Comparison of Speed Control of Induction Motor using PID and LPV microcontrollers on myRIO

Industries are moving from scalar control to vector control based induction motor drives on a very large extent. Scalar control technique is comparatively easy, requires less computational time and cheaper. On the other hand, vector control technique is quite difficult, requires large number of calc

Project Title

Comparison of Speed Control of Induction Motor using PID and LPV microcontrollers on myRIO

Project Area of Specialization

Robotics

Project Summary

Industries are moving from scalar control to vector control based induction motor drives on a very large extent. Scalar control technique is comparatively easy, requires less computational time and cheaper. On the other hand, vector control technique is quite difficult, requires large number of calculations as the number of equations are too large and hence requires very fast controller and is very expensive. Hence vector control will be more efficient than scalar control.
The question arises here that to which extent former is better than latter and is it worth to spend so much time and resources on LPV? How can we make scalar control more efficient? Can vector control be made cheaper? Can both the techniques be combined to give more efficient results? All these questions and problems are of great importance for the new industry owners who want efficient as well as cheap product for their business. All of these questions and queries will be answered in this research based project.

Project Objectives

The main objectives of this project is to employ scalar control as well as vector control techniques simultaneously and compare their efficiency, response time, cost and ultimately combine both techniques to get highest efficiencies and lowest cost as much as possible.

Project Implementation Method

In our project, two control techniques are compared: scalar control and vector control

Scalar Control Technique

Scalar control is simple. Its purpose is to control the magnitude of chosen control quantities. In this case, Volts/Hertz constant control technique is used. Vector control is more complex than scalar control. It works with vector quantities controlling the desired values by using space phasors which contain all the three phase quantities in one phasor. It is also known as field-oriented control.
A proportional-integral-derivative controller (PID controller) is a control loop feedback mechanism widely used in industrial control systems. In a PID Algorithm the current speed of motor is measured and compared with our desired speed. Then by calculating the error and performing calculations it restores the actual speed to the desired speed in the optimum way i.e. here the speed is continuously checked and controlled

Vector Control Technique

In vector control or Field Oriented Control(FOC)matrix and vectors are used to represent the control quantities. This method takes into account not only successive steady-states but real mathematical equations that describe the motor itself, so that the obtained results have a better dynamic for torque variations in a wider speed range.

FOC involves controlling the components of the motor stator currents, represented by a vector, in a rotating reference frame (with a d-q coordinate system).  In order to estimate the rotor flux vector is possible to use two different strategies

DFOC (Direct Field Oriented Control): rotor flux vector is either measured by means of a flux sensor mounted in the air-gap or measured using the voltage equations starting from the electrical machine parameters.

IFOC (Indirect Field Oriented Control): rotor flux vector is estimated using the field-oriented control equations (current model) requiring a rotor speed measurement.

With these algorithms, the stator currents of the induction machine are separated into flux and torque producing components by utilizing transformation to the d-q coordinate system. On this reference frame the torque component is on the q axis and the flux component is on the d axis. 

Motor speed is measured through tachometer which will be used to compare with the reference speed. The integral of speed will give us rotor position which will be used in rotor flux estimator. Using current sensors the values of Ia and Ib will be achieved and by Park and Clark transformation we’ll get the values of torque and flux on d-q plan which in turn us to generate Va, Vb and Vc by inverse Park transformation and SVPWM which will in turn run induction motor.

Benefits of the Project

In industry, all the processes that involve induction motors require safe and smooth speed variation, reduced energy consumption, reliable soft-starting, easy installation, low running and maintenance cost and easy debugging of inverter section.

We aim to compare scalar and vector speed control techniques of a three-phase induction motor to provie all these industry's requirments more efficiently and cost effectively.

Technical Details of Final Deliverable

Inverter Circuit
LabView Simulations and results
Current Sensing Circuits
Response graphs
Comparison Results

Final Deliverable of the Project

Hardware System

Type of Industry

Education

Technologies

Robotics

Sustainable Development Goals

Quality Education, Responsible Consumption and Production

Required Resources

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