupled with IO port 2 of module 108-M and IO port 1 of module 108-(M+l) of array 700-PA, IO port 2 of module 108-(M+N) of array 700-PB is coupled with IO port 2 of module 108-M and IO port 1 of module 108-(M+l) of array 700-PC, and IO port 2 of module 108- (M+N) of array 700-PA is coupled with IO port 2 of module 108-M and IO port 1 of module 108-(M+l) of array 700-PB.

[0116] FIG. 7E is a block diagram depicting a system 100 with three arrays 700-PA, 700-PB, and 700-PC coupled together in a combined series and delta arrangement. This implementation is similar to that of FIG. 7D except with different cross connections. In this implementation, the IO port 2 of the module 108-M of the array 700-PC is coupled with the IO port 1 of the module 108-1 of the array 700-PA, the IO port 2 of the module 108-M of the array 700-PB is coupled with the IO port 1 of the module 108-1 of the array 700-PC, and the IO port 2 of the module 108- M of the array 700-PA is coupled with the IO port 1 of the module 108-1 of the array 700-PB. The arrangements of FIGs. 7D and 7E can be implemented with as little as two modules in each array 700. Combined delta and series configurations enable an effective exchange of energy between all modules 108 of the system (inter-phase balancing) and phases of power grid or load, and also allows reducing the total number of modules 108 in an array 700 to obtain the desired output voltages.

[0117] In the implementations described herein, although it is advantageous for the number of modules 108 to be the same in each array 700 within system 100, such is not required and different arrays 700 can have differing numbers of modules 108. Further, each array 700 can have modules 108 that are all of the same configuration, e.g., all modules are 108A, all modules are 108B, all modules are 108C, or others, or different configurations, e.g., one or more modules are 108 A, one or more are 108B, and one or more are 108C, or otherwise. As such, the scope of topologies of system 100 covered herein is broad.Control Methodology Examples

[0118] As mentioned, control of a system 100 can be performed according to various methodologies, such as hysteresis or PWM. Several examples of PWM include space vector modulation and sine pulse width modulation, where the switching signals for the converter 202 are generated with a phase shifted carrier technique that continuously rotates utilization of each module 108 to equally distribute power among them.

[0119] FIGs. 8C-8F are plots depicting an example implementation of a phase-shifted PWM control methodology that can generate a multilevel output PWM waveform using incrementally shifted two-level waveforms. An X-level PWM waveform can be created by the summation of (X-l) / 2 two-level PWM waveforms. These two-level waveforms can be generated by comparing a reference waveform Vref to carriers incrementally shifted by 3607(X-l). The carriers are triangular, but the implementations are not limited to such. A nine-level example is shown in FIG. 8C using four modules 108. The carriers are incrementally shifted by 3607(9-1) = 45° and compared to Vref. The resulting two-level PWM waveforms are shown in FIG. 8E. These two- level waveforms may be used as the switching signals for semiconductor switches (e.g., SI though S6) of the converters 202. As an example with reference to FIG. 8E, for a onedimensional array 700 including four modules 108 each with a converter 202, the 0° signal is for control of S3 and the 180° signal for S6 of the first module 108-1, the 45° signal is for S3 and the 225° signal for S6 of the second module 108-2, the 90 signal is for S3 and the 270 signal is for S6 of the third module 108-3, and the 135 signal is for S3 and the 315 signal is for S6 of the fourth module 108-4. The signal for S3 is complementary to S4 and the signal for S5 is complementary to S6 with sufficient dead-time to avoid shoot through of each half-bridge. FIG. 8F depicts an example single phase AC waveform produced by superposition (summation) of output voltages from the four modules 108.

[0120] An alternative is to utilize both a positive and a negative reference signal with the first (N-l) / 2 carriers. A nine-level example is shown in FIG. 8D. In this example, the 0° to 135° switching signals (FIG. 8E) are generated by comparing +Vref to the 0° to 135° carriers of FIG. 8D and the 180° to 315° switching signals are generated by comparing -Vref to the 0° to 135° carriers of FIG. 8D. However, the logic of the comparison in the latter case is reversed. Other techniques such as a state machine decoder may also be used to generate gate signals for the switches of converter 202.

[0121] In multi-phase system implementations, the same carriers can be used for each phase, or the set of carriers can be shifted as a whole for each phase. For example, in a three phase system with a single reference voltage (Vref), each array 700 can use the same number of carriers with the same relative offsets as shown in FIGs. 8C and 8D, but the carriers of the second phase are shift by 120 degrees as compared to the carriers of the first phase, and the carriers of the third phase are shifted by 240 degrees as compared to the carriers of the first phase. If a different reference voltage is available for each phase, then the phase information can be carried in the reference voltage and the same carriers can be used for each phase. In many cases the carrier frequencies will be fixed, but in some example implementations, the carrier frequencies can be adjusted, which can help to reduce losses in electric vehicle motors under high current conditions.

[0122] The appropriate switching signals can be provided to each module by the control system 102. For example, the MCD 112 can provide Vref and the appropriate carrier signals to each LCD 114 depending upon the module or modules 108 that the LCD 114 controls, and the LCD 114 can then generate the switching signals. Or all LCDs 114 in an array can be provided with all carrier signals and the LCD 114 can select the appropriate carrier signals.

[0123] The relative utilizations of each module 108 can adjusted based on status information to perform balancing or of one or more parameters as described herein. Balancing of parameters can involve adjusting utilization to minimize parameter divergence over time as compared to a system where individual module utilization adjustment is not performed. The utilization can be the relative amount of time a module 108 is discharging when system 100 is in a discharge state, or the relative amount of time a module 108 is charging when system 100 is in a charge state.

[0124] As described herein, the modules 108 can be balanced with respect to other modules 108 in an array 700, which can be referred to as intra-array or intraphase balancing, and different arrays 700 can be balanced with respect to each other, which can be referred to as interarray or interphase balancing. The arrays 700 of different subsystems can also be balanced with respect to each other. The control system 102 can simultaneously perform any combination of intraphase balancing, interphase balancing, utilization of multiple energy sources within a module, active filtering, and auxiliary load supply.

[0125] FIG. 9A is a block diagram depicting an example implementation of an array controller 900 of a control system 102 for a single-phase AC or DC array. The array controller900 can include a peak detector 902, a divider 904, and an intraphase (or intra-array) balance controller 906. The array controller 900 can receive a reference voltage waveform (Vr) and status information about each of the N modules 108 in the array 700 being controlled, e.g., state of charge (SOCi), temperature (Ti), capacity (Qi), and voltage (Vi)) as inputs, and generate a normalized reference voltage waveform (Vm) and modulation indexes (Mi) as outputs. The peak detector 902 detects the peak (Vpk) of Vr, which can be specific to the phase that controller 900 is operating with and / or balancing. The divider 904 generates Vrn by dividing Vr by its detected Vpk. The intraphase balance controller 906 uses Vpk along with the status information, e.g., SOCi, Ti, Qi, Vi, etc., to generate modulation indexes Mi for each module 108 within the array 700 being controlled.

[0126] The modulation indexes and Vm can be used to generate the switching signals for each converter 202. The modulation index can be a number between zero and one, e g., inclusive of zero and one. For a particular module 108, the normalized reference Vrn can be modulated or scaled by Mi, and this modulated reference signal (Vrnm) can be used as Vref (or - Vref) according to the PWM technique described with respect to FIGs. 8C-8F, or according to other techniques. In this manner, the modulation index can be used to control the PWM switching signals provided to the converter switching circuitry, e.g., S3-S6 or S1-S6, and thus regulate the operation of each module 108. For example, a module 108 being controlled to maintain normal or full operation may receive an Mi of one, while a module 108 being controlled to less than normal or full operation may receive an Mi less than one, and a module 108 controlled to cease power output may receive an Mi of zero. This operation can be performed in various ways by the control system 102, e.g., by the MCD 112 outputting Vm and Mi to the appropriate LCDs 114 for modulation and switch signal generation, by the MCD 112 performing modulation and outputting the modulated Vrnm to the appropriate LCDs 114 for switch signal generation, or by the MCD 112 performing modulation and switch signal generation and outputting the switch signals to the LCDs 114 or the converters 202 of each module 108 directly. Vrn can be sent continually with Mi sent at regular intervals, such as once for every period of the Vrn, or one per minute, etc.

[0127] The controller 906 can generate an Mi for each module 108 using any type or combination of types of status information, e.g., SOC, temperature (T), Q, SOH, voltage, current, described herein. For example, when using SOC and T, a module 108 can have a relatively highMi if SOC is relatively high and temperature is relatively low as compared to other modules 108 in array 700. If either SOC is relatively low or T is relatively high, then that module 108 can have a realtively low Mi, resulting in less utilization than other modules 108 in array 700. Controller 906 can determine Mi such that the sum of module voltages does not exceed Vpk. For example, Vpk can be the sum of the products of the voltage of each module’s source 206 and Mi for that module, e.g., Vpk = M1V1+M2V2+M3V3 . . . +MNVN, etc. A different combination of modulation indexes, and thus respective voltage contributions by the modules, may be used but the total generated voltage should remain the same.

[0128] The controller 900 can control operation, to the extent it does not prevent achieving the power output requirements of the system at any one time, e.g., such as during maximum acceleration of an EV, such that SOC of the energy source(s) in each module 108 remains balanced or converges to a balanced condition if they are unbalanced, and / or such that temperature of the energy source(s) or other component, e.g., an energy buffer, in each module 108 remains balanced or converges to a balanced condition if they are unbalanced. Power flow in and out of the modules can be regulated such that a capacity difference between sources does not cause an SOC deviation. Balancing of SOC and temperature can indirectly cause some balancing of SOH. Voltage and current can be directly balanced if desired, but in many implementations the main goal of the system is to balance SOC and temperature, and balancing of SOC can lead to balance of voltage and current in a highly symmetric systems where modules are of similar capacity and impedance.

[0129] Since balancing all parameters may not be possible at the same time, e.g., balancing of one parameter may further unbalance another parameter, a combination of balancing any two or more parameters, e.g., SOC, T, Q, SOH, V, I, can be applied with priority given to either one depending on the requirements of the application. Priority in balancing can be given to SOC over other parameters, e.g., T, Q, SOH, V, I, with exceptions made if one of the other parameters, e.g., T, Q, SOH, V, I, reaches a severe unbalanced condition outside a threshold.

