System for generating, storing, and managing renewable energy power

Abstract

A system for generating, storing, and managing renewable energy power, the system comprising a power generation system that utilizes renewable energy and communicates with each other, an energy storage device, and a control system, the control system including a load prediction module configured to predict the required power supply to a load connected to the system, and a weather prediction module configured to predict the energy output of the power generation system, the control system monitoring the level of the energy storage device, the output of the power generation system, and the required power of the load, predicting the level of the energy storage device based on the predicted power supply to the load, and configured to reduce the supply of electrical energy to the load when the level of the energy storage device is predicted to fall below a predetermined level.

Description

Technical Field

[0001] The present invention relates to a system for generating, storing, and managing renewable energy power. In a preferred embodiment of the present invention, the system is configured to supply power to industrial equipment at a remote site. The system may be stand alone or connected to an existing electrical grid.

Background Art

[0002] An electrical network at a remote industrial site, particularly important equipment such as a well pump, requires a highly reliable power supply. For such applications, diesel generators, gas generators, or hybrid generators are commonly used, but they require a physical fuel supply that must be transported to the remote site, which can be expensive and dangerous under certain conditions. Also, it is desirable to reduce the use of fossil fuels. Furthermore, diesel generators do not have a load control system and tend to operate in a supply surplus state, resulting in a decrease in system efficiency.

[0003] Furthermore, to ensure redundancy, a remote power supply network is equipped with multiple generators, further increasing the capital cost for installing such a system.

[0004] There is a need to address the above problems and / or at least provide useful alternatives.

Summary of the Invention

[0005] According to one aspect of the present invention, a system for generating, storing, and managing renewable energy power is provided. The system includes a power generation system that utilizes renewable energy and communicates with each other, an energy storage device, and a control system. The control system includes a load prediction module configured to predict the required power supply to a load connected to the system, and a weather prediction module configured to predict the energy output of the power generation system. The control system monitors the level of the energy storage device, the output of the power generation system, and the required power of the load, predicts the level of the energy storage device based on the expected power supply to the load, and is configured to reduce the supply of electrical energy to the load when the level of the energy storage device is predicted to fall below a predetermined level.

[0006] According to a preferred embodiment of the present invention, the power generation system includes a plurality of photovoltaic cells or wind turbines.

[0007] Preferably, the power generation system includes a plurality of photovoltaic (PV) cells grouped into at least one array, and the array communicates with a corresponding battery house including a plurality of battery cells for storing electrical energy from the PV cells. Preferably, the array includes at least one inverter for converting the generated power into alternating current power.

[0008] In a preferred embodiment, the battery house has an inverter-charger that converts input power from alternating current to direct current and output power from direct current to alternating current, and a DC-DC converter between the inverter-charger and the battery that changes the voltage of the input power to a level sufficient to charge the battery.

[0009] Preferably, the inverter charger has a short-time surge rating. The control system may be formed of a plurality of similar control modules each disposed in a respective battery house. Preferably, the control system includes a predictive controller having a first programmable logic controller (PLC) and an electric controller having a second PLC.

[0010] Preferably, the electric controller includes a software sequence that manages the startup of the inverter charger, and the software sequence enables the voltage and frequency of the inverter charger to be slowly increased to achieve a soft start of the highly inductive load device.

[0011] The predictive controller may be configured to isolate the battery to prevent overcharging. Preferably, the predictive controller receives past weather data from a remote computer terminal via a modem and an antenna. The predictive controller may receive a control instruction from a remote control computer terminal.

Brief Description of the Drawings

[0012] To more easily understand the present invention, here, only one embodiment will be described by way of example with reference to the accompanying drawings.

[0013]

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Mode for Carrying Out the Invention

[0014] FIG. 1 shows a system 100 for generating, storing, and managing renewable energy power. The system 100 is configured to supply electrical power to an industrial site in a remote location. In a preferred embodiment, the system 100 includes industrial grade equipment suitable for a harsh remote environment and resistant to high temperatures.

