The energy crisis in India is one of the major problems. Transmission of an effective power, as well as power utilization of this power, is one of the major problems. The power factor is the hidden factor, which causes a great loss of electrical energy and also harms electrical tools. The power factor of changing load can be calculated and rewarded using the static method. So we need to find out the reasons of power loss and extend the power system. Due to industrialization, the employ of inductive load boosts and therefore power system losses its efficiency. So we need to improve the power factor with a suitable method. Nowadays, the embedded system is very much popular and most of the product are developed with microcontroller based embedded technology.
What is a Power Factor?
Power factor is defined as the ratio of real power to apparent power. Where real power is the time integral of the instantaneous power measured over a full period and the apparent power is simply the product of the RMS voltage and RMS current measured over the entire period.
The time lag between the zero voltage pulse and zero current pulse duly generated by suitable operational amplifier circuits are fed to two interrupt pins of the microcontroller where the program takes over to actuate an appropriate number of relays at its output for bringing shunt capacitors into the load circuit to get the power factor till it reaches 0.95.
APFC for Industrial Power Use to Minimize Penalty
The hardware and software requirements of APFC for industrial power users to minimize penalty include Microcontroller (AT89S52/AT89C51), Relay, Relay driver, LCD, Current transformer, Inductive load, Shunt Capacitor, Push buttons, LED, 1N4007/1N4148, Resistor, Capacitor.
Keil an ARMS Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.
Compilers are programs used to convert a High-Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors.
i.e the programs written in one of the HLL like ‘C’ will compile the code to run on the system for a particular processor like x86 (underlying microprocessor in the computer).
For example, compilers for DOS platform is different from the Compilers for Unix platform So if one wants to define a compiler then the compiler is a program that translates source code into object code.
Need of APFC
Power factor also changes as a purpose of the load necessities. Maintaining a consistent power factor is difficult due to the utility of fixed capacitors. The automatic difference is the compensation to outfit the load necessities. The benefits of APFC include the following
- Constantly high power factor under variable loads
- Low energy utilization by dropping losses
- Mechanically activates appropriate capacitor steps for constant power factor
- Reduce the power factor penalty
- The load can be sensed and monitored continuously
It is a smaller computer, it has on-chip RAM, ROM, I/O ports. The features of AT89S51/52 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 MHz
- 256 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 Timer
- Dual Data Pointer
It is an electromagnetic switch, used to control the electrical devices. Copper core, magnetic flux plays the main role here.
The relay switches 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
Quad Voltage Comparator LM339
- Wide single supply voltage range 2.0VDC TO 36VDC or dual supplies ±1.0VDC to ±18VDC
- Very low supply current drain (0.8㎃) independent of supply voltage (1.0㎽/comparator at 5.0VDC)
- Low input biasing current 25㎁
- Low input offset current ±5㎁ and offset voltage
- Input common-mode voltage range includes ground
- Differential input voltage range equal to the power supply voltage
- Low output 250㎷ at 4㎃ saturation voltage
- Output voltage compatible with TTL, DTL, ECL, MOS and CMOS logic system
- Moisture Sensitivity Level 3
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.
The main goal of this project is designed to reduce penalties for manufacturing units using APFC (automatic power factor correction) unit.
In this project, two zero crossing detectors are employed for sensing zero crossing of current and voltage. The time pause between the zero-voltage pulse as well as the zero-current pulse is accordingly produced by appropriate op-amp (operational amplifier) circuits in comparator mode are fed to two interrupt pins of a microcontroller. It shows time lag on an LCD.
The program takes over to activate a suitable number of relays from its o/p to carry shunt capacitors into the load circuit to obtain the power factor until it achieves near unity. The interfacing of relays and capacitor bank can be done with the microcontroller using a relay driver. This project uses an 8051 family microcontroller.
In addition, this project can be improved with TCS (thyristor control switches) in its place of relay control to keep away from contact pitting frequently encountered by controlling of capacitors due to high inrush current.
From the above information, finally, we can conclude that this technique is used to beat power losses due to small power factors related with common domestic and small industrial units. By connecting appropriate capacitors to the circuit the power factor can be improved and the value becomes closer to unity, therefore reducing line losses and enhancing the efficiency of an industry. Furthermore, any doubts regarding this concept or to implement any electrical projects, please give your feedback by commenting in the comment section below. Here is a question for you, what are the applications of power factor?