AC coupling controller to facilitate power flow between power grid, power source, and building

Abstract

The present disclosure provides an AC coupling controller that facilitates power flow between a power grid, a power source, and a building. A controller transitions supply of power from a grid to a building to supply power from one of a plurality of power sources to the building such that during the transition, a rate of power supplied to the building remains constant, and satisfying power demand from the building via more than the one of the power sources after the transition such that a rate of power supplied by the one of the power sources is reduced.

Description

Technical Field

[0001] This disclosure relates to power management for homes and other buildings. Background Technology

[0002] Depending on the geographical and environmental context, home (or other building) energy systems may include solar panels and other renewable energy sources. Such systems may also include batteries, such as lithium-ion batteries, to store electricity generated from these renewable sources for use during periods of low energy production, such as nighttime when solar power is weak. This stored energy can be used via an inverter that converts the direct current (DC) from the batteries into alternating current (AC), the form required by most appliances.

[0003] Connecting to the traditional power grid ensures that homes can still draw energy when production and storage reserves from renewable energy sources are insufficient. This also allows homeowners to sell excess energy back to the grid, further offsetting the problem using systems such as net metering. Energy management systems are used to manage these various energy flows.

[0004] An energy management system may include sensors that detect parameters related to the supply and / or demand of electricity. Summary of the Invention

[0005] An energy management system includes a circuit system arranged to selectively transfer power among a power grid, multiple power sources, and a building. The energy management system also includes a controller that switches the supply of power from the power grid to the building from one of the power sources, such that during the switch, the rate of power supplied to the building remains constant. After the switch, the controller meets the building's power demand via more than one of the power sources, such that the rate of power supplied by the one power source is reduced.

[0006] A method includes commanding a power grid and at least one of a plurality of power sources to concurrently meet the power demand from a building, such that as the power demand from the building changes, the rate at which the power supplied from the power grid to the building remains constant and greater than zero.

[0007] An energy management control system includes a controller that meets the power demand from a building via a power grid and electric vehicles, such that as the power demand from the building changes, the rate at which power is supplied from the power grid to the building remains constant and greater than zero. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an electrical system that uses the power grid to meet the electricity needs of households.

[0009] Figure 2 and Figure 3 yes Figure 1 A diagram illustrating how an electricity system can switch from grid power to other energy sources while continuing to meet household electricity needs.

[0010] Figure 4 yes Figure 1 A diagram illustrating how the power system redistributes its supply among other energy sources while continuing to meet household electricity needs.

[0011] Figure 5 yes Figure 1 A diagram illustrating how an electrical system maintains a constant power supply from the grid while using other energy sources to meet household electricity needs.

[0012] Figure 6 yes Figure 1 A schematic diagram of an electrical system that stores excess electricity generated from other energy sources. Detailed Implementation

[0013] This document describes embodiments. However, it should be understood that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The drawings are not necessarily drawn to scale. Some features may be enlarged or minimized to show details of specific components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art.

[0014] The various features shown and described with reference to any of the accompanying drawings can be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, for a particular application or implementation, various combinations and modifications of features consistent with the teachings of this disclosure may be desired.

[0015] Home-based alternative energy and energy storage systems are becoming increasingly common. They can be used to support household electricity needs. That is, these alternative sources and storage systems can be used in conjunction with or replace grid electricity.

[0016] This disclosure presents an architecture and control strategy for facilitating power transfer between the power grid, various alternative power sources (e.g., electric vehicles, solar panels, home energy storage systems, etc.), and homes or other buildings. The architecture may, for example, include an AC coupling system and an AC coupling controller. The control strategy may, for example, include synchronizing the power source with the grid at zero current, shifting the home's power supply from the grid to at least one of the power sources, redistributing the supply among the power sources, operating the power sources such that the power delivered from the grid remains constant, and transferring excess power generated by one of the power sources to another of the power sources for storage.

[0017] Synchronizing a power source with the grid at zero current involves matching the voltage, frequency, and phase angle of the power source with those of the grid. The connection is initiated at the moment when the phase angle difference between the grid and the power source results in no transient current flow. This is often ideal because it minimizes transient currents that can occur when connecting the power source to the grid, which in turn reduces stress on the electrical system and increases its reliability and lifespan.

