Speed control of motor using Variable frequency drive

Project Title

Speed control of motor using Variable frequency drive

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

The main purpose of designing a Variable Frequency Drive was to save significant amount of energy for industries as well as for domestic purposes reducing the net electricity bills. This project is mostly power electronics based. Various electronic components are used for the designing of thi drive plus some extra features have been added to the drive to improve its efficiency.A single phase AC input will be converted to 3 phase system by the use of invertors. A pure AC sine wave is the output. Arduino is used for programming and the technique used for speed control is Pulse Width Modulation. At the final stage we used a conveyor belt to test the speed control of our Induction motor.  VFD offers a very good response to pumping system. Reduces the flow with VFD, motor consume very less power. So significant amount of power can be saved with the help of Variable Frequency Drive. VFD also serves as Soft Starter, during starting motor draws 6 times more current than rated current. While starting with VFD, motor draws very less current and also provides a Smooth Start. So the losses occur in motor can be eliminated. Thus we can conclude that Variable frequency drives (VFD’s) are often recommended as a way to save pumping energy and it will help for conservation of electrical energy for our future generation.

Project Objectives

The main objectives of this project includes

Energy Saving

Low Cost

Reduced Electricity Bills

Less Equipment Damage

Increased Efficiency

Power Consumption in Low cost

Reduced Starting Current

Smooth Start of Motor

Variable Speed of Induction Motor

Project Implementation Method

The technique used for Speed Controlling is Pulse Width Modulation.Pulse Width Modulation (PWM) . VFDs provide a more sinusoidal current output to control frequency and voltage supplied to an AC motor. PWM VFDs are more efficient and typically provide higher levels of performance. A basic PWM VFD consists of a converter, DC link, control logic, and an inverter.

The converter section consists of a fixed diode bridge rectifier which converts the three-phase power supply to a DC voltage.  Capacitors smooth the converted DC voltage. The rectified DC value is approximately 1.35 times the line-to-line value of the supply voltage. The rectified DC value is approximately 650 VDC for a 480 VAC supply.

Output voltage and frequency to the motor are controlled by the control logic and inverter section. The inverter section consists of six switching devices. Six IGBTs with heat sink are used in this section. The control logic uses a microprocessor to switch the IGBTs on and off providing a variable voltage and frequency to the motor.

Benefits of the Project

VFDs use in process control result in more efficient operating systems due to automation of systems.

Reduced Mechanical stress

As, motors starts on direct- on- line startup are associated with high in-rush current and poor power factor. It also increases stress on mechanical system. Use of VFDs improve operating conditions by giving smooth controlled startup and energy saving in running and startup. Benefits of these includes elimination of uncontrolled in-rush current, power wastage is eliminated and life of motor and driver machine are increased.

Improved Electrical System

Power Factor use of diode Supply Bridge for rectification, electrical VFDs operate at near unity power factor over the whole speed range, which is supply, delivers mostly real power.Our  PWM drive convert the three phase AC line voltage to a fixed-level DC voltage regardless of inverter output speed and power hence provide constant power factor regardless of power factor of load machine and controller installation configuration.

Technical Details of Final Deliverable

Our project is designing of to a Variable Frequency Drive (VFD). The purpose of this drive is to convert the speed of Induction motor to a variable speed according to the demand and need of equipment. VFD’s have a huge advantage over other drives because they can improve the power factor and can be also reduce cost while providing maximum efficiency. The input will be a single phase AC supply which will be given to the bridge rectifier which will convert this AC signal to DC. A capacitor will be added to convert this DC signal to pure DC and to remove any ripples. A Controller will manage any changes which we want to make in our voltage and frequency. The DC signal will now be converted to AC signal again through IGBT’s that act as a switch. The technique used by our inverter will be Pulse Width Modulation to modulate the signal to variable frequency. This AC output will be given to our 3 phase induction motor which can now run at a variable speed.

Final Deliverable of the Project Hardware SystemCore Industry Energy Other Industries Others Core Technology OthersOther Technologies Shared EconomySustainable Development Goals Responsible Consumption and ProductionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	61870
IGBT's	Equipment	6	400	2400
Arduio Mega	Equipment	1	1200	1200
Conveyor Belt	Equipment	1	12000	12000
LCD 2*4	Equipment	1	800	800
Temperature Sensor	Equipment	1	2550	2550
RPM Meter Module	Equipment	1	1900	1900
Arduino Uno	Equipment	1	850	850
Capacitors	Equipment	18	200	3600
12 Volts Charger	Equipment	1	450	450
Circuit Breaker	Equipment	2	600	1200
PC817	Equipment	12	60	720
Connectors	Miscellaneous	12	100	1200
PCB's manufacturing cost	Equipment	5	1300	6500
Relays	Equipment	4	250	1000
Three phase Induction Motor	Equipment	1	25500	25500