[0130] Balancing between arrays 700 of different phases, or arrays of the same phase, e.g., if parallel arrays are used, can be performed concurrently with intra-phase balancing. FIG. 9B depicts an example implementation of an Q-phase (or Q-array) controller 950 configured for operation in an Q-phase system 100, having at least arrays 700, where is any integer greater than one. The controller 950 can include one inter-phase (or inter-array) controller 910 and Qintraphase balance controllers 906-PA . . . 906-PQ for phases PA through PQ, as well as peak detector 902 and divider 904 (FIG. 9A) for generating normalized references VrnPA through VrnPQ from each phase-specific reference VrPA through VrPQ. The intraphase controllers 906 can generate Mi for each module 108 of each array 700 as described with respect to FIG. 9A. The interphase balance controller 910 is configured or programmed to balance aspects of modules 108 across the entire multi-dimensional system, for example, between arrays of different phases. This may be achieved through injecting common mode to the phases, e.g., neutral point shifting, or through the use of interconnection modules described herein or through both. Common mode injection involves introducing a phase and amplitude shift to the reference signals VrPA through VrPQ to generate normalized waveforms VrnPA through VrnPQ to compensate for unbalance in one or more arrays, and is described further in Inf 1. Appl. No. PCT / US20 / 25366 incorporated herein.

[0131] The controllers 900 and 950, as well as the balance controllers 906 and 910, can be implemented in hardware, software or a combination thereof within a control system 102. The controllers 900 and 950 can be implemented within the MCD 112, distributed partially or fully among LCDs 114, or may be implemented as discrete controllers independent of the MCD 112 and the LCDs 114.Interconnection (IC) Module Examples

[0132] The modules 108 can be connected between the modules of different arrays 700 for the purposes of exchanging energy between the arrays 700, acting as a source for an auxiliary load, or both. Such modules are referred to herein as interconnection (IC) modules 108IC. The IC module 108IC can be implemented in any of the already described module configurations (108 A, 108B, 108C) and others to be described herein. The IC modules 108IC can include any number of one or more energy sources, an optional energy buffer, switch circuitry for supplying energy to one or more arrays and / or for supplying power to one or more auxiliary loads, control circuitry, e.g., a local control device, and monitor circuitry for collecting status information about the IC module itself or its various loads, e.g., SOC of an energy source, temperature of an energy source or energy buffer, capacity of an energy source, SOH of an energy source, voltage and / or current measurements pertaining to the IC module, voltage and / or current measurements pertaining to the auxiliary load(s), etc.

[0133] FIG. 10A is a block diagram depicting an example implementation of a system 100 capable of producing Q-phase power with Q arrays 700-PA through 700-PQ, where £1 can be any integer greater than one. In this and other implementations, the IC module 108IC can be located on the rail side of arrays 700 such the arrays 700 to which module 108IC are connected, e.g., arrays 700-PA through 700-PQ in this implementation, are electrically connected between module 108IC and outputs, e.g., SIO1 through SIOQ, to the load. Here, the module 108IC has Q IO ports for connection to IO port 2 of each module 108-N of arrays 700-PA through 700-PQ. In the configuration depicted here, the module 108IC can perform interphase balancing by selectively connecting the one or more energy sources of module 108IC to one or more of the arrays 700-PA through 700-PQ, or to no output, or equally to all outputs, if interphase balancing is not required. The system 100 can be controlled by control system 102 (not shown, see FIG. 1A).

[0134] FIG. 10B is a schematic diagram depicting an example implementation of a module 108IC. In this implementation, the module 108IC includes an energy source 206 connected with energy buffer 204 that in turn is connected with switch circuitry 603. The switch circuitry 603 can include switch circuitry units 604-PA through 604-PQ for independently connecting energy source 206 to each of arrays 700-PA through 700-PQ, respectively. Various switch configurations can be used for each unit 604, which in this implementation is configured as a half-bridge with two semiconductor switches S7 and S8. Each half bridge is controlled by control lines 118-3 from the LCD 114. This configuration is similar to the module 108A described with respect to FIG. 3A. As described with respect to the converter 202, the switch circuitry 603 can be configured in any arrangement and with any switch types, e.g., MOSFET, IGBT, Silicon, GaN, etc., suitable for the requirements of the application.

[0135] The switch circuitry units 604 are coupled between positive and negative terminals of energy source 206 and have an output that is connected to an IO port of module 108IC. The units 604-PA through 604-PQ can be controlled by the control system 102 to selectively couple voltage +Vic or -Vic to the respective module I / O ports 1 through Q. The control system 102 can control switch circuitry 603 according to any desired control technique, including the PWM and hysteresis techniques mentioned herein. Here, the control circuitry 102 is implemented as an LCD 114 and an MCD 112 (not shown). The LCD 114 can receive monitoring data or status information from monitor circuitry of the module 108IC. This monitoring data and / or otherstatus information derived from this monitoring data can be output to the MCD 112 for use in system control as described herein. The LCD 114 can also receive timing information (not shown) for purposes of synchronization of the modules 108 of the system 100 and one or more carrier signals (not shown), such as the sawtooth signals used in PWM (FIGs. 8C-8D).

[0136] For inter-phase balancing, proportionally more energy from the source 206 can be supplied to any one or more of arrays 700-PA through 700-PQ that is relatively low on charge as compared to other arrays 700. Supply of this supplemental energy to a particular array 700 allows the energy output of those cascaded modules 108-1 thru 108-N in that array 700 to be reduced relative to the unsupplied phase array(s).

[0137] For example, in some example implementations applying PWM, the LCD 114 can be configured to receive the normalized voltage reference signal (Vrn), e.g., from MCD 112, for each of the one or more arrays 700 that module 108IC is coupled to, e.g., VmPA through VrnPQ. The LCD 114 can also receive modulation indexes MiPA through MiPQ for the switch units 604-PA through 604-PQ for each array 700, respectively, from the MCD 112. The LCD 114 can modulate (e.g., multiply) each respective Vrn with the modulation index for the switch section coupled directly to that array (e.g., VrnA multiplied by MiA) and then utilize a carrier signal to generate the control signal(s) for each switch unit 604. In other implementations, the MCD 112 can perform the modulation and output modulated voltage reference waveforms for each unit 604 directly to the LCD 114 of the module 108IC. In still other implementations, all processing and modulation can occur by a single control entity that can output the control signals directly to each unit 604.

[0138] This switching can be modulated such that power from the energy source 206 is supplied to the array(s) 700 at appropriate intervals and durations. Such methodology can be implemented in various ways.

[0139] Based on the collected status information for the system 100, such as the present capacity (Q) and SOC of each energy source in each array 700, the MCD 112 can determine an aggregate charge for each array 700, e.g., aggregate charge for an array can be determined as the sum of capacity times SOC for each module 108 of that array 700. The MCD 112 can determine whether a balanced or unbalanced condition exists, e.g., through the use of relative difference thresholds and other metrics described herein, and generate modulation indexes MiPA through MiPQ accordingly for each switch unit 604-PA through 604-PQ.

[0140] During balanced operation, the modulation index Mi for each switch unit 604 can be set at a value that causes the same or similar amount of net energy over time to be supplied by the energy source 206 and / or the energy buffer 204 to each array 700. For example, the modulation index Mi for each switch unit 604 could be the same or similar, and can be set at a level or value that causes the module 108IC to perform a net or time average discharge of energy to the one or more arrays 700-PA through 700-PQ during balanced operation, so as to drain the module 108IC at the same rate as other modules 108 in the system 100. In some implementations, the modulation index Mi for each unit 604 can be set at a level or value that does not cause a net or time average discharge of energy during balanced operation, e.g., that causes a net energy discharge of zero. This can be useful if the module 108IC has a lower aggregate charge than other modules in the system.

[0141] When an unbalanced condition occurs between arrays 700, then the modulation indexes of the system 100 can be adjusted to cause convergence towards a balanced condition or to minimize further divergence. For example, the control system 102 can cause the module 108IC to discharge more to the array 700 with low charge than the others, and can also cause modules 108-1 through 108-N of that low array 700 to discharge relatively less, e.g., on a time average basis. The relative net energy contributed by the module 108IC increases as compared to the modules 108-1 through 108-N of the array 700 being assisted, and also as compared to the amount of net energy module 108IC contributes to the other arrays. This can be accomplished by increasing the modulation index Mi for the switch unit 604 supplying that low array 700, and by decreasing the modulation indexes of modules 108-1 through 108-N of the low array 700 in a manner that maintains Vout for that low array at the appropriate or required levels, and maintaining the modulation indexes for other switch units 604 supplying the other higher arrays relatively unchanged or decreasing them.

[0142] The configuration of the module 108IC in FIGs. lOA-lOB can be used alone to provide interphase or interarray balancing for a single system, or can be used in combination with one or more other modules 108IC each having an energy source and one or more switch portions 604 coupled to one or more arrays. For example, a module 108IC with Q switch portions 604 coupled with Q different arrays 700 can be combined with a second module 108IC having one switch portion 604 coupled with one array 700 such that the two modules combine toservice a system 100 having Q+l arrays 700. Any number of modules 108IC can be combined in this fashion, each coupled with one or more arrays 700 of system 100.

[0143] Furthermore, IC modules can be configured to exchange energy between two or more subsystems of a system 100. FIG. 10C is a block diagram depicting an example implementation of a system 100 with a first subsystem 1000-1 and a second subsystem 1000-2 interconnected by IC modules. Specifically, the subsystem 1000-1 is configured to supply three-phase power, PA, PB, and PC, to a first load (not shown) by way of system I / O ports SIO1, SIO2, and SIO3, while the subsystem 1000-2 is configured to supply three-phase power PD, PE, and PF to a second load (not shown) by way of system VO ports SIO4, SIO5, and SIO06, respectively. For example, the subsystems 1000-1 and 1000-2 can be configured as different packs supplying power for different motors of an electric vehicle or as different racks supplying power for different microgrids.

