Project Documentation. Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit

Transcription

1 Project Documentation Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit

2 A Few Project Examples Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit Solar Powered Led Street Light with Auto Intensity Control Street Light that Glows on Detecting Vehicle Movement Three Phase Fault Analysis with Auto Reset on Temporary Fault and Permanent Trip Otherwise Ultra Fast Acting Electronic Circuit Breaker War Field Spying Robot with Night Vision Wireless Camera by Android Applications IOT based Home Automation Over the Cloud Four Quadrant DC Motor Speed Control with Microcontroller RFID based Paid Car Parking ACPWM Control for Induction Motor Arduino based Underground Cable Fault Detection Auto Metro Train to Shuttle between Stations Density Based Traffic Signal with Remote Override in Emergency Detecting Power Grid Synchronization Failure on Sensing Frequency or Voltage Beyond Acceptable Range GSM based Monthly Electricity Energy Meter Billing and SMS upon GSM with User Programmable Number Features together with Onsite Display to the user Wireless Power Transfer Home automation under WiFi through Android apps from any smart phone Prepaid Energy Meter with GSM Interface Pick N Place Robotic Arm and Movement Controlled by Android Wirelessly Wireless Home Appliance like Fan Speed Control using RF Communication Over Voltage- Under Voltage Protection Thyristor Controlled Power for Induction Motor Cyclo Converter using Thyristors Three Phase Fault Analysis with Auto Reset on Temporary Fault and Permanent Trip Otherwise High Voltage DC up to 2KV From AC by Using Diode and Capacitors in Voltage Multiplier Circuit Solar Power Charge Controller Speed Checker to Detect Rash Driving on Highways Smooth Start of a Single Phase Induction Motor Android Phone Speech Recognition Sensed Voice Operated Notice Board Display Automatic Wireless Health Monitoring System in Hospitals for Patients Closed Loop Control for a Brushless DC Motor to Run at the Exactly Entered Speed Wireless Electronic Notice Board by GSM With User Programmable Number Features Solar Powered Auto Irrigation System Smooth Start of a Single Phase Induction Motor Hidden Active Cell Phone Detector

3 Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit Project Summary - Automatic Power Factor Compensation (APFC) is achieved by engaging number of shunt capacitor in parallel to inductive loads. The time lag between zero voltage and zero current is fed to the microcontroller (8051 family) that drives relays from its output for bringing shunt capacitors automatically across the load till the power factor reaches 0.9. Abstract The project is designed to minimize penalty for industrial units by using automatic power factor correction unit. Power factor is defined as the ratio of real power to apparent power. This definition is often mathematically represented as KW/KVA, where the numerator is the active (real) power and the denominator is the (active + reactive) or apparent power. Reactive power is the non working power generated by the magnetic and inductive loads, to generate magnetic flux. The increase in reactive power increases the apparent power, so the power factor also decreases. Having low power factor, the industry needs more energy to meet its demand, so the efficiency decreases. In this proposed system the time lag between the zero voltage pulse and zero current pulse duly generated by suitable operational amplifier circuits in comparator mode are fed to two interrupt pins of the microcontroller. It displays the time lag between the current and voltage on an LCD. The program takes over to actuate appropriate number of relays from its output to bring shunt capacitors into the load circuit to get the power factor till it reaches near unity. The microcontroller used in the project belongs to 8051 family. Further the project can be enhanced by using thyristor control switches instead of relay control to avoid contact pitting often encountered by switching of capacitors due to high in rush current. Block Diagram Breakout Boards Used Refer individual data sheets 1. AC to DC Power Supply 5V Push Button Motherboard 3. LCD Module for 4 Bit Input 4. Zero Voltage Sensing Module 5. Power Factor Correction Module 6. 5 Load Relay Driver Module

4 1. AC to DC Power Supply 5V Needs 12v input ac to deliver unfiltered DC,unregulated 12 volt DC(Ur DC) by on board bridge regulator and filtering capacitors and regulated 5 volt DC through heat sink mounted LM7805 regulator the output of which terminated at specified connectors ( P dc ) for maximum of about 300mA. Unfiltered DC being pulsating DC, available, can be used for waveform comparison whenever required. Physical Image Layout Diagram Circuit

