37064 - Electrical Drives T

Academic Year 2019/2020

  • Docente: Angelo Tani
  • Credits: 9
  • SSD: ING-IND/32
  • Language: Italian
  • Moduli: Angelo Tani (Modulo 1) Luca Zarri (Modulo 2)
  • Teaching Mode: Traditional lectures (Modulo 1) Traditional lectures (Modulo 2)
  • Campus: Bologna
  • Corso: First cycle degree programme (L) in Automation Engineering (cod. 9217)

Learning outcomes

Operation modalities and performances of the motor drives for the automation: brushless motors, induction motors, stepper motors and direct drive actuators. Dynamic models of DC and AC electric motors. Control schemes for electric drives. Sizing of actuation systems.

Course contents

Introduction
General information on electrical machines and drives. Review of electrical engineering. Magnetic materials and conductive materials. Magnetic circuits. Electromechanical energy conversion principles. Heat dissipation in electrical machines.

Principles of static electric energy conversion
Introduction to power electronic components. Controlled and uncontrolled rectifiers, choppers, three-phase inverters, square-wave and PWM control techniques.

DC motor drives
DC motors: structure, operating principle, mathematical model, mechanical characteristic. Speed regulation with armature and excitation control. Constant torque and constant power operation. Axes and spindle drives. Features of drives with controlled rectifiers. Features of drives with choppers. Drive structures for operation on two and four quadrants. Block diagram of the DC motor. Analysis of electromechanical transients with voltage supply. Torque control. Speed control. Analysis and tuning of torque and speed regulators. Simulation of complete motor drives in MATLAB-Simulink environment.

Brushless DC motor drives
Brushless DC motors: structure and operating principle. Phase supply sequence according to the rotor position. Six-step operation. Switching transients and torque oscillations. Motor drive block scheme. Applications.

Brushless AC motor drives
Synchronous motors with round rotor and salient pole rotor: structure and operating principle. Synchronous motors with permanent magnets. Machine equations, vectorial diagrams and torque expression in steady-state conditions. Operating characteristics with voltage and frequency supply. Inverter power supply for speed control. Multi-motor drives. Closed-loop operation with current control. Brushless AC motors. Power supply technology with PWM current regulators. Block diagram of the motor drive. Dynamic model of synchronous machines based on the theory of d-q axes. Field-oriented control. Analysis of limit performance in torque and speed. Simulation of complete motor drives in the MATLAB-Simulink environment.

Induction motor drives

Induction motors: structure, operating principle, equivalent circuit, mechanical characteristic. Inverter power supply for speed control. Open-loop control schemes. Volt per Hertz control. Acceleration ramps. Closed-loop control schemes. Slip frequency control. Constant torque and constant power operation. Dynamic model of induction machines based on d-q axes theory. Field-oriented control of induction motors. Direct and indirect torque control techniques. Rotor flux estimation. Torque and speed limits of induction motor drives. Simulation of complete motor drives in the MATLAB-Simulink environment.

Stepper motor drives
Stepper motors: structure and principle of operations. Simplified dynamic model. Power supply circuits and control techniques. Analysis of low and high speed instability problems. Analysis of torque limits as function of the supply frequency. Simulation of complete motor drives in the MATLAB-Simulink environment.

Readings/Bibliography

It is not necessary to buy specific books. The pdf files of the slides utilized during the lessons are indispensable and sufficient for the preparation for the exam. They are available on IOL. For further considerations:

I. Boldea, S. A. Nasar : ELECTRIC DRIVES, CRC Press, New York, 1999.

P. Vas: VECTOR CONTROL of AC MACHINES, Oxford University Press, New York, 1990.

T.J.E. Miller: SWITCHED RELUCTANCE MOTORS AND THEIR CONTROL. Clarendon Press, Oxford, 1993.

W. Leonard: CONTROL OF ELECTRICAL DRIVES. Springer-Verlag, Berlin, 2001.

Teaching methods

The frontal lessons are supported by exercises with Personal Computer (MATLAB-Simulink).

Assessment methods

The learning assessment is based on a final written test. If desired, it is possible to take an additional oral test. The final grade will be the average of the marks of the written test and the optional oral test.

Teaching tools

Lessons and exercises are carried out with the help of a personal computer and a computer projector (Power Point, MATLAB-Simulink). The pdf files of the slides utilized during the lessons are available on IOL.

Office hours

See the website of Angelo Tani

See the website of Luca Zarri

SDGs

Affordable and clean energy Industry, innovation and infrastructure Sustainable cities

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.