Energy management systems

Abstract

Battery configured for use with a storage system of an energy management system, comprising: a battery management unit (BMU) which includes a control system module that is functionally connected to a microinverter and configured to control the operation of the microinverter based on a state of charge (SoC) of the storage system.

Description

BACKGROUND 1. Territory of Revelation

[0001] Embodiments of the present disclosure generally relate to energy management systems and, for example, storage systems that include activation of a power conversion unit (PCU) based on tare losses and loads. 2. Description of the state of the art

[0002] Energy management systems are well-known and can include one or more storage systems (e.g., with one or more battery types) and a corresponding power conversion unit (PCU), such as a battery inverter, a hybrid inverter, or a microinverter. While conventional storage systems coupled with battery / hybrid inverters are suitable for their intended use, such systems can have shortcomings. For example, tare losses are defined as the losses of a storage system battery due to PCUs drawing power from the battery without actively supplying one or more loads. For instance, if the battery reaches an extremely low state of charge (EL), or extremely low supply state (ELS), the PCUs continuously draw power from the grid to prevent deep discharge of the battery.Over a 24-hour period, consumption can be, for example, 300 to 350 Wh / battery (assuming, for example, a continuous battery loss of 10-13 W). Over longer periods, such as when photovoltaic (PV) power is unavailable, the battery tends to continuously consume energy, leading to customer complaints. A relatively large inverter (e.g., a 10 kW inverter) operating at around 200 W can have a load of <2%, which is very inefficient, and a relatively large inverter operating at 0 W consumes 130 W or more of power, which is a waste of energy.

[0003] In light of the above, the inventor hereby provides improved storage systems that include tare loss and load-based activation of a power conversion unit (PCU). SUMMARY

[0004] According to some aspects of the present disclosure, a battery is provided that is configured for use with a storage system of an energy management system, which has a battery management unit (BMU) that has a control system module that is functionally connected to a microinverter and is configured to control the operation of the microinverter based on a state of charge (SoC) of the storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In order to understand in detail how the aforementioned features of the present disclosure can be understood, a more precise description of the disclosure, which has been briefly summarized above, can be given by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only one typical embodiment of this disclosure and are therefore not to be considered as limiting its scope, since the disclosure also permits other equally effective embodiments. Fig. Figure 1 is a block diagram of an energy conversion system that corresponds to at least some embodiments of the present disclosure; Fig. 2 is a block diagram of an AC battery system designed for use with the system consisting of Fig. 1 is configured according to at least some embodiments of the present disclosure; Fig. Figure 3 is a diagram of the conversion efficiency (%) versus PM AC watts (W), according to at least some embodiments of the present disclosure; Fig. Figure 4 is a power-versus-time graph for power generated, power consumed, battery charging and battery discharging according to at least some embodiments of the present disclosure; Fig. Figure 5 is a diagram of the efficiency (%) versus the AC power in (VA) according to at least some embodiments of the present disclosure; Fig. Figure 6 is a diagram of an efficiency curve at <10% load, according to at least some embodiments of the present disclosure; Fig. Figure 7 is a diagram of an efficiency curve at >10% load, according to at least some embodiments of the present disclosure; Fig.Figure 8 is a diagram of the AC connection tare loss according to at least some embodiments of the present disclosure; Fig. Figure 9 is a diagram comparing the efficiency of batteries according to at least some embodiments of the present disclosure; Fig. Figure 10 is a diagram comparing the efficiency of batteries according to at least some embodiments of the present disclosure; Fig. Figure 11 is a diagram of a battery efficiency versus load according to at least some embodiments of the present disclosure; and Fig. Figure 12 is a diagram showing active and inactive (idle / standby) battery PCUs used with the power conversion system. Fig. 1 are configured according to at least some embodiments of the present disclosure. DETAILED DESCRIPTION

[0006] As described above, the inventors here provide improved storage systems that include tare-loss and load-based activation of a power conversion unit (PCU). For example, a battery configured for use with an energy management system includes a battery management unit (BMU) that has a control system module functionally connected to a microinverter and configured to control the operation of the microinverter (e.g., turning the microinverter on or off) based on the state of charge (SoC) of the storage system. Compared to conventional storage systems, the inventive concepts described here are configured to provide a battery with relatively high efficiency and relatively low standby losses.Furthermore, the concepts described here according to the invention can be used with both network-connected and network-independent systems.