[0144] In this implementation, each module 108IC is coupled with a first array of subsystem 1000-1 (via IO port 1) and a first array of subsystem 1000-2 (via IO port 2), and each module 108IC can be electrically connected with each other module 108IC by way of I / O ports 3 and 4, which are coupled with the energy source 206 of each module 108IC as described with respect to module 108C of FIG. 3C. This connection places the sources 206 of the modules 108IC-1, 108IC-2, and 108IC-3 in parallel, and thus the energy stored and supplied by the modules 108IC is pooled together by this parallel arrangement. Other arrangements such as serious connections can also be used. The modules 108IC are housed within a common enclosure of subsystem 1000-1, however the interconnection modules can be external to the common enclosure and physically located as independent entities between the common enclosures of both subsystems 1000.

[0145] Each module 108IC has a switch unit 604-1 coupled with IO port 1 and a switch unit 604-2 coupled with I / O port 2, as described with respect to FIG. 10B. Thus, for balancing between subsystems 1000, e.g., inter-pack or inter-rack balancing, a particular module 108IC can supply relatively more energy to either or both of the two arrays to which it is connected, e.g., the module 108IC-1 can supply to array 700-PA and / or array 700-PD. The control circuitry can monitor relative parameters, e.g., SOC and temperature, of the arrays of the different subsystems and adjust the energy output of the IC modules to compensate for imbalances between arrays or phases of different subsystems in the same manner described herein as compensating forimbalances between two arrays of the same rack or pack. Because all three modules 108IC are in parallel, energy can be efficiently exchanged between any and all arrays of the system 100. In this implementation, each module 108IC supplies two arrays 700, but other configurations can be used including a single IC module for all arrays of the system 100 and a configuration with one dedicated IC module for each array 700, e.g., six IC modules for six arrays, where each IC module has one switch unit 604. In all cases with multiple IC modules, the energy sources can be coupled together in parallel so as to share energy as described herein.

[0146] In systems with IC modules between phases, interphase balancing can also be performed by neutral point shifting (or common mode injection) as described above. Such a combination allows for more robust and flexible balancing under a wider range of operating conditions. The system 100 can determine the appropriate circumstances under which to perform interphase balancing with neutral point shifting alone, inter-phase energy injection alone, or a combination of both simultaneously.

[0147] IC modules can also be configured to supply power to one or more auxiliary loads 301, e.g., at the same voltage as source 206, and / or one or more auxiliary loads 302, e.g., at voltages stepped down from source 302. FIG. 10D is a block diagram depicting an example implementation of a three-phase system 100 A with two modules 108IC connected to perform interphase balancing and to supply auxiliary loads 301 and 302. FIG. 10E is a schematic diagram depicting this example implementation of a system 100 with emphasis on modules 108IC-1 ad 108IC-2. Here, the control circuitry 102 is again implemented as LCD 114 and MCD 112 (not shown). The LCDs 114 can receive monitoring data from modules 108IC (e.g., SOC of ESI, temperature of ESI, Q of ESI, voltage of auxiliary loads 301 and 302, etc.) and can output this and / or other monitoring data to the MCD 112 for use in system control as described herein. Each module 108IC can include a switch portion 602A, or 602B described with respect to FIG. 6C, for each load 302 being supplied by that module, and each switch portion 602 can be controlled to maintain the requisite voltage level for load 302 by LCD 114 either independently or based on control input from MCD 112. In this implementation, each module 108IC includes a switch portion 602A connected together to supply the one load 302, although such is not required.

[0148] FIG. 10F is a block diagram depicting another example implementation of a three- phase system configured to supply power to one or more auxiliary loads 301 and 302 withmodules 108IC-1, 108IC-2, and 108IC-3. In this implementation, the modules 108IC-1 and 108IC-2 are configured in the same manner as described with respect to FIGs. 10D-10E. The module 108IC-3 is configured in a purely auxiliary role and does not actively inject voltage or current into any array 700 of the system 100. In this implementation, the module 108IC-3 can be configured like module 108C of FIG. 3B, having a converter 202B,C (FIGs. 6B-6C) with one or more auxiliary switch portions 602A, but omitting switch portion 601. As such, the one or more energy sources 206 of the module 108IC-3 are interconnected in parallel with those of the modules 108IC-1 and 108IC-2, and thus this implementation of the system 100 is configured with additional energy for supplying the auxiliary loads 301 and 302, and for maintaining charge on the sources 206A of the modules 108IC-1 and 108IC-2 through the parallel connection with the source 206 of module 108IC-3.

[0149] The energy source 206 of each IC module can be at the same voltage and capacity as the sources 206 of the other modules 108-1 through 108-N of the system, although such is not required. For example, a relatively higher capacity can be desirable in an implementation where one module 108IC applies energy to multiple arrays 700 (FIG. 10A) to allow the IC module to discharge at the same rate as the modules of the phase arrays themselves. If the module 108IC is also supplying an auxiliary load, then an even greater capacity may be desired so as to permit the IC module to both supply the auxiliary load and discharge at relatively the same rate as the other modules.Second Life Energy Source Examples

[0150] Energy sources 206 described herein can be used in systems 100 described herein in both first life and second life applications. A first life of a source 206 is an original application in which source 206 is used. For example, the first life application is the first implementation in which sources 206 are put to use by the first customer of sources 206 after their original manufacture (and not refurbishment). The user of sources 206 in their first life will typically have received sources 206 from the manufacturer, distributor, or original equipment manufacturer (OEM). Batteries 206 used in a first life application will typically have the same electrochemistry (e.g., will have the same variant of lithium ion electrochemistry (e.g., LFP, NMC)) and will have the same nominal voltage and will have a capacity variation across the pack or system that is minimal (e.g., 5% or less). Use of an energy storage system with batteries 206 in their first life application will result in batteries 206 having a longer lifespan in that firstlife application, and upon removal from that first life application, the batteries 206 will be more similar in terms of capacity degradation than batteries from a first life application not using the energy storage system.

[0151] As used herein, a “second life” application is any application or implementation after the first life application (e.g., a second implementation, third implementation, fourth implementation, etc.) of source 206. A second life energy source refers to any energy source (e.g., battery or HED capacitor) implemented in that source’s second life application.

[0152] An example of a first life application for batteries 206 is within an energy storage system for an EV. Then, at the end of that life (e.g., after 100,000 miles of driving, or after degradation of the batteries within that battery pack by a threshold amount), the batteries 206 can be removed from the battery pack, optionally subjected to refurbishing and testing, and then implemented in a second life application that can be, e.g., used within a stationary energy storage system (e.g., residential, commercial, or industrial energy buffering, EV charging station energy buffering, renewable source (e.g., wind, solar, hydroelectric), energy buffering, and the like) or another mobile energy storage system (e.g., battery pack for an electric car, bus, train, or truck). Similarly, the first life application can be a first stationary application and the second life application can be a stationary or mobile application.

[0153] For the second life application, the sources 206 can be selected and / or utilized by the system 100 to minimize (or at least reduce) any differences in initial capacity and nominal voltage. For example, sources 206 having a capacity difference of 5% or more can be included within the system 100 and operated to provide energy for a load. In another example, an operator or automated system can select sources 206 for the system 100 that have a capacity difference within a threshold amount, e.g., to reduce the initial capacity differences between sources of the system 206. If the modules 108 are compatible with both the first and second life application, e.g., with or without reconfiguration, the modules 108 can be selected for the second life application based on the capacity difference of the sources 206 of the modules 108.

[0154] The system 100 can adjust utilization of each source 206 individually such that the sources 206 within the system 100 or packs of the system 100 are relatively balanced in terms of SOC or total charge (SOC times capacity) as the pack or system 100 is discharged, even though the sources 206 in the system 100 can have widely varying capacities. Similarly, the system 100 can maintain balance as the pack or system 100 is charged. The sources 206 can vary not only interms of capacity but also in nominal voltage, power rating, electrochemical type, e.g., a combination of LFP and NMC batteries, and the like. Thus, the system 100 can be used such that all modules 206 within the system 100 or each pack of the system 100 are second life energy sources, or such that a combination of first life and second life energy sources are used, having various combinations of different characteristics.

[0155] In one example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having energy capacity variations of 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5-30%, 10- 30%, and / or 20-30%.

[0156] In another example, a system 100 includes second energy life sources 206, and optionally one or more first life energy sources 206, having energy capacity per mass density variations of 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5-30%, 10-30%, and / or 20-30%.

[0157] In another example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having peak power per mass density variations of 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5-30%, 10-30%, and / or 20-30%.

[0158] In another example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having nominal voltage variations of 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5- 30%, 10-30%, and / or 20-30%.

[0159] In another example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having operating voltage range variations of 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5-30%, 10-30%, and / or 20-30%.

[0160] In another example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having maximum specified current rise time variations of 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5-30%, 10-30%, and / or 20-30%.

[0161] In another example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having specified peak current variations of2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more, 30% or more, 5-30%, 10-30%, and / or 20-30%.

[0162] A variation of X% (e.g., 5% or more, or 5 to 30%) can be met by a variation between the module 108 having the highest value for that parameter and the module 108 having the lowest value for that parameter within the system 100. For example, a variation of 5% or more in capacity can be met by a system 100 where the module 108 with the lowest capacity source 206 has a capacity that is 95% or less than that of the module 108 with the highest capacity source 206. For each and every implementation and parameter disclosed herein, the time at which the system 100 having one or more second life sources satisfies the X% variation condition in that parameter can be at installation of the system 100, at commissioning of the system 100, after replacement of one source 206 with another source 206, after operation of system 100 for 10 hours or more, after operation of system 100 for 100 hours or more, after operation of system 100 for 1000 hours or more, and / or after operation of system 100 for 10,000 hours or more. For example, a variation of capacity of 5% or more can occur after system 100 is operated for 1000 hours, even though the variation in capacity was not present at the time of commissioning. This reflects the capability of the implementations of system 100 to continue to operate with and account for capacity differences between sources 206 that grow over time of operation.

[0163] In another example, a system 100 includes second life energy sources 206, and optionally one or more first life energy sources 206, having variations of electrochemical type, e.g., lithium ion batteries with non-lithium ion batteries, or different lithium ion batteries, e.g., any combination of NMC, LFP, LTO, or other lithium ion battery types.

