A storage system configured to be used in an energy management system

Abstract

A storage system configured for use in an energy management system is provided, including a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries, and a controller configured to determine the remaining time until each of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is exhausted in order to balance the power of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to power systems, and more particularly to a storage system configured for use in an energy management system.

Background Art

[0002] Conventional AC storage systems provide the required energy storage (kWh) and the required AC power (kW). The typical AC storage system requirements for the required power are a function of the energy storage required for the housing complex. For example, in a residential AC storage system, a house that requires a storage capacity of 5 kWh may simply require a continuous output capacity of up to 5 kW (e.g., a 5 kW inverter). Conversely, a house that requires a storage capacity of 20 kWh may require a continuous output capacity of 9 kW. The general curve of the continuous output capacity as a function of the total stored energy can be defined as P = P o + k*E, where P o is the minimum continuous output, k is the storage power conversion coefficient, and E is the maximum stored energy of the AC storage system. P o (assuming a housing complex with a very small energy storage requirement, for example) is generally a non-zero value, and k can be the slope of the curve. Thus, for a 4-hour storage, the slope may be approximately 0.25, and for a 24-hour storage, the slope may be approximately 0.07. The C-rate may also be defined in the curve as the rated output divided by the stored energy. For example, if the required output is 9 kW and the stored energy is 20 kWh, the C-rate can be 0.45 (e.g., 9 kW / 20 kWh).

[0003] However, since modular AC power storage systems can be scalable according to the storage needs of users, the selection of an optimal inverter can sometimes be difficult to achieve. For example, if a user needs a 20 kWh storage capacity and chooses to use 5 kWh storage size modules, four 5 kWh storage size modules are required, each using a 5 kWh inverter. The continuous output capacity of such an AC power storage system is 20 kW (e.g., 4 * 5 kW), which is more than twice the required total continuous output capacity of 9 kW, and is associated with additional costs for an AC power storage system that is too large in terms of output. Further, if the user selects 20 kWh storage size modules, a single 9 kW inverter can be used, but such an AC power storage system is too large and too costly for an AC power storage system that requires less than 20 kWh.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] Therefore, in fact, an optimal system may have a combination of AC battery modules with different C-rates so as to be optimally configured to provide the required power and required energy. If the AC battery modules may have differences in the ability to provide power, a balancing system is required to ensure that the power is provided at a rate that ensures that the batteries deplete all of their energy almost simultaneously.

Means for Solving the Problems

[0006] According to some aspects of the present disclosure, a storage system configured for use in an energy management system includes a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries, and a controller configured to determine the remaining time until each of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is depleted, in order to balance the power of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

[0007] According to some aspects of the present disclosure, a method for managing a storage system configured for use in an energy management system includes determining the remaining time until each of a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is depleted, and balancing the power of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

[0008] According to some aspects of the present disclosure, a non-transitory computer-readable storage medium storing instructions that, when executed by a processor, perform a method for managing a storage system configured for use in an energy management system includes determining the remaining time until each of a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is depleted, and balancing the power of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

[0009] To enable a more detailed understanding of the features described above of the present disclosure, a more specific description of the present disclosure briefly summarized above may be made by reference to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only typical embodiments of the present disclosure and should not be regarded as limiting its scope, as the present disclosure may admit other equally effective embodiments.

Brief Description of the Drawings

[0010]

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DETAILED DESCRIPTION

[0011] According to the present disclosure, methods and apparatuses configured for use in an energy management system are disclosed herein. For example, the storage system may comprise a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries. The controller is configured to determine the remaining time until each of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is depleted in order to balance the power of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries. The methods and apparatuses described herein provide significant cost advantages compared to conventional methods and apparatuses by supplying power and energy that are closely tailored to the needs of the user. Further, the battery balancing method described herein has little additional cost to add to an energy management system for power conversion that is already in place.

[0012] FIG. 1 is a block diagram of an energy management system (System 100) for power conversion using one or more embodiments of the present disclosure. This figure depicts only one variation of the innumerable possible system configurations and devices that can utilize the present disclosure.