[0015] The system 100 includes a power generation system 110 that utilizes renewable energy and communicates with each other, an energy storage device 120, and a control system 130.

[0016] The control system 130 includes a load prediction module in the form of an electrical controller 134 configured to predict the required power supply to a load 140 connected to the system 100, and a weather prediction module 132 configured to predict the availability of solar energy and the energy output of the power generation system 110.

[0017] The control system 130 monitors the level of the energy storage device 120, the output of the power generation system 110, and the required power of the load 140, predicts the level of the energy storage device 120 based on the predicted power supply to the load 140, and is configured to reduce the supply of electrical energy to the load 140 when the level of the energy storage device 120 is predicted to fall below a predetermined level.

[0018] <Power Generation System and Energy Storage Device> In the illustrated embodiment, the power generation system 110 is a solar power generation facility and includes three separate solar arrays 110a, 110b, 110c of photovoltaic (PV) cells. It will be understood that the power generation system 110 may be similarly configured to utilize power from a wind or tidal energy source. It will also be understood that the number of solar arrays 110 can be varied according to the power demand of the industrial site and can include one or more arrays.

[0019] Figure 2 shows an actual physical embodiment of the system 100. It can be seen that each PV array 110 includes a plurality of solar panels 112, and more specifically, will be described below with reference to FIGS. 3 to 6. In this embodiment, two energy storage devices 120 are illustrated, and an inverter 113 is disposed between the power solar array 110 and the energy storage device 120, and the energy storage device 120 is also referred to here as a battery house.

[0020] Each battery house 120 includes a plurality of battery cells, and the battery cells can be of any commercially available type such as lithium-ion or lead-acid. Although two battery houses are shown, a system having three or more battery houses is also possible.

[0021] As shown in FIG. 5, the solar panels 112 within each array 110a, 110b, 110c are coupled together in a hinged or concertina arrangement so as to be foldable with respect to each other in a generally packed configuration (FIG. 3), and are then deployed and spread out in a deployed configuration as shown in FIGS. 4 and 5 and fixed to the ground. A ground-mounted solar solution is utilized that is safer, more cost-effective, and faster to deploy than conventional single-axis solar trackers and similar solar tracking solutions.

[0022] Advantageously, each solar array can be quickly installed with a minimal amount of base infrastructure. Also, as shown in FIG. 6, each array 110 can accommodate terrain level variations of up to 350 mm, or panel angle variations of plus / minus 5 degrees, reducing the need for extensive site preparation prior to installation of the system 100.

[0023] FIG. 2 shows a specific commercial embodiment corresponding to a remote location in the state of Queensland, Australia. In this embodiment, the array 110 includes up to 90 solar panels mounted on a rack and is optimized for the 540 - 550 W module class of the utility-scale solar industry.

[0024] In the embodiment of FIG. 2, modeling and report data indicate that the load varies between 8.6 kW and 36.1 kW throughout the year. To meet the energy demand, a solar plant component with 540 solar panels at 540 watts per panel and a total capacity of 292 kW is selected. These solar panels are divided into six groups, each group consisting of 90 × 540 W panels. Each group has six strings of 15 × 540 W panels, and each group feeds one 50 kW PV inverter 113, which incorporates 6 × MPP trackers (one per string).

[0025] The site layout is desirably optimized to minimize the required amount of AC (alternating current) cable wiring and cable trays. The DC (direct current) connection points from the group will be at the center of the array set and will supply the PV inverter 113 located on the south side of the array.

[0026] System 100 has two interconnected energy storage devices 120a, 120b, also known as battery houses. Each battery house 120a, 120b has the battery section and the electrical / control section incorporated in the same way as much as possible, but in reality, there will be a lead battery house and a slave battery house. Each battery house will have two control systems, a Hybrid Controller and a Load Management and Weather Forecasting Controller.

