Course syllabus

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ENM056 Electrical machines - design and analysis, LP1 HT19 (7.5 hp)

Course is offered by the Department of Electrical Engineering

Contact details

Responsible division: Division of Electric Power Engineering, Visiting address: Hörsalsvägen 11

Course purpose

The aim of the course is to teach students about (1) principles and procedure to design a permanent magnet synchronous machine for electric propulsion, and (2) methods to analyze steady-state and dynamic performance of induction machines used in industrial applications.

Schedule

TimeEdit

Some information about lab and design assignment will be published in this website.

Course literature

An internal textbook (in PDF) will be uploaded in this course website. It is in draft version and includes most (but not all) knowledge required for the course. For the completed contents of the course, please refer to the lecture PPTs, tutorial materials, design assignment, and lab instruction. These materials will be provided in this course website part by part. 

For further reading about the machine design and analysis in general, please read reference materials:

  • Design of Rotating Electrical Machines, by Juha Pyrhönen, published by John Wiley & Sons.
  • Electric Machinery Fundamentals, by Stephen Chapman, published by McGrawHill.

Course design

The course covers the following sections:

  1. Introduction of the course and different electrical machines.
  2. Electromagnetics, magnetic circuits and torque generation.
  3. Rotating magnetic field.
  4. Winding arrangements and calculations.
  5. Machine modeling in different coordinate systems.
  6. Induction machine.
  7. Permanent magnet synchronous machine.
  8. Synchronous generator.
  9. Electrical machines for traction applications.

Course arrangement
This course runs in the first quarter of each academic year. The course comprises of:

  • 18 lectures (2 × 45 min per lecture),
  • 8 tutorials (2 × 45 min per tutorial),
  • 1 session of practical laboratory work on induction machine (1 × 4 hours),
  • 3 sessions of modelling and simulation on induction machine in computer room (2 × 45 min per session),
  • 6 sessions of design assignment in computer room (2 × 45 min per session).

Lectures and tutorials are held in a large lecture room. The practical laboratory work (the class is divided into small groups) will be in the Grundkurslabb (Room 3502) found in the Division of Electric Power Engineering (Hörsalsvägen 11, after the Division entrance, go up the stairs and turn around to the left). Simulation and design (the class is divided into small groups as well) will be held in the common computer rooms.

Practical lab work (compulsory)
There is one session of practical lab work to determine parameters of an induction motor and measure the starting performance. Before coming to the lab, the home assignments must be done and the safety instructions must be read and understood. This may be asked by teachers before the lab work can start. Students with insufficient preparation are not qualified to do the lab.

Modeling and simulation (compulsory)
There are 3 sessions of computer exercise (MATLAB) for modeling and simulation of the induction machine measured in the practical lab. The session is used for students to build the induction machine model with the measured parameters, simulate the start-up, and compare the simulated results with the measured ones. The students are expected to explain the comparisons to the teachers. The teachers will give “Passed” if the comparisons and explanations are reasonable.

  • Design assignment (compulsory, max 20 points)
    All students are required to take part in the design assignment, in which the knowledge learnt in the lectures and tutorials will be used.
  • The goal is for students to use the knowledge learnt in the course to design their own motors (PMSMs for electric vehicles) under given specifications.
  • Design assignment will be done in small groups of 3-4 persons. The students are grouped randomly by the end of the first week. Adjustments can be made for the students who have possible conflicts in schedule with other courses. These students must inform the teachers in the first 2 days after course starts. The same group will do the practical lab work and simulation exercise.
  • Design instructions and consultancy will be arranged in 6 dedicated sessions in computer room. The design work is expected to be conducted in MATLAB.
  • Report including specifications, design process, design results and motivations for the selections of key parameters should be sent to the design assignment teacher in 7 days after the final written examination. One report per group is required.
  • The score will be given based on the quality of the report (max 15 points) and design results (max 5 points).

Canvas is used for the course organisation and communication between teachers and students. 

Missing of the report deadline and lab appointments You should be clear how missed deadlines and revisions are handled.

Changes made since the last occasion

  • There are no significant changes in the contents since the last year. Some improvements on the schedule occur. 
  • This course (ENM056) is introduced as a new course in 2018 to replace ENM055 Electric Drive 1.
  • The old course is ENM055 Electric Drive 1. There are re-exams for ENM055 arranged in academic calendar year 2018/2019, 2019/2020.

