Teachings
70/0053M  ELECTROTECHNICS
Academic Year 2021/2022
Free text for the University
 Professor

ALESSANDRA FANNI (Tit.)
 Period

Annual
 Teaching style

Convenzionale
 Lingua Insegnamento

ITALIANO
Informazioni aggiuntive
Course  Curriculum  CFU  Length(h) 

[70/89] ELECTRICAL, ELECTRONIC AND COMPUTER ENGINEERING  [89/10  Ord. 2016] ELETTRICA  12  120 
[70/89] ELECTRICAL, ELECTRONIC AND COMPUTER ENGINEERING  [89/20  Ord. 2016] ELETTRONICA  12  120 
[70/89] ELECTRICAL, ELECTRONIC AND COMPUTER ENGINEERING  [89/30  Ord. 2016] INFORMATICA  12  120 
Objectives
Teaching goal of the class of Electrothecnics is to enable the student to acquire knowledge, skills and abilities consistent with the educational objectives of the degree course in Electrical and Electronics Engineering and Computer Science, declined according to the five Dublin Descriptors, and detailed below.
Knowledge and understanding
The student will acquire knowledge and understanding of the constitutive relations of the lumped components, the fundamental relationships of circuit theory, theorems and methods for the analysis of circuits in steady state, the symbolic method, theorems and methods for the analysis of circuits in sinusoidal regime, the approach to the state variables for the analysis of the dynamic behavior of a circuit, the use of the Laplace transform for the circuit analysis, the frequency analysis of a circuit. The student must also acquire knowledge and understanding of the fundamentals of the theory of electromagnetism and the operating principles of induction machines.
Applied Knowledge and understanding
The student will be able to apply his knowledge and understanding to: analyze a lumped circuit in steady state, sinusoidal and periodic state; derive the complete response of a circuit in the time domain and in the Laplace domain. He will be able to demonstrate a professional approach to the modeling of an electromagnetic device using the lumped circuit representation and the analysis of simple passive and active filters. He must be able to analyze symmetrical and balanced and unbalanced threephase systems and be able to determine the fault currents in a three phase circuit. He must be able, in addition, to analyze a magnetic circuit to determine the parameters of the equivalent circuits in mutually coupled circuits and analyze a singlephase transformer.
Making judgments
The student will be able to evaluate the applicability of the theorems and methods for the analysis of lamped circuits to electrical devices at both steady state regime and in the dynamic behavior. He will be able to build the related lumped circuit models for medium complexity devices and he will be able to solve these models with the circuit theory tools. He will perform the frequency analysis of circuits and will recognize the type of passive and active filters. He will develop his own independent judgment that will allow him to clearly express technical concepts relevant to the study of electrical circuits and will be able to solve circuit problems never solved previously. The student, finally, will develop the ability to critically evaluate the results of the circuit analysis.
Communication skills
The educational approach and the knowledge assessment methods, get the student used to communicate the concepts and the methods learned, as well as to formalize the problems in terms of lumped circuit models and to discuss solutions to specialists and nonspecialists.
Learning abilities
The educational approach will enable the student to integrate the knowledge gained from other courses (especially Mathematics and Physics, Systems Analysis and Measures) as well as various other sources in order to achieve a broad understanding of the issues related to the circuits analysis and to electrical and magnetic devices. This approach will allow him to develop the skills needed to deal with successive classes with a high degree of autonomy.
Prerequisites
Knowledge: In order to successfully undertake the study of Electrotechnics the student must have adequate knowledge of fundamental methodological aspects that distinguish the basic sciences (calculus, geometry, physics). In particular, it is of fundamental importance the knowledge of: matrix algebra in the real and complex domain, derivatives, integrals, ordinary differential equations, Fourier series, Laplace transforms, fundamental laws of electromagnetism.
Skills: The skills acquired from previous teachings regard the ability to: know how to solve algebraic equations in real and complex algebra, knowing how to derive and integrate functions, ability to solve systems of differential equations, knowing how to apply the Laplace transforms. Knowing how to make the relationships between the electrical quantities in the resistors, capacitors, and inductors.
Skills: The skills acquired in previous classes are essential to the understanding, interpretation, critical analysis and solving moderately difficult problems in the context of circuit theory.
It is recommended to have passed the following tests: Mathematical Analysis 1, Applied Mathematics, Physics 2, some of which are, however, listed among the prerequisites of the Programme Study.
Contents
First module: I° semester 60 hours
Lumped circuits (16 hours)
Physical quantities and electrical circuits, Assumptions of validity, voltage and current, first and second Kirchhoff's laws, Components and ports, descriptive variables, power and energy, conventions. General properties of components and circuits. Resistor, capacitor, inductor, independent voltage and current controlled generators, operational amplifier, mutually coupled inductors, ideal transformers. Real components. Components in series and in parallel, stardelta transformation.
Staty state circuits (20 hours)
Graph of a circuit and topological notions, fundamental methods of analysis: links and nodes. Tellegen's theorem and the superposition principle. Thevenin's and Norton's theorems. Theorem of maximum power transfer.
Circuits in sinusoidal regime (24 hours)
Sinusoidal functions and phasors. Properties phasor and derivative of a phasor. Analysis in the phasor domain. Impedance and admittance. Network Analysis in sinusoidal regime. Theorems. Power and energy. Passive bipoles. Conservation of complex power (Boucherot). Theorem of the maximum power transfer. Addictivity of powers. The problem of power factor correction. Frequency response. Resonant circuits. Passive filters. Active filters.
Second module: II semester, 60 hours