[0027] Each battery house 120 is a modular unit, and multiple battery houses can be connected in parallel for greater power requirements and redundancy. The modular system design enables the system described here to be quickly mobilized and demobilized at the customer site.

[0028] In the embodiment described here, two battery banks 120 are arranged and interconnected. Each has 192 × 2V × 2000Ah cells and each is 768kWh in total (1536kWh with a total of 384 batteries). Each battery bank is to be charged by six PV inverters supplying a common bus, and each battery bank is charged from this common bus.

[0029] As shown in FIG. 1, the system is AC-coupled and incorporates an inverter-charger 121 and a DC-DC converter 123 to manage battery charging and system voltage. The DC system voltage is nominally 384V at the battery bank and 600V at the DC link in the inverter / charger system. By using an inverter-charger and a DC-DC converter, the system can accommodate different battery configurations, handle stacking and unstacking of batteries within the battery house 120, and cope with failures of individual battery cells. The voltage of the battery bank can range from 30V to 800V.

[0030] To enable the system 100 to be used with industrial equipment having a high inductive load, such as large transformers, large pumps, and crushers, the inverter-charger has a short time surge rating and operates with the voltage and frequency rising slowly during startup. This will be described in more detail below.

[0031] FIG. 7 shows an example of the battery house 120. The battery house 120 has a frame 122, a door 124 with a ventilation section, a maintenance hatch 126, and a heat extractor 128 in the form of a turbine vent. The space 129 shown with the door removed is reserved for the hardware of the control system.

[0032] <Overview of the Electrical System> FIG. 8 shows a schematic diagram of an electrical system 150 for the system 100. In this embodiment, two power generation systems 110a, 110b and two energy storage devices 120a, 120b are shown.

[0033] Each power generation system 110 has three PV subsystems 112 in accordance with the above description. Each energy storage device 120 has, as described above, an inverter 121, a battery subsystem 125, and a DC-DC converter 123 (not shown). Energy storage devices 120a, 120b are connected to the microgrid subsystem 136. Power generation systems 110, 110b are connected to the switchgear subsystem 138. The switchgear subsystem 138 is connected to a distribution subsystem 139 that connects system 100 to the load 140.

[0034] The control system 130 may be a separate part or may be integrally formed within the battery house 120. A separate control system may be provided for each battery house 120, or all the battery houses may be controlled by a single control system. In a preferred embodiment, each battery house 120 can have a separate control system 130 for redundancy, but it will be understood that a single battery house 120 may include the control system 130 and function as a master controller.

[0035] The control system 130 monitors and adjusts the PV harvesting from the power generation system 110 and the battery charging process, and synchronizes the two battery houses 120 with each other. The loads in demand are supplied by a system that charges the battery. In an off-grid application, the controller defines the system set point and operates in a voltage source mode with droop control.

[0036] The control system 130 includes a predictive controller 132 with a first programmable logic controller (PLC) and an electrical controller 134 with a second PLC. It will be understood that these controllers may be separate units or may be part of a single unit.

[0037] The prediction controller 132 receives weather data, uses this data to predict the availability of solar energy, and thereby predicts the energy output of the power generation system. This data is received from the modem and antenna 135. The prediction controller 132 can be configured to prevent overcharging when a period during which the energy output is expected to exceed the demand is anticipated. This is done by changing the charging voltage. The electrical controller follows a predetermined battery charging curve / regime according to the state of charge.

[0038] Furthermore, if it is desired to override the programmed system operation, an operation instruction can be received from a remote terminal. In a preferred embodiment, the system 100 can be integrated into a user's remote monitoring system such as a supervisory, control and data acquisition (SCADA) system to enable remote control and monitoring from a remote location.

