# ELECTROTECNICS

OVERVIEW

Electric Circuit Analysis (Resistive-only DC, Transient, Steady State AC and Three-phase analyses).

## AIMS AND CONTENT

LEARNING OUTCOMES

The course gives the essential elements for understanding of analysis and exploitation of the electromagnetic phenomena. In the first part of the course the instruments for static and quasi-static analysis by circuit methods are introduced. In the second part of the course the principal application aspects of exploitation of power electromagnetic phenomena are introduced: electrical motors, power electronics and power electrical systems.

AIMS AND LEARNING OUTCOMES

The aim of this course is to enable Students to the basic knowledge necessary to study and solve simple Circuital Models, with particular attention to power aspects.

The basic methods for Linear, Time Independent and Lumped Parameter Circuit Analysis will be adressed, and the techniques for their application to the problems will be proposed. The analysis will be made within time-domain (Resistive-Only DC, Transient Analysis), and within frequency domain (Steady State AC).

At the end of the course, Student shall have correctly understood the basic concepts of Electric Circuit Analysis, shall be able to correctly classify the different types of Circuit problems, and to correctly formulate the solution, arriving, when and where possible, to determine their analytical solution.

PREREQUISITES

The course does not require particular prerequisites. In the same time, Students should know the basis of algebric computation with real and complex numbers and the meaning of linear differential equation of firsrt and second order with constant coefficients.

Teaching methods

Due to "nCOVID-19" healthy emergency, all the lectures will be provided in remote way via Microsoft TEAMS platform. Obviously, if restrictions will be changed and/ore removed theory lectures and related exercises will be provided in the first semester in frontal mode.

SYLLABUS/CONTENT

*The Circuit Model: basic concepts and lows*

Current and Voltage. Potential Difference. The Electric Circuit: Model inherent Hypotheses and Limits. Circuit components: Terminals and Connectors, Bipoles and Multipoles, Limit Surface. Lumped Parameter Circuits. Reference directions for Voltage and Current. Kirchhoff’s Voltage and Current Laws. Linearly independent relations among Kirchhoff’s Laws, and elementary selection techniques.

Component’s Equations expressed on voltage-current plane. Elementary bipoles: Resistor, Open Circuit, Short Circuit, Voltage and Current Ideal Generators. Representation of Components on voltage-current plane.

Instantaneous Electric Power. Power of a Bipole. Power Conventions for Generators and Loads. Power dissipated by a Resistor. Joule effect. Tellegen’s Theorem. Conservation of Power. Graphs, oriented Graphs, and their application to Circuit Analysis.

*Resistive-only Circuits.*

Definitions and inherent Hypotheses. Resistor: Linear, Time-Independent Resistor, its constitutive equation (Ohm’s Law). Definition of Resistance and Conductance. Concept of equivalent network, formulae of equivalent network of Resistors in series and in parallel, Voltage Divider and Current Shunt. Network reduction techniques. The star-delta transform. Theorems for resistive networks: Thevenin’s, Norton’s and determination of equivalent networks. Maximum power transfer theorem. Real generators, Millmann’s Theorem. Superposition Theorem and its application. Description of general techniques for Circuit Analysis (Nodal and Loop Analysis).

*Capacitors, inductors, coupled inductors.*

Ideal capacitor and inductor, elementary properties. Characteristic equations, stored energy, initial conditions, state variables. Formulae of equivalent network of Capacitors and Inductors in series and in parallel. Real components.

*Dynamic Circuit Equations, and their solution.*

The solution of Linear Ordinary Differential Equations with constant coefficients. General and Particular Integral, initial conditions, characteristic polynomials. Solution of simple first-order R-C or L-R Circuits. Behaviour of inductors and capacitors during sudden variations of state variables. Circuit of second order with Inductors and Capacitors. Roots of characteristic polynomial, and their relationship with output waveforms. Natural response and forced response. Example of solution of simple dynamic circuits.

*Equations of circuits in Steady State Alternate Current (SSAC), and their solution.*

Representation of sinusoidal waveforms through the use of complex numbers: the phasors. Definition of impedance and admittance for all types of linear components. Extension of already defined network theorems to the networks in SSAC. Voltage drop across a line. Power factor correction. Example of solution of simple linear circuits of applicative significance.

Power in SSAC: instantaneous power, active power, reactive power, complex power. Tellegen’s Theorem for SSAC networks. Balance of active and reactive power.

Resonance and antiresonance conditions.

Techniques for the practical solution of SSAC networks: power balance method, methods based on impedance computations, equivalence theorems in SSAC (Thevenin’s, Norton’s, Millmann’s Theorem, Superposition Theorem and its application)

Example of solution of simple linear circuits.