[0007] Fig. Figure 1 is a block diagram of a system 100 (energy management system) for energy conversion using one or more embodiments of the present disclosure. This diagram represents only one variant of the countless possible system configurations and devices that can utilize the present disclosure.

[0008] System 100 is a microgrid that can operate in both islanded and grid-connected states (i.e., when connected to another power grid, such as one or more other microgrids and / or a commercial power grid). System 100 may include one or more power converters. In at least some embodiments, System 100 includes a plurality of power converters 102-1, 102-2, ... 102-N, 102-N+1, and 102-N+M, collectively referred to as power converters 102 (which may also be referred to as current converters); a plurality of DC power sources 104-1, 104-2, ... 104-N, collectively referred to as current sources 104; and a plurality of energy storage / delivery devices 120-1, 120-2, ... 120-M, collectively referred to as energy storage / delivery devices 120. a system control 106 (e.g., a DER control such as a gateway); a multitude of BMUs 190-1, 190-2, ....190-M (Battery Management Units), collectively referred to as BMUs 190; a system controller 106; a bus 108; a load center 110; and an optional MID 140 (microgrid intermediate device (or an island intermediate device IID) or a relay isolator or the like). In some embodiments, such as those described here, the energy storage / delivery devices are rechargeable batteries (e.g., an array of multi-C-rate AC batteries, various types of lithium-ion batteries, or the like), which may be referred to as batteries 120, although in other embodiments the energy storage / delivery devices may be any other suitable device for storing and delivering the stored energy. In general, each of the batteries 120 comprises a plurality of cells connected in series and / or parallel.

[0009] Each power converter 102-1, 102-2...102-N is coupled to a DC source 104-1, 104-2...104-N in a one-to-one correspondence, although in some other embodiments several DC sources may be coupled to one or more of the power converters 102, which convert DC to DC. In at least some embodiments several power converters may be connected to a single DC source (e.g. six (6) power converters may be connected to a DC source (a storage system)), as described in more detail below. The power converters 102-N+1, 102-N+2... 102-N+M are each coupled via BMUs 190-1, 190-2..., 190-M to a plurality of energy storage / delivery devices 120-1, 120-2... 120-M to form AC batteries 180-1, 180-2...180-M. Each of the power converters 102-1, 102-2...102-N+M includes a corresponding controller 114-1, 114-2...114-N+M (collectively referred to as the inverter controllers 114) for controlling the operation of the power converters 102-1, 102-2...102-N+M.

[0010] In some embodiments, such as the one described below, the DC sources 104 are DC sources and the power converters 102 are bidirectional inverters, such that the power converters 102-1...102-N convert DC from the DC sources 104 into grid-compliant AC, which is coupled into the bus 108, and the power converters 102-N+1...102-N+M convert (during discharge of the energy storage device) DC from the batteries 120 into grid-compliant AC, which is coupled into the bus 108, and also (during charging of the energy storage device) convert AC from the bus 108 into a DC output, which is stored in the batteries 120 for later use. The DC sources 104 can be any suitable DC source, such as... B. an output from a previous power conversion stage, a battery, a renewable energy source (e.g.a solar panel or photovoltaic (PV) module, a wind turbine, a hydroelectric power system, or a similar renewable energy source) or the like (e.g., a regulated DC power source based on a car battery with 12 V, 24 V, or 48 V) to provide direct current. In other embodiments, the power converters 102 may be other types of converters (e.g., DC-to-DC converters), and the bus 108 is a DC bus. In such embodiments, the battery may provide 60 V, which is sent to various DC converters to drive, for example, 5 V, 9 V, 12 V, 15 V, 20 V, etc., all of which may be direct DC outputs for charging one or more DC devices, such as mobile phones, laptops, speakers, LED lights, etc. These are independent of the battery that supplies the power converters for the AC outputs.

[0011] The power converters are connected via bus 108 (which may also be referred to as AC line or power grid, AC generator (propane, LGP or the like, AC from wind turbines, etc.)) to the system controller 106 (e.g., a DER controller such as a gateway). The system controller 106 generally comprises a CPU coupled to each of the support circuits and memory containing a system control module for controlling certain operational aspects of the system 100 and / or monitoring the system 100 (e.g., issuing specific command and control instructions to one or more of the power converters 102, acquiring data regarding the performance of the power converters 102, and the like). The system controller 106 is capable of communicating with the power converters 102 (e.g.,DC / AC power converters, DC / DC power converters (which may be housed in the same enclosure or in separate enclosures) via wireless and / or wired communication (e.g., powerline communication) to enable certain functional control and / or monitoring of the power converters 102.