[0018] When power sources are connected, the voltage amplitude of the power sources should equal the voltage amplitude of the grid. This ensures that no large current flows due to voltage differences at the connection points. Inverters play a role in voltage matching, especially in power sources that generate DC power (such as solar panels). These inverters can be designed to convert DC to AC and adjust the output voltage to match the grid voltage in response to corresponding commands. Maximum Power Point Tracking (MPPT) allows inverters to maximize the power output from some of the power sources (e.g., solar panels) while converting it to AC by adjusting voltage and current. Despite variations in sunlight and temperature, MPPT allows the power source to operate at its optimal power point. Inverters can further adjust their output voltage to conform to grid standards in response to grid voltage changes by monitoring the grid voltage and dynamically adjusting the output.

[0019] The power source should operate at the same frequency and phase as the grid. Since the grid frequency reflects the balance between supply and demand, connecting a source with a different frequency can lead to fluctuations and instability. Furthermore, connecting a power source when its voltage waveform is 180 degrees out of phase with the grid will result in high inrush current, for example. Inverters can control frequency and phase synchronization. Phase-locked loops (PLLs) can be used to lock onto the grid frequency and phase. A PLL adjusts the inverter's output frequency and phase by changing the switching rate of the inverter's power electronics, ensuring that the output frequency and phase match the grid frequency and phase. Algorithms within the inverter can continuously monitor the grid and adjust the inverter's output to maintain synchronization. This can include dynamic adjustments to handle slight changes in the grid frequency, which may occur due to changes in load or generation elsewhere on the grid.

[0020] The synchronization process begins with detecting the frequency, voltage, and phase angle of the power grid using sensors and electronic measuring circuits. Based on this information, known control algorithms adjust the output of power electronic devices to match the grid. This involves adjusting the timing of switching actions within the inverter or converter to, for example, shift the phase angle of the output power. Once the output is synchronized with the grid in terms of frequency, voltage, and phase angle, a switch or relay can connect the power supply to the grid. Automatic synchronization relays allow this connection to occur at the correct time. After connection, the system continuously monitors grid conditions and adjusts its output to maintain synchronization, thus adapting to any changes in grid frequency or voltage that may occur due to varying loads or generation elsewhere in the system.

[0021] refer to Figure 1 The energy management system 10 includes an AC coupling system 12 and an AC coupling controller 14. The energy management system 10 is arranged to connect to the power grid 16 and other energy sources 18 and supply energy to the home 20. The AC coupling controller 14 communicates with / controls the other energy sources 18, which in this example include an electric vehicle 22, a solar (photovoltaic) system 24 (solar panels, inverter), and a battery (battery energy storage) system 26 (storage cells, inverter). The AC coupling system 12 includes a circuit system 28 electrically connecting each of the other energy sources 18 to the home 20, and a switch 30 configured to selectively connect the power grid 16 to the other energy sources 18 and the home 20.

[0022] When switch 30 is closed, power from grid 16 can flow to home 20. In this example, home 20 requires 10kW and the grid supplies 10kW. In preparing to obtain some of the power from other energy sources 18 to supply to home 20, AC coupling controller 14 synchronizes those other energy sources 18 that will supply power to home 20 with grid 16. As mentioned above, AC coupling controller 14 detects the frequency, voltage, and phase angle of the power from grid 16 via known sensors and electronic measurement circuitry, and commands the inverters of those other energy sources 18 that will supply power to home 20 to adjust the timing of their switching actions to match the frequency, voltage, and phase angle of the power from grid 16.

[0023] refer to Figure 2 Household 20 continues to require 10kW. However, AC coupling controller 14 has reduced the power supply from the grid to 5kW and increased the power supplied from electric vehicle 22 to 5kW—continuing to meet the needs of household 20. That is, when AC coupling controller 14 reduces the power from grid 16 via a command to the converter connected to grid 16, it concurrently increases the power from electric vehicle 22 via a command to electric vehicle 22, so that the total power supplied to household 20 remains constant.

[0024] refer to Figure 3 The AC coupling controller 14 has reduced the power supply from the grid to 0kW and increased the power supplied from the electric vehicle 22 to 10kW: the electric vehicle 22 is fully responsible for meeting the power needs of the household 20.

[0025] refer to Figure 4 The AC coupling controller 14 then redistributes the power supply among the other energy sources 18. The AC coupling controller 14 commands the electric vehicle 22 to reduce its power supply and concurrently commands the solar system 24 to increase its power supply, so that the net power delivered to the home 20 remains constant. In this example, the AC coupling controller 14 commands the electric vehicle 22 to supply 8 kW and the solar system 24 to supply 2 kW, which is sufficient to meet the 10 kW demand from the home 20.

