Renewable energy power generation, storage and management system

Abstract

A renewable energy power generation, storage, and management system includes a power generation system utilizing renewable energy, an energy storage device, and a control system, which communicate with each other, where the control system includes: a load prediction module configured to predict a power source required by a load connected to the system; and a weather prediction module configured to predict an energy output of the power generation system wherein the control system is configured to monitor a level of the energy storage device, an output of the power generation system, and a power requirement of the load, and to predict the level of the energy storage device based on an expected power supply of the load, and reduce the supply of electrical energy to the load when the predicted level of the energy storage device falls below a predetermined level.

Description

Technical Field

[0001] The present invention relates to a renewable energy generation, storage and management system. In a preferred embodiment of the present invention, the system is configured to supply power to industrial devices at a remote site. The system can be independent or connected to an existing power grid. Background Art

[0002] Grids at remote industrial sites require a reliable power source, especially for critical installations such as well pumps. Diesel, gas or hybrid generators are often used for such applications, but they require a physical fuel supply that must be transported to the remote site, which can be expensive and unsafe in some cases. It is also desirable to reduce the use of fossil fuels. In addition, diesel generators lack a load control management system and tend to operate in an oversupplied state, reducing system efficiency.

[0003] Additionally, multiple generators are provided in the remote power supply network for redundancy, further increasing the capital cost of installing such systems.

[0004] There is a need to address the above problems, and / or at least provide a useful alternative. Summary of the invention

[0005] According to one aspect of the present invention, there is provided a renewable energy power generation, storage and management system, comprising a power generation system utilizing renewable energy, an energy storage device and a control system, each of which communicates with each other, wherein the control system comprises:

[0006] a load prediction module configured to predict power required by loads connected to the system; and

[0007] a weather prediction module configured to predict energy output of the power generation system;

[0008] The control system is configured as follows:

[0009] monitoring the level of the energy storage device, the output of the power generation system and the power requirements of the load, and forecasting the level of the energy storage device based on the expected power supply of the load;

[0010] When it is predicted that the level of the energy storage device will drop below a predetermined level, the supply of electrical energy to the load is reduced.

[0011] According to a preferred embodiment of the present invention, the power generation system comprises a plurality of photovoltaic cells or wind turbines.

[0012] Preferably, the power generation system comprises a plurality of photovoltaic (PV) cells grouped into at least one array, the or each array being in communication with a respective battery compartment comprising a plurality of battery cells for storing electrical energy from the PV cells. Preferably, the or each array comprises at least one inverter to convert the generated electricity into AC electricity.

[0013] In a preferred embodiment, each battery compartment has

[0014] an inverter charger for converting input power from AC to DC and converting output power from DC to AC, and

[0015] A DC-DC converter, located between the inverter charger and the battery, is used to modify the voltage of the input power to a level sufficient to charge the battery.

[0016] Preferably, the inverter charger has a short-time surge rating. The control system may be formed by a plurality of similar control modules, each of which is disposed in a respective battery compartment. Preferably, the control system comprises a predictive controller and an electrical controller, the predictive controller comprising a first programmable logic controller (PLC), and the electrical controller comprising a second PLC.

[0017] Preferably, the electrical controller includes a software sequence for managing the start-up of the inverter charger, said sequence allowing the voltage and frequency of the inverter charger to be slowly ramped up, providing a soft start for highly inductive load devices.