[0012] In some embodiments, the control unit 106 can be a gateway that receives data (e.g., power data) from the power converters 102 and transmits the data and / or other information (e.g., via the internet) to a remote device or system, such as a master controller (not shown). Additionally or alternatively, the gateway can receive information from a remote device or system (not shown) and transmit the information to the power converters 102 and / or use the information to generate control commands that are issued to the power converters 102.

[0013] The power converters 102 (which, as mentioned above, can be AC / DC converters or DC / DC converters) are coupled to the load center 110 via the bus 108, and the load center 110, which in at least some embodiments can be coupled to the power grid via the MID 140, can be an optional component, as mentioned above. When the system 100 is coupled to the power grid (e.g., a commercial grid or a larger microgrid) via the MID 140, it can be referred to as grid-tied; when it is disconnected from the power grid via the MID 140, the system 100 can be referred to as island-operated, a microgrid, off-grid, or the like. The MID 140 determines when the disconnection from / connection to the power grid should take place (e.g., the MID 140 can detect a grid fluctuation, a fault, a failure, or the like) and carries out the disconnection / connection.After disconnection from the power grid, System 100 can continue to generate electricity as a controlled island using the buffer control techniques described herein, without posing safety risks to any personnel who may be working on the power grid. MID 140 includes a disconnect component (e.g., one or more disconnect relays) for physically disconnecting / connecting System 100 to / from the power grid. In some embodiments, MID 140 may additionally include an autotransformer for coupling System 100 to a two-phase load, which may exhibit an asymmetry with a certain neutral current (examples include US grid systems such as 120V / 240V split single-phase systems and EU systems such as 230V LN / 400V LL). In certain embodiments, the system controller 106 includes MID 140 or a portion thereof.

[0014] The power converters 102 convert the direct current from the DC sources 104 and the discharging batteries 120 into grid-compliant alternating current and couple the generated output power into 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 to the power grid (if connected to the grid). Additionally or alternatively, the generated energy can be stored for later use, e.g., using batteries, heated water, hydro pumps, conversion of H₂O to hydrogen, or the like. Generally, the system 100 is connected to the commercial power grid, although in some embodiments the system 100 is completely disconnected from the commercial power grid and operates as an independent microgrid.

[0015] In some embodiments, the alternating current generated by the power converters 102 is single-phase alternating current. In other embodiments, the power converters 102 generate three-phase alternating current.

[0016] This section describes a storage system designed for use with an energy management system such as the one from ENPHASE. ® available energy management system ENSEMBLE ® is configured. Fig. Figure 2 is, for example, a block diagram of an AC battery system 200 (e.g., a storage system) according to one or more embodiments of the present disclosure. Alternatively, the AC battery system 200 can also be a DC battery system with a corresponding battery and DC / DC power converters.

[0017] The AC battery system 200 comprises a BMU 190 coupled to a battery 120 and a power converter 102. A pair of metal-oxide-semiconductor field-effect transistors (MOSFETs), or BJTs, or IGBTs, or similar switches—switches 228 and 230—are connected in series between a first terminal 240 of the battery 120 and a first terminal of the inverter 144, such that the body diode cathode terminal of switch 228 is coupled to the first terminal 240 of the battery 120, and the body diode cathode terminal of switch 230 is coupled to the first terminal 244 of the power converter 102. The gate terminals of switches 228 and 230 are coupled to the BMU 190; these switches are configured to control charging into or discharging from the battery.

[0018] A second terminal 242 of the battery 120 is coupled to a second terminal 246 of the power converter 102 via a current measuring module 226, which measures the current flowing between the battery 120 and the power converter 102.

[0019] The BMU 190 is coupled to the current measurement module 226 to obtain information about the measured current and also receives an input 224 from the battery 120 indicating the battery cell voltage and temperature. The BMU 190 is coupled to the gate terminals of each of the switches 228 and 230 to control switch 228 for battery discharge and switch 230 for battery charging, as described here. The BMU 190 is also coupled via the first terminal 244 and the second terminal 246 to supply an inverter bias control voltage (which may also be referred to as the bias control voltage) to the inverter 102, as described below.

