The present invention in general relates to solar power conditioning unit (PCU). The present invention in particular relates to an IoT based solar power conditioning unit with dynamic depth of discharge control.
BACKGROUND AND PRIOR ART
[002] The use of solar energy as a source of energy for various types of devices is well known in the art. The solar energy is collected during the daytime via a solar panel electrically connected to the energy storage device. The energy stored in the energy storage device is discharged to power the device.
[003] While solar powered devices work well under a variety of operating conditions, they periodically require service to replace the energy storage device, i.e. battery. A characteristic of an energy storage device, such as a battery, is a finite number of charge cycles. Therefore, the energy storage device has to be periodically replaced, and a long life cycle is more cost effective. At the same time, it may be difficult to service the solar powered device due to the physical location of the device. This problem is solved by power conditioning unit integrated with solar powered device that efficiently distributes energy to prolong the life of the battery.
[004] In general, a power conditioner for a solar power generation system includes an inverter unit as a main circuit, an inverter driver unit, a controller unit, a display unit, an operation unit, and a power supply circuit unit which provides required power to each of these units. The display unit provides respective indications of instantaneous output power and integral power of the power conditioner that are detected and calculated by the controller unit, or an indication of a period power amount which can arbitrarily be initialized by a user.
[005] Reference may be made to the following Prior Arts:
[006] 1725/DEL/2013 describes a solar power conditioning unit with dynamic depth of discharge control comprising a solar panel with main control to charge battery bank through grid power for supplying power to operate load by sharing mechanism controlled by main controller, which automatically measures the power from solar panel and grid and reduces the charging current from the grid proportionally to the solar panel charging current and in case the panel current reduces the grid charging current is automatically increased for charging battery of battery bank.
[007] IN 202114011707 relates to a solar tracker (1) for capturing solar radiation comprising a support (1a), a rotating shaft (1b), and at least one solar panel (1c). The solar tracker (1) also comprises a tracking system (2) capable of operating the rotating shaft (1b) for optimal placement of the solar panel (1c) and a blocking system (3) connected to the rotating shaft (1b). The tracking system (2) comprises a control subsystem (2a) and an operating subsystem (2b) connected to a junction box (7) with a microchip programmed to generate a signal sent by the control system (2a) and to send an unblocking command to the blocking system (3) before allowing the operating system (2b) to move the rotating shaft (1b). Once the solar panel (1c) has reached the optimal position, the blocking system (3) is blocked again.
[008] CN102195523A relates to an intelligent photovoltaic power supply system which comprises a solar panel, a lithium ion battery pack and an intelligent management unit, wherein the intelligent management unit comprises a solar panel interface, a lithium ion battery pack interface, a load interface, an RS485 communication interface, a measuring and sampling circuit, a measuring signal modulating circuit, a dynamic charging and discharging management integrated circuit, an output voltage regulating and stabilizing circuit, a microprocessor and an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor); the measuring and sampling circuit is connected with the solar panel through the solar panel interface; the dynamic charging and discharging management integrated circuit is respectively connected with the measuring and sampling circuit and the output voltage regulating and stabilizing circuit; the measuring signal modulating circuit is connected with the measuring and sampling circuit; and the microprocessor is respectively connected with the RS485 communication interface, the measuring signal modulating circuit, the dynamic charging and discharging management integrated circuit and the MOSFET.
[009] CN201656512U discloses an intelligent solar voltaic power supply deice, which comprises a solar panel, a lithium ion battery group and an intelligent management unit. The intelligent management unit comprises a solar panel interface, a lithium ion battery group interface, a load interface, anRS485 communication interface, a measuring sampling circuit, a measuring signal conditioning circuit, a dynamic charge-discharge management integrated circuit, an output voltage adjusting and stabilizing circuit, a microprocessor and an MOSFET, wherein the measuring sampling circuit is connected with the solar panel through the solar panel interface, the dynamic charge-discharge management integrated circuit is respectively connected with the measuring sampling circuit and the output voltage adjusting and stabilizing circuit, the measuring signal conditioning circuit is connected with the measuring sampling circuit, and the microprocessor irrespectively connected with the RS485 communication interface, the measuring signal conditioning circuit, the dynamic charge-discharge management integrated circuit and the MOSFET.
[010] Reference may be made to an article entitled Comparison of Different Battery Types for Electric Vehicles” by Citation C Iclodean et al 2017 IOP Conf. Ser.: Mater. Sci. Eng. 252 012058 talks about implementation of four different types of batteries for Electric Vehicles on the same model to evaluate the vehicle's autonomy and the efficiency of these battery types on a driving cycle, in real time, digitized by computer simulation.
