Course detail

# Electrical machines 2

The course presents the electrical machines from the point of view of basic physical laws in relation to the theory of electrical machines. The course aims to extend the knowledge of magnetic circuits, windings, cooling and to introduce the basic principles of design of electrical machines. The students will be acquainted with finite element method with reference to analysis and design of electrical machines.

Learning outcomes of the course unit

Graduate of the course is able to
- describe, modify and apply the basic design approach of magnetic circuit and winding to the transformer, permanent magnet DC motor and BLDC motor,
- modify the magnetic circuit and winding of the transformer, electromagnet, permanent magnet DC motor and BLDC motor to meet the required parameters,
- calculate the parameters of the transformer, electromagnet, permanent magnet DC motor, BLDC motor and permanent magnet synchronous motor (steady-state operation),
- explain, calculate and apply the fundamental design factors,
- draw and describe the waveform of magnetic flux density in the air-gap of permanent magnet DC motor, BLDC motor and permanent magnet synchronous motor (PMSM); sketch the slotting effect and the armature reaction effect,
- draw and explain the waveform of the back-emf of DC motor,
- describe the construction, driving and control of BLDC motor and PMSM,
- draw and explain the waveform of the back-emf and idealized phase currents of BLDC motor and PMSM,
- prepare 2D FEM model of the transformer, electromagnet, permanent magnet DC motor, BLDC motor under steady-state operation; compare the results
- prepare basic program using LUA language to control the FEMM program and model.

Prerequisites

The subject knowledge on the secondary school level is required and student should also be able to - define and explain terms: self and mutual inductance; energy of coil and set of coils; energy density; forces in magnetic field, - identify the materials usually employed in design of common electrical machines, describe their properties and draw their basic characteristics, - describe the construction of transformer, electromagnet, DC machine with excitation winding and synchronous machine with excitation winding, - explain the fundamentals of operation of transformer, electromagnet, DC machine with excitation winding and synchronous machine with excitation winding, - identify and explain the losses in transformer, DC machine with excitation winding and synchronous machine with excitation winding, - draw and explain the equivalent circuit of transformer, calculate its parameters from measured values, - identify the common types of armature winding of DC machines, describe their properties, advantages, disadvantages, - describe and explain the DC motor commutation process, - explain the term of armature reaction, - describe the basic properties of three-phase windings, explain the occurrence of rotating magnetic field.

Co-requisites

Not applicable.

Recommended optional programme components

Not applicable.

Meeker, D. C.: Finite Element Method Magnetics, Version 4.2, User’s Manual (EN)
Fitzgerald,Kingsley,Kusko: Electric Machinery,McGraw-Hill (EN)
Patočka, M.: Magnetické obvody. Elektronický učební text, FEKT, VUT Brno, 2005. (CS)
Pyrhonen, J., Jokinen, T., Hrabovcova, V.: Design of Rotating Electrical Machines. Wiley, 2009 (EN)
Hendershot, J. R. Jr., Miller, T.J.E.: Design of Brushless Permanent-Magnet Motors. Oxford: Magna Physic Publishing and Clarendon Press, 1994. ISBN 978-0198593898 (EN)

Planned learning activities and teaching methods

Not applicable.

Assesment methods and criteria linked to learning outcomes

Control tests - maximum 10 points
Computer exercises and project - maximum 20 points
Final Exam - maximum 70 points; to pass the exam it is necessary to gain at least 30 points.

Language of instruction

English

Work placements

Not applicable.

Course curriculum

Lecture
1. Electromagnetic field, fundamental equations, introduction to Finite Element Method.
2. Losses and efficiency, materials properties.
3. Transformers, design of magnetic circuit and winding.
4. Application of modern materials, electrical machines dimensioning.
5. Principle of electromagnets, electromechanical energy conversion.
6. Construction and design of electromagnets.
7. DC machines, magnetic circuit, excitation and armature winding.
8. Permanent magnets properties and design of DC permanent magnet motors.
9. Magnetic circuit and construction of permanent magnet synchronous machines and BLDC motor, generated voltage.
10. BLDC motor, design of magnetic circuit and winding.
11. Temperature field and cooling.
12. Design of cooling system of electrical machines.
13. Mechanical analysis for electrical machines.

Computer exercises
1. Introduction to FEMM program. Preprocessor, meshing, postprocessor.
2. Air-core coil, iron-core coil, simple magnetic circuit with one and more coils.
3. Transformer. Magnetostatic analysis.
4. Transformer. AC magnetic analysis.
5. Electromagnet in cartesian coordinates, energy, co-energy, force.
6. Electromagnet in cylindrical coordinates, effect of magnetic circuit design on electromagnet characteristics.
7. Permanent Magnet DC Motor - design.
8. Permanent Magnet DC Motor - FEMM model.
9.BLDC motor - design.
10.BLDC motor - FEMM model.
11. Thermal analysis of electrical machines.
12. Temperature field of transformer.
13. Structural analysis of the rotor.

Aims

Not applicable.

Classification of course in study plans

• Programme EEKR-BC Bachelor's

branch BC-SEE , 3. year of study, summer semester, 5 credits, compulsory

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