Distributed optimization for hybrid ac-dc microgrids

Abstract

A microgrid system includes a plurality of energy resource systems including direct current (DC) energy resource systems and alternating current (AC) energy resource systems configured to supply power to the microgrid, a plurality of local controllers respectively associated with the energy resource systems for controlling the respective energy resource systems, and a microgrid controller. Each local controller is configured to determine an available output power of the respective energy resource system based on one or more operational constraints and send an indication of the available output power to the microgrid controller. The microgrid controller is configured to determine a net available DC output power available from the DC energy resource systems and a net available AC output power available from the AC energy resource systems based on the available output power indicated by each local controller.

Description

Technical Field

[0001] This disclosure generally relates to microgrids, and for example to a microgrid controller configured to control or manage the operation of a microgrid. Background Technology

[0002] A microgrid is a self-sufficient energy system that provides service to a specific geographic area, such as a university campus, hospital complex, commercial center, community, mining site, drilling site, etc. A microgrid contains one or more distributed energy resources (DERs) that generate electricity for it (e.g., solar panels, wind turbines, fuel cells, photovoltaic (PV) cells, generators, energy storage devices (e.g., batteries, capacitors), and / or other energy sources). Some microgrids are configured as off-grid power distribution systems (e.g., independent microgrids or islands) that are not connected to a larger power distribution system (e.g., a macrogrid) operated by, for example, a power company or power plant. Some microgrids are capable of operating in grid-connected mode and / or independent mode. In grid-connected mode, a microgrid can operate while connected to and synchronized with a larger power distribution system. In independent mode, a microgrid can be disconnected from a larger power distribution system and operate as an independent microgrid. A microgrid controller can control whether the microgrid operates in grid-connected or independent mode, for example, based on a schedule or based on the fulfillment of one or more conditions.

[0003] Microgrids can include different types of loads and different types of DERs with varying power characteristics. For example, some loads, such as electric vehicles, can be direct current (DC) loads, while some loads, such as heating, ventilation, and air conditioning (HVAC) systems and household appliances, can be alternating current (AC) loads. Additionally, some DERs, such as PV cells, fuel cells, and energy storage devices, can supply DC power, while some DERs, such as generator sets (e.g., diesel engine-driven generators), wind turbines, and the utility grid, can supply AC power. Therefore, a microgrid can be a hybrid AC-DC microgrid, which includes one or more DC buses for distributing DC power and one or more AC buses for distributing AC power. Many microgrid systems lack efficient ways to manage all types of loads and all types of DERs in a hybrid AC-DC microgrid, where DC power supply, DC power demand, AC power supply, and AC power demand are dynamically changing.

[0004] U.S. Patent Publication 2023 / 0307922 (“'922 Publication”) discloses a method and system for microgrid control. The system disclosed in '922 includes a controller that receives data from field components and then controls the components based on the received data. The system monitors load demand and generates control signals to control power generation components to supply the necessary power to support the load demand. Power generation components may include batteries, solar / wind power generation devices, or diesel generators. However, '922 Publication does not disclose how to optimize a hybrid AC-DC microgrid to efficiently dispatch and utilize both DC and AC power.

[0005] The microgrid system disclosed herein solves one or more of the problems described above and / or other problems in the art. Summary of the Invention

[0006] A microgrid system may include: a plurality of energy resource systems configured to supply power to the microgrid, wherein the plurality of energy resource systems includes a DC energy resource system configured to supply DC power and an AC energy resource system configured to supply AC power; a plurality of local controllers, wherein each of the plurality of local controllers is associated with a corresponding energy resource system among the plurality of energy resource systems for controlling the corresponding energy resource system; a plurality of power buses configured to deliver power from the plurality of energy resource systems to one or more loads; and a microgrid controller, wherein each local controller is configured to determine the available output power of the corresponding energy resource system based on one or more operating constraints and to send an indication of the available output power to the microgrid controller, and wherein the microgrid controller is configured to determine the net available DC output power available from the DC energy resource system and the net available AC output power available from the AC energy resource system based on the available output power indicated by each local controller.

[0007] A method for optimizing a hybrid microgrid including DC loads and AC loads may include: receiving energy resource information from each of a plurality of energy resource systems, wherein the plurality of energy resource systems includes DC energy resource systems configured to supply DC power and AC energy resource systems configured to supply AC power, and wherein the energy resource information includes available output power; determining, by the microgrid controller, a net available DC output power obtainable from the DC energy resource system and a net available AC output power obtainable from the AC energy resource system based on the available output power indicated by each energy resource system; determining, by the microgrid controller, a net DC load corresponding to the DC load; and determining, by the microgrid controller, a net DC load corresponding to the AC load. The corresponding net AC load; the microgrid controller dispatches power from the plurality of energy resource systems to the DC load and the AC load, including preferentially dispatching the net available DC output power to the DC load to satisfy at least a portion of the net DC load, and preferentially dispatching the net available AC output power to the AC load to satisfy at least a portion of the net AC load; and after satisfying the net DC load, the microgrid controller dispatches the remaining DC portion of the net available DC output power to the AC load to satisfy at least an additional portion of the net AC load, or after satisfying the net AC load, the microgrid controller dispatches the remaining AC portion of the net available AC output power to the DC load to satisfy at least an additional portion of the net DC load. Attached Figure Description

[0008] Figure 1 A system according to one or more embodiments is shown.

[0009] Figure 2 A microgrid according to one or more embodiments is shown.

[0010] Figure 3 A system according to one or more embodiments is shown.

[0011] Figure 4 An AC-DC hybrid microgrid according to one or more embodiments is shown.

[0012] Figure 5 This is a flowchart of an exemplary process associated with distributed optimization for hybrid AC-DC microgrids.

[0013] Figure 6 This is a diagram of an exemplary component of a microgrid controller associated with distributed optimization for hybrid AC-DC microgrids. Detailed Implementation

[0014] This disclosure relates to a power distribution system and is applicable to any system that distributes and / or receives power via a power grid. Some aspects relate to a microgrid controller configured to control one or more components and / or systems associated with a microgrid, including energy resource systems and / or loads. The microgrid controller can control the state of the microgrid based on the satisfaction of one or more conditions.

[0015] Many microgrid systems lack efficient ways to manage all types of loads and all types of DERs in hybrid AC-DC microgrids, where DC power supply, DC power demand, AC power supply, and AC power demand are dynamically changing. For example, in a microgrid with DC-coupled DERs connected to the AC grid, optimization problems using AC grid constraints neglect DC grid constraints, such as branch flow limitations, DC parameters, and DC-side losses. Ignoring DC grid constraints can lead to suboptimal DC power flow and reduced energy efficiency. Similarly, for a microgrid with AC-coupled DERs connected to the DC grid, optimization problems using DC grid constraints neglecting AC grid constraints can also lead to suboptimal AC power flow and reduced energy efficiency.

[0016] Furthermore, for microgrids with centralized controllers that handle (e.g., process) all optimization problems, scheduling DC-coupled DERs can be problematic during stand-alone mode, when the microgrid is disconnected from the larger power distribution system (e.g., macrogrid). For example, handling all optimization problems for all DERs is computationally demanding. When a microgrid controller is designed to handle all optimization problems, it may be limited by processing bandwidth and other processing resources that could become bottlenecks. In some cases, it may be necessary to process some tasks in parallel to optimize microgrid performance, which may be impossible due to the microgrid controller's processing constraints. In other cases, conflicts may arise where some processing tasks should take precedence over others, leading to inefficiencies. Therefore, due to processing constraints, the microgrid controller may become overwhelmed by processing tasks and may not be able to handle all tasks appropriately at optimal timing.

[0017] Some embodiments disclosed herein provide a microgrid system that may include a microgrid controller configured as a central computing resource, distributed local controllers configured as distributed computing resources, and an aggregator, which operate together to optimize performance in a hybrid AC-DC microgrid. Each local controller in the distributed local controllers may be configured to control a corresponding DER among a plurality of DERs. The distributed local controllers may be configured to perform parallel computations to process data to solve a corresponding optimization problem. For example, each local controller may process data and solve a corresponding optimization problem associated with the corresponding DER. Thus, the distributed local controllers can perform processing and optimization subtasks (e.g., local-level processing tasks) that would typically be handled by a centralized controller such as a microgrid controller.

[0018] By handling and optimizing subtasks, distributed local controllers can reduce the processing demands on the microgrid controllers that would typically be used to perform these subtasks (e.g., reducing their computational load). Therefore, the microgrid controller can dedicate its own processing resources to performing system-level processing tasks and system-level monitoring and control, rather than local-level processing, monitoring, and control. Distributed local controllers enable more efficient handling of local-level tasks at the distributed local controller level and more efficient handling of system-level tasks at the microgrid controller level. For example, distributed local controllers can overcome the processing constraints of centralized controllers, enabling microgrid systems to handle processing tasks more efficiently.