[0164] A system 100 can include second life energy sources 206, and optionally one or more first life energy sources 206, having any combination of the characteristics provides in the preceding examples.Examples of Short Circuit Fault Response Management

[0165] System 100 can be configured such that each module 108 can detect short circuit faults and respond in one of multiple ways depending on the fault severity. FIG. 11 A depicts an example embodiment of system 100 having a single array 700 of N modules 108. Each module 108 includes converter 202, energy buffer 204, energy source 206, and a current manager 1102. As described herein, current can flow into and out of module 108 through converter 202.Current that passes through energy source 206 generally approximates the load current passing through module 108 and is referred to as II. This load current II can pass in a positive direction or a negative direction depending on the state of operation (discharge or charge) or the polarity of the load current which can be sinusoidal. The voltage over the DC link of module 108-1 is indicated by VDCL.

[0166] Each module can include an LCD 114, or otherwise be associated with an LCD 114 (such as two or more modules 108 sharing an LCD 114). LCD 114 can bidirectionally communicate with the components of module 108 by way of communication bus 118. This can include the reading of measurements and status information from the various components and the sending of control signals or instructions to the various components. LCD 114 can also bidirectionally communicate with MCD 112, which in turn can coordinate system action based on information reported from each LCD 114.

[0167] Each current manager 1102 can be configured to limit current flow to energy buffer 204 when buffer 204 is being charged, such as during system startup. Each current manager 1102 can also be configured to sense or measure the amount of current passing through module 108 and report this measured current to LCD 114 for processing. Each current manager 1102 can also be configured to detect a short circuit, indicated by a rapid rise in current above a current limit threshold, and generate a rapid interrupt signal. Each current manager 1102 can also be configured to enable or cause an open circuit disconnect (blocking load current flow) in response to a detected short circuit.

[0168] FIG. 1 IB is a block diagram depicting an example embodiment of current manager 1102. Here, current manager 1102 includes a current sensor 1110, a measurement circuit 1112, a rapid short detector 1114, and a current limiter 1116. Measurement circuit 1112 can measure the magnitude and / or direction of current in the load path with current sensor 1110, which can be for example a shunt resistor. This magnitude and direction information (MD) can be communicated to LCD 114 over bus 118, either in the form of an analog or digital signal. If analog, LCD 114 can convert to digital form and determine if the direction is as expected and within normal operating limits. If the current is not within operating limits, such as would indicate a short circuit fault, then this condition can be reported to MCD 112 over bus 115. Both MCD 112 and LCD 114 can take independent corrective actions, such as shutting off system 100, bypassing the module 108 in which the fault has occurred, and taking corrective action with current limiter1116. The processing of the current magnitude and direction by LCD 114 may take too much time to rectify a short circuit fault. To compensate for this, the magnitude and / or direction information can be also sent from measurement circuit 1112 to rapid short detector 1114, which can be a hardware-based current threshold monitor that rapidly detects if the load current exceeds a hardware set current threshold. If detector 1114 detects a short circuit, then an interrupt INT can be generated and sent to current limiter 1116, which can take action to limit the current through module 108 in response to the short circuit.

[0169] FIG. 11C is a block diagram depicting an example embodiment of current limiter 1116. Here, limiter 1116 includes a first current path 1121 that passes through a switch 1123, that is configured here as a semiconductor switch QI with a gate signal controlled by LCD 114. Limiter 1116 also includes a second current path 1122 that passes through a variable resistor 1124, which can be a negative temperature coefficient (NTC) thermistor or a positive temperature coefficient (PTC) thermistor, and a safety disconnect 1126, which can be a fuse or breaker. A variable resistor 1124, such as an NTC thermistor, has an initially high resistance that decreases with temperature, so as to initially limit the current flow. Current limiter 1116 can perform several functions based on the state of switch 1123.

[0170] During startup when energy buffer 204 is being charged, switch 1123 can be opened to pass the charge current through path 1122. The presence of variable resistor 1124 limits this charge current, sometimes referred to as inrush current, and protects the components of module 108 from overheating. When LCD 114 detects that energy buffer 204 is charged, then LCD 114 can issue instructions to close switch 1123 to cause the module’s current to pass through path 1121, bypassing variable resistor 1124 and safety disconnect 1126. During operation, if rapid short detector 1114 detects a short circuit and generates interrupt INT, then this signal causes switch 1123 to open, forcing the module’s current to flow through path 1122 where safety disconnect 1126 is present to disconnect path 1122 (e.g., blow the fuse) and prevent flow of the short circuit current. This configuration permits the use of a relatively small fuse having a low current rating as disconnect 1126. This embodiment avoids the use of a large, expensive fuse with a much higher current rating placed in a position 1128 that is constantly on the load path, which would introduce a source of constant power loss to each module 108.

[0171] FIG. 1 ID is a block diagram depicting an example embodiment of current sensor 1110 and measurement circuit 1112. Here, current sensor 1110 is configured as a shunt resistor.Measurement circuit 11 12 includes a first stage differential amplifier 1130 and a second stage single end converter 1132. Differential amplifier 1130 measures voltages Vn and V12 across resistor 1110 and, by referencing a midpoint reference voltage VM, determines the magnitude and direction of the current II passing through resistor 1110. Differential amplifier 1130 outputs this information as differential voltages V01 and V02, which are in turn input to single end converter 1132, which converts voltages V01 and V02 into a single ended output signal MD. In other embodiments, measurement circuit 1112 can output the differential voltages V01 and V02 directly to LCD 114 for processing and to rapid short detector 1114, or alternatively generate the magnitude and / or direction information directly as a single ended signal and output to LCD 114 and detector 1114.

[0172] FIG. 1 IE is a schematic diagram depicting an example embodiment of rapid short detector 1114. Here, detector 1114 includes a first comparator 1141 and a second comparator 1144, each of which have a first input, the signal MD, and a second input, which is a threshold set by resistor pairs 1142 and 1143, and 1145 and 1146, respectively. Comparator 1141 can detect whenever signal MD indicates an excessive current in a first direction, while comparator 1144 can detect whether signal MD indicates an excessive current in the opposite direction. If either condition is true the comparators generate the INT interrupt signal which can be used, either directly or indirectly, to turn switch 1123 off and redirect the short circuit current through disconnect 1126. This provides a rapid mechanism by which to disconnect current flow through a module 108 experiencing a short circuit across the DC link or elsewhere.Examples of Shoot-Through Fault Protection

[0173] System 100 can be configured such that each module 108 can detect and prevent shoot through faults in each converter 202. A shoot through fault is when both switches of a half bridge converter are simultaneously on (in the current conducting state) for a brief period of time, allowing a transient short circuit condition to occur across the DC link. Shoot-through can happen due to a malfunction in gate driver circuitry, or due to noise induced in converter 202 or control and driver circuitry, for example in conditions of high dv / dt or di / dt. The shoot through prevention embodiments can be implemented in either analog- or digital-based control circuits.

[0174] Prior circuits and techniques for detecting shoot through are typically based on de-sat detection methods that are mainly used for medium voltage applications, for example, where the DC link voltage is greater than 400V. Such approaches need a built-in feature of de-sat detectionthat is usually not available in off-the-shelf gate driver integrated circuits. Other prior techniques utilize shunt resistors or hall sensors to detect shoot through current, and these approaches need very high bandwidth to detect the fast rise time associated with short circuit current.

[0175] Prior techniques cannot be applied to low-voltage applications where the DC link voltage is in the range of, for example, 50V to 150V. Existing de-sat detection methods are not suitable for low-voltage applications because the low voltage MOSFET has considerably low on- resistance (in the range of one to several milliohms) compared to medium voltage MOSFETs that have on-resistances in the range of tens of milliohms. The tolerance of existing de-sat detection approaches thus causes significant error in the detected current in low-voltage applications. Other methods use additional parts to detect short circuit current which adds cost and complexity.

[0176] FIG. 12A is a schematic diagram depicting an example embodiment of a module 108 having a shoot through detection circuit 1202. Detection circuit 1202 is located in the gate driver circuitry in close physical proximity to the converter 202 to minimize the effect of noise in communicating from circuit 1202 to converter 202. Circuit 1202 can detect when the gate control signals for the switches of converter 202 would cause a shoot through condition to occur, e.g., when both transistors S3 and S4 (or alternatively S5 and S6) are instructed to turn on simultaneously. When a shoot through condition is detected, circuit 1202 can intervene and force one or both gate control signals to a value that equates to the respective transistor(s) being turned off (the current blocking state). Circuit 1202 can be implemented with or without a latch that, when present, maintains each transistor in the half bridge in an off state until the gate driver circuit is turned off or reset. When the latch is not present, the half bridge transistors are temporarily disabled but then free to resume operation.

[0177] Here, in FIG. 12A, LCD 114 outputs the control signals for each switch of converter 202: CSSA, CS4A, CSSA, and Cs6A. Shoot through detection circuit 1202 receives the signals and checks for shoot through condition for the first half bridge pair (S3 and S4), and again for the second half bridge pair (S5 and S6). If a shoot through condition is detected for either or both pairs, one or both of the violating gate control signals for each pair is changed to force the respective transistor(s) to the off state (current blocking, or open state). The control signals, in their original or corrected forms as the case may be, are then output as signals CSSB, CS4B, CSSB, and Cs6B, to the gate driver circuitry (not shown) and then to switches S3-S6.

[0178] FIG. 12B is a schematic diagram depicting an example embodiment of shoot through detection circuit 1202 configured to operate without a latch. For ease of illustration, the logic for correcting shoot through for switches S3 and S4 is shown, with the understanding that such logic would be duplicated within circuit 1202 for switches S5 and S6. The control signals Cs.3A and Cs4A from LCD 114 are input to NAND gate 1210, which will detect shoot through by generating a logic low level whenever both control signals are logic high. The logic low level output by gate 1210 is fed to a first AND gate 1212 that will produce a logic low level as the output Cs3B. Similarly, the logic low level output by gate 1210 is fed to a second AND gate 1214 that will produce a logic low level as the output Cs4B. In this manner when both control signals CSSA and Cs4A are high, they are both converted to low levels to turn both transistors off and prevent shoot through. In this and the other embodiments described herein, circuit 1202 can be configured to force only one of the two gate control signals to the off state to stop the shoot through but still permit current flow from or into the module.