[011] Reference may be made to an article entitled IOT-BASED BATTERY PARAMETER MONITORING SYSTEM FOR ELECTRIC VEHICLE by Anjali Vekhande Ashish Maske, 2020 IJCRT | Volume 8, Issue 7 July 2020 | ISSN: 2320-2882 talks about of monitoring the performance of the vehicle using IoT techniques is proposed so that the monitoring can be done directly. Based on experimental results, the system is capable to detect degraded battery performance and sends notification messages to the user for further action. In this proposed system an indication of the battery’s voltage, current, and the remaining charge capacity is calculated in a real-time scenario. To monitor these battery parameters, we have developed a data acquisition system by building a PIC based system. Further, data are also displayed on an Android mobile device and are stored in a server database. We have developed a realistic model to create the final product for our proposed system.
[012] Reference may be made to an article entitled IoT-Based Battery Monitoring System for Electric Vehicle by Mohd Helmy et.al, January 2018 International Journal of Engineering & Technology 7(4.31):505-510 talks about the application of Internet-of-things (IoT) in monitoring the performance of electric vehicle battery. It is clear that an electric vehicle totally depends on the source of energy from a battery. However, the amount of energy supplied to the vehicle is decreasing gradually that leads to the performance degradation. This is a major concern for battery manufacture. In this work, the idea of monitoring the performance of the vehicle using IoT techniques is proposed, so that the monitoring can be done directly. The proposed IoT-based battery monitoring system is consists of two major parts i) monitoring device and ii) user interface. Based on experimental results, the system is capable to detect degraded battery performance and sends notification messages to the user for further action.
[013] Reference may be made to an article entitled IoT enabled Electric Vehicle’s Battery Monitoring System by Assad Mohd et.al, The 1st EAI International Conference on Smart Grid Assisted Internet of Things at: Sault Ste. Marie, Canada July 2017 talks about a real-time Battery Monitoring System (BMS) using coulomb counting method for SoC estimation and messaging based MQTT as the communication protocol. The proposed BMS is implemented on hardware platform using appropriate sensing technology, central processor, interfacing devices and the Node-RED environment. An optimization model aimed at maximizing the trade revenue for EVs’ aggregator is presented aimed at enabling the smart charging.
[014] Reference may be made to an article entitled PWM based solar charge controller using IoT by Dr H Ravishankar Kamath June 8, 2021 talks about the system capable of identifying the battery charging conditions under different circumstances whenever needed and can be further upgraded to track other utensils. There are diverse modules utilized in solar charge controller circuit which makes it as an IoT based device like Arduino Ethernet shield (W5100), Atmega328p, solar panel, battery, which is hugely cost-effective and also low energy utilization. The proposed system has been rendered to accord the PWM based solar charge controller and its response by utilizing webservers and the laptops/cell phones.
[015] US Patent No. 6,118,248 describes batteries having a built-in controller to extend the battery service run time. The battery has a built-in controller that includes a converter, which may be capable of operating below the voltage threshold of typical electronic devices. The controller more efficiently regulates the voltage of the electrochemical cell and allows for a controlled discharge or an optimal discharge depth in order to extend the service run time of the battery. This patent does not talk about hybrid charging i.e. (charging from two sources in this built in controller).
[016] US Patent No. 6,163,131 provides single-cell batteries having a built-in controller. The discharge sub-controller preferably optimizes the service run time of the battery by controlling the discharge depth of the cell in order to maximize number of and the efficiency of the charge cycles, and the controller circuit may additionally include a charge sub-controller circuit. The charge sub-controller circuit safely and efficiently controls the charging of the electrochemical cell(s) of the battery in which the controller circuit is integrated. This patent does not talk about hybrid charging.
[017] Publication No. KR20110085719 discloses apparatuses for grid connecting a standalone solar power streetlight system to reduce installation costs and maintenance costs by maintaining depth of discharge and reducing necessary capacity while being charged in a battery. In this patent also only one source of charging is there.
[018] Publication No. JP7038130 is related to a method to elongate a battery service life by controlling discharge depth. A battery is determined in quantity of discharge correspondent to the quantity of daily electric power generation of a solar cell counting the quantity of electric power generation of it with an integrating wattmeter and the battery is discharged to be half as much in capacity as its full capacity when the battery is almost overcharged, whereby the battery can be protected against deterioration and efficiently utilized. This patent does not talk about hybrid charging.