[0019] In some implementations, the aggregator can enable iterative coordination between the distributed local controller and the microgrid controller. The aggregator can be a cloud-based aggregator communicatively coupled between the distributed local controller and the microgrid controller, or it can be integrated as a separate processing module within the microgrid controller. The aggregator can be configured to facilitate information exchange between the distributed local controller and the microgrid controller's main processor. The aggregator can communicate via communication protocols such as Modbus or Controller Area Network (CAN) to optimize the control of the microgrid's DER and loads.

[0020] Therefore, microgrid systems can address the problems present in microgrids with DC-coupled DERs connected to the AC grid. For example, when power flow is optimized using only AC grid constraints, DC branch flow limitations, DC-side losses, and other DC parameters are neglected. This can lead to suboptimal power flow and reduced energy efficiency. Furthermore, scheduling DC-coupled DERs during stand-alone mode becomes challenging when AC optimization is performed in a centralized manner using a single centralized controller. The microgrid system disclosed herein can efficiently solve subproblems using parallel computing through a distributed local controller. These subproblems can be optimization problems related to the operation or functionality of the DER. Additionally, an aggregator can provide iterative coordination by establishing information exchange between the distributed local controller and the microgrid controller. Iterative coordination enables the optimization of the operation of DC-coupled DERs, AC-coupled DERs, DC loads, and AC loads provided in a hybrid AC-DC microgrid, taking into account both AC and DC constraints, to efficiently utilize both DC and AC power. By deploying a hybrid AC-DC distributed optimization scheme, both AC and DC constraints can be considered to optimize power flow, thereby achieving improved energy efficiency and efficient scheduling of DC-coupled and AC-coupled DERs in various operating modes, including grid-connected and stand-alone modes.

[0021] Microgrid systems configured with a hybrid AC-DC distributed optimization scheme can be scalable and adaptable to different microgrid applications (e.g., mining, building, and utility power) with DC-coupled DERs for generation. Microgrid systems configured with a hybrid AC-DC distributed optimization scheme can help improve power flow in a hybrid AC-DC microgrid by considering both DC and AC constraints. Therefore, power generation can be optimized to meet net load, resulting in economical and reliable operation. Microgrid systems configured with a hybrid AC-DC distributed optimization scheme can optimize dispatch and power flow in both grid-connected and stand-alone modes. Microgrid systems configured with a hybrid AC-DC distributed optimization scheme can avoid reliance on a single centralized controller and avoid being subject to single points of failure. Alternatively, the microgrid system can use a local controller at each DER, using a distributed approach employing parallel computing to optimize the operation of each DER. Microgrid systems configured with a hybrid AC-DC distributed optimization scheme can adapt to dynamic system constraints based on the availability of power supplied by one or more DERs and / or based on one or more types of loads connected to the microgrid. Microgrid systems equipped with hybrid AC-DC distributed optimization schemes can achieve optimization at both the local and system levels using aggregators. These schemes can provide non-hierarchical, agent-based distributed optimization that can be computed either internally or externally to the microgrid controller.

[0022] Figure 1 A system 100 according to one or more embodiments is shown. The system 100 may include a human-machine interface (HMI) 102, an external controller 104, a power system 106, and one or more loads 108.

[0023] Power system 106 may be a microgrid or other type of power distribution system capable of supplying power to one or more loads 108. In some cases, power system 106 may be an off-grid power distribution system. In some cases, power system 106 may be configured to operate in grid-connected mode and stand-alone mode. Power system 106 may include a microgrid controller 110, an unstable group 112 of the energy resource system (e.g., an unstable group of DER), a stable group 114 of the energy resource system (e.g., a stable group of DER), and interfaces 116 and 118. Generally, "off-grid" can mean that the power distribution system is not connected to a larger power distribution system operated by, for example, a power company or other large-scale power plants supplying power to a geographic area, park, compound, etc. However, the techniques disclosed herein can still be applied to power distribution systems connected to a larger power distribution system. For example, the larger power distribution system may operate as a primary provider or a secondary provider, and power system 106 may operate as the other of the primary and secondary provider roles.

[0024] The unstable group 112 of the energy resource system may include one or more energy generator systems 120. Each energy generator system 120 may include a generator (e.g., an engine-driven generator, fuel cell, PV cell, or other power generation system) and a local generator controller communicatively coupled to the microgrid controller 110. Thus, each energy generator system 120 can generate electricity from a corresponding power source. Each local generator controller can control how much electricity the corresponding generator generates, control the rate of power distribution, and / or obtain status information corresponding to the corresponding generator. Each local generator controller may be controlled by the microgrid controller 110.

[0025] The stabilization group 114 of the energy resource system may include one or more energy storage systems (ESS) 122. Each energy storage system 122 may include an electrical storage device (e.g., one or more batteries and / or capacitors) and a local ESS controller communicatively coupled to the microgrid controller 110. Each local ESS controller may control the flow of power into or out of the corresponding electrical storage device, including charging and discharging the corresponding electrical storage device, controlling the rate of power flow, and / or obtaining state information corresponding to the corresponding electrical storage device, such as state of charge (SOC), state of health (SOH), discharge limits, and other device parameters. Each local ESS controller may be controlled by the microgrid controller 110.

[0026] System 100 may also include one or more circuit breakers 124 (e.g., distribution circuit breakers or switches), which may be individually controlled by microgrid controller 110 to connect or disconnect a corresponding load 108 from power system 106. The one or more circuit breakers 124 may be part of one or both of interfaces 116 and 118.

[0027] HMI 102 may include one or more processors and may be configured to receive and process one or more inputs from a user, such as an operator. Additionally, HMI 102 may be configured to provide one or more prompts or outputs to the user. Therefore, HMI 102 may be a user terminal configured to interact with a user to process user-provided information and / or commands, provide information (e.g., status information) to the user, and / or perform one or more tasks or functions in response to processing user-provided information and / or commands. HMI 102 may be communicatively coupled to an external controller 104, which may be communicatively coupled to a microgrid controller 110. In some embodiments, HMI 102 may be communicatively directly coupled to the microgrid controller 110. External controller 104 may send commands to and receive information from the microgrid controller 110. For example, external controller 104 may send commands to microgrid controller 110 based on information received from HMI 102. Therefore, external controller 104 may be a controller for user commands. External controller 104 may be integrated with HMI 102. External controller 104 may be a controller for a larger power distribution system (e.g., a macro grid, power plant, and / or power facility provider).

[0028] Power system 106 can supply power to one or more loads 108. Typically, power system 106 can provide alternating current (AC) power at a specific voltage and current. Microgrid controller 110 can control one or more energy storage systems 122 to momentarily inject power when power system 106 needs it, or momentarily absorb excess power generated by power system 106. Therefore, one or more energy storage devices in energy storage system 122 can act as power-consuming devices on one or more energy generator systems 120 or as a power source for one or more energy generator systems 120, thereby ensuring that the system bus frequency of the unstable group 112 of the energy resource system is maintained at the nominal value. In other words, microgrid controller 110 can control the stable group of energy resource system 114 to stabilize the load of the unstable group 112 of the energy resource system, so as to maintain the unstable group 112 of the energy resource system at a relatively constant load, which can reduce the recurrence of frequency deviations from the nominal value.

[0029] The microgrid controller 110 can be integrated with or disconnected (but connected to) interfaces 116 and 118, energy generator system 120, and energy storage system 122, or a combination thereof. In this way, a user can, according to user preferences, add or remove energy generator system 120 to increase / decrease system power generation, and / or add or remove energy storage system 122 to increase / decrease system energy storage capacity, through interaction with HMI 102. For example, if an additional load 108 is expected to be connected to power system 106, the user may prefer to add additional energy generator system 120 and / or add additional energy storage system 122 to increase load capacity, or remove energy generator system 120 and / or remove energy storage system 122 to reduce load capacity if load 108 is expected to be disconnected from power system 106. Additionally, the microgrid controller 110 can be configured to add or remove energy generator system 120 and / or add or remove energy storage system 122 from power system 106 based on meeting one or more conditions. In some cases, the microgrid controller 110 can be configured to add or remove the energy generator system 120 and / or add or remove the energy storage system 122 from the power system 106 based on a schedule.

[0030] One or more loads 108 can be any device capable of connecting to a power distribution system such as power system 106 to receive power. Examples of loads may include heavy machinery (e.g., electric mining machines, tractors, etc.), personal devices, appliances, heating, ventilation and air conditioning (HVAC) systems, industrial drilling rigs, residential power distribution systems, etc. Load 108 may include one or more unstable loads, such as one or more cyclic loads. Load 108 may include unidirectional loads (e.g., loads that can only receive power from power system 106), bidirectional loads (e.g., loads that can both receive power from and supply power to power system 106), charging loads (e.g., loads including rechargeable batteries), necessary loads (e.g., loads that require uninterrupted service), and / or unnecessary loads (e.g., loads that do not require uninterrupted service). Loads may be assigned different priorities based on load type, load classification, and / or operating status or mode.