[0020] The configuration of the body diodes of switches 228 and 230 allows the current to be blocked in one direction, but not in the other, depending on the state of switches 228 and 230. If switch 228 is active (i.e., on) while switch 230 is inactive (i.e., off), battery discharge is activated to allow current flow from battery 120 through the body diode of switch 230 to power converter 102. If switch 228 is inactive while switch 230 is active, battery charging is activated to allow current flow from power converter 102 through the body diode of switch 228 to battery 120. When both switches 228 and 230 are active, the system is in normal mode, in which battery 120 can be charged or discharged.

[0021] The BMU 190 comprises support circuits 204 and a memory 206 (e.g., a non-volatile, computer-readable storage medium), each coupled to a CPU 202 (central processing unit). The CPU 202 may comprise one or more processors, microprocessors, microcontrollers, and combinations thereof, configured to execute non-volatile software instructions to perform various tasks according to the embodiments of this disclosure. The CPU 202 may additionally or alternatively include one or more application-specific integrated circuits (ASICs). In some embodiments, the CPU 202 may be a microcontroller having internal memory for storing control firmware that, when executed, provides the control functionality described herein.The BMU 190 can be implemented using a general-purpose computer which, when running specific software, becomes a specialized computer for carrying out various embodiments of the present disclosure.

[0022] The support circuits 204 are well-known circuits used to enhance the functionality of the CPU 202. Such circuits include, among others, a cache, power supplies, clock circuits, buses, input / output (I / O) circuits, and the like. The BMU 190 can be implemented using a general-purpose computer which, when running specific software, becomes a specialized computer for performing various embodiments of the present disclosure. In one or more embodiments, the CPU 202 can be a microcontroller having internal memory for storing control firmware which, when executed, provides the control functionality described herein.

[0023] Memory 206 can include random-access memory, read-only memory, removable disk memory, flash memory, and various combinations of these memory types. Memory 206 is sometimes referred to as main memory and can be used in part as cache or buffer memory. Memory 206 generally stores the OS 208 (operating system), possibly for the inverter controller 114, which may be supported by the CPU's capabilities. In some embodiments, the OS 208 may be one of several commercially available operating systems, such as Linux, Real-Time Operating System (RTOS), and the like, but is not limited to these.

[0024] Memory 206 stores non-volatile, processor-executable instructions and / or data that can be executed and / or used by the CPU 202 to perform, for example, one or more discharge protection procedures, as described in more detail below. These processor-executable instructions may include firmware, software, and the like, or a combination thereof. Memory 206 stores various forms of application software, such as a sensing system module 210, a switch control module 212, a control system module 214, and an inverter bias control module 216. Memory 206 also stores a database 218 for storing data relating 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, the detection system module 210, the switch control module 212, the control system module 214, the inverter bias control module 216 and / or the database 218 or parts thereof are implemented in software, firmware, hardware or a combination thereof.

[0025] The acquisition system module 210 receives the cell voltage and temperature information from the battery 120 via input 224, receives the current measurements provided by the current measurement module 226, and delivers the cell voltage, cell temperature and measurement current information to the control system module 214 for use as described here.

[0026] The switch control module 212 controls the switches 228 and 230 as determined by the control system module 214. The control system module 214 offers various battery management functions, including protection functions (e.g., overcurrent protection (OC), overtemperature protection (OT), and hardware fault protection), measurement functions (e.g., averaging the measured battery cell voltage and battery current over, for example, 100 ms to suppress 50 Hz and 60 Hz ripple), state-of-charge (SoC) analysis (e.g., using a coulomb meter 250 to determine current flow and use this flow to estimate the battery SoC; synchronizing the estimated SoC values ​​with the battery voltages (e.g., setting the SoC to an upper limit, e.g., 100%, at maximum battery voltage; setting the SoC to a lower limit, e.g., 0%, at minimum battery voltage; shutting down the SoC if the power converter 102 never drives the battery 120 to these limits; and the like), balancing (e.g.,Autonomous charge equalization across all cells of a battery so that it is equal (which can occur at the end of charging, at the end of discharging, or in some embodiments at both). The BMU 190 determines the estimated state of charge (SoC) by setting upper and lower SoC limits based on the end of battery charging and discharging, respectively, and by tracking the current flow and cell voltage (i.e., the battery voltage) between these events.