[0013] System 100 is a microgrid that can operate in both an islanded state and a grid-connected state (i.e., when connected to another power grid (one or more other microgrids and / or a commercial power grid)). System 100 includes a plurality of power converters (sometimes called power conditioners) 102-1, 102-2, …… 102-N, 102-N+1, and 102-N+M collectively referred to as power converter 102, a plurality of DC power supplies 104-1, 104-2,...... 104-N collectively referred to as power source 104, a plurality of energy storage / supply devices 120-1, 120-2,...... 120-M collectively referred to as energy storage / supply device 120, a system controller 106, a plurality of BMUs 190-1, 190-2,...... 190-M collectively referred to as battery management unit (BMU) 190, a system controller 106, a bus 108, a load center 110, and an island interconnect device (IID) 140 (sometimes called a microgrid interconnect device (MID)). In some embodiments, such as the embodiments described herein, the energy storage / supply device may be a rechargeable battery (e.g., a multi-C rate AC battery pack) sometimes called battery 120, but in other embodiments, the energy storage / supply device may be other suitable devices for storing energy and providing the stored energy. Generally, each of the batteries 120 includes a plurality of cells connected in series, for example, eight cells are connected in series to form the battery 120.

[0014] Each of the power converters 102-1, 102-2......102-N is coupled to a respective one of the DC power supplies 104-1, 104-2......104-N in a one-to-one correspondence. However, in some other embodiments, a plurality of DC power supplies 104 may be coupled to one or more of the power converters 102. The power converters 102-N+1, 102-N+2......102-N+M are each coupled to a respective one of the plurality of energy storage devices / supply devices 120-1, 120-2......120-M via a respective one of the BMU 190-1, 190-2......190-M to form respective AC batteries 180-1, 180-2......180-M. Each of the power converters 102-1, 102-2......102-N+M includes a respective controller 114-1, 114-2......114-N+M (collectively referred to as the inverter controller 114) for controlling the operation of the corresponding power converter 102-1, 102-2......102-N+M.

[0015] In some embodiments, such as the embodiments described below, the DC power supply 104 is a DC power supply, the power converter 102 is a bidirectional inverter, and the power converters 102-1......102-N convert DC power from the DC power supply 104 into grid-corresponding AC power coupled to the bus 108, and the power converters 102-N+1...102-N+M convert DC power from the battery 120 (during discharge of the energy storage device) into grid-corresponding AC power coupled to the bus 108, and also convert AC power from the bus 108 into DC output stored in the battery 120 for later use (during charging of the energy storage device). The DC power supply 104 may be a suitable DC source, such as the output from a previous power conversion stage, a battery, a renewable energy source (e.g., a solar panel or a photovoltaic (PV) module, a wind turbine, a hydroelectric power system, or a similar renewable energy source) for supplying DC power. In other embodiments, the power converter 102 may be another type of converter (such as a DC-DC converter), and the bus 108 may be a DC power bus.

[0016] The power converter 102 is coupled to the system controller 106 via a bus 108 (which may also be referred to as an AC line or grid). The system controller 106 generally includes a CPU coupled to each of the support circuits, and a memory including a system control module for controlling some operational aspects of the system 100 and / or monitoring the system 100 (e.g., issuing commands and control instructions to one or more of the power converters 102, collecting data related to the performance of the power converters 102, etc.). The system controller 106 can communicate with the power converter 102 by wireless and / or wired communication (e.g., power line communication) to perform certain operation control and / or monitoring of the power converter 102.

[0017] In some embodiments, the system controller 106 may be a gateway that receives data (e.g., performance data) from the power converter 102 and communicates the data and / or other information to a remote device or system, such as a master controller (not shown), (e.g., via the Internet). Additionally or alternatively, the gateway may receive information from a remote device or system (not shown), communicate the information to the power converter 102, and / or use the information to generate control commands issued to the power converter 102.