[0031] Generally, one or more loads 108 can receive power from power system 106 and use the power according to the operation of one or more loads 108. Users of power system 106 and one or more loads 108 can connect / disconnect one or more loads 108 by electrically connecting one or more loads 108 to interfaces 116 and 118 of power system 106. For example, interfaces 116 and 118 may have AC plugs / sockets to connect one or more loads 108 in parallel to one or more energy generator systems 120 and one or more energy storage systems 122 of power system 106. One or more loads 108 may include a local load controller that can collect load information and send the load information to microgrid controller 110. The load information may include information indicating the load type, load classification, and / or the operating status or mode of load 108. The load may be active (real) or reactive to allow for power quality-based dispatching methods. The load information may include load data of the load, such as maximum load and minimum load. For rechargeable loads, load information may include maximum charging load, maximum state of charge, minimum state of charge, current state of charge, and available discharge energy as a function of the current state of charge. Load information may be received by microgrid controller 110 via interfaces 116 and 118, which may include one or more communication interfaces coupled to microgrid controller 110.

[0032] Interfaces 116 and 118 may also have multiple generator connections and multiple energy storage connections. Multiple generator connections may be hardwired electrical connections and / or AC plugs / sockets to connect one or more energy generator systems 120 in parallel to at least one load 108 and one or more energy storage systems 122. Multiple energy storage connections may be hardwired electrical connections and / or AC plugs / sockets to connect one or more energy storage systems 122 in parallel to one or more loads 108 and one or more energy generator systems 120. For example, power system 106 may or may not allow the addition / removal of energy generator systems 120 and / or the addition / removal of energy storage systems 122. Therefore, depending on the configuration, interfaces 116 and 118 may include: (1) hardwired electrical connections connecting at least one energy generator system 120; (2) AC plugs / sockets for connecting / disconnecting at least one energy generator system 120; (3) hardwired electrical connections connecting at least one energy storage system 122; and / or (4) AC plugs / sockets for connecting / disconnecting at least one energy storage system 122. Interfaces 116 and 118 can be coupled to the system bus (e.g., power bus) of the power system 106. The system bus can enable one or more of the energy storage systems 122 to draw power from one or more energy generator systems 120 and / or one or more loads 108 (e.g., for charging and / or storing power).

[0033] One or more energy generator systems 120 may also include a communication interface. The communication interface of one or more energy generator systems 120 enables them to communicate with a microgrid controller 110. For example, one or more energy generator systems 120 may be connected to the microgrid controller 110 via wired or wireless communication. One or more energy generator systems 120 may provide generator data (e.g., energy resource information) to the microgrid controller 110. For each of the one or more energy generator systems 120, the generator data may include load data and / or generator parameters. Load data may include current (e.g., instantaneous) load and / or past load data as seen by one or more energy generator systems 120 (if one or more energy generator systems 120 store such data locally). Current / past load data may include voltage (e.g., in volts) and / or current (e.g., in amperes) measured by one or more sensor components included in the energy generator system 120. Generator parameters may include a generator set maximum threshold and a generator set minimum threshold. Alternatively, to reduce transmission bandwidth, generator parameters may be omitted from the generator data, and one or more energy generator systems 120 may transmit generator parameters during the initial configuration process between one or more energy generator systems 120 and the microgrid controller 110. The generator setting maximum threshold and generator setting minimum threshold may respectively indicate the maximum and minimum power load that the generator of the energy generator system 120 can support.

[0034] One or more energy storage systems 122 may be any energy storage device capable of storing and outputting AC power. For example, one or more energy storage systems 122 may include at least one of the following: electrochemical energy storage devices (e.g., batteries), electrical energy storage devices (e.g., capacitors, supercapacitors, or superconducting magnetic energy storage devices), mechanical energy storage devices (e.g., flywheels, pump systems, etc.), and / or any combination thereof. One or more energy storage systems 122 may (individually or collectively) include an inverter, such that one or more energy storage systems 122 can act as an electrical-consuming device or a power source. One or more energy storage systems 122 may also include electronic control mechanisms to control (1) how much load one or more energy storage systems 122 draws, or (2) how much AC power one or more energy storage systems 122 outputs.

[0035] One or more energy storage systems 122 may also include a communication interface. The communication interface of one or more energy generator systems 122 enables the one or more energy storage systems 122 to communicate with the microgrid controller 110. For example, the one or more energy storage systems 122 may be connected to the microgrid controller 110 via wired or wireless communication. The one or more energy storage systems 122 may provide energy storage data (e.g., energy resource information) to the microgrid controller 110 and may receive instructions from the microgrid controller 110.

[0036] For each of at least one energy storage device, the energy storage data may include the current energy level (e.g., currently stored kilowatt-hours), the total energy storage capacity (e.g., capacity in kilowatt-hours), and / or discharge / charge parameters. The current energy level may be measured by a battery meter of the energy storage device. The battery meter may be one or a combination of a voltmeter, an ampere-hour meter, and / or an impedance-based meter. The discharge / charge parameters may indicate the discharge and charge amounts of the respective energy storage devices of one or more energy storage systems 122. Alternatively, to reduce transmission bandwidth, the discharge / charge parameters may be omitted from the energy storage data, and the one or more energy storage systems 122 may transmit the discharge / charge parameters when they are first connected to the microgrid controller 110.

[0037] One or more energy storage systems 122 may receive requests (e.g., instructions) for energy storage data to provide energy storage data and / or continuously provide energy storage data to the microgrid controller 110. Instructions may include energy storage device dispatch (ESD) instructions. ESD instructions may include instructions to inject power into or draw power from the system bus of the power system 106. ESD instructions may be provided in control signals (e.g., communication signals that provide ESD instructions). At least one ESD instruction may be used to quickly stabilize the load, thereby stabilizing the bus frequency of the power system 106 in a time-efficient manner, rather than attempting to stabilize the load using only one or more energy generator systems 120. One or more energy storage systems 122 may control inverters and electronic control mechanisms according to ESD instructions to control (1) the amount of load drawn by one or more energy storage systems 122, or (2) the amount of AC power output generated by one or more energy storage systems 122. Reactive and / or active power may be used as modifiers of load, where reactive load may also contribute to the stabilization algorithm in addition to active or actual load.

[0038] The microgrid controller 110 may include: at least one memory device (e.g., one or more memories) for storing instructions (e.g., program code); at least one processor for executing the instructions from the memory device to perform a set of desired operations; and a communication interface (e.g., coupled to a communication bus) for facilitating communication between various system components. The instructions may be computer-readable instructions for executing a control application. The communication interface of the microgrid controller 110 enables the microgrid controller 110 to communicate with one or more energy generator systems 120 and one or more energy storage systems 122. When executing the control application, the microgrid controller 110 may receive generator data and energy storage data (e.g., energy resource information), process the generator data and energy storage data to generate one or more ESD instructions, and output the ESD instructions to one or more energy generator systems 120 and / or one or more energy storage systems 122.

[0039] To process generator and energy storage data to generate ESD commands, the control application may include load stabilization functions and / or SOC functions. The control application may also include generator setting limit functions and / or energy storage discharge / charge limit functions to generate ESD commands. In some cases, the load stabilization function may be activated when power system 106 is configured to operate in stand-alone mode to provide off-grid load stabilization. The microgrid controller 110 may automatically activate or deactivate the aforementioned system functions based on the presence or absence of system parameters (e.g., no generator setting minimum threshold is available) or the satisfaction of one or more system conditions.

[0040] Generally, the load stabilization function ensures that the system bus frequency of one or more energy generator systems 120 is maintained at its nominal value by allowing one or more energy storage systems 122 to absorb / inject a certain amount of power. The amount of power can be determined based on the difference from the instantaneous load and the moving average of the load. Simultaneously, the SOC function ensures that one or more energy storage systems 122 are charged to a target SOC or target SOC range, preventing the SOC of one or more energy storage systems from drifting too low or too high outside the desired operating range (e.g., the target SOC range). The target SOC or target SOC range enables at least one energy storage system 122 to provide long-term beneficial use for system 100, such as having an operating range usable by the power system 106, and / or avoiding degradation ranges for one or more energy storage systems 122.