*Three-phase circuits.*

Definitions and reasons leading to introduce three-phase circuits. Three-phase circuits with balanced (3 conductors) or unbalanced (4 conductors) load. Phase and line voltages. Symmetric/unsymmetrical systems. Balanced/unbalanced loads. Positive, negative sequences. Phase and line currents. Power in three-phase circuits. Solution of simple circuits.

Examples of solution of three-phase circuits, both balanced and unbalanced.

RECOMMENDED READING/BIBLIOGRAPHY

Besides the books in Bibliography, available in Department Library, on AulaWeb are available copies slides and notes.

**Reference (for OPTIONAL study deepening on specific subjects)**

- M. Repetto, S. Leva: “Elettrotecnica – Elementi di Teoria ed Esercizi”, 2^ edn, Città Studi Edizioni, Torino, 2018
- L. Verolino: “Elementi di Reti Elettriche”, 1^ edn, EdiSES, Napoli, 2019
- C. K. Alexander, M.N.O. Sadiku: “Circuiti elettrici” III edn., McGraw Hill Italia, 2008.
- C. K. Alexander, M.N.O. Sadiku: “Foudamentals of Electric Circuits" Circuiti elettrici” V ed. McGraw Hill, 2013
- G. Rizzoni: “Elettrotecnica – Principi e applicazioni”, II edn., McGraw Hill Libri Italia, 2008

## TEACHERS AND EXAM BOARD

**Ricevimento:** Students wishing further clarifications are received on appointment (e-mail: massimo.brignone@unige.it), both using remote meetings (via Microsotf Teams) as well as frontal meeting. Obviously the second option is strectly dependent on the "nCOVID-19" emergency.

Exam Board

MASSIMO BRIGNONE (President)

MANSUETO ROSSI

ANDREA BONFIGLIO (President Substitute)

## LESSONS

Teaching methods

Due to "nCOVID-19" healthy emergency, all the lectures will be provided in remote way via Microsoft TEAMS platform. Obviously, if restrictions will be changed and/ore removed theory lectures and related exercises will be provided in the first semester in frontal mode.

LESSONS START

According to the official teaching calendar

## EXAMS

Exam description

Written (or through partial written tests during the year, to be decided during the lessions), and oral.

Assessment methods

**Warning: depending on the health emergency "nCOVID-19", the examination structure reported below may be subject to significant variations.**

The examination of **ELECTROTECNICS **is based on a set of four partial written tests that the Student must solve (unless there are serious issues to be evaluated case-by-case), and one oral discussion, lasting about 30 minutes, after the end of the course. In case the Student was absent to one or more partial tests without valid reasons, or the result was not sufficient, the examination will be based on a written test comprising the complete program of the module. The marking will be organized as follows: max. 14 points for the written examination (both for the set of partial tests, and for the complete written examination), max. 17 points for the oral examination. To be admitted to the oral examination, the marking of written test (partial or complete) must be at least 8/14. The final point is the sum of the marks of written and oral examinations.

Exam schedule

Date | Time | Location | Type | Notes |
---|---|---|---|---|

08/06/2021 | 09:30 | GENOVA | Scritto + Orale | La prova scritto avrà luogo nel giorno e nell'ora indicata. La prova orale, per chi ammesso secondo le modalità descritte nel manifesto del corso, avrà luogo nel pomeriggio dello stesso giorno indicativamente a partire dalle ore 14:30, ma comunque da concordare al termine della prova scritta. The written part of the test will take place on the day and at the time indicated. The oral part, for those admitted according to the methods described in the course description, will take place in the afternoon of the same day approximately starting at 2.30 pm, but in any case to be agreed at the end of the written part. |

06/07/2021 | 09:30 | GENOVA | Scritto + Orale | La prova scritto avrà luogo nel giorno e nell'ora indicata. La prova orale, per chi ammesso secondo le modalità descritte nel manifesto del corso, avrà luogo nel pomeriggio dello stesso giorno indicativamente a partire dalle ore 14:30, ma comunque da concordare al termine della prova scritta. The written part of the test will take place on the day and at the time indicated. The oral part, for those admitted according to the methods described in the course description, will take place in the afternoon of the same day approximately starting at 2.30 pm, but in any case to be agreed at the end of the written part. |

07/09/2021 | 09:30 | GENOVA | Scritto + Orale | La prova scritto avrà luogo nel giorno e nell'ora indicata. La prova orale, per chi ammesso secondo le modalità descritte nel manifesto del corso, avrà luogo nel pomeriggio dello stesso giorno indicativamente a partire dalle ore 14:30, ma comunque da concordare al termine della prova scritta. The written part of the test will take place on the day and at the time indicated. The oral part, for those admitted according to the methods described in the course description, will take place in the afternoon of the same day approximately starting at 2.30 pm, but in any case to be agreed at the end of the written part. |