[0018] The forecast controller may be configured to isolate the battery to prevent overcharging. Preferably, the forecast controller receives historical weather data from a remote computer terminal via a modem and an antenna. The forecast controller may receive control instructions from a remote control computer terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order that the present invention may be more readily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0020] Figure 1 is a schematic diagram of a renewable energy generation, storage and management system according to a preferred embodiment of the present invention;

[0021] Figure 2 is a perspective view of a preferred embodiment of the system;

[0022] Figure 3 It is a side view of the solar array on the system, with the PV panels of the array arranged in a stack;

[0023] Figure 4 yes Figure 3 A plan view of a solar array of FIG. 1 , with the PV panels in an expanded arrangement;

[0024] Figure 5 is a side view of a solar cell array in a first use condition;

[0025] Figure 6 is a side view of a solar cell array in another use condition;

[0026] Figure 7 is a perspective view of a battery compartment of the system;

[0027] Figure 8 is a system diagram of the electrical system for said system;

[0028] Fig. 9 is a graphical view of the load management system; and

[0029] Fig.10 is another view of the load management system. DETAILED DESCRIPTION

[0030] Renewable energy generation, storage and management system 100 Figure 1 As shown. The system 100 is configured to provide power to an industrial site at a remote location. In a preferred embodiment, the system 100 includes an industrial-grade device suitable for harsh remote environments and capable of withstanding high temperatures.

[0031] The system 100 includes a power generation system 110 using renewable energy, an energy storage device 120 and a control system 130 , each of which communicates with each other.

[0032] The control system 130 includes a load prediction module in the form of an electrical controller 134 and configured to predict the power supply required by the 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.

[0033] The control system 130 is configured to monitor the level of the energy storage device 120, the output of the power generation system 110, and the power demand of the load 140, and predict the level of the energy storage device 120 based on the expected power supply of the load 140, and reduce the supply of power to the load 140 when the level of the energy storage device 120 is predicted to drop below a predetermined level.

[0034] Power generation systems and energy storage devices

[0035] In the illustrated embodiment, the power generation system 110 is a solar device and includes three separate solar arrays 110a, 110b, 110c composed of photovoltaic (PV) cells. It should be understood that the power generation system 110 can be similarly configured to utilize electricity from wind or tidal energy. It will also be understood that the number of solar arrays 110 can vary depending on the power needs of the industrial site and can include one or more arrays.

[0036] Figure 2 1 shows an actual physical embodiment of the system 100. It can be seen that each photovoltaic array 110 includes a plurality of solar panels 112, which will be referred to below. Figures 3 to 6 In this embodiment, two energy storage devices 120 are shown, and an inverter 113 is disposed between the solar cell array 110 and the energy storage device 120 , which is referred to herein as a battery house.

[0037] Each battery compartment 120 includes a plurality of battery cells, which may be of any commercially available type, such as lithium-ion, lead-acid, etc. Although two battery compartments are shown, systems having more than two battery compartments are possible.

[0038] like Figure 5 As shown, the solar panels 112 in each array 110a, 110b, 110c are connected together in a hinged or concertina arrangement so as to be able to form a compact configuration ( Figure 3 ) roughly fold over each other and then expand to Figure 4 and Figure 5 The solar tracker is shown in the deployed configuration and secured to the ground. Using a ground mounted solar solution is safer, more cost effective and faster to deploy than traditional single axis solar trackers or similar solar tracking solutions.

[0039] Advantageously, each solar array can be installed quickly and requires minimal infrastructure. Figure 6 As shown, each array 110 can accommodate terrain variations of up to 350 mm or positive and negative panel angle variations of 5 degrees, thereby reducing the need for extensive site preparation prior to installing the system 100.

[0040] Figure 2A specific commercial embodiment is shown corresponding to a remote area in Queensland, Australia. In this embodiment, the array 110 includes up to 90 solar panels mounted on a rack and is optimized for the 540-550W module class for the utility-scale solar industry.

[0041] exist Figure 2 In the example, the modeling and reporting data show that the load varies between 8.6kW and 36.1kW throughout the year. To meet the energy needs, the following solar power plant components were selected - 540 540-watt solar panels with a total capacity of 292kW. These solar panels will be divided into 6 groups, each consisting of 90x 540W panels. Each group has six 15x540W panel strings, each group powers a 50kW photovoltaic inverter 113, which contains 6 MPP trackers (one for each string).

[0042] The site layout is preferably optimized to minimize AC cabling and cable tray requirements. The DC connection point from these groups will be located in the center of the array group and will power the PV inverter 113 which will be located in the south of the array.