[0041] One or more energy generator systems 120 may include engine-driven generators (e.g., generator sets) that provide AC power to an electrical system 106, which can supply AC power to at least one load 108. Generally, an engine-driven generator can be any device that converts prime mover (mechanical energy) into electrical power to output AC power. An engine-driven generator may be a gas turbine generator. In such gas turbine generators, rapid changes in load from at least one load 108 may cause the system bus frequency to deviate from its nominal value. The system bus frequency may be the frequency of the generator's electrical components. For example, such gas turbine generators may have an isochronous frequency control regulator that attempts to maintain the system bus frequency to its nominal value in response to changes in the load of one or more loads 108. Therefore, during transient load charging (e.g., load transients), the system bus frequency may change as the load on the engine-driven generator changes. However, due to the motional inertia of the physical components of the engine-driven generator (e.g., the rotor of the stator-rotor system), the rate at which the system bus frequency returns to its nominal value is slower than expected. A slow return rate can degrade the power quality of power system 106. The power quality of power system 106 can be determined based on the voltage, frequency, and waveform of the power output to one or more loads 108. High power quality ensures continuity of service to one or more loads 108, enabling them to operate normally as expected. Low power quality may cause one or more loads 108 to fail, fail prematurely, or not operate at all.

[0042] Therefore, avoiding load transients can contribute to providing better power quality. However, in general, controlling the load of one or more loads 108 may be impossible or undesirable. Alternatively, the microgrid controller 110 can control one or more energy storage systems 122 of the stable group 114 of the energy resource system to act as power-consuming devices or energy sources, so that one or more energy generator systems 120 of the unstable group 112 of the energy resource system can maintain the system bus frequency at the nominal value, thereby ensuring better power quality.

[0043] Figure 2 A microgrid 200 according to one or more embodiments is shown. The microgrid 200 may be a combination of... Figure 1An example of the described power system 106. Microgrid 200 may include multiple DERs 202. The multiple DERs 202 may include N energy generator systems 120 and M energy storage systems 122, where N and M are integers greater than zero. For example, the multiple DERs 202 may include a first energy generator system 120-1 and an Nth energy generator system 120-N. Additionally, the multiple DERs 202 may include a first energy storage system 122-1 and an Mth energy storage system 122-M. Each energy generator system 120 may include a generator 204 and a local generator controller 206. Each energy storage system 122 may include an energy storage device 208 (e.g., one or more batteries and / or capacitors) and a local ESS controller 210.

[0044] Each energy generator system 120 may be coupled to power bus 212 to provide power to one or more loads connected to power bus 212. Additionally, each energy storage system 122 may be coupled to power bus 212 to provide power to or draw power from power bus 212 (e.g., to provide power to or draw power from one or more components and / or one or more energy generator systems 120 connected to power bus 212, such as one or more loads).

[0045] Microgrid 200 may also include microgrid controller 110, which is communicatively coupled to a local controller (e.g., local generator controller 206 and local ESS controller 210) of each DER 202 via communication bus 214. Communication bus 214 also enables microgrid 200 to communicate with one or more loads and / or one or more load management systems (e.g., charging systems, queue management systems, local load controllers, etc.). In some cases, two or more communication buses 214 may be provided. For example, one communication bus may be provided for communication with the local controller, and another communication bus may be provided for communication with one or more loads and / or one or more load management systems.

[0046] Each local generator controller 206 may include any suitable hardware, software, and / or firmware to sense and control the corresponding generator 204, send information to and receive information from the microgrid controller 110. For example, the local generator controller 206 may be configured to sense, determine, and / or store generator data for its corresponding generator 204. Generator data can be sensed, determined, and / or stored in any conventional manner. Each local generator controller 206 may (e.g., based on instructions or control signals received from the microgrid controller 110) control whether the corresponding generator 204 is connected to or disconnected from the power bus 212.

[0047] Each local ESS controller 210 may include any suitable hardware, software, and / or firmware to sense and control the corresponding electrical storage device 208, and to send and receive information from the microgrid controller 110. For example, the local ESS controller 210 may be configured to sense, determine, and / or store various characteristics of its corresponding electrical storage device 208. Such characteristics of the corresponding electrical storage device 208 may in particular include the current SOC, current energy, minimum SOC threshold, maximum SOC threshold, and discharge limit of the corresponding electrical storage device 208. These characteristics of each corresponding electrical storage device 208 may be sensed, determined, and / or stored in any conventional manner. Each local ESS controller 210 may (e.g., based on instructions or control signals received from the microgrid controller 110) control whether the corresponding electrical storage device 208 is connected to or disconnected from the power bus 212.

[0048] The microgrid controller 110 can receive or determine the demand for charging or discharging from the microgrid 200, and can be configured to determine and send signals to distribute the total charging request and / or total discharging request among all DERs in the plurality of DERs 202.

[0049] When performing the power distribution function, the microgrid controller 110 can distribute a certain amount of power from each energy generator system 120 to one or more loads 108. One or more loads 108 can be connected to the power bus 212 via one or more circuit breakers 124 to receive power from the power bus. When performing the power distribution function, the microgrid controller 110 can allocate total charging requests and / or total discharging requests among the energy storage systems 122 based on the available energy capacity of each energy storage system 122. Available energy capacity corresponds to the amount of energy that the energy storage system 122 can receive in response to a total charging request (available charging energy), or the amount of energy that the energy storage system can release in response to a total discharging request (available discharging energy). Available charging energy is a function of the energy storage system's maximum state of charge, current state of charge, and current energy, and available discharging energy is a function of the energy storage system 122's minimum state of charge and current energy. The microgrid controller 110 can determine the available charge / discharge capacity (e.g., SOC) of each energy storage system 122, the desired charge / discharge of each energy storage system 122, the remaining power of each energy storage system 122, and / or the SOH of each energy storage system 122.

[0050] Therefore, the microgrid controller 110 regulates the power supply of the microgrid 200 so that at any given time, a precise amount of desired power flows into or out of the power system 106. The microgrid controller 110 can cooperate with the local generator controller 206 and the local ESS controller 210 to regulate the power supply of the microgrid 200. The microgrid controller 110 can transmit control signals (e.g., commands) to the local generator controller 206 and the local ESS controller 210 to activate (e.g., bring it online), deactivate (take it offline), or reduce (limit or regulate to a target output) one or more of the DER 202. Alternatively, the microgrid controller 110 can transmit control signals to one or more switches 213 to control the switching state (e.g., on or off) of one or more switches 213, for example, to connect one or more DER 202 to or disconnect one or more DER 202 from the microgrid 200 (e.g., power bus 212). Switches 213 can be integrated into a combination... Figure 1 The description is in one or both of interfaces 116 and 118.

[0051] In some cases, two or more power buses 212 may be provided. For example, power buses may be provided to couple one or more generators 204 to one or more energy storage devices 208 to charge one or more energy storage devices 208. For example, the microgrid controller 110 may selectively couple generators 204 to energy storage devices 208 to charge energy storage devices 208. Thus, power buses 212 may be part of the power distribution network of the microgrid 200, which may include one or more power buses for distributing power between load 108 and / or DER 202.

[0052] The microgrid 200 may include an interface 216 for connecting the microgrid 200 to a power distribution system 218, such as a macrogrid, and disconnecting the microgrid 200 from the power distribution system. The power distribution system 218 may include an external controller 104 (e.g., a macrogrid controller), such as in conjunction with... Figure 1The external controller 104 may be coupled to interface 216 to transmit control signals, such as commands or requests, to microgrid controller 110. Interface 216 may include one or more electrical connections for connecting microgrid 200 to power distribution system 218. Interface 216 may include one or more switches or circuit breakers controlled by microgrid controller 110 to connect microgrid 200 to power distribution system 218 and disconnect microgrid 200 from power distribution system. For example, one or more switches or circuit breakers of interface 216 may connect power bus 212 (or another system bus) to power distribution system 218 or disconnect power bus 212 (or another system bus) from power distribution system. Therefore, microgrid controller 110 can configure microgrid 200 to operate in grid-connected mode by connecting microgrid 200 to power distribution system 218, or configure microgrid 200 to operate in stand-alone mode by disconnecting microgrid 200 from power distribution system 218.

[0053] Figure 3 A system 300 according to one or more embodiments is illustrated. The system 300 may include combinations of... Figure 1 and Figure 2The microgrid controller 110 is described. Additionally, system 300 includes one or more microgrids, including an AC microgrid 302a, a DC microgrid 302b, and / or an AC-DC hybrid microgrid 302c. AC microgrid 302a may include AC loads and AC DERs (e.g., AC energy resource systems). DC microgrid 302b may include DC loads and DC DERs (e.g., DC energy resource systems). AC-DC hybrid microgrid 302c may include AC loads, AC DERs, DC loads, and / or DC DERs. System 300 may include switches 304a, 304b, and / or 304c, which can be selectively enabled and disabled by microgrid controller 110 to control power routing between AC microgrid 302a, DC microgrid 302b, and / or AC-DC hybrid microgrid 302c. For example, the microgrid controller 110 can enable one or more switches 304a, 304b, and / or 304c to route AC power from the AC microgrid 302a to the DC microgrid 302b and / or the AC-DC hybrid microgrid 302c to power one or more loads in the DC microgrid 302b and / or the AC-DC hybrid microgrid 302c. The microgrid controller 110 can also enable one or more switches 304a, 304b, and / or 304c to route DC power from the DC microgrid 302b to the AC microgrid 302a and / or the AC-DC hybrid microgrid 302c to power one or more loads in the AC microgrid 302a and / or the AC-DC hybrid microgrid 302c. The microgrid controller 110 enables one or more switches 304a, 304b, and / or 304c to route DC power and / or AC power from the AC-DC hybrid microgrid 302c to the AC microgrid 302a and / or the DC microgrid 302b to power one or more loads in the AC microgrid 302a and / or the DC microgrid 302b.