5 Push Button Motherboard 8051 motherboard with all standard connections having all 4 ports open ended mounted with a set of additional 8 push button switches S1 to 8 for imposing logic inputs manually. Use female to female jumper wires for interfacing to peripherals. Requires 5 volt Dc Physical Image Layout Diagram Circuit

6 3. LCD Module for 4 Bit Input 16 character 2 line LCD display with adjustable intensity provision by 10K PRESET suitable for both 4 bit (D4 to D7 & controls at J1) alternatively 8 bit (D0 to D7 at J2) data input & 3 control input at J3. It needs additionally control circuit board using microcontroller and other accessories to complete specific projects.needs 5vDC Physical Image Layout Diagram Circuit

7 4. Zero Voltage Sensing Module Needs pulsating DC of about 12v & 5V DC to develop 5 V narrow pulses at zero cross of waveform using dual OP AMP LM358. Having dual OP AMPs it can be used both for voltage and current as well (ZVS1,ZVS2). Physical Image Layout Diagram Circuit

8 5. Power Factor Correction Module On board arrangements available with a CT (Current Transformer) duly wired with selection switches (SLIDE SWITCH) for using external linear load like lamp, inductive load like ac motor or a ballast, together to carry out experiments on power factor with different loads(not included). Requires mains utility supply and peripherals like a ballast, or an induction motor and a mains lamp etc. It needs additionally a control circuit board using microcontroller, relay board and accessories like pf correction capacitors to complete the project. Physical Image Layout Diagram Circuit

9 6. 5 Load Relay Driver Module 5 nos of 12 volt relay( Relay 1 to 5) with open ended NO-C-NC ( N=Normally, NC=Normally closed, C= Common) contact terminals and all common terminal are shorted fed to another connector as Input for any external 6A load to get activated upon small signal from any microcontroller /Arduino.Requires 12V dc and very few sensing power from 5 signal sources Physical Image Circuit Layout Diagram

10 Project wiring diagram with Breakout boards interconnections

11 Connections Required to Complete the Project

12 Complete Circuit Diagram

13 Circuit Explanation: Connections The output of power supply which is 5v DC is connected to the 40th pin of microcontroller and gnd to the 20th pin of microcontroller. Port 0.1 to 0.4 are connected to Pin 1 to 4 of relay driver IC ULN2003. Port 0.5 to 0.7 are connected to Pin 4,5 and 6 of LCD display. Port 2.0 to 2.7 are connected to Pin 7 to 14 of data pins of LCD display. Port 3.2 is connected to output of the Op-Amp (A) LM339. Port 3.3 is connected to output of OP-Amp (B) LM339. Working The output of the regulator 7805 is given to the Microcontroller 40th pin. The pulsating dc is fed to 3.3K and 1K Resistors. The unregulated voltage is fed to output which is 5v is fed to 40th pin of Microcontroller. The output of the 7812 regulator is 12v and is fed to op-amp. In this circuit we have another bridge rectifier it gives an output as pulsating dc corresponding to the current flowing across the load. The LCD display is connected to corresponding pins. Relay driver drive s relay s and the contacts of relays switch ON the shunt capacitors. Description of ZVS and ZCS: In order to generate ZVS (Zero Voltage Sensing) pulses first we need to step down the supply voltage to 12V and then it is converted into pulsating D.C. Then with the help of potential divider the voltage of 3 V is taken, which is given to a comparator LM339 part A. The comparator generates the zero crossing pluses by comparing this pulsating D.C with a constant D.C of 0.6 V forward voltage drop across a silicon diode. Similarly for ZCS (Zero Current Sense) the voltage drop proportional to the load current across a resistor of 10R/10W is taken and is stepped up by a CT to feed to a bridge rectifier to generate pulsating dc for the comparator to develop ZCS as explained above like ZVS. The zero crossing pulses from a pulsating D.C both for ZVS and ZCS are shown in the figure below.