[0043] The system 100 has two interconnected energy storage devices 120a, 120b, also referred to as battery rooms. Each battery room 120a, 120b contains as many identical battery sections and electrical / control sections as possible, but in practice there will be a lead and slave battery room. Each battery room will have 2 control systems: a hybrid controller and a load management and weather forecast controller.

[0044] Each battery compartment 120 is a modular unit and multiple battery compartments can be connected in parallel to meet greater power requirements and redundancy. The modular system design allows the system described herein to be quickly mobilized and demobilized at a customer site.

[0045] In the embodiment described herein, there are 2 battery banks 120 arranged and interconnected. Each battery bank has 192 2V x 2000Ah cells, with a total capacity of 768kWh per battery bank (1536kWh from 384 cells). Each battery bank will be charged by 6 photovoltaic inverters connected to a common bus from which the battery banks are charged.

[0046] like Figure 1As shown, the system is AC coupled and contains 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 pack and nominally 600V at the DC link in the inverter / charger system. Using the inverter charger and DC-DC converter, the system can accommodate different battery arrangements, allowing stacking and unstacking of batteries in the battery compartment 120, as well as failure of individual battery cells. The battery pack voltage may range from 30V to 800V.

[0047] To allow system 100 to be used with industrial devices having highly inductive loads, such as large transformers or large pumps or crushers, the inverter charger has a short time surge rating and operates with a slow ramping up voltage and frequency during startup, as will be described in further detail below.

[0048] Figure 7 An example battery room 120 is shown in FIG. The battery room 120 has a frame 122, a door 124 with a vented portion, a maintenance hatch 126, and a heat sink 128 in the form of a turbine vent. As shown, with the door removed, space 129 is reserved for control system hardware.

[0049] Electrical System Overview

[0050] Figure 8 A schematic diagram of an electrical system 150 of the system 100 is shown in FIG. In this embodiment, two power generation systems 110a, 110b and two energy storage devices 120a, 120b are shown.

[0051] According to the above description, each power generation system 110 has three PV subsystems 112. As described above, each energy storage device 120 has an inverter 121, a battery subsystem 125, and a DC-DC converter 123 (not shown). The energy storage devices 120a, 120b are connected to a microgrid subsystem 136. The power generation systems 110, 110b are connected to a switchgear subsystem 138. The switchgear subsystem 138 is connected to a distribution subsystem 139, which connects the system 100 to a load 140.

[0052] The control system 130 may be a separate component or integrally formed within the battery compartment 120. A separate control system may be provided for each battery compartment 120, or a single control system may control all of the battery compartments. In a preferred embodiment, each battery compartment 120 may have a separate control system 130 for redundancy, but it should be understood that a single battery compartment 120 may contain a control system 130 and act as a master controller.

[0053] The control system 130 will monitor and regulate the PV collection from the power generation system 110 and the battery charging process and synchronize the two battery chambers 120 with each other. The system will power the required loads and charge the batteries. In off-grid applications, the controller will define the system set points and operate in voltage source mode with droop control.

[0054] The control system 130 includes a predictive controller 132, which includes a first programmable logic controller (PLC), and an electrical controller 134, which includes a second PLC. It should be understood that the controllers may be separate units or part of a single unit.

[0055] The forecast controller 132 receives weather data and uses this data to predict the availability of solar energy and thus the energy output of the power generation system. This data is received from the modem and antenna 135. The forecast controller 132 can be configured to prevent overcharging during periods when the expected energy output exceeds demand. This is achieved by changing the charging voltage. Depending on the state of charge, the electrical controller follows a predetermined battery charging curve / regime.

[0056] In addition, when it is necessary to override the programmed system operation, operating instructions can be received from the remote terminal. In a preferred embodiment, the system 100 can be integrated into the user's remote monitoring system, such as a supervisory control and data acquisition (SCADA) system, to allow control and monitoring from a remote location.