[0018] The power converter 102 is coupled to the load center 110 via the bus 108, and the load center 110 is coupled to the power grid via the IID 140. When coupled to the power grid (e.g., a commercial grid or a larger microgrid) via the IID 140, the system 100 may be referred to as grid-connected, and when disconnected from the power grid via the IID 140, the system 100 may be referred to as self-sufficient. The IID 140 determines when to disconnect from / connect to the power grid (e.g., the IID 140 may detect grid fluctuations, disturbances, outages, etc.) and performs the disconnection / connection. When disconnected from the power grid, the system 100 can continue to generate power as an intentional island using the droop control techniques described herein, without imposing safety risks on any linemen who may be working on the grid. The IID 140 includes a disconnect component (e.g., a disconnect relay) to physically disconnect / connect the system 100 from the power grid. In some embodiments, the IID 140 may further include a single-winding transformer to couple the power system 100 to a split-phase load that may have some neutral current imbalance therein. In some embodiments, the system controller 106 includes the IID 140 or a portion of the IID 140.

[0019] The power converter 102 converts DC power from the DC power source 104 and the discharging battery 120 into grid-compatible AC power and couples the generated output power to the load center 110 via the bus 108. The power is then distributed to one or more loads (e.g., one or more devices) and / or (when connected to the power grid) to the power grid. Additionally or alternatively, the generated energy may be stored for later use, e.g., in a battery, hot water, pumped hydroelectric storage, H 2It may be stored using conversions such as from oxygen to hydrogen. Generally, system 100 is coupled to the commercial power grid, but in some embodiments, system 100 operates as an independent microgrid, completely separated from the commercial grid.

[0020] In some embodiments, the AC power generated by power converter 102 is single-phase AC power. In other embodiments, power converter 102 generates three-phase AC power.

[0021] A storage system configured to be used in an energy management system such as an Enphase® Energy System is described herein. For example, FIG. 2 is a block diagram of an AC battery system 200 (e.g., a storage system) according to one or more embodiments of the present disclosure.

[0022] AC battery system 200 includes a battery 120 and a BMU 190 coupled to an inverter 102. A pair of metal-oxide-semiconductor field-effect transistor (MOSFET) switches, namely switch 228 and switch 230, are coupled in series between a first terminal 240 of battery 120 and a first terminal 244 of the inverter, with the body diode cathode terminal of switch 228 coupled to the first terminal 240 of battery 120 and the body diode cathode terminal of switch 230 coupled to the first terminal 244 of inverter 102. The gate terminals of switches 228 and 230 are coupled to BMU 190.

[0023] A second terminal 242 of battery 120 is coupled to a second terminal 246 of inverter 102 via a current measurement module 226 that measures the current flowing between battery 120 and inverter 102.

[0024] The BMU 190 is coupled to the current measurement module 226 to receive information regarding the measured current and receives an input 224 from the battery 120 indicative of the battery cell voltage and temperature. The BMU 190 is coupled to the gate terminals of each of the switch 228 and the switch 230 to drive the switch 228 to control battery discharge and to drive the switch 230 to control battery charging, as described herein. The BMU 190 is also coupled to the first terminal 244 and the second terminal 246 to provide an inverter bias control voltage (sometimes referred to as a bias control voltage) to the inverter 102, as further described below.

[0025] The configurations of the body diodes of the switch 228 and the switch 230 allow current to be blocked in one direction but not in the reverse direction depending on the states of each of the switch 228 and the switch 230. When the switch 228 is active (i.e., on) and the switch 230 is inactive (i.e., off), battery discharge is enabled, allowing current to flow from the battery 120 through the body diode of the switch 230 to the inverter 102. When the switch 228 is inactive and the switch 230 is active, battery charging is enabled, allowing current flow from the inverter 102 to the battery 120 through the body diode of the switch 228. When both switches 228 and 230 are active, the system is in a normal mode in which the battery 120 can be charged or discharged.

[0026] The BMU 190 includes a support circuit 204 and a memory 206 (e.g., a non-transitory computer-readable storage medium), each coupled to a central processing unit (CPU) 202. The CPU 202 may comprise one or more processors, microprocessors, microcontrollers, and combinations thereof configured to execute non-transitory software instructions to perform various tasks according to embodiments of the present disclosure. The CPU 202 may alternatively or additionally comprise one or more application-specific integrated circuits (ASICs). In some embodiments, the CPU 202 may be a microcontroller having internal memory for storing controller firmware that provides the controller functionality described herein when executed. The BMU 190 may be implemented using a general-purpose computer that becomes a dedicated computer for implementing various embodiments of the present disclosure when executing certain software.