14 This circuit consists of DC power supply unit, zero voltage crossing detectors, Microcontroller, LCD display, Relays and Capacitor bank Load circuit. Let us see how it operates. The required DC power supply for Microcontroller and other peripherals is supplied by the DC power supply. For the calculation of the power factor by the Microcontroller we need digitized voltage and current signals. The voltage signal from the mains is taken and it is converted into pulsating DC by bridge rectifier and is given to a comparator which generates the digital voltage signal. Similarly the current signal is converted into the voltage signal by taking the voltage drop of the load current across a resistor of 10 ohms. This A.C signal is again converted into the digital signal as done for the voltage signal. Power Factor Test Layout: An arrangement with supply source 230v, one lamp, 2 numbers low value resistors of 10R/10W for measuring current,a choke are all connected in series.the lamp in series is required as the circuit uses a standard 40 watt fluorescent ballast as inductor and it can not be connected direct to mains as it is not designed for that. Capacitors are required to be connected in parallel through relay contacts across the inductor to improve power factor. While the SW2 switch is off, the ballast / choke acts as an inductor and same current will flow in R1 and R2. A CT is used the primary side of one terminal is connected to the common point of R1and R2 and the other point of the CT goes to the common point of a SPDT S1 switch. While the SPDT switch is moved to right then the CT primary connects across R2 and the voltage drop proportional to the current is sensed by it to develop increased voltage at its primary. This voltage is given to the current sensing circuit that uses a bridge rectifier for getting corresponding DC for further processing. While the SPDT switch is moved to left then the CT connects across R1 and the voltage drop proportional to the current is sensed by it to develop increased voltage at its primary. While no capacitors are switched the voltage drop across R1 and R2 are same. This voltage drop is proportional to lagging current. Thus the primary voltage from the CT provides lagging current reference to the current sensing circuit. The microcontroller based control circuit thus receives zero current reference and compares with the zero voltage reference for calculating the power factor based on their time difference. Microcontroller output develops logic high for appropriate no. of port pins to feed to ULN2003 the relay driver to switch on capacitors through its NO contacts to come in parallel to the inductive load that is the choke. So depending on the time difference required number of relays are switched on, thereby switching additional capacitors till the power factor is near unity. Once the capacitors are switched on the R2 current becomes compensated while current flowing through R1 remains unchanged which is the lagging current. Thus depending on the switch S1 position one can sense the lagging current or the compensated current and the display provides accordingly the time delay between voltage, current with power factor display. In case a linear load is required switch S2 is closed that by-passes the choke L2 and the CT in this case reads unity power factor.

15 A Few BreakoutBoard Examples Arduino Nano Motherboard 12v AC to DC Power Supply 5V Zero Voltage Sensing Module 555 Module in Abstable Mode Under Voltage / Over Voltage Sensing with Logic Ouput MAX232 Board +DB9 Male MAX232 Board+DB9 Female 12v DC Motor Driver using L293D Power Factor Correction Module Underground Cable Fault Detection Module 48 White LED Array-6V 96 White LED Array-12 V LCD Module for 4 Bit Input WiFi Module using ESP8266 and IOT-Cloud Solar Charge Controller 6V 5 Load Relay Driver Module Volt, Current & Temp Sensing Module Buzzer Amplifier Module IR Photodiode Interupting Module Red & Green LED Indicator Module 12v DC Motor Overload Control Module Matrix Keypad 4x3 Robotics Multifunction Chasis 433 MHz RF+HT12E Encoder 433 MHz RF+HT12D Decoder DTMF Encode with Binary Output 38 KHz IR receiver TSOP Module 4 Way Traffic Junction Module Bi-polar Stepper Driver+ULN2003 Metal Detector Module Optocoupler+Four TRIAC with Snubber Optocoupler+Four Back to Back SCR with Snubber ZVS Optocoupler+Four TRIAC with Snubber ZVS Optocoupler+Four Back to Back SCR with Snubber Circuit Breaker using triac Optocoupler+SCR Bridge Pair with Snubber 8051+Push Button Motherboard 8051+ADC0808 Motherboard 8051+ADC0804 Motherboard DS1307 RTC 24C02 EEPROM IC 4 in 1- Seven Segment Display Street light with Sensors

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