[0039] The control system 130 includes a software sequence that provides a black start operation and manages the startup of the inverter - charger 121. This sequence enables the voltage and frequency of the inverter - charger 121 to be slowly increased to provide a soft start to high - inductive load equipment. This makes it possible to energize the magnetic field of the transformer and enables the system to have the ability to drive the transformer. Conventional types of inverters used in solar / battery installations cannot energize the transformer because when a high load is detected, they consider this as a short - circuit and disable the operation. By enabling the energization of the transformer, the system 100 can convert a 400V standard output to a voltage in the range of 11 - 33kV. It will be understood that the system 100 can supply power to a single transformer or multiple transformers, thereby enabling the switching of the output power and the operation of multiple different machines.

[0040] <Energy Management System> In the prior art energy management systems used in solar / battery facilities, it was difficult to obtain a stable reference, so it was difficult to supply power to industrial equipment not connected to the power grid. Connecting to a larger grid can solve such problems, but this is impossible in remote areas. This system can solve this problem because the control system 130, particularly the inverters 121 / 113, monitors the load and functions as a grid-forming inverter that sets the frequency of the network.

[0041] As described above, the control system 130 predicts the charge level of the battery house 120. This is done through the calculation of the instantaneous battery energy in kWh from the electric controller 134, weather data, the system battery capacity, and the load on the system monitored by the electric controller 134.

[0042] In the illustrated embodiment, the electrical load 140 includes a plurality of pumps, and each pump can be assigned a priority value according to the importance of its operation. During use, the control system 130, particularly the electric controller 134, provides a load management function by shifting, as necessary, the pumps performing low-priority operations to a low-power mode to conserve the energy stored in the battery. This can occur when the state of charge of the battery falls below a predetermined threshold and there is no immediate prospect of replenishment. For example, during dark periods of the day without power generation, when the electric controller 134 detects a low state of charge (SOC) and dynamically indicates that the SOC will fall below a critical level (identified during commissioning) by the time power generation is expected, the electric controller 134 sends a command to the PLC (not shown) that controls the pumps to change their operating mode to a manual mode with a low-speed setpoint. This can also occur when the SOC falls below the critical level during any period regardless of energy generation. When the predicted SOC falls below a predetermined depth of discharge (DOD) setpoint, a DOD alarm is set. The predicted energy deficit below the DOD setpoint is calculated.

[0043] The load schedule provides the system with the data necessary for the load limiting system to schedule a reduction in the pump speed demand. The data is stored and displayed as a table of load information such as priorities, valid flags, and what the low-power loads are. The load limiting module calculates the energy deficit and the time until that deficit is reached, and creates an estimated energy reduction by adding load reduction to each predicted time slot.

[0044] Figure 9 graphically shows seven days of predicted data and how the estimated battery energy (SOC) 160 changes, showing the variable estimated solar power 162, the estimated battery energy 164 due to load limiting, and the minimum battery level 166.

[0045] Figure 10 shows the prediction data in more detail, indicating an energy shortage 168 based on the time from the start until reaching a low SOC / DOD 170 and the point in time when the energy satisfies the lower limit 172.

[0046] Load reduction is performed by reducing the power of each load (pump), and the load reduction is calculated for each load. The priority of the loads can be set from the interface of the electric controller 134 and can also be overwritten via an external computer terminal or network. The display of the controller 134 can notify the user that the load schedule priority is remotely controlled.

[0047] When the load limit software knows the energy shortage, it performs calculations, subtracts the reduction amount of the lowest-priority load, i.e., the load of the lowest-priority pump, from the shortage amount, and conducts a test again. If there is still a shortage, the program continues until the shortage disappears or the end of the schedule is reached. If the end is reached with a remaining shortage, an alarm is issued. Since the program is constantly evaluating, the pump is returned to full speed when the load limit program knows the high predicted battery energy. The pumps are commanded in order from the highest priority to the lowest priority.