[0027] The support circuit 204 is a well-known circuit used to facilitate the functionality of the CPU 202. Such circuits include, but are not limited to, cache, power supply, clock circuit, bus, input / output (I / O) circuit, and the like. The BMU 190 may be implemented using a general-purpose computer that becomes a dedicated computer for implementing various embodiments of the present disclosure when executing certain software. In one or more embodiments, the CPU 202 may be a microcontroller having internal memory for storing controller firmware that provides the controller functionality described herein when executed.

[0028] Memory 206 can include random access memory, read-only memory, removable disk memory, flash memory, and various combinations of these types of memory. Memory 206 may be referred to as main memory, and part of it may be used as cache memory or buffer memory. Memory 206 generally stores an operating system (OS) 208 of the inverter controller 114 that can be supported by the CPU capabilities if necessary. In some embodiments, the OS 208 may be one of several commercially available operating systems, including but not limited to LINUX, a real-time operating system (RTOS), etc.

[0029] Memory 206 stores non-transitory processor-executable instructions and / or data that can be executed and / or used by the CPU 202 to implement one or more methods for discharge protection, as will be described in more detail below. These processor-executable instructions may include firmware, software, etc., or some combination thereof. Memory 206 stores various forms of application software, such as a collection system module 210, a switch control module 212, a control system module 214, and an inverter bias control module 216. Memory 206 further stores a database 218 for storing data related to the operation of the BMU 190 and / or the present disclosure, such as one or more thresholds, equations, formulas, curves, and / or algorithms for the control techniques described herein. In various embodiments, one or more of, or a portion of, the collection system module 210, the switch control module 212, the control system module 214, the inverter bias control module 216, and the database 218 are implemented in software, firmware, hardware, or a combination thereof.

[0030] The collection system module 210 acquires cell voltage and temperature information from the battery 120 via the input 224, acquires the measured current value provided by the current measurement module 226, and provides cell voltage, cell temperature, and measured current information to the control system module 214 for use as described herein.

[0031] The switch control module 212 drives the switches 228 and 230 as determined by the control system module 214. The control system module 214 provides various battery management functions including protection functions (e.g., overcurrent (OC) protection, overtemperature (OT) protection, and hardware fault protection), measurement functions (e.g., averaging the measured battery cell voltage and battery current over, e.g., 100 ms to remove 50 and 60 Hz ripple), state of charge (SOC) analysis (e.g., determining the current flow and using the current flow to estimate the battery SOC, synchronizing the estimated SOC value to the battery voltage (setting the SOC to an upper limit such as 100% at the maximum battery voltage, setting the SOC to a lower limit such as 0% at the minimum battery voltage, etc.), turning off the SOC if the inverter 102 does not drive the battery 120 to these limits, etc.), and a Coulomb gauge 250 for determining such things), and balancing (e.g., autonomously balancing the charge equally across all cells of the battery, which can be done at the end of charge, at the end of discharge, or in some embodiments both at the end of charge and at the end of discharge). Based on the end of battery charge and the end of discharge, the BMU 190 determines the estimated SOC by establishing estimated SOC upper and lower limits respectively and tracking the current flow and cell voltage (i.e., battery voltage) between these events.

[0032] The inverter controller 114 includes a support circuit 254 and a memory 256, each coupled to a central processing unit (CPU) 252. The CPU 252 may include one or more processors, microprocessors, microcontrollers, and combinations thereof configured to execute non-transitory software instructions to perform various tasks according to embodiments of the present disclosure. The CPU 252 may alternatively or additionally include one or more application specific integrated circuits (ASICs). In some embodiments, the CPU 252 may be a microcontroller having internal memory for storing controller firmware that provides the controller functionality described herein when executed. The inverter controller 114 may be implemented using a general purpose computer that becomes a dedicated computer for implementing various embodiments of the present disclosure when executing certain software.

