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Electromechanical Energy Conversion

Code:

LEEC22118

Sigla:

CEE

Áreas Científicas
Classificação	Área Científica
OFICIAL	Electric Power Systems

Ocorrência: 2022/2023 - 1S

Ativa?	Yes
Unidade Responsável:	Departamento de Engenharia Eletrotécnica
Curso/CE Responsável:	Electrical and Computer Engineering

Ciclos de Estudo/Cursos

Sigla	Nº de Estudantes	Plano de Estudos	Anos Curriculares	Créditos UCN	Créditos ECTS	Horas de Contacto	Horas Totais
EEC	7	Plano de Estudos	3	-	6	75	162

Língua de trabalho

Portuguese

Objetivos

The course aims to contribute to a student scientific training in the area of electromechanical energy conversion, namely the study of the direct current machines (MCC),the three-phase synchronous machines (MST), as motor and generator, and the variable and the switched reluctance machine (MRV, MRC).

Resultados de aprendizagem e competências

The student, completing the study of this subject, should be able to:
1-Understand/explain the constitution of MCC, MST, MRV, MRC and justify with laws and rules the respective operating principles;
2-Obtain/estimate the parameters of the equivalent schemes of the MCC and the MST in steady state.
3-Apply the mathematical model of MCC and MST to predict operating points.
4-Analyze the powers diagram and predict the performance of MCC, MST;
5- Use Matlab to simulate the working regimes of the MCC and MST in steady state.

Modo de trabalho

Presencial

Pré-requisitos (conhecimentos prévios) e co-requisitos (conhecimentos simultâneos)

For this course it is important the student have previous knowledge of:
- analysis of electrical circuits in continuous current and alternating current;
- magnetic circuits;
- electromagnetism;
- mathematical mastery of the Complex numbers
- use of sofware with mathematical language.

Programa

THEORETICAL-PRACTICAL PART
I. INTRODUCTION/REVIEWS
1. Principles and laws of Electricity and Electromagnetism (Laws d'Ohm, Hopkinson, Kirchhoff. Lorentz-Laplace force. Ampère's law and Faraday's law. Rules for determining meanings.)
2. Importance of Electromechanical Energy Conversion.

II. DIRECT CURRENT MACHINE (MCC)
1. Working principle of an elementary DC machine.
2. Constitution of the direct current machine.
3. Direct Current Machine. Types, equations, characteristics, energy diagram and efficiency.

III. SYNCHRONOUS MACHINE (MS)
1. General Constitution:
1.1. Constitution. Stator, Rotor, speed, salient pole machines (hydraulic turbines) and cylindrical rotor (turboalternators).
1.2. Working principle of alternators and elementary motors.
1.3. Inductor System. Independent excitement and self-excitement.
1.4. Stator windings. F.e.m. induced.
1.5. Cooling (air, hydrogen, water).
2. Alternator Operation:
2.1. No load. F.m.m., flux waves in air gap line.
2.2. Wtih load. Pulsating and rotating fields. Armature magnetic reaction
under load. Short-circuit test.
3. Permanent Regime. Phasor Diagrams:
3.1. Equivalent Circuit (unsaturated cylindrical rotor).
3.2. Unsaturated and saturated synchronous reactance.
3.3. Salient pole effects.
3.4. Introduction to theory of two reactances. Phasor diagram and relationships between phasors.
3.5. Power and torque electromagnetic.
3.6. Losses and income. Energy diagram. Alternator adjustment.
4. Alternator Characteristics:
4.1. No load. Short-circuit. External.
4.2. Power - load angle.
4.3. Regulation.
4.4. Mordey curves.
5. Parallel Synchronous Machines:
5.1. Reasons for parallel association.
5.2. Conditions for the connection and operation.
5.3. Synchronism detection (rotating, simultaneous and synchronoscope fires).
5.4. Alternator connection to infinite power network.
5.5. Load sharing.
6. Synchronous Motor:
6.1. Operation with constant load and variable excitation. Mordey curves.
6.2. Operation with constant excitation and variable load.
6.3. Condenser (compensator) synchronous.
6.4. Synchronous motor starting processes.