[0048] Several instruments and status signals are directly wired to the control system 130 to provide monitoring of the status of the battery enclosure and equipment. The average temperature and voltage are calculated for each battery house 120, and a high alarm is generated when any battery temperature deviates from the desired set value. When any battery voltage deviates from the desired set value, high and low alarms are generated. This function is necessary for monitoring battery performance and serves as a trigger for additional logging. When any PLC detects a signal status that deviates from the normal operating parameters, such as deviating from 0 - 10V / 4 - 20mA or a wire break, a transmitter failure alarm is generated.

[0049] System 100 further includes a revenue-grade power meter for accurately measuring the renewable energy used by the load at the site, thereby enabling the user to claim carbon credits. Such a system also enables the owner / operator of System 100 to bill the user for the energy provided.

[0050] When configuring System 100 for a particular site, design tools are used to determine the required size and / or number of the power generation system and the energy storage device. The design tools do this by analyzing past weather data over a predetermined period, such as 20 years. Based on the past weather data, predictions can be made regarding the availability of renewable energy, such as wind or solar power, thereby providing information for sizing the power generation system. Predictions of the load can also be made based on past load data.

[0051] Taking into account the weather data and the load data, particularly the size, timing, and reliability, the required size of the energy storage system can be determined so that the availability of a given system can reliably meet a given level of reliability.

[0052] <Battery Management System> The control system 130 is equipped with a multi-purpose battery management system that can accommodate various battery solutions, such as lead-acid batteries and lithium-ion batteries. The battery management system supervises the charging process and prioritizes optimizing the battery health for long-term performance. The battery management system is flexible and can be adapted to new battery technologies as needed.

[0053] The battery management system functions to maintain the energy storage device 120 within its functional range to ensure power supply to the load 140 for system stability. When the state of charge exceeds 100%, an alarm is issued. When the state of charge is below 100%, if available, the energy storage device 120 can be charged from the power generation system. When the state of charge is below 40%, another alarm is issued, and when the state of charge is below 35%, the system shuts down. When multiple energy storage devices 120 are used, it will be understood that each can be controlled individually.

[0054] A four-stage charging process including four stages of bulk mode, absorption mode, float mode, and equalisation mode can be adopted. These modes are designed and optimized based on parameters such as charging efficiency, implementation difficulty, and the impact on the state-of-health (SOH), which is a quantitative expression of the essential battery life, with the basic aim of recharging the battery bank to a high state of charge. In the case of lead-acid batteries, the process is as follows.

[0055] In the bulk mode, the battery is charged at the maximum charging current by gradually increasing the charging voltage until the maximum charging current is reached. The purpose of this mode is to effectively charge the battery at the nominal charging current, but since it may lead to gas generation and corrosion of the lead plates, charging at this high current for a long time should be avoided.

[0056] When the charging voltage reaches the float voltage, the mode changes to the absorption mode, the charging voltage is kept constant, and the charging current gradually decreases to minimize the effects of gas generation and lead plate corrosion. When a certain time has elapsed or the tapered current charging falls below the threshold, the next mode is entered. When using a four-stage charging algorithm, the next mode varies depending on whether equal charging is required.

[0057] When equalizing charging is not required, at the completion of absorption charging, the system switches to float mode charging, and the charging voltage is continuously maintained at the float voltage (trickle charging). Therefore, in this mode, the battery charge state is kept constant during float charging. This is important because lead-acid batteries cannot be left discharged for a long time and can be used to top-up the energy storage device 120 after not being used for a long time.

[0058] When equalizing charging is required, upon completion of absorption charging, the system switches to equalizing mode charging. Equalizing charging sets the charging voltage one step higher than the float voltage and performs overcharging for a short period. The gas generated during this time is sufficient to decompose the sulfation that adheres to the lead-acid battery plates and reduces the charge storage efficiency. This enables individual cells to be fully charged and keeps all cells within the allowable range of voltage balance.