[0033] The support circuit 254 is a well-known circuit used to facilitate the functionality of the CPU 252. Such circuits include, but are not limited to, cache, power supply, clock circuit, bus, input / output (I / O) circuit, and the like. The inverter controller 114 may be implemented using a general purpose computer that becomes a dedicated computer for implementing various embodiments of the present disclosure when executing certain software. In one or more embodiments, the CPU 252 may be a microcontroller having internal memory for storing controller firmware that provides the controller functionality described herein when executed.

[0034] Memory 256 can include random access memory, read-only memory, removable disk memory, flash memory, and various combinations of these types of memory. Memory 256 may be referred to as main memory, and some may be used as cache memory or buffer memory. Memory 256 generally stores an operating system (OS) 258 of inverter controller 114 that can be supported by CPU capabilities if necessary. In some embodiments, OS 258 may be one of several commercially available operating systems, including but not limited to LINUX, a real-time operating system (RTOS), etc.

[0035] Memory 256 stores non-transitory processor-executable instructions and / or data that can be executed and / or used by CPU 252. These processor-executable instructions may include firmware, software, etc., or some combination thereof. Memory 256 stores various forms of application software, such as a power conversion control module 270 for controlling bidirectional power conversion and a battery management control module 272.

[0036] BMU 190 performs droop control (semi-passive) that enables the batteries to substantially deplete their charge simultaneously, and controls the batteries to charge a battery with less remaining time until depletion using a battery with more remaining time until depletion, based on the remaining time until each of the batteries depletes its charge, in order to balance the batteries 120 (e.g., a multi-C rate AC battery set), and communicates with system controller 106 for this purpose, as will be described in more detail below.

[0037] FIG. 3 is a graph 300 of continuous output capability versus total stored energy according to at least one embodiment of the present disclosure. As shown in FIG. 3, a storage system (e.g., a multi-C-rate battery) may have a continuous output capability (e.g., kW) and a total stored energy (kWh). Further, as described above, the C-rate may be defined in the curve as the rated output divided by the stored energy. For example, if the required output is 5 kW and the stored energy is 5 kWh, the C-rate can be 1 (e.g., 5 kW / 5 kWh).

[0038] FIG. 4 is a graph 400 of the state of charge over time, FIG. 5 is a graph 500 of power over time, and FIG. 6 is a graph 600 of battery discharge power over time according to at least one embodiment of the present disclosure. For example, a given storage system (e.g., storage system 200) can include a plurality of batteries (e.g., five batteries). Two of the batteries may have a rating of 2 Wh, two of the batteries may have a rating of 4 Wh, and a fifth battery may have a rating of 8 Wh. Each of the batteries may start, for example, at a state of charge of 80% (FIG. 4). Under the control of the system controller 106, the storage system can be configured to provide power to one or more loads (e.g., the combined load) (FIG. 5). For example, during a first time period (at about 2 seconds, see the dashed line), the storage system is configured to supply, for example, about 750 W of power using five batteries to match the combined load, and the system controller 106 is configured to charge / discharge the five batteries based on the power rating and / or C-rate of each battery. For example, at about 2 seconds, the system controller 106 can start discharging the 8 Wh battery and two 4 Wh batteries to supply power to the combined load and charge the two 2 Wh batteries (see the 2-second time point in FIGS. 4-6). After about 7.5 seconds (e.g., a second time period, see the dashed line), the storage system may be configured to supply about 1400 W of power (e.g., for more than 50 seconds) to match the combined load, and the system controller 106 may be configured to start discharging the two 2 Wh batteries to make up for additional power requirements. The system controller 106 continues to discharge the five batteries for about 50 seconds until all five batteries are fully discharged simultaneously or substantially simultaneously. See, for example, FIGS. 4 and 6.

[0039] FIG. 7 is a flowchart of a method 700 for managing a storage system configured to be used in an energy management system according to at least one embodiment of the present disclosure.

[0040] In 702, method 700 includes determining the remaining time until each battery of a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is exhausted. For example, system controller 106 can determine the state of charge (SOC) of each of the five batteries described above with respect to FIGS. 4-6. For example, the remaining time of the battery, T R can be calculated using Equation (1). T R = E R / P C ............., (1) where E R is the remaining energy and P C is the current power supplied by the battery, assuming the output power remains the same. If the supplied power is not constant, P C is the average power supplied during the remaining discharge of the battery.