[0057] The control system 130 provides black start operation and includes a software sequence for managing the startup of the inverter charger 121, which allows the voltage and frequency of the inverter charger 121 to slowly rise, providing a soft start for highly inductive load devices. This allows the magnetic field of the transformer to be energized, thereby providing the system with the ability to drive the transformer. Inverters previously used with solar / battery equipment cannot power the transformer because they detect the high load and think it is a short circuit, thereby stopping operation. By being able to energize the transformer, the system 100 can convert a standard output of 400v to a voltage in the range of 11 to 33kv. It should be understood that the system 100 can power a single transformer or multiple transformers, allowing switching of output power and operation of multiple different machines.

[0058] Energy Management System

[0059] Prior art energy management systems used with solar / battery equipment have had difficulty powering industrial installations that are not connected to the grid due to the difficulty in obtaining a stable reference. Connecting to a larger grid can solve such problems, but this is not possible in remote areas. The present system can solve this problem because the control system 130 (particularly the inverter 121 / 113) monitors the load and acts as a grid-forming inverter that sets the network frequency.

[0060] As described above, the control system 130 will predict the charge level of the battery compartment 120. This is accomplished by calculating the instantaneous battery energy (in kWh) from the electrical controller 134, weather data, system battery capacity, and system load, as monitored from the electrical controller 134.

[0061] In the illustrated embodiment, the electrical load 140 includes a plurality of pumps, each of which may be assigned a priority value based on the criticality of its operation. In use, the control system 130, and in particular the electrical controller 134, will provide a load management function by switching pumps with lower priority operations to a low power mode to conserve energy stored in the battery when needed. This may occur if the battery state of charge drops below a predetermined threshold and is not expected to be replenished soon. For example, if the electrical controller 134 detects a low state of charge (SOC) during a dark period of the day when no power is generated, and dynamically indicates that the SOC will drop below a critical level (determined during commissioning) when power generation is expected, the controller 134 will send a command to the PLC controlling the pump (not shown) to change its operating mode to a manual mode with a low speed set point. This will also occur if the SOC drops below a critical level at any time, regardless of energy generation. When the predicted SOC drops below a given DOD (depth of discharge) set point, a DOD alarm will be set. The amount of predicted energy below the DOD set point (deficit) is calculated.

[0062] Load scheduling provides the system with the data needed to schedule pump speed reduction requests for the load-shed system. The data is stored and displayed in the form of a table of load information such as priority, enable flags and their low power loads. The load shedding module will calculate the energy deficit and the time until the deficit is reached by adding the load reduction to each forecast time slot to create an estimated energy reduction.

[0063] Fig. 9 The seven-day forecast data is graphically presented, along with how the estimated battery energy (SOC) 160 changes, including variable estimated solar energy 162 , estimated battery energy with load shedding 164 , and minimum battery level 166 .

[0064] Fig.10A closer look at the forecast data is shown, showing the energy deficit 168 based on the time from start to reach low SOC / DOD 170 and the point at which the energy reaches a low limit 172 .

[0065] Load reduction is performed by reducing the power to each load (pump) and the load reduction is calculated for each load. The load priority can be set from an interface on the electrical controller 134 and can also be overwritten via an external computer terminal or network. A display on the controller 134 can inform the user that the load scheduling priority is remotely controlled.

[0066] When the load shedding software sees an energy deficit, it does a calculation and subtracts the load reduction for the lowest priority load (i.e. lowest priority pump) from the deficit and then tests again. If there is still a deficit, the program will continue until there is no deficit or the end of the program is reached. If there is a residual deficit at the end, an alarm will sound. As the program continues to evaluate, as the load shedding program sees a higher projected battery energy, the pumps will return to full speed. Pumps are prioritized from highest to lowest.