[0054] System 300 may include one or more converters 306a, 306b, and / or 306c for converting power from one form to another. For example, one or more converters 306a, 306b, and / or 306c may include an AC-to-DC converter for converting AC power to DC power, and / or a DC-to-AC converter for converting DC power to AC power. The AC-to-DC converter may be used to convert AC power from AC microgrid 302a or from AC-DC hybrid microgrid 302c into DC power for delivery to DC microgrid 302b. The DC-to-AC converter may be used to convert DC power from DC microgrid 302b or from AC-DC hybrid microgrid 302c into AC power for delivery to AC microgrid 302a. When power is exported to AC-DC hybrid microgrid 302c, AC-to-DC converters and / or DC-to-AC converters may also be used depending on the type of power exported / imported and the type of load powered within AC-DC hybrid microgrid 302c.

[0055] In some implementations, one or more power buses may be coupled to power distribution system 218 for exporting power to and / or importing power from power distribution system 218. Depending on the type of load being powered (e.g., DC loads within DC microgrid 302b and / or AC-DC hybrid microgrid 302c), one or more converters 306a, 306b, and / or 306c may be used to convert DC power to AC power for export to power distribution system 218, and / or convert AC power from power distribution system 218 to DC power. Microgrid controller 110 may control switch 308 for connecting power distribution system 218 to one or more of microgrids 302a, 302b, and / or 302c.

[0056] The microgrid controller 110 may include an aggregator 310 and a processing and control unit 312. The aggregator 310 may receive information from microgrids 302a, 302b, and 302c and the power distribution system 218, and aggregate this information for further processing by the processing and control unit 312. For example, the aggregator 310 may receive load information, such as load demand, from loads, and energy resource information, such as available output power and power type, from the DER. The aggregator 310 may receive utility data, such as available import power, from the power distribution system 218. Additionally, the aggregator 310 may receive export requests from the power distribution system 218, requesting power to be exported from microgrids 302a, 302b, and 302c to the power distribution system 218, and / or receive indications from the power distribution system 218 of the amount of available import power, indicating the amount of power available from the power distribution system 218 to be imported into microgrids 302a, 302b, and 302c. In some implementations, aggregator 310 may be a cloud-based aggregator that connects to a cloud network of servers, databases, and / or local controllers via the Internet.

[0057] The processing and control unit 312 can process the information aggregated by the aggregator 310 to make control decisions and generate control signals based on these decisions. For example, the processing and control unit 312 can generate control signals for activating or deactivating one or more DERs within one or more microgrids 302a, 302b, and 302c. Alternatively, the processing and control unit 312 can generate control signals for controlling the output power of one or more DERs. Alternatively, the processing and control unit 312 can generate control signals for activating or deactivating one or more loads within one or more microgrids 302a, 302b, and 302c. Alternatively, the processing and control unit 312 can generate control signals for controlling the dispatch of AC and / or DC power from one or more DERs to one or more loads. Alternatively, the processing and control unit 312 can generate control signals for controlling the charging and discharging of the ESS. Alternatively, the processing and control unit 312 may generate control signals for controlling one or more switches 304a, 304b, 304c, and / or 308 to control power routing within the system 300 (including, where appropriate, routing power via one or more converters 306a, 306b, and / or 306c for power conversion to meet different types of load demands).

[0058] Figure 4 An AC-DC hybrid microgrid 400 according to one or more embodiments is shown. The AC-DC hybrid microgrid 400 may include a combination of Figure 1-3The microgrid controller 110 is described. An AC-DC hybrid microgrid 400 may include multiple energy resource systems configured to supply electricity. These multiple energy resource systems may include a DC energy resource system 402 configured to supply DC power, such as a PV, fuel cell, and / or ESS. Alternatively, the multiple energy resource systems may include an AC energy resource system 404 configured to supply AC power, such as a generator set and / or wind turbine.

[0059] The AC-DC hybrid microgrid 400 may include multiple local controllers 406 for multiple energy resource systems, such as combined Figure 2 Similarly, each local controller 406 can be associated with a corresponding energy resource system among multiple energy resource systems to obtain information about and control that corresponding energy resource system. Multiple local controllers 406 can be connected to the microgrid controller 110 via one or more communication buses for exchanging information with and receiving control signals from the microgrid controller 110.

[0060] DC energy resource system 402 can be connected to DC load 408 via one or more DC power buses. Therefore, DC energy resource system 402 can directly supply DC power to DC load 408. Conversely, AC energy resource system 404 can be connected to AC load 410 via one or more AC power buses. Therefore, AC energy resource system 404 can directly supply AC power to AC load 410. Thus, AC-DC hybrid microgrid 400 can include multiple power buses configured to deliver power from multiple energy resource systems to one or more loads.

[0061] The AC-DC hybrid microgrid 400 may include multiple local controllers 412 for DC loads 408 and AC loads 410. Each local controller 412 may be associated with a corresponding load to obtain information about and control that load. The multiple local controllers 412 may be connected to the microgrid controller 110 via one or more communication buses to exchange information with and receive control signals from the microgrid controller 110.

[0062] The microgrid controller 110 may include a collector 310 and a processing and control unit 312, such as in combination Figure 3Similarly described. Aggregator 310 can aggregate energy resource information received from multiple local controllers 406 and / or aggregate load information received from multiple local controllers 412. Processing and control unit 312 can process the aggregated energy resource information and / or aggregated load information. Processing and control unit 312 can also generate control signals based on one or more control algorithms to optimize the AC-DC hybrid microgrid 400 based on one or more system operating constraints. For example, processing and control unit 312 can generate control signals based on one or more control algorithms to optimize the efficiency of AC-DC hybrid microgrid 400, maximize the number of loads to be supported within AC-DC hybrid microgrid 400, operate in an efficiency mode where all generators are deactivated, and / or reduce the operating costs (e.g., energy costs) of AC-DC hybrid microgrid 400.

[0063] Each local controller 406 can obtain energy resource information from its corresponding energy resource system and solve the optimization problem of the corresponding energy resource system based on one or more operational constraints. The energy resource information may include measurement data, forecast data, and / or pre-stored data measured by the local controller 406, such as manufacturer data associated with the operating parameters of the corresponding energy resource system.

[0064] The energy resource information obtained by the local controller 406 may include current power output (e.g., real-time power output level in kilowatts or megawatts), maximum and minimum capacity based on current operating conditions, fuel / resource availability (e.g., fuel level of generator set or irradiation level of solar panels), ESS SoC, operating status (e.g., fault condition, maintenance requirements, and / or operating temperature), current operating efficiency and any losses due to impedance or other factors, and / or cost information (e.g., cost per unit of electricity generated, which may fluctuate based on fuel cost or other variables).

[0065] The "optimization problem" can refer to mathematical computation where the primary objective is to determine the best way to operate the energy resource system to achieve a specific objective, such as minimizing cost or emissions, while meeting load requirements and maintaining stability within the AC-DC hybrid microgrid 400. The local controller 406 can use an algorithm that defines the primary objective (e.g., minimizing cost, maximizing efficiency, or reducing emissions). The local controller 406 can select an algorithm from multiple algorithms based on indications received from the microgrid controller 110 that specify the primary objective.

[0066] The local controller 406 can use one or more operational constraints to perform calculations to solve optimization problems. Operational constraints can include conditions that the solution must meet, such as power output limits, resource availability, and system stability. AC operational constraints can include voltage and frequency stability to ensure voltage and frequency levels remain within acceptable ranges, active and reactive power requirements to balance active and reactive power to maintain power quality, thermal limits to ensure that heating effects on cables, transformers, and other equipment do not cause temperatures to exceed one or more thresholds, and / or harmonic limits to ensure that harmonics do not exceed limits to avoid interference with equipment and power quality. DC operational constraints can include voltage level limits to maintain the DC bus voltage within set thresholds, voltage drop limits to constrain voltage drops across DC distribution lines, current capacities to ensure that current does not exceed cable and equipment ratings, and conversion efficiency related to energy losses during DC-AC or AC-DC conversion. The microgrid controller 110 can select AC and / or DC operational constraints based on the desired system configuration. Alternatively, the microgrid controller 110 may receive AC operating constraints and / or DC operating constraints from an external controller and / or HMI based on the desired system configuration. The microgrid controller 110 may provide AC operating constraints to the local controller 406 of the AC energy resource system 404, and may provide DC operating constraints to the local controller 406 of the DC energy resource system 202.