[0041] Therefore, if the state of energy is known, the remaining time can be calculated using Equation (2). T R = (SOE * E O ) / P C ........, (2) where E O is the initial capacity of the battery. To ensure that the remaining time is the same (or approximately the same) among the batteries, when the maximum load is applied, T RM can be calculated using Equation (3). T RM = (SOE * E O ) / P C = SOE / C RATE ..........(3)

[0042] Balance T RM among the batteries to ensure that all batteries are exhausted simultaneously when the maximum load is applied. Therefore, the balancing control period for each battery, i, can be calculated using Equation (4). T RMi= State of Energy (SOE) i / C RATEi ........... . (4)

[0043] Furthermore, when the state of health (SOH) reflects the fully charged energy capacity relative to the initial state of the battery, the balancing period can be calculated using Equation (5). T RM = (SOE * E O * SOH) / P C = (SOE * SOH) / C RATE ........ . (5)

[0044] Therefore, when SOC is used instead of SOE, T R the advanced proxy can be calculated using Equation (6). T' RM = (SOC * SOH) / C RATE ........... . (6)

[0045] Without loss of generality, the remaining time can be normalized to a time period, T N such that the balancing parameter is always less than 1. For example, T N can be chosen to be 24 hours, and the normalized T R can be calculated using Equation (7). TN RM = (SOC i * SOH i ) / (C RATEi * TN) ......... . (7)

[0046] In at least some embodiments, the system controller 106 can communicate with each BMU of the battery to determine the state of charge of the battery. In at least some embodiments, a single BMU can be connected to multiple batteries.

[0047] Next, at 704, method 700 includes balancing the power of a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries. For example, while supplying power to the overall load, system controller 106 can continuously communicate with the BMU to monitor the state of charge of each battery, and use one or more of equations (1) - (7) to charge and discharge each battery as needed until all of the batteries are fully discharged simultaneously or almost simultaneously.

[0048] In at least some embodiments, between 702 or 704, the system controller 106 can perform a frequency loop to facilitate ensuring that all of the batteries deplete their energy simultaneously or nearly simultaneously. 1. For example, in frequency loop control, an AC system has a characteristic where the output power can be a function of the frequency. For example, when the frequency is increased, the output power increases. In the case of a system powered by a battery, increasing the output power decreases the time it takes to deplete the battery. That is, the higher the frequency, the less time to depletion, as shown by graph 802. For the system to remain synchronized, all of the AC sources (e.g., battery 120) of the system must operate at the same frequency. Each AC source has a controller that adjusts the AC source frequency to match the bus frequency. Refer to the dashed line in graph 802, which shows the state where AC source 804 and AC source 806 (two different AC sources on the same bus) are operating at the same frequency. Due to the characteristics of AC source 806, AC source 806 discharges in a shorter time than AC source 804, but this can be changed by biasing the AC source controller frequency, causing the curve to move up or down. The bias can be implemented as shown in FIG. 8. For example, 808 represents a variable controller bias for maintaining the bus frequency. 810 sets a fixed offset to the bias, and 812 adds an adjustable bias that is a function of the time TN to depletion. As shown in FIG. 8, the bias is actually a negative bias (negative sign reference in adder 814). Thus, as TN increases, the actual bias decreases, leading to a lower frequency and lower output power from the AC source. With an appropriate system controller design, using such a loop control method, each AC source (e.g., AC source 804 and AC source 806) will ultimately automatically adjust so that each AC source aligns to the same TN, causing all of the batteries to deplete simultaneously (as shown in FIG. 4). In at least some embodiments, the frequency loop control is based on the C-rate of the battery, the power rating of the battery, the state of charge of the battery, the health of the battery, etc.For example, as shown in FIG. 8, the inventors have found an improved control algorithm that balances the weighted SOC based on the C-rate and SOH. For example, TN. RM is calculated using Equation (7) and can be used by the system controller 106 to perform frequency loop control in a conventional manner to facilitate the guarantee that all of the batteries will deplete their energy simultaneously or nearly simultaneously. Suitable frequency loop control techniques that can be used with the methods and apparatus described herein can include the frequency loop control techniques disclosed in U.S. Patent No. 10,951,037 and U.S. Patent Publication No. 20210296903 of the same owner.