[0067] Several instrumentation and status signals will be hardwired directly into the control system 130 to provide monitoring of the battery enclosure and device status. The average temperature and voltage of each battery compartment 120 will be calculated and a high alarm will be issued if any battery temperature exceeds the desired set point. High and low alarms will be generated if any battery voltage exceeds the desired set point. This feature is required for battery performance monitoring and will trigger additional historical records. If the PLC detects a signal status outside of normal operating parameters, such as 0-10V / 4-20mA or a broken wire, a transmitter fault alarm will be generated.

[0068] The system 100 also includes a revenue-grade meter for accurately measuring the renewable energy used by the site load, thereby allowing users to apply for carbon credits. Such a system can also allow the owner-operator of the system 100 to charge users for the energy provided.

[0069] When configuring the system 100 for a particular site, a design tool is used to determine the required size and / or number of power generation systems and energy storage devices. The design tool does this by analyzing historical weather data over a predetermined time period (e.g., 20 years). Based on the historical weather data, the availability of renewable energy sources such as wind or solar can be predicted, which provides information for sizing the power generation system. Load forecasting can also be performed based on historical load data.

[0070] Taking into account weather and load data, in particular taking into account magnitude, timing and reliability, the required size of the energy storage system can be determined to ensure that the predetermined system availability is met with a predetermined confidence level.

[0071] Battery Management System

[0072] The control system 130 has a versatile battery management system that can accommodate a variety of battery solutions, such as lead acid and lithium ion. The battery management system oversees the charging process and prioritizes optimizing battery health for long-term performance. The battery management system is flexible and can adapt to new battery technologies as needed.

[0073] The battery management system is used to keep the energy storage device 120 within its functional range to ensure power availability to the load 140 for system stability. If the state of charge is greater than 100%, an alarm is issued. In the case of a state of charge below 100%, the energy storage device 120 can be charged from the power generation system if available. When the state of charge is below 40%, another alarm is issued, and if the state of charge is below 35%, the system is shut down. It should be understood that if multiple energy storage devices 120 are used, each can be controlled separately.

[0074] A four-stage charging process can be used, including the following stages, bulk mode, absorption mode, float mode and equalisation mode. These modes are designed and optimized based on parameters such as charging efficiency, difficulty of implementation and impact on the state of health (SOH), to recharge the battery pack to a high state of charge, which is essentially a quantitative representation of the battery life. For lead-acid batteries, the process is as follows.

[0075] In batch mode, the battery is charged at the maximum charge current by gradually increasing the charge voltage until the maximum charge current is reached. The purpose of this mode is to charge the battery efficiently at the nominal charge current, however, it should not be charged at this high current for a long time as this may cause gassing and lead plate corrosion.

[0076] Once the charge voltage reaches the float voltage, the mode switches to absorption mode, where the charge voltage is held constant and the charge current is gradually reduced to minimize the effects of gassing and lead corrosion. After a certain amount of time or a gradually decreasing current charge drops below a threshold, the next mode will occur. When using the 4-stage charging algorithm, the next mode will vary depending on whether equalization charging is required.

[0077] When equalization charging is not required, the system will switch to floating mode charging when absorption charging is completed. In floating mode, the charging voltage will be continuously maintained at the floating voltage (trickle charging). Therefore, in this mode, the battery's state of charge remains consistent throughout the floating charging process, which is important for lead-acid batteries because they cannot be discharged for a long time and can be used to charge the energy storage device 120 after a long period of inactivity.

[0078] When equalization charging is required, the system switches to equalization mode charging when absorption charging is completed. Equalization charging sets the charging voltage to a step above the float voltage to overcharge it for a short period of time, during which the gas generated is sufficient to decompose the sulphate deposited on the lead-acid plates, which reduces storage efficiency. This also enables all individual cells to be fully charged, ensuring that all cells remain within the voltage balance tolerance.