IV. Variable reluctance and switched reluctance machines. Working principle. Applications.

Bibliografia Obrigatória

Jesus Fraile Mora; Máquinas Eléctricas, McGraw-Hill, 2003. ISBN: 84-481-3913-5
A.E.Fitzgerald; D.C. Kingsley; Alexander Kusko; Máquinas Eléctricas, McGraw-Hill, 1975. ISBN: ISBN: 0-07-090132-5
Stephen J. Chapman; Electric Machinery Fundamentals, McGraw-Hill, 1991. ISBN: 0-07-100972-8
Diogo P.L. Brandão; Máquinas Eléctricas- Introdução Máquinas Eléctricas de Corrente Contínua, F.C.Gulbenkian, 1984
Vincent del Toro; Fundamentos de Máquinas Elétricas , Prentice-Hall do Brasil, 1994. ISBN: 85-7054-053-1

Métodos de ensino e atividades de aprendizagem

In this UC the student-centered teaching/learning methodology is applied. In this context, study materials will be made available on the Moodle platform and a set of activities will be proposed by theme that students must carry out inclass or partially asynchronously to achieve the respective learning objectives. In the moodle platform the students will be able to self-assess their knowledge through formative tests. The laboratory component will be face to face. The active participation of the student in their learning process will be encouraged, making use of their critical spirit in the development of laboratory tests, the respective reports and discussion.

Software

Matlab
Octave

Tipo de avaliação

Distributed evaluation without final exam

Componentes de Avaliação

Designation	Peso (%)
Teste	65,00
Trabalho laboratorial	35,00
Total:	100,00

Componentes de Ocupação

Designation	Tempo (Horas)
Estudo autónomo	55,00
Frequência das aulas	75,00
Trabalho laboratorial	32,00
Total:	162,00

Obtenção de frequência

Continuous evaluation and assessment with final exam

Students who intend to attend the UC under continuous evaluation are subject to the assiduity and have the obligation to carry out laboratory work and all summative assessments.
The continuousevaluation of the theoretical-practical component is composed of the weighted average of thre summative assessments (MCC, MST, MR).
The final classification of the theoretical-practical component (C_TP) is calculated as follows:
C_TP = 0.35 MCC + 0.4 MST + 0.25 MR
The minimum grade of the practical theoretical component is 9.5.
If the students, after taking all the summative tests, have not obtained the minimum grade for their approval, they may, at the time of the exam, repeat the evaluation on one of the study machines to obtain approval for the UC.

Throughout the semester, the student will perform mandatory laboratory-based work, from which he will prepare the respective reports that will be presented and discussed (L1 and L2). From your activity, in the laboratory component, you will be assigned a classification L, which is the arithmetic average rounded to the tenths of the work performed: L=(L1+L2)/2.


Assessment regime with final exam (E), it is required to carry out the laboratory work. The written test for the final exam consists of three parts; direct current machine; synchronous machine and; machines of reluctance. The marks obtained in the parts performed in the exam replace those eventually obtained in the mini-tests on the same content of the continuous assessment. Students who have L>9.5 and E >9.5 will be approved with the classification C determined by rounding up to the units of:
C= (0.35 L + 0.65 E)
Examination are done at scheduled times at the School level.

For any evaluation moment (mini tests face to face or exam), a student may be asked to take an oral evaluation, to be agreed, to confirm the knowledge revealed in the summative assessments. The classification of the oral exam replaces the classification of the moment of assessment in question. If the student does not attend the oral exam, without justification, the assessment in question will be canceled.

Fórmula de cálculo da classificação final

The evaluation in the Continuous Assessment regime of the theoretical-practical component (C_TP) is composed of the weighted average of the five summative assessments (MCC , MST, MR) and defined as follows:
  C_TP = 0,35 MCC + 0,4 MST + 0,25 MR
The evaluation of the continuous assessment of the laboratory (L) component is;
  L=(L1+L2)/2
Students who have a grade of L>9.5 and C_TP > 9.5 will be approved with a Final (C_F) grade of;
  C_F = (0.35 L + 0.65 C_TP)

Evaluation in the assessment regime by final exam (E) is required to carry out laboratory work (L). Students who have a grade of L>9.5 and E>9.5 will be approved with a final grade of;
   C_F = (0.35 L + 0.65 E)

The final evaluation of the two assessment regimes is rounded up to units.