[0059] The equalization mode is not required for all charge cycles but is an important function for lead-acid batteries. The system determines when the equalization mode is needed based on the following allowable conditions: · The previous equalization was performed more than 28 days ago · The available sunlight on the day is expected to be sufficient to complete equalizing charging

[0060] When the logical AND of both these conditions becomes TRUE, the equalization required flag is set. Based on these conditions, the system determines whether equalizing charging can be performed based on the provided weather forecast. If sufficient sunlight is predicted for the day, the system starts equalizing charging after the absorption charging stage is completed.

[0061] If insufficient solar irradiation is predicted, the sufficient solar availability tag is not displayed, the equalization mode is postponed for 24 hours, and checked again the next day. If the equalization charge is not completed within one day, it continues on each subsequent day until a total of 8 hours of equalization charge is completed. When 8 hours of equalization charge is completed, the equalization charge completion tag is displayed and the equalization charge counter is reset to 28 days.

[0062] To those skilled in the art, many modifications of the above embodiments will be apparent without departing from the scope of the present invention. For example, although system 100 has been described as an off-grid application, it can also be connected to an existing power distribution network.

[0063] Throughout this specification and the following claims, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", are to be interpreted as including the recited integer or step or group of integers or steps and not as excluding any other integer or step or group of integers or steps.

[0064] References in this specification to prior publications (or information derived therefrom) or known matters shall not be construed as an admission or acknowledgment that such prior publication (or information derived therefrom) or known matter forms part of the common general knowledge in the field to which this specification pertains, or as any form of suggestion thereof.

Claims

1. A system for generating, storing, and managing renewable energy power, the system comprising a power generation system that utilizes renewable energy, an energy storage device, and a control system, which communicate with each other, the control system including a load prediction module configured to predict the necessary power supply to a load connected to the system, and a weather prediction module configured to predict the energy output of the power generation system, the control system monitoring the level of the energy storage device, the output of the power generation system, and the required power of the load, predicting the level of the energy storage device based on the expected power supply to the load, and being configured to reduce the supply of electrical energy to the load when the level of the energy storage device is predicted to fall below a predetermined level. System.

2. The power generation system includes a plurality of photovoltaic cells or wind turbines. The system according to claim 1.

3. The power generation system includes a plurality of photovoltaic (PV) cells grouped into at least one array, the array communicating with a corresponding battery house including a plurality of battery cells for storing electrical energy from the PV cells. The system according to claim 1.

4. The array includes at least one inverter for converting the generated power into alternating current power. The system according to claim 3.

5. The battery house has an inverter - charger for converting input power from alternating current to direct current and output power from direct current to alternating current, and a DC - DC converter between the inverter - charger and the battery for changing the voltage of the input power to a level sufficient to charge the battery. The system according to claim 3 or 4.

6. The inverter - charger has a short - time surge rating. The system according to claim 5.

7. The control system is formed of a plurality of similar control modules each disposed in a respective battery house. The system according to any one of claims 3 to 6.

8. The control system includes a prediction controller comprising a first programmable logic controller (PLC), and an electric controller comprising a second PLC. The system according to any one of the preceding claims.

9. When dependent on claim 5, the electric controller includes a software sequence for managing the startup of the inverter charger, and the software sequence enables the voltage and frequency of the inverter charger to be slowly increased to achieve a soft start of high inductive load equipment. The system according to claim 8.

10. The prediction controller is configured to isolate the battery to prevent overcharging. The system according to claim 8.

11. The prediction controller receives past weather data from a remote computer terminal via a modem and an antenna. The system according to claim 10.

12. The prediction controller receives a control instruction from a remote control computer terminal. The system according to claim 10 or 11.

13. Each said PLC includes an electric drive system. The system according to any one of claims 8 to 12.

14. Each said PLC includes a variable frequency drive. The system according to claim 13.

15. A method of configuring a system for generating, storing, and managing renewable energy power, comprising: (a) analyzing past weather data; (b) analyzing past load data; (c) specifying the size and / or number of power generation and energy storage devices to provide a predetermined power availability at an industrial load site; (d) The method according to claim 15, the system according to any one of claims 1 to 14, method.

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