[0027] The inverter controller 114 comprises support circuits 254 and a memory 256, each coupled to a CPU 252 (central processing unit). The CPU 252 can comprise one or more processors, microprocessors, microcontrollers, and combinations thereof, configured to execute non-transient software instructions to perform various tasks according to the embodiments of this disclosure. The CPU 252 can additionally or alternatively include one or more application-specific integrated circuits (ASICs). In some embodiments, the CPU 252 can be a microcontroller having internal memory for storing control firmware that, when executed, provides the control functionality described herein.The inverter control 114 can be implemented using a general-purpose computer which, when certain software is executed, becomes a specialized computer for carrying out various embodiments of the present disclosure.

[0028] The support circuits 254 are known circuits used to enhance the functionality of the CPU 252. Such circuits include, among others, a cache, power supplies, clock circuits, buses, input / output circuits, and the like. The inverter control 114 can be implemented with a general-purpose computer, which, when certain software is executed, becomes a specialized computer for carrying out various embodiments of the present disclosure. In one or more embodiments, the CPU 252 can be a microcontroller that has internal memory for storing control firmware, which, when executed, provides the control functionality described herein.

[0029] Memory 256 can include random-access memory, read-only memory, removable disk memory, flash memory, and various combinations of these memory types. Memory 256 is sometimes referred to as main memory and can be partially used as cache or buffer memory. Memory 256 generally stores the OS 258 (operating system), possibly for the inverter controller 114, which may be supported by the CPU's capabilities. In some embodiments, the OS 258 may be, but is not limited to, a number of commercially available operating systems, such as Linux, Real-Time Operating System (RTOS), and the like.

[0030] Memory 256 stores non-volatile processor-executable instructions and / or data that can be executed and / or used by CPU 252. These processor-executable instructions can include firmware, software, and the like, or a 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.

[0031] The BMU 190 communicates with the system controller 106 to perform a balancing of the batteries 120 (e.g., multi-C-rate accumulation of AC batteries) based on the remaining time before each battery is depleted, to perform buffer control (semi-passive) that allows the batteries to be depleted at essentially the same time, and to perform battery control to charge batteries with a shorter remaining time before depletion using batteries with a longer remaining time before depletion.

[0032] The inventors offer solutions to the problems associated with conventional storage systems. The improved storage systems described herein include, for example, tare loss and load-based activation of a power conversion unit (PCU) (and, in at least some embodiments, operation of the system at low load). For example, the concepts according to the invention can be used in at least some embodiments in conjunction with tare loss at low SoC (as described above), tare loss at 100% SoC, load-based power conversion unit (PCU) activation for single-phase operation, and load-based power conversion unit (PCU) activation for three-phase operation, as described in more detail below.For example, the inventive concepts described here are configured, at least in some embodiments, to reduce tare losses during continuous operation, i.e., when a house is operated under normal load conditions (e.g., between 200 W and 500 W). In cases where a storage system has six (6) microinverters, the controller (e.g., the controller 114) is configured to switch off five (5) of the six (6) microinverters (e.g., each with 640 W), thereby significantly reducing losses.

[0033] Regarding, for example, the tare loss at low SoC, in at least some embodiments, once a battery (e.g., battery 120) reaches 5% SoC, the battery will no longer support any loads; that is, all microinverters (the power converter 102, also referred to as PCU) will be put into an idle state. In at least some embodiments, the BMU 190 is configured to put the microinverter into an idle state. Furthermore, the BMU 190 disables SoC maintenance, enables ELS recovery, and modifies load-based PCU production to keep one (1) PCU active for the next point. The BMU 190 is also configured to operate the battery cyclically in ELS mode between 2.49% and 4.51%, with the one (1) micro-inverter operating at a power of approximately 400 W to 450 W, which can be based on a point 302 with the highest efficiency (see e.g.the efficiency curve 300 in . Fig. 3 for the battery). The inventor has found that operating one (1) micro-inverter with approximately 400W-450W results in a charging cycle of <15 min for 100Wh (e.g., less impact on the efficiency curve 300 with consistent behavior). Additionally, 100Wh are charged into the battery with an efficiency of >97.5% => 100 / 0.965 = 103.6Wh energy consumption (e.g., reduction in energy consumption).