[0179] Under normal operating conditions, control signals Cs3A and Cs4A will each be low, or one will be low and the other will be high. These state combinations result in gate 1210 outputting a logic high value. The other input to gate 1212 is the signal Cs3A itself, which when processed with the logic high from gate 1210, will result in AND gate 1212 producing the same logic level as that held by CSSA, thus passing through the value of Cs3A to output signal Cs3B. Similarly, the other input to gate 1214 is the signal CS4A itself, which when processed with the logic high from gate 1210, will result in AND gate 1214 producing the same logic level as that held by Cs4A, thus passing through the value of Cs4A to output signal Cs4B. AS this embodiment has no latch, when the shoot through condition resolves, the circuit of FIG. 12B will permit normal operation to resume.

[0180] FIG. 12C is a schematic diagram depicting an example embodiment of shoot through detection circuit 1202 configured to operate with a latch. Again, for ease of illustration, the logic for correcting shoot through for switches S3 and S4 is shown, with the understanding that such logic would be duplicated within circuit 1202 for switches S5 and S6. The control signals CSSA and Cs4A from LCD 114 are input to AND gate 1211, which will detect shoot through by generating a logic high level whenever both control signal inputs are logic high.

[0181] The output of AND gate 1211 is then fed through latch 1216 which inverts the logic high level indicative of shoot through to a logic low level and outputs the logic low level to ANDgates 1212 and 1214, which in turn will produce logic low levels as output signals Cs3B and Cs4B, which disables switches S3 and S4 in the case of shoot through. Latch 1216 maintains this logic low level in place to keep output signals Cs3B and Cs4B in their logic low states and thus disable operation of switches S3 and S4 until circuit 1202 is powered off or reset.

[0182] Latch 1216 includes a first NOR gate 1218 and a second NOR gate 1220. The input to latch 1216 also forms the input to NOR gate 1218, while the output from NOR gate 1220 forms the second input to NOR gate 1218. The output of NOR gate 1218 is the output signal of latch 1216 that is routed to AND gates 1212 and 1214. A first input to NOR gate 1220 is the output of NOR gate 1218, and a second input to NOR gate 1220 is a permanent logic low value introduced by a pulldown resistor connected to ground. The output of NOR gate 1220 is output from latch 1216 as a shoot through detection signal, which can be routed to LCD 114 and used to generate a shoot through output notification to MCD 112 and / or the user. Operation of circuit 1202 of FIG. 12C performs in a similar manner to that described with respect to FIG. 12B under normal conditions. If no shoot through is detected, then latch 1216 will invert the logic low level output by AND gate 1211 to a logic high level that, when input to AND gates 1212 and 1214, enables normal operation. Latch 1216 will only latch when a logic high level is output by AND gate 1211.

[0183] Also provided herein is an embodiment similar to that of FIG. 12C but with a variable delay feature introduced to latch 1216. This variable delay will prevent latch 1216 from permanently latching a signal while module 108 are system 100 is powered on. FIG. 12D is a schematic view depicting an embodiment of latch 1216 having a delay circuit 1222. The delay circuit includes a capacitor connected between the power supply and the input 1223 of NOR gate 1220 having the pulldown resistor. When power is applied to module 108, the input 1223 sees a logic high value while the capacitor is charging, which prevents the latch function. When the capacitor is fully charged after a delay, input 1223 will see a low value by way of the pulldown resistor and parallel diode. The size of the capacitor used in delay circuit 1222 can be varied to adjust the amount delay. This prevents latch 1216 from improperly latching a transient condition during system startup.

[0184] The embodiments of FIGs. 12B-D utilize hardware-based techniques without software (including firmware) to detect shoot through and can be advantageous in situations where an alternative detection technique utilizing software undergoes a malfunction. However,the embodiments described herein are not limited to solely hardware-based techniques and can utilize solely software-based solutions as well as a combination of both software and hardware.Examples of Seamless Mode Transitioning with Pre-Connection Grid Matching

[0185] System 100 can be configured such that when operating in conjunction with a grid and a local area power system, e.g., a microgrid, system 100 transitions between modes in seamless (including near-seamless) manner. A microgrid is a collection of electrical sources and loads that can operate in an island configuration or a grid-tied condition, and offer higher reliability, lower costs, and improved power quality to customers. Microgrids can also offer services that improve the reliability of the bulk power system. Seamless transitions refer to the changes in operating modes of the microgrid and / or its constituent distributed energy resources (DER) with minimal impact to the loads.

[0186] FIG. 13 is a block diagram depicting an example of grid-connected system 1400 in which system 100 is connected to a load 101 and a grid 1430 using circuit contactors 1415. Any of the implementations of system 100 described in this specification can be used in grid- connected system 1400. System 100 can provide power to load 101 and receive power from grid 1430 (or load 101). In this example, system 100 and load 101 can be referred to as a micro-grid that is connected to grid 1430. Grid 1430 can be a utility-operated power grid that also provides power to the micro-grid load 101.

[0187] System 100 can be configured to operate in multiple modes. One example mode is grid-tied mode, which can also be referred to as grid-following mode. When system 100 is connected to grid 1430 and grid 1430 is operating normally, e.g., without an error or other condition causing system 100 to disconnect from grid 1430, system 100 can operate in the grid- tied mode in which system 100 follows the voltage, frequency, and phase of grid 1430 while regulating the amount of current provided to load 101. In other words, system 100 can provide, to load 101, AC power (e.g., single-phase AC signal or multi-phase AC signals) having a regulated current at the same voltage, frequency, and phase as the one or more AC signals provided by grid 1330.

[0188] Another example mode is stand-alone mode, where system 100 supplies the load 101 with a voltage whose frequency, amplitude, and / or phase could be different from that of grid 1330. When system 100 detects an error or other condition for which system 100 is configured to disconnect from grid 1430, e.g., an island or islanding condition, system 100 can disconnectfrom grid 1430 and operate in stand-alone mode. An example of an islanding condition is a blackout or other short term or long term loss of power from grid 1430, typically in all phases of a multi-phase system 1400. System 100 can disconnect entirely from grid 1430 and continue providing power to load 101 in stand-alone mode. In stand-alone mode, system 100 can act as a voltage controller to regulate the voltage provided to load 101 such that the voltage, frequency, and phase of the AC power provided to load 101 matches the last known voltage, frequency, and phase of grid 1430 before system 100 disconnected from grid 1430.

[0189] System 100 can also be configured to operate in other modes. For example, system 100 can be configured to operate in a grid-tied rectifier mode, grid-tied charger / discharger mode. Grid-tied rectifier mode is a mode in which system 100 is connected to grid 1430 and modules 108 of system 100 regulate a DC bus voltage to provide power to a DC load 101. Grid-tied charger / discharger mode is a mode in which system 100 is connected to grid 1430 and modules 108 of system 100 regulate a charging or discharging current to charge or discharge an energy source 206.

[0190] FIG. 14A is an electrical equivalence diagram depicting the example of the grid- connected system 1400 in which the energy system 100 is connected to the micro-grid load 101 and the grid 1430. This depicts a single phase version of system 1400, but can be equally applied to multiphase (e.g., two-phase, three-phase, four-phase, etc.) and split phase implementations by duplicating all components shown here for each phase including PLL 1450 (MCD 112 can operate for multiple phase is not duplicated). System 100 includes an output fdter 1412 configured to filter the voltage output by all of modules 108 of system 100 to provide precise and accurate output voltages. The filtered output voltage is connected to load 101 and grid 1430 at nodes 1414 and 1401, which may include terminals.

[0191] Contactors 1415 can switch between a closed state that permits current flow and an open state that blocks current flow. Contactors 1415 include a main contactor 1415-1 configured to connect and disconnect system 100 to and from both load 101 and grid 1430 (depending on the states of contactors 1415-2 and 1415-3). Contactor 1415-2 is configured to connect and disconnect load 101 from system 100 and grid 1430 (depending on the states of contactors 1415- 1 and 1415-3). Contactor 1415-3 is configured to connect and disconnect grid 1430 to system 100 and load 101 (depending on the states of contactors 1415-1 and 1415-2).

[0192] MCD 112 of system 100 (or alternatively another microgrid controller) can be communicably coupled to contactors 1415 to control operation of contactors 1415. MCD 112 can issue a control signal that causes contactors 1415 to selectively open and close, in any combination, depending on the mode of operation of system 100 and / or the status of system 100, load 101, or grid 1430. For example, when system 100 detects an islanding condition, MCD 112 can open contactor 1415-3 to disconnect system 100 and load 101 from grid 1430. MCD 112 can also transition to the stand-alone mode of operation in response to detecting the islanding condition.

[0193] Load 101 has an impedance that can be represented by a resistor, capacitor, and / or inductor depending on the type(s) of load(s) connected to system 100. Similarly, grid 1430 has an impedance that can be represented by a resistor and inductor. The impedance of grid 1430 can vary based on the quality of grid 1430 and the current condition of grid 1430, e g., whether power is present on grid 1130.

[0194] In a microgrid, transitions can occur within a given distributed energy resource (DER) between grid-forming and grid-following operating modes. In addition, the microgrid can be grid-connected or islanded from grid 1430. Whenever there are transitions in the operating modes of a microgrid or DER, such as system 100, or certain kinds of faults, there is the risk of impact to the loads and the microgrid. The impact can range from negligible to severe transients that can cause a local black out and even damage the loads and DER. Due to its low-inertia and smaller generation capacity, microgrids are particularly susceptible to transients. Therefore, methods and devices that minimize transients and facilitate seamless transitions are valuable and useful to DERs and microgrids.

[0195] Referring to FIG. 14A, initially, system 100’s filter capacitor 1440 is discharged and the voltage across it is zero. When system 100 is starting and connecting to grid 1430, if the main contactor 1415-1 first closes when the grid-voltage is closer to a high instantaneous value, then a significant inrush current will flow to charge capacitor 1440. Since the impedance of grid 1430 does not help to limit the inrush current since it is usually relatively small. Prior approaches have employed a pre-charge circuit to limits the inrush current by initially connecting capacitor 1440 to grid 1430 via an auxiliary contactor connected to a relatively large impedance. Subsequently, the main contactor 1415-1 closes to initiate grid-connection and inverter operation, thereby bypassing the auxiliary pre-charge circuit. Alternatively, some designers use arelatively large inductance between system 100 and the point of connection (POC) at contactor 1415-1 that limits the inrush current and also fdters the output of system 100. These prior approaches utilize additional components that add cost, size, energy losses, and reduce reliability.