[0067] The local controller 406 can use one or more variables to perform calculations to solve an optimization problem. Variables may include the power output of the energy resource system, power flow, and / or factors affecting economic dispatch. Depending on the complexity and interdependencies of the variables, the optimization problem may involve linear or nonlinear programming.

[0068] Each local controller 406 can parse priority information from the energy resource information associated with the corresponding energy resource system and send the priority information to the aggregator 310. The priority information may include available output power (e.g., the maximum power that the corresponding energy resource system can provide based on an optimization solution), current output power (e.g., the real-time power output of the corresponding energy resource system), reserve capacity (e.g., available reserves that can be accessed if load demand surges), generation cost (e.g., the current marginal cost of generation for economic dispatch), SOH, operational readiness status, and / or operational constraints.

[0069] Aggregator 310 can aggregate supply and demand information to calculate the total available output power and total net load for each power type (e.g., net available DC output power, net available AC output power, net DC load, and net AC load). Processing and control unit 312 can compare the total available output power and total net load for each power type. For example, processing and control unit 312 can compare net available DC output power and net DC load, for example, to determine whether there is a DC power surplus or shortage based on the difference between net available DC output power and net DC load. Processing and control unit 312 can compare net available AC output power and net AC load, for example, to determine whether there is an AC power surplus or AC power shortage based on the difference between net available AC output power and net AC load.

[0070] In addition, the processing and control unit 312 can use algorithms based on aggregated information to allocate power on the energy resource system in the most economical and efficient way, while meeting all load requirements and all operational constraints to achieve economical power dispatch.

[0071] In addition, if demand exceeds supply, the processing and control unit 312 can predict potential demand and plan supplementary actions (e.g., bring additional energy resource systems online) based on aggregated information.

[0072] Therefore, the processing and control unit 312 can implement scheduling strategies based on aggregated information to allocate the total available power from the energy resource system based on load demand.

[0073] For example, aggregator 310 can determine the load type, including identifying whether the connected load is a DC load 408 or an AC load 410, and calculate the net load for each power type. Processing and control unit 312 can prioritize power scheduling for each power type, such that DC power is first scheduled to DC loads and then used to process the demands of AC loads, and vice versa. Therefore, processing and control unit 312 can prioritize DC power for DC loads and AC power for AC loads.

[0074] If a particular power type is insufficient to satisfy the net load of the same power type, the processing and control unit 312 can control the power conversion of another power type to compensate for the shortage. For example, if there is excess DC power after satisfying the net DC load, the processing and control unit 312 can convert the excess DC power into supplementary AC power and route the supplementary AC power to AC load 410. Alternatively, if there is excess AC power after satisfying the net AC load, the processing and control unit 312 can convert the excess AC power into supplementary DC power and route the supplementary DC power to DC load 408.

[0075] The AC-DC hybrid microgrid 400 may include a power transmission system 413, which includes one or more converters 414 (e.g., DC-to-AC converters and AC-to-DC converters), a transmission switch 416, and a transmission switch 418. The microgrid controller 110 may control one or more converters 414, transmission switches 416, and transmission switches 418. For example, the processing and control unit 312 may enable the transmission switch 416 to route excess DC power from the DC bus to one or more converters 414 to convert it into supplemental AC power. The one or more converters 414 may deliver the supplemental AC power to the AC bus for one or more AC loads 410. Thus, the power transmission system 413 may transmit excess DC power to the AC side of the AC-DC hybrid microgrid 400 to assist in AC power shortages. Alternatively, the processing and control unit 312 may enable the transmission switch 418 to route excess AC power from the AC bus to one or more converters 414 to convert it into supplemental DC power. One or more converters 414 can deliver supplemental DC power to the DC bus for use by one or more DC loads 408. Thus, the power transmission system 413 can transfer excess AC power to the DC side of the AC-DC hybrid microgrid 400 to assist in DC power shortages.

[0076] In some implementations, if there is no excess power of a particular type to meet a shortage of another power type, the processing and control unit 312 may activate one or more additional energy resource systems to meet the net DC load and / or net AC load. Alternatively, the processing and control unit 312 may import additional power from the power distribution system 218 (e.g., an AC utility grid) to meet the net DC load and / or net AC load. For example, the processing and control unit 312 may activate the switch 420 connecting the power distribution system 218 to the AC bus to import AC power from the power distribution system 218. If the imported AC power is needed on the DC side, the processing and control unit 312 may control the power transmission system 413 to convert the imported AC power into DC power. The processing and control unit 312 may disable the switch 420 to disconnect the power distribution system 218 from the AC bus.

[0077] The processing and control unit 312 can dynamically balance the power supply from various energy resource systems based on real-time demand, constraints, and cost-effectiveness. The processing and control unit 312 ensures efficient operation of the AC-DC hybrid microgrid 400 while maintaining stability and minimizing cost.

[0078] In some implementations, each local controller 406 may determine the available output power of the corresponding energy resource system based on one or more operational constraints and send an indication of the available output power to the microgrid controller 110 (e.g., to the aggregator 310). Each local controller 406 may also determine the available output power of the corresponding energy resource system based on optimizing the performance of the corresponding energy resource system according to one or more operational constraints.

[0079] Aggregator 310 can identify, based on information received from multiple local controllers 406, which types of loads are connected to the AC-DC hybrid microgrid 400, including AC loads and / or DC loads. Aggregator 310 can determine the net available DC output power from DC energy resource system 402 and the net available AC output power from AC energy resource system 404 based on the available output power indicated by each local controller 406. Aggregator 310 can determine the net DC load corresponding to DC load 408 connected to the AC-DC hybrid microgrid 400, and determine the net AC load corresponding to AC load 410 connected to the AC-DC hybrid microgrid 400.

[0080] The processing and control unit 312 can dispatch power from multiple energy resource systems to one or more loads, including prioritizing the dispatch of available DC power from net available DC output power to DC load 408 to satisfy at least a portion of the net DC load, and prioritizing the dispatch of available AC power from net available AC output power to AC load 410 to satisfy at least a portion of the net AC load. One or more DC power buses can be used to route the dispatched DC power to DC load 408. One or more AC power buses can be used to route the dispatched AC power to AC load 410.

[0081] Therefore, the processing and control unit 312 can dispatch power to one or more loads, including preferentially allocating net available DC output power to DC load 408 to satisfy at least a portion of the net DC load, and preferentially allocating net available AC output power to AC load 410 to satisfy at least a portion of the net AC load. After satisfying the net DC load with net available DC output power, the processing and control unit 312 can dispatch the remaining DC portion of the net available DC output power to AC load 410 to satisfy the net AC load, or after satisfying the net AC load with net available AC output power, the processing and control unit 312 can dispatch the remaining AC portion of the net available AC output power to DC load 408 to satisfy the net DC load. The processing and control unit 312 can control one or more converters 414 to convert the remaining DC portion into additional AC power to satisfy the net AC load, and / or convert the remaining AC portion into additional DC power to satisfy the net DC load.

[0082] Aggregator 310 can calculate the DC difference between net available DC output power and net DC load to determine whether the DC difference indicates that the net available DC output is sufficient to meet the net DC load. Processing and control unit 312 can, based on the DC difference indicating that the net available DC output is sufficient to meet the net DC load, dispatch at least a portion of the net available DC output power to DC load 408 to meet the net DC load. Processing and control unit 312 can, based on the DC difference indicating that the net available DC output is insufficient to meet the net DC load, dispatch the net available DC output power to DC load 408 to partially meet the net DC load.

[0083] Additionally, aggregator 310 can calculate the AC difference between net available AC output power and net AC load to determine whether the AC difference represents excess AC power. Processing and control unit 312 can route at least a portion of the excess AC power to a power converter to convert said portion of the excess AC power into supplementary DC power, and schedule the supplementary DC power to at least partially satisfy the net DC load, based on the assumption that the DC difference is insufficient to meet the net DC load and that the AC difference represents excess AC power.

[0084] Additionally, the processing and control unit 312 can determine whether the combination of supplemental DC power and net available DC output power is insufficient to meet the net DC load. Based on this, the processing and control unit 312 can activate one or more additional energy resource systems to meet the net DC load. In other words, if the sum of supplemental DC power (e.g., converted from an AC DER) and net available DC output power (e.g., provided by a DC DER) is insufficient to meet the net DC load, the processing and control unit 312 can add, activate, or bring one or more additional energy resource systems online to meet the net DC load. The sum of supplemental DC power and net available DC output power can be considered as an updated net available DC output power derived from DC power and AC-to-DC conversion power.