[0026] refer to Figure 5 The AC coupling controller 14 can maintain a constant power supply from the grid 16 regardless of the power demand of household 20, and balance the power demand of household 20 by supplying power from other energy sources 18. In this example, even if household 20 is demanding 10kW, the AC coupling controller 14 commands the converter connected to the grid 16 to continuously supply 1kW. The AC coupling controller 14 compensates for the difference between the household demand and the constant power supplied by the grid 16 via other energy sources 18. The AC coupling controller 14 commands the solar system 24 to supply the difference (e.g., 9kW). In this way, the demand for resources from the grid 16 can be kept constant, and the additional power required by household 20 can be met via other energy sources 18.

[0027] refer to Figure 6 The solar system 24 generates more electricity than the home 20 needs. This can occur during peak sunlight hours. The AC coupling controller 14 instructs the electric vehicle 22 (or battery system 26) to store the excess electricity. Even when other energy sources 18 generate excess electricity, the AC coupling controller 14 maintains a stable power supply from the grid 16. Alternatively, the AC coupling controller 14 can redirect excess electricity from other energy sources 18 back to the grid 16 instead of drawing power from the grid 16.

[0028] The algorithms, methods, or processes disclosed herein may be delivered to or implemented by a computer, controller, or processing device, which may include any dedicated electronic control unit or programmable electronic control unit. Similarly, the algorithms, methods, or processes may be stored in various forms as data and instructions executable by a computer or controller, including but not limited to information permanently stored on a non-writable storage medium such as a read-only memory device and information reproducibly stored on a writable storage medium such as an optical disc, random access memory device, or other magnetic and optical media. The algorithms, methods, or processes may also be implemented as software executable objects. Alternatively, the algorithms, methods, or processes may be implemented, in whole or in part, using suitable hardware components such as application-specific integrated circuits, field-programmable gate arrays, state machines, or other hardware components or devices, or firmware, a combination of hardware and software components.

[0029] While exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms covered by the claims. Furthermore, the language used in this specification is descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of this disclosure. For example, the terms "controller" and "multiple controllers" may be used interchangeably herein, as the functionality of a controller may be distributed across several controllers / modules, all of which may communicate via standard technologies.

[0030] As previously described, features of various embodiments can be combined to form other embodiments of the invention that may not be explicitly described or shown. While various embodiments may have been described as offering advantages or preferences over other embodiments or prior art implementations in terms of one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics can be compromised to achieve desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. Therefore, embodiments described as less desirable than other embodiments or prior art implementations in terms of one or more characteristics are not outside the scope of this disclosure and may be desirable for a particular application.

[0031] According to the present invention, an energy management system is provided, comprising: a circuit system arranged to selectively transmit power among a power grid, a plurality of power sources, and a building; and a controller programmed to switch from supplying power from the power grid to the building to supplying power to the building from one of the power sources, such that during the switch, the rate of power supplied to the building remains constant, and after the switch, the power demand from the building is met via more than one of the power sources, such that the rate of power supplied by the one of the power sources decreases.

[0032] According to an embodiment, the controller is further programmed to meet the power demand from the building via the power grid and the power source, such that as the power demand from the building changes, the rate at which power is supplied from the power grid to the building remains constant and greater than zero.

[0033] According to an embodiment, the controller is further programmed to meet the power demand from the building via the power grid and the power source, such that the rate at which power is supplied from the power source to the building varies as the power demand from the building changes.

[0034] According to an embodiment, the controller is further programmed to transfer the excess power to one of the power sources for storage in response to an excess power generated by another of the power sources exceeding the power demand from the building.

[0035] According to an embodiment, one of the power sources is an electric vehicle.

[0036] According to an embodiment, the power source includes an electric vehicle, a solar panel, or a battery.

[0037] According to the present invention, a method includes: commanding a power grid and at least one of a plurality of power sources to concurrently meet the power demand from a building, such that as the power demand from the building changes, the rate at which the power supplied from the power grid to the building remains constant and greater than zero.

[0038] In one aspect of the invention, the method includes commanding the power grid and at least one of the plurality of power sources to concurrently meet the power demand from the building, such that as the power demand from the building changes, the rate at which power is supplied to the building by the at least one of the power sources changes.