[019] US Patent No. 8,350,521 is directed to systems and methods for control of power charge/discharge from energy storage system. A system sensor and a control computer and/or energy storage unit may be on the customer side. After easy installation on the customer side, a customer need not change the customer's behavior; the system may operate automatically. Another advantage of utilizing the smart charge system may be that the energy storage depth of discharge is reduced resulting a longer working life of the energy storage component. Charging is done with the single source, there is no hybrid charging option.
[020] US Patent No. 6,835,491 provides batteries having a built-in controller to extend the battery service run time. The battery has a built-in controller that includes a converter, which may be capable of operating below the voltage threshold of typical electronic devices. The controller more efficiently regulates the voltage of the electrochemical cell and allows for a controlled discharge or an optimal discharge depth in order to extend the service run time of the battery. This patent does not talk about hybrid charging.
[021] Publication No. WO2007016661 relates to controlling operation of a battery to assure termination of discharge of the battery before damaging the battery. The battery operation is terminated if the extant depth of discharge is within the first range of the maximum depth of discharge or if the battery voltage is within the second range of the minimum battery voltage. This patent does not talk about hybrid charging.
[022] Patent No. 7,834,580 provides a solar powered apparatus that includes a battery, at least one photovoltaic cell and a DC-capable AC appliance. The controller monitors the battery and also controls the second subsystem so as to protect the battery by limiting the depth of discharge. In this patent also there is no grid charging or sharing of charge.
[023] Remote Area Power Supply provides hybrid power conditioner designed to operate with an external AC source to enhance capacity or operate as a standalone unit. In the event the battery capacity drops below 50% Depth of Discharge (DOD) or the site load increases above a preset level, the diesel generator will be automatically started and brought on line in parallel with the inverter to supply the load and/or charge the batteries. Once the batteries have reached a predetermined level of charge the available solar energy will be utilized to reduce the load on the diesel generator which will subsequently be brought off line, stopped provided the site load is not excessive leaving the inverter to again supply the load.
[024] Though there are technologies in prior art to control the charge and discharge of batteries, there still exists a need for more intelligent power charge and discharge system particularly for grid connected photovoltaic system which effectively utilizes the batteries in conjunction with a variable power generator.
[025] Therefore, the present invention proposes a power conditioning unit (PCU) with DOD control that optimally uses the stored charge of a rechargeable battery and optimizes the depth of discharge while discharging the battery under variable load conditions to avoid misuse/ over discharge of the batteries.
OBJECTS OF THE INVENTION
[026] The principal object of the present invention is to provide an IoT based solar power conditioning unit with dynamic depth of discharge control.
[027] Another object of the present invention is to provide a an IoT based solar power conditioning unit with dynamic depth of discharge control which calculates the demand of connected load and based on solar availability supplies the power directly to the load without charging the battery fully to save the battery life.
SUMMARY OF THE INVENTION
[028] According to this invention, there is provided an IoT based solar power conditioning unit with dynamic depth of discharge control. A solar panel is provided with solar charge controller system with memory unit to log the data locally and communication interface to communicate with the IoT based central system. The solar power conditioning unit calculated the demand of connected load and based on solar availability supplies the power directly to the load without charging the battery fully to save the battery life.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[029] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
[030] Figure 1 shows: Block diagram of according to the present invention;
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[031] The present invention provides an IoT based solar power conditioning unit with dynamic depth of discharge control. A solar panel is provided with solar charge controller system with memory unit to log the data locally and communication interface to communicate with the IoT based central system. The solar power conditioning unit calculated the demand of connected load and based on solar availability supplies the power directly to the load without charging the battery fully to save the battery life.
[032] The IoT based central system (1A) with remote data logging which is in communication with the main controller (1). The user tracks and sends the movement commands to motor, by means of sensors for detecting the position of the sun and a power source connected to the motor.
[033] The main controller (1) with communication interface charges battery bank through grid power for supplying power to operate load (5) by sharing mechanism controlled by main controller, wherein the controller measures the power from solar panel (2) and grid (3) and communicates it to the central server (1A). The system reduces the charging current from the grid proportionally to the solar panel charging current, if the panel current reduces for some reason the grid charging current is automatically increased so that battery of battery bank (4) can be charged properly.
[034] The hand held device (6) communicates with the central system so that user may or may not reduce the charging current from the grid proportionally to the solar panel charging current and in case the panel current reduces the grid charging current is automatically increased for charging battery of battery bank.