[0034] Alternatively or additionally, in at least some embodiments, one or more devices (mechanisms) can be used that are configured to interrupt the DC paths from the battery to a DC / DC converter or inverter in order to implement the inventive concepts described herein. For example, manual disconnect switches, automatic electronic switches (e.g., MOSFETs, IGBTs, SSRs, etc.), protective switches (e.g., magnetic repulsion, thermal protection), etc., can be used in conjunction with or instead of the BMU 190 to interrupt DC paths from the battery before DC is supplied to a DC / DC converter or inverter.

[0035] Regarding tare loss at low SoC (e.g., FET-based), in at least some battery configurations operating off-grid, the FETs (e.g., switches 228 and 230 inside the battery) open as soon as the battery reaches 2.5% SoC. Once open, the BMU 190 (e.g., the control system module 214, BMCC) and the microinverters completely shut down, allowing the battery to survive for approximately 14 days without entering an unrecoverable state. Once the battery reaches, for example, a VLS state (e.g., 5% SoC), the control system module 214 opens the FETs, and the BMU 190 and the microinverter are switched off. In at least some embodiments, the control system module 214 is configured to wake up the BMU 190 after a predetermined period of time (e.g., x hours, minutes, or seconds).(based on the SoC drop) to monitor the battery's SoC and perform SoC calibration. After the BMU 190 has monitored the battery's SoC level and performed the SoC calibration, it powers down again for a predetermined period (e.g., x hours, minutes, or seconds). For example, if the battery's SoC drops to 3.5%, the control system module 214 is configured to wake up one (1) microinverter and charge the battery from 3.5% to 4.49% at a high-efficiency point (e.g., between 400 W and 450 W mentioned above), and then turn the FETs back on to power down the BMU 190 and the microinverter. When PV generation exceeds the loads (e.g., => energy is available to charge the battery), the control system module 214 closes the FETs to close the BMU 190, the microinverters wake up, and the battery begins to charge.The inventor has discovered that by opening the FETs, the battery's energy consumption is almost zero and the battery does not need to be charged for several days (e.g., expected to be >5 days) when no PV is available.

[0036] Furthermore, with regard to tare loss at 100% SoC, the BMU 190 is configured such that once the battery reaches 100% SoC and PV is available, even if a gateway (e.g., the system controller 116) continues to send 100% charging bias, only one (1) microinverter will be in an active state and all other microinverters will be in an idle state (e.g., grid-connected battery) / standby state (e.g., off-grid).

[0037] With regard to the load-dependent activation of the power conversion unit (PCU) for single-phase operation, the loads in a typical household are between 100 W and 500 W for most of the day (e.g., >80% of the time), and the PV power available for charging the battery is at a similar level (see, e.g., curve 400 in [reference]). Fig. 4) The concepts according to the invention described here are configured to deliver a high-efficiency battery even at such low loads, something string inverters are unable to achieve. Furthermore, operating microinverters at 97.5% efficiency instead of microinverters at 87% efficiency (less than 70% for string inverters) offers a gain in cycle efficiency of approximately 20%, which corresponds to about 300 kWh for a house with 300 cycles per year (see, for example, curve 500 in [reference]). Fig.5) In at least some embodiments, the BMU 190 is configured to activate the next PCU as soon as any microinverter is 90% or more utilized (see, for example, curve 700 in Fig. 7), which results in the microinverters operating in the high efficiency range of the microinverters (see e.g. curve 600 in Fig. 6) In grid-connected systems, the BMU 190 is configured to keep inactive PCUs idle, and when the load increases or decreases, the PCUs are activated as shown in Table 1, which contains an arbitrary list of example parameters for illustration. Table 1 POWER FOR NEXT PCU ACTIVATION (W) PCUs ACTIVE LOAD PERCENTAGE OF EACH PCU WHEN THE NEXT PCU IS SWITCHED ON 576 1 45% 1152 2 60% 1728 3 68% 2304 4 72% 2880 5 75% 3456 6 NOT APPLICABLE

[0038] For example, in standby mode, the power consumption is 1.5 - 2.15W / PCU => for 5 PCUs = 10.75W. In idle mode, the power consumption is 0.4 - 0.5W / PCU => for 5 PCUs = 2.5W (e.g., >75% reduction compared to standby mode).

[0039] In off-grid systems, the BMU 190 is configured to maintain one inactive PCU in standby mode. In some embodiments, the BMU 190 is configured to maintain several inactive PCUs in standby mode and several inactive PCUs in idle mode. The PCUs are configured to transition from standby to active mode in approximately 10 µs and from idle to active mode in approximately 40 ms. Additionally, the system level (e.g., System 100) is configured to transition from standby to active mode in approximately 5 s and from idle to active mode in approximately 5 s, and the IQSC transition time (e.g., of System 116) can be approximately 60 ms.