[0039] In one aspect of the invention, the method includes switching from supplying power from the power grid to the building to supplying power from one of the power sources to the building, such that during the switching, the rate of power supplied to the building remains constant.

[0040] In one aspect of the invention, the method includes, after the transition, meeting the power demand from the building via more than one of the power sources, such that the power rate supplied by the one of the power sources is reduced.

[0041] In one aspect of the invention, the method includes, in response to an excess of power generated by another of the power sources exceeding the power demand from the building, transferring the excess power to one of the power sources for storage.

[0042] In one aspect of the invention, the power source includes an electric vehicle, a solar panel, or a battery.

[0043] According to the present invention, an energy management control system is provided, comprising: a controller programmed to meet the power demand from a building via a power grid and an electric vehicle, such that as the power demand from the building changes, the rate at which power is supplied from the power grid to the building remains constant and greater than zero.

[0044] According to an embodiment, the controller is further programmed to meet the power demand from the building via the power grid and the electric vehicle, such that the rate at which the power is supplied from the electric vehicle to the building varies as the power demand from the building changes.

[0045] According to an embodiment, the controller is further programmed to switch from supplying power from the power grid to the building to supplying power from the electric vehicle to the building, such that the rate of power supplied to the building remains constant during the switch.

[0046] According to an embodiment, the controller is further programmed to meet the building's power demand via the electric vehicle and other power sources after the transition, such that the rate of power supplied from the electric vehicle to the building is reduced.

[0047] According to an embodiment, the controller is further programmed to store excess power generated by the other source in the power supply into the electric vehicle.

[0048] According to an embodiment, the other power source includes a solar panel or a battery.

Claims

1. An energy management system, comprising: A circuit system arranged to selectively transmit power among a power grid, multiple power sources, and buildings; as well as A controller is programmed to switch from supplying power to the building from the grid to supplying power to the building from one of the power sources, such that during the switch, the rate of power supplied to the building remains constant, and after the switch, the power demand from the building is met via more than one of the power sources, such that the rate of power supplied by the one of the power sources decreases.

2. The energy management system of claim 1, wherein the controller is further programmed to meet the power demand from the building via the power grid and the power source, such that as the power demand from the building changes, the rate of power supplied from the power grid to the building remains constant and greater than zero.

3. The energy management system of claim 2, wherein the controller is further programmed to meet the power demand from the building via the power grid and the power source, such that the rate at which power is supplied from the power source to the building varies as the power demand from the building changes.

4. The energy management system of claim 1, wherein the controller is further programmed to transfer the excess power to one of the power sources for storage in response to an excess power generated by another of the power sources exceeding the power demand from the building.

5. The energy management system of claim 1, wherein one of the power sources is an electric vehicle.

6. The energy management system of claim 1, wherein the power source includes an electric vehicle, a solar panel, or a battery.

7. A method comprising: The power grid and at least one of a plurality of power sources are ordered to concurrently meet the power demand from the building, such that as the power demand from the building changes, the rate at which the power supplied from the power grid to the building remains constant and greater than zero.

8. The method of claim 7, further comprising commanding the power grid and at least one of the plurality of power sources to concurrently meet the power demand from the building, such that as the power demand from the building changes, the rate at which power is supplied to the building by the at least one of the power sources changes.

9. The method of claim 7, further comprising switching from supplying power to the building from the power grid to supplying power to the building from one of the power sources, such that during the switching, the rate of power supplied to the building remains constant.

10. The method of claim 9, further comprising, after the transition, meeting the power demand from the building via more than one of the power sources, such that the power rate supplied by the one of the power sources is reduced.

11. The method of claim 7, further comprising, in response to an excess of power generated by another of the power sources exceeding the power demand from the building, transferring the excess power to the other of the power sources for storage.

12. The method of claim 7, wherein the power source includes an electric vehicle, a solar panel, or a battery.

13. An energy management and control system, comprising: A controller is programmed to meet the building’s power demand via the power grid and electric vehicles, such that the rate at which the power supplied from the power grid to the building remains constant and greater than zero as the power demand from the building changes.

14. The energy management control system of claim 13, wherein the controller is further programmed to meet the power demand from the building via the power grid and the electric vehicle, such that the rate at which the power supplied by the electric vehicle to the building varies as the power demand from the building changes.

15. The energy management control system of claim 13, wherein the controller is further programmed to switch from supplying power from the grid to the building to supplying power from the electric vehicle to the building, such that during the switch, the rate of power supplied to the building remains constant.

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