[0085] Alternatively, the processing and control unit 312 may determine whether the combination of supplemental DC power and net available DC output power is insufficient to meet the net DC load. Based on this, the processing and control unit 312 may import additional power from the power distribution system 218 to meet the net DC load. In other words, if the sum of supplemental DC power (e.g., converted from an AC DER) and net available DC output power (e.g., provided by a DC DER) is insufficient to meet the net DC load, the processing and control unit 312 may import power from the power distribution system 218 to meet the net DC load.

[0086] Alternatively, the processing and control unit 312 may calculate the AC difference between the net available AC output power and the net AC load to determine whether the AC difference represents an AC power shortage. The processing and control unit 312 may, based on the DC difference being insufficient to meet the net DC load and based on the AC difference representing an AC power shortage, enable one or more additional energy resource systems to meet the net DC load, or import additional power from the power distribution system 218 to meet the net DC load.

[0087] In some implementations, aggregator 310 may calculate the AC difference between net available AC output power and net AC load to determine whether the AC difference indicates that the net available AC output is sufficient to meet the net AC load. Processing and control unit 312 may, based on the AC difference indicating that the net available AC output is sufficient to meet the net AC load, dispatch at least a portion of the net available AC output power to AC load 410 to meet the net AC load. Alternatively, processing and control unit 312 may, based on the AC difference indicating that the net available AC output is insufficient to meet the net AC load, dispatch the net available AC output power to AC load 410 to partially meet the net AC load.

[0088] Additionally, aggregator 310 can calculate the DC difference between the net available DC output power and the net DC load to determine whether the DC difference represents excess DC power. Processing and control unit 312 can route at least a portion of the excess DC power to a power converter to convert said portion of the excess DC power into supplementary AC power, and schedule the supplementary AC power to at least partially satisfy the net AC load, based on the assumption that the AC difference is insufficient to meet the net AC load and that the DC difference represents excess DC power.

[0089] Additionally, the processing and control unit 312 can determine whether the combination of supplemental AC power and net available AC output power is insufficient to meet the net AC load. Based on this, the processing and control unit 312 can activate one or more additional energy resource systems to meet the net AC load. In other words, if the sum of supplemental AC power (e.g., converted from a DC-to-AC converter) and net available AC output power (e.g., provided by an AC converter) is insufficient to meet the net AC load, the processing and control unit 312 can add, activate, or bring one or more additional energy resource systems online to meet the net AC load. The sum of supplemental AC power and net available AC output power can be considered as an updated net available AC output power derived from the AC power and DC-to-AC conversion power.

[0090] Alternatively, the processing and control unit 312 may determine whether the combination of supplemental AC power and net available AC output power is insufficient to meet the net AC load. Based on this, the processing and control unit 312 may import additional power from the power distribution system 218 to meet the net AC load. In other words, if the sum of supplemental AC power (e.g., converted from a DC DER) and net available AC output power (e.g., provided by an AC DER) is insufficient to meet the net AC load, the processing and control unit 312 may import power from the power distribution system 218 to meet the net AC load.

[0091] Alternatively, aggregator 310 may calculate the DC difference between net available DC output power and net DC load to determine whether the DC difference represents a DC power shortage. Processing and control unit 312 may, based on the AC difference being insufficient to meet the net AC load and based on the DC difference representing a DC power shortage, activate one or more additional energy resource systems to meet the net AC load, or import additional power from power distribution system 218 to meet the net AC load.

[0092] Because the local controller 406 of each energy resource system will perform optimizations and coordinate with the aggregator 310 or the central controller, this will reduce the computational load on the central controller (e.g., the microgrid controller 110). This will make the microgrid control system scalable.

[0093] Figure 5 This is a flowchart of an exemplary process 500 associated with distributed optimization for hybrid AC-DC microgrids. Figure 5 One or more process blocks can be executed by a microgrid controller (e.g., microgrid controller 110). Alternatively or concurrently, Figure 5 One or more process frames may be executed by another device or group of devices that are separate from or include the microgrid controller, such as another device or component inside or outside the hybrid AC-DC microgrid.

[0094] like Figure 5 As shown, process 500 may include receiving energy resource information from each of a plurality of energy resource systems, the energy resource information including available output power (block 510). For example, as described above, microgrid controller 110 may receive energy resource information from each of the plurality of energy resource systems. The plurality of energy resource systems may include DC energy resource systems configured to supply DC power and AC energy resource systems configured to supply AC power.

[0095] like Figure 5As further shown, process 500 may include determining the net available DC output power from the DC energy resource system and the net available AC output power from the AC energy resource system based on the available output power indicated by each energy resource system (block 520). For example, as described above, microgrid controller 110 may determine the net available DC output power from the DC energy resource system and the net available AC output power from the AC energy resource system based on the available output power indicated by each energy resource system.

[0096] like Figure 5 As further shown, process 500 may include determining the net DC load corresponding to the DC load (block 530). For example, as described above, microgrid controller 110 may determine the net DC load corresponding to the DC load.

[0097] like Figure 5 As further shown, process 500 may include determining the net AC load corresponding to the AC load (block 540). For example, as described above, microgrid controller 110 may determine the net AC load corresponding to the AC load.

[0098] like Figure 5 As further shown, process 500 may include dispatching power from multiple energy resource systems to DC and AC loads (block 550). For example, as described above, microgrid controller 110 may dispatch power from multiple energy resource systems to DC and AC loads. Dispatching power from multiple energy resource systems to DC and AC loads may include preferentially dispatching net available DC output power to DC loads to satisfy at least a portion of the net DC load, and preferentially dispatching net available AC output power to AC loads to satisfy at least a portion of the net AC load; and after satisfying the net DC load, dispatching the remaining DC portion of the net available DC output power to AC loads to satisfy at least an additional portion of the net AC load, or after satisfying the net AC load, dispatching the remaining AC portion of the net available AC output power to DC loads to satisfy at least an additional portion of the net DC load.

[0099] although Figure 5 An exemplary block diagram of process 500 is shown, but in some embodiments, process 500 may include more than Figure 5 The boxes depicted may be more boxes, fewer boxes, different boxes, or boxes with different arrangements. Alternatively, two or more boxes in process 500 may be executed in parallel.

[0100] Figure 6This is a diagram of exemplary components of a microgrid controller 110 associated with distributed optimization for a hybrid AC-DC microgrid. The microgrid controller 110 may include a bus 610, a processor 620, a memory 630, input components 640, output components 650, and / or communication components 660.

[0101] Bus 610 may include one or more components that enable wired and / or wireless communication between components of the microgrid controller 110. Bus 610 may connect components via, for example, operative coupling, communicative coupling, electronic coupling, and / or electrical coupling. Figure 6 Two or more components are coupled together. For example, bus 610 may include electrical connections (e.g., wires, traces and / or leads) and / or wireless buses.

[0102] Processor 620 may include a central processing unit, microprocessor, controller, microcontroller, digital signal processor, field-programmable gate array, application-specific integrated circuit, and / or another type of processing unit. Processor 620 may be implemented in hardware, firmware, or a combination of hardware and software. Processor 620 may include one or more processors capable of being programmed to perform one or more operations or processes described elsewhere herein. For example, processor 620 may include aggregator 310 and / or processing and control unit 312. As described above, processor 620 may generate control signals to control components of a hybrid AC-DC microgrid and to dispatch power within the hybrid AC-DC microgrid.

[0103] Memory 630 may store information related to the operation of microgrid controller 110, one or more instructions, and / or software (e.g., one or more software applications). Memory 630 may include one or more memories, such as those coupled (e.g., communicatively coupled) to one or more processors (e.g., processor 620) via bus 610. The communicative coupling between processor 620 and memory 630 enables processor 620 to read and / or process information stored in memory 630 and / or store information in memory 630.

[0104] Input component 640 enables microgrid controller 110 to receive inputs, load information, generator data, energy storage data, status information, scheduling information, and / or control signals (e.g., control signals from macrogrid controllers). Output component 650 enables microgrid controller 110 to provide outputs, such as one or more control signals for controlling loads, energy storage systems, circuit breakers, switches, and other components associated with the microgrid described herein. Communication component 660 enables microgrid controller 110 to communicate with other devices, such as local controllers, switches, converters, and public power grids, via wired and / or wireless connections. For example, communication component 660 may include a receiver, transmitter, and / or transceiver.

[0105] The microgrid controller 110 can perform one or more operations or processes described herein. For example, a non-transitory computer-readable medium (e.g., memory 630) can store a set of instructions (e.g., one or more instructions or code) for execution by the processor 620. The processor 620 can execute the set of instructions to perform one or more operations or processes described herein. One or more processors 620 executing the set of instructions can cause one or more processors 620 and / or the microgrid controller 110 to perform one or more operations or processes described herein. Hard-wired circuitry can be used in place of or in combination with instructions to perform one or more operations or processes described herein. Alternatively or additionally, the processor 620 can be configured to perform one or more operations or processes described herein. Therefore, the embodiments described herein are not limited to any particular combination of hardware circuitry and software.