[0196] System 100 can be configured to limit inrush current by matching the grid voltage at the point of connection (across nodes 1414 and 1401, or alternatively across nodes 1411 and 1401). For example, if system 100 is disconnected from grid 1430 by way of open contactor 1415-1, and system 100 is intended or instructed to enter into a grid following mode, then system 100 can utilize phase locked loop (PLL) 1450 to acquire the voltage and phase angle (and optionally frequency) at the point of connection. This information can be reported to MCD 112, which in turn can control the array 700 to produce an AC signal that matches the acquired voltage and phase angle at the point of connection. As described elsewhere herein, MCD 112 can generate a reference signal for the modules 108 of array 700, where this reference signal has a normalized voltage and phase angle based on that acquired by PLL 1450. System 100 can have a preprogrammed knowledge of the characteristics of output filter 1412 and can utilize this to ensure that the voltage and phase angle of the produced AC signal closely matches that of grid 1430 at or near the point of connection. In some embodiments, MCD 112 utilizes feedforward control to produce this AC signal, where the DC-link voltage in each module (as reported by LCDs 114) is used with the desired voltage setpoint obtained by PLL 1450 to produce the reference signal.

[0197] The command to close contactor 1415-1 can be is given, either by MCD 112 or a different controller of system 1400, and, in the case of contactor 1415-1 being an electromechanical relay, this closure will occur after a short but non-negligible delay. Because system 100 is matching the detected voltage phase angle of grid 1430, at the moment where contactor 1415-1 closes the two voltage signals will match. Thus upon closure of contactor 1415-1, there will be no significant voltage mismatch and the inrush current to capacitor 1440 will be significantly reduced as compared to a technique that does not match at the point of connection. At any time after closure, system 100 can change its mode of control to a normal technique, such as one based on feedback control, where both the feedforward information and the feedback of the current or voltage (for current control or voltage control, respectively) as measured from the grid 1430 are used to calculate the reference signal. In a multiphase system1430, a discrete PLL 1450 (implemented in hardware and / or software or firmware) can be used for each phase, with the information generated by each discrete PLL 1450 then utilized by MCD to generate discrete independent reference signals for each array 700 of the multiphase system 100.Examples of Seamless Mode Transitioning with Partial Phase Loss

[0198] Also provided herein are embodiments of seamless transition from a grid-connected, grid-following mode to a grid-forming mode due to unintentional island, including partial gridforming due to loss of less than all phases (partial island), and grid open-phase fault detection. Most island detection techniques do not consider fault ride-through (continuing to provide power to the load) in the case of phase loss in a 3-phase or other multiphase system, which is a grid fault (fallen conductor, or open conductor). Ride-through is often not a requirement for grid- connected inverters. In fact, grid connection standards such as IEEE 1547-2018 require the inverter to disconnect within two seconds of such a fault occurring, similar to the case of an unintentional island. However, the standard also allows for the possibility of an intentional island being created. If contactor 1415-1 or 1415-3 at the point of common coupling opens, an intentional island can be formed and maintained without violation of the grid codes. Most 3- phase grid-connected inverters are not capable of riding through this fault partly due to the control strategies employed, often referred to as DQ-current control. DQ control typically does not optimally or efficiently adjust to grid imbalance. Phase loss is equivalent to a type of grid imbalance. The ability to ride-through this fault and support load 101 until the intentional island is formed provides enhanced seamless transition capability for system 100.

[0199] The embodiments are not a priori dependent on any specific island detection technique so long as the technique has a quick detection time, such as one second or less, and can detect an island condition for less than all phases of a multiphase system.

[0200] FIG. 14B is a flow diagram depicting an example embodiment of a method 1460 of operating an energy storage system 100 connected to a grid and microgrid load. When control system 102 of system 100 detects the loss of a phase in grid 1430 in a multiphase system 1400 (at 1462), or the loss of more than one phase (but not all) in grid 1430 in the multiphase system 1400, such as by impedance monitoring, then control system 102 can transition the lost phase from a grid-following mode to a grid-forming mode while maintaining the non-lost phase or phases in the grid-following mode (at 1464).

[0201] Control system 102 can then determine the voltage and frequency and phase angle to be used to form the lost phase and generate a system AC signal in grid forming mode to replace the grid AC signal that was lost (at 1466). As described herein, this can entail generation of a reference signal for the array corresponding to the lost phase where that reference signal is the same as the reference signal for an array corresponding to a non-lost phase but shifted by the appropriate phase angle.

[0202] In the two-phase system, the lost phase will use the voltage and frequency from the non-lost phase but shifted by the appropriate phase angle (180 degrees). In a three-phase system, the lost phase can use the voltage and frequency from either remaining non-lost phases, but shifted by the appropriate phase angle (+ / - 120 degrees depending on the non-lost phase that is used as a source). If two phases are lost in a three-phase system, then the two lost phases will use the voltage and frequency from the remaining non-lost phase, but again shifted by the appropriate phase angle (+ / - 120 degrees). Similar rationale is used in instances of four or more phases where less than all phases are lost. The selection of a non-lost phase to use as a source for the lost phase can be based on the healthier of the non-lost phases (e.g., within voltage thresholds, within frequency thresholds, within phase angle thresholds, within impedance thresholds, and / or any combination thereof). If all remaining non-lost phases are healthy, then the control system 102 can select a phase arbitrarily or based on prior coded selection. Control system 102 then forms the AC signal of the lost phase or phases accordingly in order to maintain power in all phases to the microgrid load 101.

[0203] Optionally, system 100 can control the formed lost phase in such a manner as to cause the grid contactor 1415-3 associated with that phase to open. This can be done, for example, by controlling the formed lost phase to be below the undervoltage trip limit or the underfrequency trip limit of contactor 1415-3. This is preferably performed within two seconds (or other standardized time requirement) of the loss of phase event, to cause contactor 1415-3 to open (or trip) within the required time, resulting in an intentional island event. Control system 102 can then switch control strategy for system 100 from the partial grid-following and partial gridforming strategy to a wholly grid-forming strategy for all phases, resuming by following the requested setpoints of voltage and frequency. This approach inherently determines a type of grid fault (open phase) that can be communicated to the utility through supervisory system (e.g., Supervisory Control and Data Acquisition, or SCAD A) for diagnostics and repairs.

[0204] Various aspects of the present subject matter are set forth below, in review of, and / or in supplementation to, the implementations described thus far, with the emphasis here being on the interrelation and interchangeability of the following embodiments. In other words, an emphasis is on the fact that each feature of the embodiments can be combined with each and every other feature unless explicitly stated or taught otherwise.

[0205] In many example embodiments, an energy storage system is provided that includes: a plurality of modules, each module including an energy source, an energy buffer, and a power converter, wherein each of the plurality of modules is connected together in an array, wherein each module is communicatively coupled with a local control device, and wherein each module is configured to measure a magnitude of load current passing through the module and communicate the magnitude to the local control device and to a rapid short circuit detector.

[0206] In some embodiments, each module includes a current sensor and a current measurement circuit configured to measure the load current passing through the current sensor. The current measurement circuit can include a differential amplifier and a single end converter. The single end converter can output the magnitude of load current to the local control device and to the rapid short circuit detector.

[0207] In some embodiments, the rapid short circuit detector includes a hardware comparator, wherein a first input to the hardware comparator is the magnitude of load current, a second input to the hardware comparator is a hardware set voltage threshold, and the output from the comparator is an interrupt signal. The system can further include a current limiter circuit configured to receive the interrupt signal and limit current through the module when the interrupt signal indicates a short circuit. The current limiter circuit can include a safety disconnect and a variable resistor on a first current path, and a switch on a second current path, wherein opening of the switch routes current along the first current path. The safety disconnect can be a fuse and the variable resistor can be a negative temperature coefficient thermistor. The switch can be configured to open when the interrupt signal indicates a short circuit.

[0208] In many example embodiments, an energy storage system is provided that includes: a plurality of modules, each module including an energy source, an energy buffer, and a power converter, wherein each of the plurality of modules is connected together in an array, wherein each module is communicatively coupled with a local control device, and wherein each module further includes a current limiter on a load current path of the module, the current limiterincluding a safety disconnect and a variable resistor on a first current path, and a switch on a second current path, wherein current is routed along the first current path when the switch is open, and wherein current is routed along the second current path and substantially bypasses the first current path when the switch is closed.

[0209] In some embodiments, the local control device can be configured to open the switch to limit inrush current to the energy buffer.

[0210] In some embodiments, the local control device can be configured to open the switch when a short circuit fault is detected.

[0211] In some embodiments, the system further includes a hardware short circuit detector configured to detect a short circuit and open the switch in response. The hardware short circuit detector can be configured to detect the short circuit and open the switch in response without the use of software instructions.

[0212] In many example embodiments, an energy storage system is provided that includes: a plurality of modules, each module including an energy source and a power converter including a first transistor and a second transistor each having a current conducting state and a current blocking state, wherein each of the plurality of modules is connected together in an array, and wherein each module includes: detection logic configured to receive gate control signals for the first and second transistors, detect whether the gate control signals result in a fault condition where the gate control signals both indicate the current conducting state at the same time and, if the fault condition is present, change at least one gate control signal to indicate the current blocking state.

[0213] In some embodiments, for a respective module, the detection logic receives the gate control signals from a local control device associated with that respective module.

[0214] In some embodiments, the detection logic is configured to: if the fault condition is present, change both gate control signals to indicate the current blocking state.

[0215] In some embodiments, the power converter includes a full bridge converter including a first half bridge and a second half bridge, and wherein the detection logic is configured to: receive gate control signals for the first and second half bridges, detect whether the gate control signals result in a shoot through fault condition for the first half bridge or the second half bridge and, if the fault condition is present for either the first half bridge or the second half bridge, change at least one gate control signal to resolve the shoot through fault condition.