[035] The central server monitors and compares the state of charge in dynamic load, mains availability, available battery power and solar power, if the solar power is low, the battery power is fed through the load and if the generated solar power is more than or equal to the load, the solar power is fed directly to the load.
[036] The central system monitors the battery status battery and in case battery is discharged beyond a certain limit than the solar power is fed to the battery to charge it.
[037] User can set the reference parameters at the central system using hand held device based upon the battery charging and discharging time. As the battery charging and discharging time decreases over time the central system calculates the percent decay and the reference parameters changes accordingly.
[038] The controller constantly monitors the rate of charging or discharging current of the battery and logs the data in the central system as well as to the local data logger. The central system calculates depth of discharge of the battery. The central system also sets low battery cut off point according to the depth of discharge of the battery. This process increases the battery life and maintains the battery gravity. Once the set threshold is achieved during the operation, the battery discharge is stopped and mains recovery is enabled, if grid is available. The system is then transferred to mains mode and charging battery takes place using power supplied by both grid and solar. The charging takes place in the sharing mode that is the grid charging current is reduced proportionally to the solar power. As the solar charging current increases the current from grid is reduced and ultimately the battery is charged only from solar energy and grid charging current reduces to zero.
[039] The battery AH measurement is done with the help of coulomb counting method. In this method the current signal is integrated over time to accumulate the ampere hour. The AH measurement is also done separately for charging from solar power and from grid charging. The discharging current is used to calculate the AH drawn from the battery.
[040] The battery depth of discharge is controlled dynamically depending on the history of the battery status.
[041] The battery state of charge is calculated based on the Ah input from solar and grid and Ah output from battery by load. Relying on the net Ah available in the battery the battery state is determined.
[042] One imperative factor for the battery health is the equalization process in which the battery is charged to a higher boost voltage so that the imbalance in the battery at cell level is reduced and the sulphation from the cell plates is removed. When the periodic equalization is given to the battery the overall health of the battery improves and it helps in enhancing the battery life.
[043] The PCU once powered up continuously reads the charging and discharging profile of the battery and keeps log of all the information in the central system, critical information such as battery voltage, battery net AH, battery state of charge , temperature etc. which are periodically updated in the memory. The real time clock is maintained, to maintain the periodic equalization.
[044] The PCU also generates the load profile of the system on periodic basis; typical average load profile is stored in the memory and based on everyday reading average daily load is calculated based on this the battery charging is controlled. The mains power is used to charge the battery only up to a level.
[045] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

WE CLAIM

1. An IoT based solar power conditioning unit with dynamic depth of discharge control comprising:
? a solar panel (2) with solar charge controller (1) system; memory unit for data logging locally and communication interface to communicate with the IoT based central system characterized in that wherein the said solar power conditioning unit calculated the demand of connected load and based on solar availability supplies the power directly to the load (5) without charging the battery fully to save the battery (4) life;
? an IoT based central system (1A) with remote data logging which is in communication with the main controller characterized in that the user tracks and sends the movement commands to motor, by means of sensors for detecting the position of the sun and a power source connected to the motor;
? main controller (1) with communication interface to charge battery bank (4) through grid (3) power for supplying power to operate load by sharing mechanism controlled by main controller, wherein the controller measures the power from solar panel and grid and communicates it to the central server;
? hand held device (6) communicating with the central system so that user may or may not reduce the charging current from the grid proportionally to the solar panel charging current and in case the panel current reduces the grid charging current is automatically increased for charging battery of battery bank (4).
2. The IoT based solar power conditioning unit with dynamic depth of discharge control as claimed in claim 1, wherein the central server monitors and compares the state of charge in dynamic load, mains availability, available battery power and solar power, if the solar power is low, the battery power is fed through the load and if the generated solar power is more than or equal to the load, the solar power is fed directly to the load.
3. The IoT based solar power conditioning unit with dynamic depth of discharge control as claimed in claim 1, wherein the central system monitors the battery status battery and in case battery is discharged beyond a certain limit than the solar power is fed to the battery to charge it.
4. The IoT based solar power conditioning unit with dynamic depth of discharge control as claimed in claim 1, wherein user can set the reference parameters at the central system using hand held device based upon the battery charging and discharging time.
5. The IoT based solar power conditioning unit with dynamic depth of discharge control as claimed in claim 1, wherein as the battery charging and discharging time decreases over time the central system calculates the percent decay and the reference parameters changes accordingly.