Circuit analysis in dynamic operation (30 hours)
Analysis in the time domain, Input / output relationships and state equations. Examples of first order and second order circuits. Electric signals: unit impulse, unit step, sinusoidal signal. Analysis in the domain of the Laplace variable and Inverse Laplace. Network Features: response of the circuit, impulse response, properties of network functions. Stability. Twoports.
Threephase systems (10 hours of lectures and 4 exercise)
Polyphase systems and symmetrical threephase systems. Connection of generators and loads. Terns of sequence. Symmetrical and balanced three phases networks. Generalized Thevenin's theorem. Unbalanced threephase networks. Power in threephase loads. Measurements in threephase systems. Aron insertion. Measures in unbalanced threephase loads. Power factor correction of threephase loads. Principle of decomposition. Analysis of threephase systems using the theory of symmetrical components. Calculation of shortcircuit currents.
Magnetic circuits (10 hours of lectures and exercise 6)
Fundamentals of the theory of stationary magnetic fields. Hysteresis and hysteresis losses. Normal curve of magnetization. Inert magnetic circuits. Analogy between electric and magnetic circuits. Direct problem and inverse problem. Calculation of the parameters of the mutual inductance. Equivalent circuits of mutually coupled circuits. Inductive transformer. Real transformer. Equivalent circuit of the real transformer. Open circuit and shortcircuit tests of the transformers. Calculation of the parameters of the equivalent circuit of the firstorder singlephase transformer. Load operation of the transformer. Theorem of Galileo Ferraris. Rotating magnetic field. Electromagnetic actions of rotating magnetic fields. Principle of operation of rotating machines.
Teaching Methods
To meet specific needs related to the epidemiological situation, teaching will be provided both in the presence and with online teaching, in order to ensure the fruition in an innovative and inclusive way.
Furthermore, the exercises can be carried out by means of remote interaction forms with the available ICT supports. Mentoring activities are also organized.
Methods and techniques of teaching in the presence interaction:
interaction between teacher through the use of remote connection, email and news in the website https://www.unica.it/unica/it/ateneo_s07_ss01.page?contentId=SHD30374.
Interaction between the content:
1) Retrieve the contents of the courses Physics 2, and Mathematics.
2) References to the content and methods used in the course of Systems Analysis.
3) References to the data circuit analysis methods in other areas not purely electrical and electronic.
4) Reference to engineering problems being also head to different disciplines.
Verification of learning
The manner in which it is ascertained the effective acquisition by the students of the expected learning outcomes are:
Specific selfassessment questionnaire proposed in the classroom and regarding the prerequisites.
Selfassessment of knowledge, skills and competences acquired through interactive exercises in the classroom with the teacher and support staff in the classroom.
Evidence of learning during the year: 2 intermediate writing tests consisting in solving a series of exercises on different parts of the program of the course. In particular, with the written test the student will have to demonstrate knowledge of the basic techniques and methodologies for: time domain analysis of singlephase and threephase linear circuits in steady state and in their dynamic functioning; the analysis of the same circuits in the frequency domain and in the domain of the Laplace variable; analysis of magnetic circuits.
Written tests can be held at a distance using computer aids (Moodle, Teams,
etc.).
Written and oral examination during the sessions (fortnightly following the Faculty Academic Calendar). The written test consists in solving a series of exercises on the program of the course. In particular, with the written test the student will have to demonstrate knowledge of the basic techniques and methodologies for: time domain analysis of singlephase and threephase linear circuits in steady state and in their dynamic functioning; the analysis of the same circuits in the frequency domain and in the domain of the Laplace variable; analysis of magnetic circuits. Written tests can be held at a distance using computer aids (Moodle, Teams,
etc.).
During the oral exam the student will have to demonstrate to be able to critically discuss the exercises performed during the written test. He will also have to demonstrate to have understood the fundamental relations of the circuit theory, the theorems and the methods for the analysis of circuits both with the symbolic method and with the state variable approach, which with the use of the Laplace transform. The student must also demonstrate that he has acquired knowledge and understanding of the fundamentals of the theory of electromagnetism and the principles of operation of induction machines.
This method (Written and oral examination) is designed to ensure the effective acquisition by students of knowledge, skills and abilities consistent with the educational objectives of teaching as well as to increase his communication skills. Also the oral tests can be held at a distance.
The final score is out of thirty, weighing each time the rating attributed to the different exercises according to the commitment required for their solution both in terms of content and computational complexity.
The rating 18/30 is granted when knowledge / skills of matter are at least elementary, the 30/30 rating, with possible honors, is granted if the knowledge is excellent.
Texts
The following texts are recommended for the exam and for further study:
1. Alexander, Sadiku, Electrical Circuits, Mc Graw Hill
The solution of the exercises of the text is available at http://www.ateneonline.it/alexander/areastudenti.asp
2. Perfetti, Electric Circuits, Zanichelli
3. Rizzoni, Electrical Engineering, Principles and Applications, McGraw Hill
4. Civalleri, Electrical, Levrotto and Bella, Torino
5. Repetto, Lever, Electrical, CittàStudi Editions
6. Biorci, Fundamentals of Electrical Engineering, UTET
7. www.autocircuits.org contains an electric circuits simulator.
More Information
Slides and lecture notes are available in the web site https://sites.unica.it/circuittheorygroup/education/. At the same site the exercises with the solutions are available.