[0216] In some embodiments, the detection logic outputs the gate control signals without logic level change if no fault condition is present.

[0217] In some embodiments, the detection logic can be configured to permit normal operation of the power converter to resume as soon as the fault condition in the received gate signals is resolved.

[0218] In some embodiments, the detection logic can be configured to latch at least one gate control signal to indicate the current blocking state when the fault condition occurs.

[0219] In some embodiments, the detection logic can include a latch including a delay circuit, wherein the latch is configured to latch at least one gate control signal to indicate the current blocking state when the fault condition occurs provided that the fault condition occurs after a delay.

[0220] In many embodiments, a method of connecting an energy storage system to a grid is provided, where the energy storage system includes a control system and a plurality of modules, each module including an energy source and a power converter, wherein each of the plurality of modules is connected together in an array, and the method includes: acquiring a voltage and a phase angle of a grid AC signal from a node between the energy storage system and the grid; generating a system AC signal by the array, wherein the system AC signal matches the grid AC signal; and connecting the energy storage system to the grid.

[0221] In some embodiments, the voltage and the phase angle of the grid AC signal is acquired with a phase locked loop of the control system.

[0222] In some embodiments, generating the system AC signal by the array includes: generating, by the control system, a reference signal for the plurality of modules in the array, wherein the reference signal is based on the voltage and the phase angle; and controlling, by the control system, the power converter of each of the plurality of modules based on the reference signal to generate the system AC signal by the array.

[0223] In some embodiments, the method further includes generating the reference signal with a feedforward control technique. The method can include, after connecting the energy storage system to the grid, generating the system AC signal with a feedback control technique.

[0224] In some embodiments, connecting the energy storage system to the grid includes instructing an electromechanical relay between the energy storage system and the grid to close.

[0225] In some embodiments, the method is performed while the energy storage system is connected to a microgrid load.

[0226] In some embodiments, the energy storage system includes an output filter having a capacitor, and wherein generating the system AC signal to match the gird AC signal limits inrush current to the capacitor when the energy storage system is connected to the grid.

[0227] In many embodiments, a method of operating a multiphase energy storage system connected to a multiphase grid is provided, where the energy storage system includes a control system and a plurality of modules, each module including an energy source and a power converter, wherein the plurality of modules are connected together to form at least one array for each AC phase signal of the multiphase grid, the method including: detecting a loss of a first grid AC signal having a first phase angle; transitioning control of a first system AC signal generated by a first array of the energy storage system from a grid-following to a grid-forming mode, wherein the first system AC signal corresponds to the lost first grid AC signal; and generating the first system AC signal with the first array such that the first system AC signal is based on a non-lost grid AC signal and adjusted to have the first phase angle.

[0228] In some embodiments, the method further includes generating the first system AC signal such that the first system AC signal does not meet an undervoltage or underfrequency threshold of a first contactor of the grid.

[0229] In some embodiments, the method further includes generating the first system AC signal such that the first system AC signal does not meet an undervoltage or underfrequency threshold of a first contactor of the grid; detecting the opening of the first contactor; and reporting the loss of the first grid AC signal to a utility operating the grid.

[0230] In some embodiments, generating the first system AC signal with the first array such that the first system AC signal is based on the non-lost grid AC signal and adjusted to have the first phase angle includes: using voltage and frequency setpoints of the non-lost grid AC signal adjusted by a phase angle offset to generating the first system AC signal.

[0231] In some embodiments, generating the first system AC signal with the first array such that the first system AC signal is based on the non-lost grid AC signal and adjusted to have the first phase angle includes: generating, by the control system, a reference signal for the first array that is a phase angle offset version of a reference signal for a second array of the energy storagesystem, wherein the second array generates a second system AC signal corresponding to a nonlost second grid AC signal.

[0232] In many embodiments, a method of operating a multiphase energy storage system connected to a multiphase grid is provided, where the energy storage system includes a control system and a plurality of modules, each module including an energy source and a power converter, wherein the plurality of modules are connected together to form at least one array for each AC phase signal of the multiphase grid, the method including: detecting a loss of a first grid AC signal having a first phase angle and a second grid AC signal having a second phase angle; transitioning control of a first system AC signal generated by a first array of the energy storage system from a grid-following to a grid-forming mode, wherein the first system AC signal corresponds to the lost first grid AC signal; transitioning control of a second system AC signal generated by a second array of the energy storage system from a grid-following to a grid-forming mode, wherein the second system AC signal corresponds to the lost second grid AC signal; generating the first system AC signal with the first array such that the first system AC signal is based on a non-lost third grid AC signal and adjusted to have the first phase angle; and generating the second system AC signal with the second array such that the second system AC signal is based on the non-lost third grid AC signal and adjusted to have the second phase angle.

[0233] In the aforementioned embodiments, the control system can include processing circuitry and non-transitory memory on which is stored a plurality of instructions that, when executed by the processing circuitry, cause the control system to perform its functions.

[0234] The term “module” as used herein refers to one of two or more devices or subsystems within a larger system. The module can be configured to work in conjunction with other modules of similar size, function, and physical arrangement (e.g., location of electrical terminals, connectors, etc.). Modules having the same function and energy source(s) can be configured identical (e.g., size and physical arrangement) to all other modules within the same system (e.g., rack or pack), while modules having different functions or energy source(s) may vary in size and physical arrangement. While each module may be physically removable and replaceable with respect to the other modules of the system (e.g., like wheels on a car, or blades in an information technology (IT) blade server), such is not required. For example, a system may be packaged in a common housing that does not permit removal and replacement any one module, without disassembly of the system as a whole. However, any and all embodiments herein can beconfigured such that each module is removable and replaceable with respect to the other modules in a convenient fashion, such as without disassembly of the system.

[0235] The term “output” is used herein in a broad sense, and does not preclude functioning in a bidirectional manner as both an output and an input. Similarly, the term “input” is used herein in a broad sense, and does not preclude functioning in a bidirectional manner as both an input and an output.

[0236] The terms “terminal” and “port” are used herein in a broad sense, can be either unidirectional or bidirectional, can be an input or an output, and do not require a specific physical or mechanical structure, such as a female or male configuration.

[0237] The term “nominal voltage” is a commonly used metric to describe a battery cell, and is provided by the manufacturer (e.g., by marking on the cell or in a datasheet). Nominal voltage often refers to the average voltage a battery cell outputs when charged, and can be used to describe the voltage of entities incorporating battery cells, such as battery modules and subsystems and systems of the present subject matter.

[0238] The term “C rate” is a commonly used metric to describe the discharge current divided by the theoretical current draw under which the battery would deliver its nominal rated capacity in one hour.

[0239] Different reference number notations are used herein. These notations are used to facilitate the description of the present subject matter and do not limit the scope of that subject matter. Some figures show multiple instances of the same or similar elements. Those elements may be appended with a number or a letter in a “-X” format, e.g., 123-1, 123-2, or 123-PA. This -X format does not imply that the elements must be configured identically in each instance, but is rather used to facilitate differentiation when referencing the elements in the figures. Reference to a genus number without the -X appendix (e.g., 123) broadly refers to all instances of the element within the genus.

[0240] Processing circuitry can include one or more processors, microprocessors, controllers, and / or microcontrollers, each of which can be or can be part of a discrete or stand-alone chip or distributed amongst (and a portion of) a number of different chips. Any type of processing circuitry can be implemented, such as, but not limited to, personal computing architectures (e.g., such as used in desktop PC’s, laptops, tablets, etc.), field programmable gate array (FPGA) architectures, proprietary architectures, custom architectures, and others. Processing circuitrycan be an application specific integrated circuit (ASIC), an application specific standard part (ASSP), or all or a part of a system-on-ship (SoC). Processing circuitry can include a digital signal processor, which can be implemented in hardware and / or software. Processing circuitry can execute software instructions stored on memory that cause processing circuitry to take a host of different actions and control other components.

[0241] Processing circuitry can also perform other software and / or hardware routines. For example, processing circuitry can interface with communication circuitry and perform analog-to- digital conversions, encoding and decoding, other digital signal processing, multimedia functions, conversion of data into a format (e.g., in-phase and quadrature) suitable for provision to communication circuitry, and / or can cause communication circuitry to transmit the data (wired or wirelessly).

[0242] Any and all communication signals described herein can be communicated wirelessly except where noted or logically implausible. Communication circuitry can be included for wireless communication. The communication circuitry can be implemented as one or more chips and / or components (e.g., transmitter, receiver, transceiver, and / or other communication circuitry) that perform wireless communications over links under the appropriate protocol (e.g., Wi-Fi, Bluetooth, Bluetooth Low Energy, Near Field Communication (NFC), Radio Frequency Identification (RFID), proprietary protocols, and others). One or more other antennas can be included with communication circuitry as needed to operate with the various protocols and circuits. In some embodiments, communication circuitry can share antenna for transmission over links. RF communication circuitry can include a transmitter and a receiver (e.g., integrated as a transceiver) and associated encoder logic.

[0243] Processing circuitry can also be adapted to execute the operating system and any software applications, and perform those other functions not related to the processing of communications transmitted and received.

[0244] Computer program instructions for carrying out operations in accordance with the described subject matter may be written in any combination of one or more languages, including computer and programming languages. A non-exhaustive list of examples includes hardware description languages (HDLs), SystemC, C, C++, C#, Objective-C, Matlab, Simulink, SystemVerilog, System VHDL, Handel-C, Python, Java, JavaScript, Ruby, HTML, Smalltalk, Transact-SQL, XML, PHP, Golang (Go), “R” language, and Swift, to name a few.

[0245] Memory, storage, and / or computer readable media can be shared by one or more of the various functional units present, or can be distributed amongst two or more of them (e.g., as separate memories present within different chips). Memory can also reside in a separate chip of its own.

