Solar energy is changed into a current by using PV (photovoltaic) cells. Throughout the daytime, the energy keep within the batteries is used to run the pump for agriculture. This project aims at developing a controlled charging mechanism providing protections for overcharge condition, deep discharge condition and below voltage state of the battery. This planned system is comprised of a solar water pump that reduces the utilization of inverters etc, so reducing the price of the project. Using the charge-controlled mechanism; the pump is operated at four totally different time slots. Difficulties like shifting the pump ON/OFF manually are overcome using this project.
There exists an intrinsic real clock (RTC) that keeps chasing the time and so switches ON/OFF the pump consequently. MOSFET’s are utilized by the charge controller as power semiconductor switches to confirm cutting off the load (DC Pump) in conditions like low battery or overload, while, the junction transistor is employed to bypass the solar power to a dummy load whereas the battery gets absolutely charged. So the battery is shielded from obtaining overcharged.
Solar Water Pump Control Power Saving Applications
The solar water pump control with four different time slots for power saving applications project can be built with a Battery, MOSFET, Photovoltaic cells/solar cells, Power supply block, Voltage regulator (lm 7805), Microcontroller (at89s52/at89c51), DS1307 RTC, Matrix keypad, Relay, Seven segment, BC547, Resistors and Capacitors.
An electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy. The battery has become a common power source for many household, robotics, and industrial applications. Larger batteries provide standby power for telephone exchanges or computer data centers.
MOSFET (IRF 510)
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a device used for amplifying or switching electronic signals. The basic principle of the device a voltage on the oxide-insulated gate electrode can induce a conducting channel between the two other contacts called source and drain. It is by far the most common transistor in both digital and analog circuits, though the bipolar junction transistor was at one time much more common.
BC547 (NPN –Transistor)
The BC547 transistor is an NPN Epitaxial Silicon Transistor. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors. The ratio of two currents (Ic/Ib) is called the DC Current Gain of the device and is given the symbol of hfe or nowadays Beta, (ß).
The 1N4148 is a standard small signal silicon diode used in signal processing. The 1N4148 is generally available in a DO-35 glass package and is very useful at high frequencies with a reverse recovery time of no more than 4ns. This permits rectification and detection of radio frequency signals very effectively, as long as their amplitude is above the forward conduction threshold of silicon (around 0.7V) or the diode is biased.
Photovoltaic (PV) cells are made of special materials called semiconductors such as silicon, which is currently the most commonly used. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. PV cells also all have one or more electric fields that act to force electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current, and by placing metal contacts on the top and bottom of the PV cell, we can draw that current off to use externally.
Expose the cell to light, and the energy from each photon (light particle) hitting the silicon, will liberate an electron and a corresponding hole. If this happens within range of the electric field’s influence, the electrons will be sent to the N side and the holes to the Pone, resulting in yet further disruption of electrical neutrality. This flow of electrons is current; the electrical field in the cell causes a voltage and the product of these two is power
It is a smaller computer; it has on-chip RAM, ROM, I/O ports. The main features of this microcontroller include the following.
- Compatible with MCS®-51 Products
- 8K Bytes of In-System Programmable (ISP)
- Flash memory endurance: 10,000 Write/Erase Cycles
- 4.0V to 5.5V Operating Range
- Fully Static Operation: 0 Hz to 33 MH
- z256 x 8-bit Internal RAM
- 32 Programmable I/O Lines
- Three 16-bit Timer/Counters
- Eight Interrupt Sources
- Full Duplex UART Serial Channel
- Interrupt Recovery from Power-down Mode
- Watchdog TimerDual Data Pointer
It is an electromagnetic switch, used to control the electrical devices. Copper core magnetic flux plays the main role here.
- The relay’s switch connections are usually labeled COM, NC, and NO:
- COM = Common, always connect to this; it is the moving part of the itch.
- NC = Normally Closed, COM is connected to this when the relay coil is off.
- NO = Normally Open, COM is connected to this when the relay coil is on
Relay Driver (ULN 2003)
- ULN2003 is a high voltage and high current Darlington transistor array
- It consists of seven NPN Darlington pairs that feature high-voltage outputs with common-cathode Clamp diode for switching inductive loads.
- The ULN2003 has a 2.7kW series base resistor for each Darlington pair for operation directly with TTL or 5V CMOS devices.
- Current, Output Max:500mA
- Voltage, Input Max:5V
- Voltage, Output Max:50V
A keypad is a set of buttons arranged in a block or “pad” which usually bear digits, symbols and usually a complete set of alphabetical letters. If it mostly contains numbers then it can also be called a numeric keypad. In order to detect which key is pressed from the matrix, the row lines are to be made low one by one and read the columns. Assume that if Row1 is made low, then read the columns. If any of the keys in row1 is pressed then correspondingly the column 1will give low that is if the second key is pressed in Row1, then column2 will give low.
The RTC chip is a specialized chip that just keeps track of time runs on a battery and keeps time for you even when there is a power outage!Using an RTC, you can keep track of long timelines, even if you reprogram your microcontroller or disconnect it from USB or a power plug.The RTC we’ll be using is the DS1307. It’s low cost, easy to solder, and can run for years on a very small coin cell.
Features of DS1307
- Real-time clock counts seconds, minutes, hours, date of month, month, day of week and year with leap year compensation valid up to 2100
- 56 bytes nonvolatile RAM for general data storage
- 2-wire interface (I2C)
- Automatic power fail detect
- Consumes less than 500 nA for battery back-up at 25’C
BC547 (NPN –Transistor)
The BC547 transistor is an NPN Epitaxial Silicon Transistor.It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.The ratio of two currents (Ic/Ib) is called the DC Current Gain of the device and is given the symbol of hfe or nowadays Beta, (ß).
Liquid Crystal Display (LCD)
Most common LCDs connected to the microcontrollers are 16×2 and 20×2 displays. This means 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively. The standard is referred to as HD44780U, which refers to the controller chip which receives data from an external source (and communicates directly with the LCD.
This proposed system can be built with a real-time clock (RTC) that is interfaced to an 8051 family microcontroller. While the fixed time equals the real time, then microcontroller gives the signal to the equivalent relay to switch ON the load, and then another signal to switch off as programmed by the user. Several ON/OFF times access is the biggest benefit of this project.
A matrix keypad helps to enter different time slots. A seven segment display is interfaced to the microcontroller to show time. In this project, a solar panel is used to charge a battery. A set of op-amps are used as comparators to constantly monitor panel load current, voltage etc.
Signals are also provided with the help of a green LED for completely charged battery while a set of red LEDs to specify undercharged, filled to capacity and deep discharge condition. As power semiconductor switch, charge controller also uses MOSFET to make the sure cutting off the load in low battery condition. A transistor is used to avoid the solar energy to a dummy load while the battery gets fully charged. This guard the battery from receiving overcharged.
In addition, this project can be improved by interfacing a GSM modem to the obtainable project so that the whole control of the load can be done by sending an SMS to the control unit.
This is all about solar water pump control with four different time slots for power saving applications. For any queries regarding this concept or to implement any solar-based projects please give your feedback by commenting in the comment section below. Here is a question for you, what is the main function of a solar panel?