[0106] Industrial applicability

[0107] The microgrid system described herein may include a microgrid controller configured as a central computing resource, distributed local controllers configured as distributed computing resources, and aggregators, which operate together to optimize performance in a hybrid AC-DC microgrid. The distributed local controllers may be configured to perform parallel computations to process data to solve corresponding optimization problems. For example, each local controller may process data and solve the corresponding optimization problem associated with the relevant DER. Therefore, the distributed local controllers can perform processing and optimization subtasks (e.g., local-level processing tasks) that would typically be handled by a centralized controller such as the microgrid controller.

[0108] By handling and optimizing subtasks, distributed local controllers can reduce the processing demands on the microgrid controllers that would typically be used for performing these subtasks. Therefore, the microgrid controller can dedicate its own processing resources to performing system-level processing tasks and system-level monitoring and control, rather than local-level processing, monitoring, and control. Distributed local controllers enable more efficient handling of local-level tasks at the distributed local controller level and more efficient handling of system-level tasks at the microgrid controller level. For example, distributed local controllers can overcome the processing constraints of centralized controllers, enabling microgrid systems to handle processing tasks more efficiently.

[0109] Aggregators enable iterative coordination between distributed local controllers and microgrid controllers, facilitating information exchange between the main processors of the distributed local controllers and the microgrid controllers.

[0110] Therefore, microgrid systems can address the problems present in microgrids with DC-coupled DERs connected to the AC grid. For example, when only AC grid constraints are used to optimize power flow, DC branch flow limitations, DC-side losses, and other DC parameters are ignored, leading to suboptimal power flow and reduced energy efficiency. The microgrid system disclosed herein can efficiently process local-level information to optimize one or more parameters using parallel computing through a distributed local controller, and send the optimized parameters and / or system-level information to an aggregator. Furthermore, the aggregator can provide iterative coordination by establishing information exchange between the distributed local controller and the microgrid controller. Iterative coordination enables the optimization of the operation of DC-coupled DERs, AC-coupled DERs, DC loads, and AC loads provided in a hybrid AC-DC microgrid, taking into account both AC and DC constraints, to efficiently utilize both DC and AC power. By deploying a hybrid AC-DC distributed optimization scheme, both AC and DC constraints can be considered to optimize power flow, thereby achieving improved energy efficiency and efficient scheduling of DC-coupled and AC-coupled DERs in various operating modes, including grid-connected and stand-alone modes.

Claims

1. A microgrid system, the microgrid system comprising: Multiple energy resource systems are configured to supply power to a microgrid, wherein the multiple energy resource systems include a DC energy resource system configured to supply direct current (DC) power and an AC energy resource system configured to supply alternating current (AC) power. Multiple local controllers, wherein each of the multiple local controllers is associated with a corresponding energy resource system among the multiple energy resource systems for controlling the corresponding energy resource system; Multiple power buses, the multiple power buses being configured to deliver power from the multiple energy resource systems to one or more loads; as well as microgrid controller, Each local controller is configured to determine the available output power of the corresponding energy resource system based on one or more operational constraints, and to send an indication of the available output power to the microgrid controller. The microgrid controller is configured to determine the net available DC output power from the DC energy resource system and the net available AC output power from the AC energy resource system based on the available output power indicated by each local controller.

2. The microgrid system of claim 1, wherein the microgrid controller is configured to determine the net DC load corresponding to the DC loads connected to the microgrid. The microgrid controller is configured to determine the net AC load corresponding to the AC loads connected to the microgrid, and The microgrid controller is configured to dispatch power from the plurality of energy resource systems to the one or more loads, including preferentially dispatching available DC power from the net available DC output power to the DC loads to satisfy at least a portion of the net DC loads, and preferentially dispatching available AC power from the net available AC output power to the AC loads to satisfy at least a portion of the net AC loads.

3. The microgrid system of claim 2, wherein the microgrid controller is configured to calculate the DC difference between the net available DC output power and the net DC load to determine whether the DC difference indicates that the net available DC output is sufficient to meet the net DC load. The microgrid controller is configured to, based on the DC differential, indicate that the net available DC output is sufficient to satisfy the net DC load, dispatch at least a portion of the net available DC output power to the DC load to satisfy the net DC load, and The microgrid controller is configured to dispatch the net available DC output power to the DC load to partially satisfy the net DC load, based on the DC difference indicating that the net available DC output is insufficient to satisfy the net DC load.

4. The microgrid system of claim 3, wherein the microgrid controller is configured to calculate the AC difference between the net available AC output power and the net AC load to determine whether the AC difference represents excess AC power. The microgrid controller is configured to operate based on the following: the DC difference is insufficient to meet the net DC load and the AC difference is an excess of AC power. At least a portion of the excess AC power is routed to a power converter to convert that portion of the excess AC power into supplementary DC power, and The supplementary DC power is scheduled to at least partially satisfy the net DC load.

5. The microgrid system of claim 3, wherein the microgrid controller is configured to calculate the AC difference between the net available AC output power and the net AC load to determine whether the AC difference is an AC power shortage, and The microgrid controller is configured to operate based on the fact that the DC difference is insufficient to meet the net DC load and that the AC difference is the amount of AC power shortage. Activate one or more additional energy resource systems to meet the net DC load, or Additional power is imported from the public power grid to meet the net DC load.

6. The microgrid system of claim 2, wherein the microgrid controller is configured to calculate the AC difference between the net available AC output power and the net AC load to determine whether the AC difference indicates that the net available AC output is sufficient to meet the net AC load. The microgrid controller is configured to, based on the AC difference indicating that the net available AC output is sufficient to satisfy the net AC load, dispatch at least a portion of the net available AC output power to the AC load to satisfy the net AC load, and The microgrid controller is configured to dispatch the net available AC output power to the AC load to partially satisfy the net AC load, based on the AC difference indicating that the net available AC output is insufficient to satisfy the net AC load.

7. The microgrid system of claim 6, wherein the microgrid controller is configured to calculate the DC difference between the net available DC output power and the net DC load to determine whether the DC difference represents excess DC power. The microgrid controller is configured to operate based on the following: the AC difference is insufficient to meet the net AC load and the DC difference is a DC power surplus. At least a portion of the excess DC power is routed to a power converter to convert that portion of the excess DC power into supplementary AC power, and The supplementary AC power is scheduled to at least partially satisfy the net AC load.

8. The microgrid system of claim 6, wherein the microgrid controller is configured to calculate the DC difference between the net available DC output power and the net DC load to determine whether the DC difference represents a DC power shortage, and The microgrid controller is configured to operate based on the fact that the AC difference is insufficient to meet the net AC load and that the DC difference is the amount of DC power shortage. Activate one or more additional energy resource systems to meet the net AC load, or Additional power is imported from the public power grid to meet the net AC load.

9. The microgrid system of claim 1, wherein the microgrid controller is configured to determine the net DC load corresponding to the DC loads connected to the microgrid. The microgrid controller is configured to determine the net AC load corresponding to the AC loads connected to the microgrid, and The microgrid controller is configured to dispatch power to the one or more loads, including preferentially allocating the net available DC output power to the DC loads to satisfy at least a portion of the net DC load, and preferentially allocating the net available AC output power to the AC loads to satisfy at least a portion of the net AC load.

10. A method for optimizing a hybrid microgrid including direct current (DC) loads and alternating current (AC) loads, the method comprising: The microgrid controller receives energy resource information from each of the multiple energy resource systems. The plurality of energy resource systems include DC energy resource systems configured to supply DC power and AC energy resource systems configured to supply AC power. The energy resource information mentioned therein includes available output power; The microgrid controller determines the net available DC output power from the DC energy resource system and the net available AC output power from the AC energy resource system based on the available output power indicated by each energy resource system. The net DC load corresponding to the DC load is determined by the microgrid controller; The net AC load corresponding to the AC load is determined by the microgrid controller; The microgrid controller dispatches power from the plurality of energy resource systems to the DC loads and the AC loads, including preferentially dispatching the net available DC output power to the DC loads to satisfy at least a portion of the net DC load, and preferentially dispatching the net available AC output power to the AC loads to satisfy at least a portion of the net AC load; and After satisfying the net DC load, the microgrid controller dispatches the remaining DC portion of the net available DC output power to the AC load to satisfy at least an additional portion of the net AC load, or After satisfying the net AC load, the microgrid controller dispatches the remaining AC portion of the net available AC output power to the DC load to satisfy at least an additional portion of the net DC load.

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