[0246] To the extent the embodiments disclosed herein include or operate in association with memory, storage, and / or computer readable media, then that memory, storage, and / or computer readable media are non-transitory. Accordingly, to the extent that memory, storage, and / or computer readable media are covered by one or more claims, then that memory, storage, and / or computer readable media is only non-transitory. The terms “non-transitory” and “tangible” as used herein, are intended to describe memory, storage, and / or computer readable media excluding propagating electromagnetic signals, but are not intended to limit the type of memory, storage, and / or computer readable media in terms of the persistency of storage or otherwise. For example, “non-transitory” and / or “tangible” memory, storage, and / or computer readable media encompasses volatile and non-volatile media such as random access media (e.g., RAM, SRAM, DRAM, FRAM, etc ), read-only media (e.g., ROM, PROM, EPROM, EEPROM, flash, etc.) and combinations thereof (e.g., hybrid RAM and ROM, NVRAM, etc.) and variants thereof.

[0247] It should be noted that all features, elements, components, functions, and steps described with respect to any embodiment provided herein are intended to be freely combinable and substitutable with those from any other embodiment. If a certain feature, element, component, function, or step is described with respect to only one embodiment, then it should be understood that that feature, element, component, function, or step can be used with every other embodiment described herein unless explicitly stated otherwise. This paragraph therefore serves as antecedent basis and written support for the introduction of claims, at any time, that combine features, elements, components, functions, and steps from different embodiments, or that substitute features, elements, components, functions, and steps from one embodiment with those of another, even if the following description does not explicitly state, in a particular instance, that such combinations or substitutions are possible. It is explicitly acknowledged that express recitation of every possible combination and substitution is overly burdensome, especially given that the permissibility of each and every such combination and substitution will be readily recognized by those of ordinary skill in the art.

[0248] As used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0249] While the embodiments are susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that these embodiments are not to be limited to the particular form disclosed, but to the contrary, these embodiments are to cover all modifications, equivalents, and alternatives falling within the spirit of the disclosure. Furthermore, any features, functions, steps, or elements of the embodiments may be recited in or added to the claims, as well as negative limitations that define the inventive scope of the claims by features, functions, steps, or elements that are not within that scope.

Claims

CLAIMS1. An energy storage system, comprising: a plurality of modules, each module comprising an energy source, an energy buffer, and a power converter, wherein each of the plurality of modules is connected together in an array, wherein each module is communicatively coupled with a local control device, and wherein each module is configured to measure a magnitude of load current passing through the module and communicate the magnitude to the local control device and to a rapid short circuit detector.

2. The energy storage system of claim 1, wherein each module comprises a current sensor and a current measurement circuit configured to measure the load current passing through the current sensor.

3. The energy storage system of claim 2, wherein the current measurement circuit comprises a differential amplifier and a single end converter.

4. The energy storage system of claim 3, wherein the single end converter outputs the magnitude of load current to the local control device and to the rapid short circuit detector.

5. The energy storage system of claim 1, wherein the rapid short circuit detector comprises a hardware comparator, wherein a first input to the hardware comparator is the magnitude of load current, a second input to the hardware comparator is a hardware set voltage threshold, and the output from the comparator is an interrupt signal.

6. The energy storage system of claim 5, further comprising a current limiter circuit configured to receive the interrupt signal and limit current through the module when the interrupt signal indicates a short circuit.

7. The energy storage system of claim 6, wherein the current limiter circuit comprises a safety disconnect and a variable resistor on a first current path, and a switch on a second current path, wherein opening of the switch routes current along the first current path.

8. The energy storage system of claim 7, wherein the safety disconnect is a fuse and the variable resistor is a negative temperature coefficient thermistor.

9. The energy storage system of claim 7, wherein the switch is configured to open when the interrupt signal indicates a short circuit.

10. An energy storage system, comprising: a plurality of modules, each module comprising an energy source, an energy buffer, and a power converter, wherein each of the plurality of modules is connected together in an array, wherein each module is communicatively coupled with a local control device, and wherein each module further comprises a current limiter on a load current path of the module, the current limiter comprising a safety disconnect and a variable resistor on a first current path, and a switch on a second current path, wherein current is routed along the first current path when the switch is open, and wherein current is routed along the second current path and substantially bypasses the first current path when the switch is closed.

11. The energy storage system of claim 10, wherein the local control device is configured to open the switch to limit inrush current to the energy buffer.

12. The energy storage system of claim 10, wherein the local control device is configured to open the switch when a short circuit fault is detected.

13. The energy storage system of claim 10, further comprising a hardware short circuit detector configured to detect a short circuit and open the switch in response.

14. The energy storage system of claim 13, wherein the hardware short circuit detector is configured to detect the short circuit and open the switch in response without the use of software instructions.

15. An energy storage system, comprising:a plurality of modules, each module comprising an energy source and a power converter comprising a first transistor and a second transistor each having a current conducting state and a current blocking state, wherein each of the plurality of modules is connected together in an array, and wherein each module comprises: detection logic configured to receive gate control signals for the first and second transistors, detect whether the gate control signals result in a fault condition where the gate control signals both indicate the current conducting state at the same time and, if the fault condition is present, change at least one gate control signal to indicate the current blocking state.

16. The energy storage system of claim 15, wherein, for a respective module, the detection logic receives the gate control signals from a local control device associated with that respective module.

17. The energy storage system of claim 15, wherein the detection logic is configured to: if the fault condition is present, change both gate control signals to indicate the current blocking state.

18. The energy storage system of claim 15, wherein the power converter comprises a full bridge converter including a first half bridge and a second half bridge, and wherein the detection logic is configured to: receive gate control signals for the first and second half bridges, detect whether the gate control signals result in a shoot through fault condition for the first half bridge or the second half bridge and, if the fault condition is present for either the first half bridge or the second half bridge, change at least one gate control signal to resolve the shoot through fault condition.

19. The energy storage system of claim 15, wherein the detection logic outputs the gate control signals without logic level change if no fault condition is present.

20. The energy storage system of claim 15, wherein the detection logic is configured to permit normal operation of the power converter to resume as soon as the fault condition in the received gate signals is resolved.21 . The energy storage system of claim 15, wherein the detection logic is configured to latch at least one gate control signal to indicate the current blocking state when the fault condition occurs.

22. The energy storage system of claim 15, wherein the detection logic comprises a latch including a delay circuit, wherein the latch is configured to latch at least one gate control signal to indicate the current blocking state when the fault condition occurs provided that the fault condition occurs after a delay.

23. A method of connecting an energy storage system to a grid, wherein the energy storage system comprises a control system and a plurality of modules, each module comprising an energy source and a power converter, wherein each of the plurality of modules is connected together in an array, the method comprising: acquiring a voltage and a phase angle of a grid AC signal from a node between the energy storage system and the grid; generating a system AC signal by the array, wherein the system AC signal matches the grid AC signal; and connecting the energy storage system to the grid.

24. The method of claim 23, wherein the voltage and the phase angle of the grid AC signal is acquired with a phase locked loop of the control system.

25. The method of claim 23, wherein generating the system AC signal by the array, comprises: generating, by the control system, a reference signal for the plurality of modules in the array, wherein the reference signal is based on the voltage and the phase angle; controlling, by the control system, the power converter of each of the plurality of modules based on the reference signal to generate the system AC signal by the array.

26. The method of claim 25, further comprising generating the reference signal with a feedforward control technique.

27. The method of claim 26, further comprising, after connecting the energy storage system to the grid, generating the system AC signal with a feedback control technique.

28. The method of claim 23, wherein connecting the energy storage system to the grid comprises instructing an electromechanical relay between the energy storage system and the grid to close.

29. The method of claim 23, performed while the energy storage system is connected to a microgrid load.

30. The method of claim 23, wherein the energy storage system comprises an output filter having a capacitor, and wherein generating the system AC signal to match the gird AC signal limits inrush current to the capacitor when the energy storage system is connected to the grid.

31. A method of operating a multiphase energy storage system connected to a multiphase grid, wherein the energy storage system comprises a control system and a plurality of modules, each module comprising an energy source and a power converter, wherein the plurality of modules are connected together to form at least one array for each AC phase signal of the multiphase grid, the method comprising: detecting a loss of a first grid AC signal having a first phase angle; transitioning control of a first system AC signal generated by a first array of the energy storage system from a grid-following to a grid-forming mode, wherein the first system AC signal corresponds to the lost first grid AC signal; generating the first system AC signal with the first array such that the first system AC signal is based on a non-lost grid AC signal and adjusted to have the first phase angle.

32. The method of claim 31, further comprising generating the first system AC signal such that the first system AC signal does not meet an undervoltage or underfrequency threshold of a first contactor of the grid.

33. The method of claim 31, further comprising generating the first system AC signal such that the first system AC signal does not meet an undervoltage or underfrequency threshold of a first contactor of the grid; and detecting the opening of the first contactor; and reporting the loss of the first grid AC signal to a utility operating the grid.

34. The method of claim 31, wherein generating the first system AC signal with the first array such that the first system AC signal is based on the non-lost grid AC signal and adjusted to have the first phase angle comprises: using voltage and frequency setpoints of the non-lost grid AC signal adjusted by a phase angle offset to generating the first system AC signal.

35. The method of claim 31, wherein generating the first system AC signal with the first array such that the first system AC signal is based on the non-lost grid AC signal and adjusted to have the first phase angle comprises: generating, by the control system, a reference signal for the first array that is a phase angle offset version of a reference signal for a second array of the energy storage system, wherein the second array generates a second system AC signal corresponding to a non-lost second grid AC signal.

36. A method of operating a multiphase energy storage system connected to a multiphase grid, wherein the energy storage system comprises a control system and a plurality of modules, each module comprising an energy source and a power converter, wherein the plurality of modules are connected together to form at least one array for each AC phase signal of the multiphase grid, the method comprising: detecting a loss of a first grid AC signal having a first phase angle and a second grid AC signal having a second phase angle; transitioning control of a first system AC signal generated by a first array of the energy storage system from a grid-following to a grid-forming mode, wherein the first system AC signal corresponds to the lost first grid AC signal;transitioning control of a second system AC signal generated by a second array of the energy storage system from a grid-following to a grid-forming mode, wherein the second system AC signal corresponds to the lost second grid AC signal; generating the first system AC signal with the first array such that the first system AC signal is based on a non-lost third grid AC signal and adjusted to have the first phase angle; and generating the second system AC signal with the second array such that the second system AC signal is based on the non-lost third grid AC signal and adjusted to have the second phase angle.

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