CFU: 9
Prerequisites
Basic knowledge on:
- electric machines;
- power electronics;
- static converters;
- closed loop control systems;
Preliminary Courses
None.
Learning Goals
The aim of the course is to provide students with advanced skills on the sizing, control and operation of electric drives with dc and ac motors, which allow both the analysis of the energy and dynamic performance of drives already in operation, and the choice of the most suitable solutions in the case of new installations, with particular reference to industrial automation systems.
Expected Learning Outcomes
Knowledge and understanding
The student needs:
- to show the knowledge of the methodological tools for the analysis and sizing both of the individual components of an electric drive - with particular reference to electric motors, power electronics used for their supply and to the related control systems – and of the drive as a system within an industrial process;
- know the strengths and criticalities of the different electrical drives based on different types of electrical machines, converters, sensors, and control strategies.
Applying knowledge and understanding
The student needs:
- to show ability to use by themselves the methodological tools acquired in order to identify the most suitable solutions in the case of new installations, with particular reference to industrial automation systems;
- to show ability to implement simulation programs in the Matlab / Simulink environment for the preventive analysis of the dynamic and energy performance of an electrical drive;
- to show ability to implement the control algorithms of an electrical drive on a PLC using the languages envisaged by the IEC 61131-3 standard;
- to use the theoretical knowledge acquired through analytical exercises and laboratory experiences.
Course Content - Syllabus
- Components of an electrical drives
- Dynamics of a mechanical drive
- Thermal effects in an electrical drive
- Reference standards
- Electrical drives with dc motor
- steady state control
- PID controllers
- cascade control
- some applications
- Architectures of programmable control systems
- Microcontrollers for industrial automation
- Electrical drives with induction motor
- sinusoidal steady state model of asynchronous machine
- steady state speed control
- Volt/Hertz control
- torque-speed characteristic
- slip control
- Current controlled Voltage Source Inverter
- Modulation techniques for Voltage Source Inverter
- Mathematical model of induction motor for dynamic conditions
- Vectorial control of induction motor
- stator and rotor field orientation
- direct and indirect field oriented control
- rotor flux estimators and observers
- direct torque control
- some applications
- DC brushless drives
- construction features and operating principle
- feeding strategies for speed control
- control by means of half wave and full wave converter.
- AC brushless drive
- construction features and operating principle
- feeding strategies for speed control
- field oriented control
- torque-speed characteristic
- some applications
- NPC multilevel inverter
- Single-phase asynchronous motor
- Universal motor
- Speed control of wound rotor induction motors with sub- and super- synchronous static converter cascade Kraemer and Scherbius
- Laboratory activities for using PLC to control electrical drives with induction or brushless drives
- Implementation of program for simulating vectorial controlled induction motor or brushless drives
Readings/Bibliography
W. Leonhard: Control of Electrical Drives, Springer Verlag
B.K. Bose: Power Electronics and AC Drives.
A. Del Pizzo: Azionamenti Elettrici, vol. 1 e 2, editor: Praise Worthy Prize
Teaching Method
Teacher will use:
- lectures for about 80% of total hours;
- classroom and laboratory exercises for about 20% of total hours.
Examination/Evaluation criteria
Exam type
The exam is divided into two distinct moments, albeit contiguous from a temporal point of view:
1) discussion of a project consisting of a simulation program created and implemented by each student for the modeling of drives with asynchronous / brushless motor and vector control (weight 1/4);
2) three theoretical questions relating to the fundamental contents of the course (weight 3/4).
Evaluation pattern
The verification of the simulation program referred to in point 1) above aims to ascertain the student's ability to correctly model an electric drive to predict its performance, both energetic and dynamic ones, and to size its control loops.
The questions referred to in point 2) aim to highlight the level of depth and awareness achieved by the student in the study of the fundamental topics of the course.