Learning objectives and syllabus

Learning objectives (after completion of this course, the student should be able to):

  1. describe working principle and main parts of synchronous machines and induction machines, and manufacturing process of electrical machines.
  2. model electromagnetic excitation, permanent magnets, and lamination materials considering saturation.
  3. calculate reluctance, magnetic flux, flux linkage, and inductance.
  4. calculate operating points of permanent magnets under no-load and load conditions of a permanent magnet synchronous machine (PMSM).
  5. describe various type of windings, e.g. distributed and concentrated windings, single-layer or multi-layer windings, integer slot or fractional slot windings.
  6. draw the distribution of phase coils in slots of a three-phase machine and calculate winding factors for both distributed and concentrated windings.
  7. design double-layer three-phase windings including selection of coil turns, series and parallel branches, and wire strand with a proper copper fill factor.
  8. calculate electromotive force (EMF) of a PMSM at no-load.
  9. describe different coordinate systems including three-phase and two-phase stationary coordinate systems, d-q rotating coordinate system.
  10. calculate inductances in d- and q-axis by using magnetic circuits for a PMSM and model it in d-q coordinate system.
  11. design a PMSM for electric vehicle applications, calculate power, power factor, torque, copper losses, iron losses, and efficiency.
  12. describe how geometrical parameters and material characteristics affect the performance of the PMSM.
  13. draw equivalent circuit and calculate steady-state performance of induction machines and analyze the influence of circuit parameters on torque-speed curve of induction machines.
  14. perform a practical experiment in order to determine the equivalent circuit parameters of an induction machine and acquire relevant quantities during a start-up.
  15. describe the dynamic model of the induction machine in different coordinate systems, perform a simulation of the starting process using MATLAB, and evaluate the simulated results with the measurements.
  16. draw phasor diagram and control reactive power by field current in a synchronous generator.
  17. describe different kinds of traction motors and discuss their features.
  18. identify the ethical aspects needed to be considered in design and use of electrical machines.

Link to the syllabus on Studieportalen.

Study plan

Examination form

The examination of the course (total 100 points) includes 3 parts:

  1. Lab work and simulation exercise are compulsory. Students must conduct the lab exercises according to the requirements and follow the safety instructions. Evaluation on simulations and measurements should be done together with teachers in the computer room. The work should reach the quality of “PASSED” given from the teachers. The knowledge learn from the lab work will be examined in the final examination.
  2. Design assignment (total 20 points) is compulsory. Demonstration of design programs for teachers in computer exercise time is required. The score will be given based on the quality of the report (max 15 points) and design results (max 5 points). In order to pass the course, the minimum score of the assignment is 10 points. The knowledge learn from the lab work will be examined in the final examination.
  3. Final examination (total 80 points). The examination will be arranged in the last week of the course period. Students should apply for the examination themselves online. The final examination (4 hours) will contain 6 questions. Each question may consist of several sub-questions. The final examination will cover the knowledge learnt in the lectures, the tutorials, lab work, simulation exercise, and design assignment. During the lecture and tutorial time, the important instructions, feedbacks, and arrangement for lab activities and design assignments will be provided. Some information given in the lecture and tutorial time is also critical for preparation of final examination. Therefore, attendance of these teaching moments are important. For the final examinations, use of approved Chalmers calculators (refer to the University’s Examination Regulations) is allowed. If there is any missing information in the exam questions, you can make reasonable assumptions and state them clearly. Use of dictionaries, and basic mathematics and physics handbook is allowed. A formula sheet will be provided.

Grades of the course will be evaluated based on the total points (max 100 points = 20 design assignment points + 80 final exam points). The grades are Fail, 3, 4 or 5. To get 3, 4 or 5, a student must (1) participate the practical lab work; (2) participate the computer exercise; explain the simulation/measurement results for teachers; demonstrate the design program. 55-69 points: Grade 3; 70-84 points: Grade 4; 85-100 points: Grade 5. Re-examinations are arranged 2 times per year by the university. The difficulty level is the same as the last final examination. The lab work results and the points from the design assignments will be valid for 3 years.

Old examination questions
No middle term trial examination. Old examination questions and their simplified answers will be uploaded in the course website two weeks before the final examination. 

Language:
All course activities will be conducted in English only. The exams and the report must be written in English.

 

Course summary:

Date Details Due