[0040] Fig.Figure 8 is a diagram 800 of the DC connection tare loss according to at least some embodiments of the present disclosure. The diagram 800 shows, for example, data for PCU requirements relating to tare losses at idle, tare losses in standby, and tare losses during operation (e.g., OW AC).

[0041] Fig. Figure 9 is a diagram 900 of a comparison of the efficiency between batteries (e.g. a conventional battery that does not operate according to the concepts of the invention described herein, compared to a battery that operates according to the concepts of the invention described herein, such as the ENPHASE IQ battery). Fig.Figure 10 is a diagram 1000 comparing the load efficiency between batteries (e.g., a conventional battery that does not operate according to the inventive concepts described herein, compared to a battery that operates according to the inventive concepts described herein, such as the ENPHASE IQ battery), and Fig. Figure 11 is a diagram 1100 of a battery efficiency against the load, according to at least some embodiments of the present disclosure. As in the Fig. As shown in Figures 9-10, the battery efficiency is better when using the PCUs described here than when using conventional PCUs.

[0042] Fig. Figure 12 is a diagram illustrating a multi-battery (storage) system (e.g., active and inactive (idle / standby)) that includes battery PCUs for use with the energy conversion system. Fig.1 are configured according to at least some embodiments of the present disclosure. The diagram in Fig. Figure 12 illustrates, for example, how the microinverters can be activated (e.g., one (1) battery per phase).

[0043] Similarly, the load-based PCU activation logic for a three-phase (3) battery requires PCU activation at 90% (e.g., inactive PCU held in idle (mains-connected) and idle / standby (off-grid) states, power factor (pf) control at the battery level).

[0044] For the three-phase (3) battery, for example, PCU activation is used between the batteries and between the phases based on the load. For example, three (3) phase batteries are configured to deliver symmetrical current across three (3) phases. In low-load systems, the PCUs are configured so that one (1) microinverter per battery remains active. When multiple batteries are used, one active microinverter is distributed across the phases, as shown in Fig.Figure 12 illustrates this. For example, for three (3) batteries (e.g., one battery 1202, one battery 1204, and one battery 1206, each comprising 6 (six) microinverters) and three (3) inputs (e.g., L1, L2, and L3), where input L1 activates a microinverter 1208 (top left) in battery 1202, while the microinverters (top left and right) in battery 1204 and battery 1206 are kept inactive (e.g., idle / standby). Similarly, input L2 activates a microinverter 1210 (middle left) in battery 1204, while the microinverters (middle left and right) in battery 1202 and battery 1206 are kept inactive (e.g., idle / standby mode). Similarly, input L3 activates a microinverter 1212 (bottom left) in battery 1206, while the microinverters (bottom left and right) in battery 1202 and battery 1204 are kept inactive (e.g. idle / standby).When the load increases, the microinverters are redistributed.

[0045] As mentioned above, the loads in a typical household range between 100 W and 400 W for most of the day. According to the inventive concepts described herein, the inventor has found that if the microinverter 1208 in battery 1202 remains active and the other microinverters in battery 1204 and battery 1206 remain idle until the state of charge (SoC) of battery 1202 decreases by 5% (e.g., 95% SoC remaining), and then microinverter 1208 in battery 1202 is switched to idle / standby mode and microinverter 1210 in battery 1204 is switched to active mode (e.g.,(Waking up), while the other microinverter batteries in battery 1202 and battery 1206 are idle until the state of charge (SoC) of battery 1202 is reduced by 5%, and this process is repeated for microinverter 1212 in battery 1206, providing a system-level efficiency improvement compared to conventional systems. The [reference to] . Fig. The process described in point 12 can also be achieved using the 90% logic explained above.

[0046] While the concepts according to the invention described here have been described using DC / AC converters, as noted above, for example when using DC / DC converters (e.g. modular energy storage systems (ESS)), the DC / DC converters in at least some embodiments can be configured to use a low-power or no-DC mode, as described above with respect to the AC / DC converters.

[0047] While the foregoing explanation relates to embodiments of the present disclosure, other and further embodiments of the disclosure may be developed without deviating from its basic scope, and the scope of the disclosure is determined by the following claims.

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