Speed control of single phase induction motor using PLC

In this project we are concluding that speed of induction motor is measured using tachometer and easy to control through variable frequency drive and plc. We are enhancing the power quality, power factor improvement, saving energy with the help of variable frequency drive. In this project we are usi

Project Title

Speed control of single phase induction motor using PLC

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

In this project we are concluding that speed of induction motor is measured using tachometer and easy to control through variable frequency drive and plc. We are enhancing the power quality, power factor improvement, saving energy with the help of variable frequency drive. In this project we are using various component (input module, contractor, etc.) for controlling the system. this project we are also saving the energy from VFD and protecting the induction motor from the transients currents and short circuit faults through protecting devices like (contractor, MCB) if occurrence of spike in voltage or fluctuation in voltage continuously. The purpose of this project is use to control the speed of induction motor, reducing the cost of production, saving energy and increase the power factor of the system.

Project Objectives

The purpose of this project is about controlling the output (Speed of single phase Induction motor) by changing the input of VFD using PLC and therefore as the outcome input of VFD will be changed and thus the speed of induction motor also changes accordingly. VFD  work is based on the principle of V/f method, where V stands for voltage & f stands for frequency while the flux remains constant. Basically, Programmable logic controller is used as a process controlling device which is mainly used by automation industries.

The goal of this project was motivated to control
Speed of motor using PLC (Siemens) S7-300,
converter micro master 440, incremental rotary 
encoder instead of the encoder (Siemens) because the 
incremental encoder is cheaper than encoder 
(Siemens) and performs the same action as encoder 
(Siemens) so that we adjust the parameters of count 
in hardware configuration for controlling the 
frequency measurement and adjust the parameters of 
PI control to obtain the determine the speed in PLC 
programming as shown in the results of the above
figures. Also in this project we were motivated to 
monitor the speed of three phase induction motor 
using a SCADA system. The control system is 
designed based on the most advanced technology 
which gives a high amount of flexibility and 
efficiency. Monitoring system gives facility of 
analyzing the operation of induction motor in an 
online / offline mode, which makes the system to be 
safe from any fault/error condition.

Project Implementation Method

Methods of Speed Control: -
• Stator Voltage Control Method
When the supply voltage is varied in the three-phase induction motor’s speed can be varied. Torque is proportional to the square of input voltage (supply voltage) and slip is independent of the supply voltage at the time of maximum torque. This variation in input voltage does not affect the synchronous speed of motor. 

• Stator frequency control method.

This Method State that by varying the stator frequency speed of induction can also be varied. In order to decrease the speed of mother frequency has to be decreased. If frequency is reducing while the voltage is constant. Then flux has to be increase due to this disadvantage this method is not used much widely. 

• Pole changing method. 
In squirrel cage induction motor, by changing the pole of the motor the speed can be changed. To change the no. Of pole, two or more than two stator winding will be used. They used to be in same slot as well as independent from other winding. Due to each winding will give a different number of pole that will help to vary the speed. With more no. Of winding the switching arrangements will be complex & also result in increments in cost. These all methods which are explained above have disadvantages due to that we are using. V/f method. For speed control of induction motor. 

• V/f method: -
'V' referred as voltage & 'f' is referred as frequency for speed change operations, changes made in frequency by the supply voltage which is set in a inverter results in charge in speed of induction motor

ACTUAL MECHANISM OF THE PROJECT

For the working of this project, first we need to understand the principle on which this project is working When there is a Variation in input supply frequency leads to change in speed. As getting their Product of flux and supply frequency is directly proportional to the induced stator voltage. Emf is induced by 3 phase induction motor through the faraday's law (induction) is similar to the transformer equation given that

 E or V =4.44 ? K.T.f

Here from the above equation when Stator voltage drop consider zero then

E?V V ? f ? whereas K is winding constant with T and f are the number of turns per phase and frequency.

When we changing the frequency, it’s synchronous speed changes but with decrease in frequency, it's flux will increase and Due to changing in the change in value of flux causes saturation of rotor and stator cores which will further cause increase in no load current of the induction motor .So in this process it is necessary to maintain the flux ? constant with respect to the change in the voltage simultaneously .If we decrease the frequency ,the flux will increases but at the same time if we decrease the voltage ,the flux will also decrease causing no change in flux and hence it remains constant. So, here we are keeping the ratio of V/f as constant and this is called V/ f method.

Benefits of the Project

Impact on Society

It is for the betterment of product generation which are used directly in the society therefore, it has different impacts on society. In the recent years, customers are moving towards for more reliable, and good quality product it can be only done when the production machine work with its 100% ability without any damage or disturbance because of faults therefore, Protection system provides a solution in overcoming all these problems with reliable product formation and robust control. It is the system that can provide solutions especially for industries in remote areas and small industries where there is a small number of workers, it does not need any person to look after on faults and protection as it works automatically.

Boost in the Economy

Economy is the backbone for the development of the country and protection of industrial motors can help to boost the economy. Working hours in industry and product supply are affected due to the any damage of motor because it stops the production work. But as the protection system involves it ensures continuous production and supply of product. Hence workers can do their job with ease and also industrial business can be done which in return increases economy.

Job Opportunity

With the help of automation system the production and supply increases and new job opportunities will be created. The job will not only in demand and supply but also in the maintenance of motor when the system will detect the fault and design of protection system. This will definitely improve the living standard of families through proper livelihood.

Technical Details of Final Deliverable

The experiments were conducted based on ladder 
logic programming which is a software installed on a 
personal computer according to which the PLC takes 
the sensor inputs, processes them according to the 
program and gives the output to the VFD which again 
processes this input within the drive and finally 
controls the speed and position of the motor
Through this project, we used SFB 48 (system 
function block) for controlling the Frequency 
Measurement and Continuous Control with SFB 41
"Continues control" to control technical processes 
with continuous input and output variables on 
SIMATIC S7-300 programmable logic controllers.
In SFB 41:- We putted set point as floating-point 
number and adjusted the Gain so that

1- High-limit speed of the motor is "16000.0" 
equal to 50 HZ on The Micro- Master 440.

2- Half limit the speed of the motor is "8000.0" 
equal to 25 HZ on the Micro- Master 440.

3- Quarter limit speed of the motor is "4000.0" equal 
to 12 HZ on the Micro- Master 440
 maximum frequency when we putted set 
point equal to "16000.0", the frequency appeared on 
micro-master 440 equal to 50HZ

Final Deliverable of the Project

Hardware System

Core Industry

Manufacturing

Other Industries

Petroleum

Core Technology

Robotics

Other Technologies

Sustainable Development Goals

Peace and Justice Strong Institutions, Partnerships to achieve the Goal

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com