[0079] Balance mode is not required for every charge cycle, but is still an important function required for lead-acid batteries. The system will determine when balance mode is required based on the following permissions:

[0080] The previous equalization was performed 28 days ago, and

[0081] The solar energy available on that day is expected to be sufficient to complete the equalization charge

[0082] When the logical AND of these two conditions becomes true, the equalization required flag will be set. Based on these conditions, the system will determine whether equalization charging can be performed based on the weather forecast provided. If sufficient solar insolation is predicted for the day, the system will begin equalization charging after the absorption charging phase is completed.

[0083] If insufficient solar radiation is forecast, no sufficient solar availability tag will be issued and the equalization mode will be delayed for 24 hours and rechecked the next day. If equalization charging is not completed in one day, it will continue on each following day until a total of eight hours of equalization is completed. After eight hours of equalization are completed, the equalization complete tag will be issued and the equalization counter will be reset to 28 days.

[0084] Many modifications to the above-described embodiments will be apparent to those skilled in the art without departing from the scope of the invention.For example, although the system 100 is described as an off-grid application, it may also be connected to an existing power grid.

[0085] In this specification and the claims that follow, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or steps or groups of integers but not the exclusion of any other integer or steps or groups of integers.

[0086] Any prior publication (or information derived therefrom) or any known matter mentioned in this specification is not, and should not be taken as, an admission or any form of implication that the prior publication (or information derived therefrom) or known matter constitutes part of the common general knowledge in the field to which this specification relates.

Claims

1. A renewable energy generation, storage and management system, comprising a power generation system utilizing renewable energy, an energy storage device and a control system, each of which communicates with each other, wherein: The control system comprises: a load prediction module configured to predict power required by a load connected to the system; and a weather prediction module configured to predict energy output of the power generation system; Wherein, the control system is configured as follows: monitoring the level of the energy storage device, the output of the power generation system, and the power requirement of the load, and predicting the level of the energy storage device based on the expected power supply of the load; and When it is predicted that the level of the energy storage device will drop below a predetermined level, the supply of electrical energy to the load is reduced.

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

3. The system according to claim 1, wherein: The power generation system comprises a plurality of photovoltaic (PV) cells grouped into at least one array, the or each array being in communication with a respective battery compartment comprising a plurality of battery cells for storing electrical energy from the photovoltaic cells.

4. The system according to claim 3, wherein: The or each array comprises at least one inverter for converting the generated electricity into AC power.

5. The system according to claim 3 or 4, wherein: Each battery compartment has an inverter charger for converting input power from AC to DC and converting output power from DC to AC, and A DC-DC converter, located between the inverter charger and the battery, is used to modify the voltage of the input power to a level sufficient to charge the battery.

6. The system according to claim 5, wherein: The inverter charger has a short-duration surge rating.

7. A system according to any one of claims 3 to 6, wherein: The control system is formed by a plurality of similar control modules, each control module being arranged in a corresponding battery compartment.

8. The system according to any one of claims 1 to 7, wherein: The control system includes a predictive controller including a first programmable logic controller (PLC) and an electrical controller including a second PLC.

9. The system of claim 8 when based on claim 5, wherein: The electrical controller includes a software sequence for managing the start-up of the inverter charger, the sequence allowing the voltage and frequency of the inverter charger to be slowly ramped up to provide a soft start of a highly inductive load device.

10. The system according to claim 8, wherein: The predictive controller is configured to isolate the battery to prevent overcharging.

11. The system according to claim 10, wherein: The forecast controller receives historical weather data from a remote computer terminal via a modem and an antenna.

12. The system according to claim 10 or 11, wherein: The prediction controller receives control instructions from a remote control computer terminal.

13. A system according to any one of claims 8 to 12, wherein: Each of the programmable logic controllers includes an electric drive system.

14. The system according to claim 13, wherein: Each of the programmable logic controllers includes a variable frequency drive.

15. A method of configuring a renewable energy generation, storage and management system comprising the steps of: a. Analyze historical weather data; b. Analyze historical load data; and c. Determine the size and / or quantity of power generation and storage devices to provide a predetermined power availability to the industrial load site; d. The method according to claim 15, the system according to any one of claims 1 to 14.

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