[0049] In at least some embodiments, the batteries can be the same as each other or can be different from each other. For example, some of the batteries can have the same C-rate, power rating, and / or state of charge as each other, and some of the batteries can have different C-rates, power ratings, and / or states of charge from each other. The system controller 106 acquires the C-rate, power rating, and / or state of charge of each of the batteries and uses that information during operation.

[0050] Furthermore, in at least some embodiments, as described above, the system controller 106 can be configured to charge a battery with less remaining time until depletion using a battery with more remaining time until depletion.

[0051] The above is directed to embodiments of the present disclosure, but other and further embodiments of the present disclosure can be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the following claims.

Description of the Reference Numerals

[0052] 100 System 102 Power Converter 104 Power Source 106 System Controller 108 Bus 110 Load Center 114 Inverter Controller 120 Energy Storage / Supply Device 140 Island Interconnection Device (IID) 190 Battery Management Unit (BMU) 200 AC Battery System 202 CPU 204 Support Circuit 206 Memory 208 Operating System (OS) 210 Collection System Module 212 Switch Control Module 214 Control System Module 216 Inverter Bias Control Module 218 Database 226 Current Measurement Module 228 Switch 230 Switch 240 First Terminal 242 Second Terminal 244 First Terminal 246 Second Terminal 250 Coulomb Gauge 252 Central Processing Unit (CPU) 254 Support Circuit 256 Memory 258 OS 270 Power Conversion Control Module 272 Battery Management Control Module

Claims

1. A storage system configured for use in an energy management system, comprising: a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries; and a controller configured to determine the remaining time until each of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries is exhausted, for balancing the power of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries. The storage system comprising the above.

2. The storage system according to claim 1, wherein the controller is further configured to perform frequency droop control such that all of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries deplete energy simultaneously.

3. The storage system according to claim 2, wherein the controller performs frequency droop control based on the C-rate of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

4. The storage system according to any one of claims 1 to 3, wherein at least some of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries have the same C-rate as each other, and at least some of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries have different C-rates from each other.

5. The storage system according to any one of claims 1 to 3, wherein the controller is further configured to use the battery with more remaining time until depletion to charge the battery with less remaining time until depletion.

6. A method for managing a storage system configured for use in an energy management system, the method comprising: determining the remaining time until each of a plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is exhausted; and balancing the power of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries. The method comprising the above.

7. The method according to claim 6, further comprising performing frequency droop control such that all of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries deplete energy substantially simultaneously.

8. The method according to claim 7, wherein the step of performing frequency droop control is based on the C-rate of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

9. The method according to any one of claims 6 to 8, wherein at least some of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries have the same C-rate as each other, and at least some of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries have different C-rates from each other.

10. The method according to any one of claims 6 to 8, further comprising the step of charging a battery with less remaining time until depletion using a battery with more remaining time until depletion.

11. A non-transitory computer-readable storage medium storing instructions for performing a method for managing a storage system when executed by a processor, determining the remaining time until each of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries is exhausted, balancing the power of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries A non-transitory computer-readable storage medium comprising:

12. The non-transitory computer-readable storage medium according to claim 11, further comprising performing frequency loop control so that all of the plurality of single-phase AC-coupled batteries or the three-phase AC-coupled batteries deplete energy almost simultaneously.

13. The non-transitory computer-readable storage medium according to claim 12, wherein performing the frequency loop control is based on the C-rate of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries.

14. The non-transitory computer-readable storage medium according to any one of claims 11 to 13, wherein at least some of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries have the same C-rate as each other, and at least some of the plurality of single-phase AC-coupled batteries or three-phase AC-coupled batteries have different C-rates from each other.

15. The non-transitory computer-readable storage medium according to any one of claims 11 to 13, further comprising charging a battery with less remaining time until depletion using a battery with more remaining time until depletion.

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