Subject: ELECTRIC PROPULSION SYSTEMS (A.A. 2024/2025)
Unit Electric Propulsion Systems
Related or Additional Studies (lesson)
The course aims at providing knowledge and skills needed for the analysis and evaluation of the main hybrid and electric traction systems in the automotive field, including the main devices that compose them, such as electrical machines, power converters and devices for accumulation and recovery of electrical energy and their related control and management, in order to highlight the operating and use characteristics.
It also provides students with the essential tools to analyze and understand the quantitative aspects of the modeling and design processes in order to develop and carry out a non-complex design project for a hybrid or electric drive system of a vehicle and analyze the results obtained.
For a more complete understanding of the training objectives, please refer to the reading of the learning outcomes expected following the completion of this training course.
Knowledge of the basic principles of operation of electrical machines and converters.
The subdivision of the contents for CFU is to be understood as purely indicative. It may in fact undergo changes during the course of teaching in light of the feedback from the students.
Topics related to Electric Propulsion Systems
Introduction to the main powertrain architectures and components (ECTS 0,5, 5 hours)
One dimensional analysis of the vehicle dynamics, determination of the characteristic curve
Powertrain energy flow and efficiency analysis (ECTS 1, 10 hours)
Electric motor working principle, main machine characteristic parameters
(ECTS 1, 10 hours)
Components of the control system of electric drives. Structure of the main control architectures, vector control of AC machines, spatial vector modulation.
(ECTS 1, 10 hours)
Optimal control of electrical machines: MTPA, FW and MTPV trajectories.
(ECTS 1, 10 hours)
Introduction to the electric machine design, torque equation, magnetic loading, current loading, types of winding and cooling systems.
(ECTS 1,5 15 hours)
Topics related to Electromechanical Energy Storage and Conversion
Introduction to Power Electronics:
Components of the electric drives, architectures of the main types of DC / DC and DC / AC converters, and bidirectional converters. (ECTS 0,5, 5 hours)
Introduction to the main components for energy management in electrical and hybrid vehicles, taking into consideration hybrid (HEV), plug-in hybrid (PHEV) and electric vehicles (EV) drivetrains. Design criteria for energy storage systems for electric drivetrain (battery and converters) (ECTS 1, 10 hours)
Operating principle and equivalent circuit of different technologies for energy storage systems:
Battery, supercapacitor, fuel cell (ECTS 2, 20 hours)
State of charge, Depth of Discharge, aging and state of health of batteries and battery management systems BMS (ECTS 0,5, 5 hours)
Introduction to main architectures and topologies of insulated AC/DC and DC/DC converters, even bidirectional, for grid integration of charging systems and voltage level conversion. (ECTS 2, 20 hours)
The course is delivered in English and includes face-to-face lectures (theory and calculations) with connection also in streaming for students who follow from home via the "Teams" platform. The lessons are carried out with the aid of multimedia systems and can also involve practical exercises in which students are divided in small groups (2-3 for each PC) and utilize software for the simulation of hybrid and electric traction systems (Matlab / Simulink and PLECS), solve problems and discuss the results among themselves and with the teacher. In addition, professors receive students by appointment for clarification and personalized tutoring. The teaching material will be made available at the end of each lesson through the “Teams” platform. Mathematical models will be used for numerical modeling and computer simulation with Matlab / Simulink and PLECS.
The exam will take place at the end of the course according to the official exam session calendar. The examination is composed of a practical project and an oral discussion: 1: Application project with the drafting of a report on one of the following topics: a) the simulation and design of an electric / hybrid vehicle including the storage system. b) the design of an electrical circuit for motor control. The deliverable report on the activity carried out, including simulation and/or experimental results will be graded. The evaluation of the project is expressed out of thirty (a score greater than 30 results in obtaining a grade: 30 with honors). 2: an oral exam aimed at verifying the knowledge of the course contents. The oral exam consists in the discussion of the project activity carried out and 2 questions regarding the topics of the course. The oral exam will last approximately 45 minutes. The evaluation indicators are: - Ability to use knowledge (25%) - Ability to connect knowledge (25%); - Mastery of technical language (15%); - Ability to discuss topics (20%) - Ability to deepen the topics (15%) The evaluation of the oral exam is expressed out of thirty (a score greater than 30 leads to obtaining the grade: 30 cum laude). To pass the exam both tests (application project and oral exam) must be sufficient (exceed the threshold value of 18/30). The final grade is the average of the marks obtained in the two tests, a score greater than 30 leads to obtaining the grade: 30 with honors. The grade will be determined and communicated at the end of the oral exam.
Knowledge and understanding:
at the end of the course, the students will be able to:
- Know the structure, the operating principle, and the equivalent circuit of the main systems of accumulation and recovery of electrical energy in the automotive sector;
- describe clearly the main components of a hybrid or electric drive system and their main characteristics.
Applied knowledge and understanding:
for each type of hybrid or electric system, The students will be able to recognize:
- the construction details of the electric motors;
- the principles of operation;
- the main control schemes and algorithms of electric motors;
- the guidelines and sizing formulas of the energy storage system
Autonomy of judgment
- Analyse and evaluate the quantitative aspects of the modelling and design processes of a hybrid or electric drive system of a vehicle
- Express a critical judgment on the main devices that constitute a hybrid or electric traction system including: electric machines, power converters, electrical energy storage and recovery systems and related control and management devices, in order to highlight the characteristics of operation and use.
- Clearly communicate the knowledge and understanding skills acquired.
- Use correctly and appropriately the language, concepts and models acquired to effectively discuss the design solutions and the main solutions for the sizing of hybrid or electric traction systems
Ability to learn
- Apply the knowledge and understanding skills learned to other topics related to the design of electric vehicles
- Independently update the knowledge and understanding related to the design and analysis of electric vehicles.
A. E. Fitzgerald , C. Jr. Kingsley , A. Kusko: "Electric machinery", McGraw-Hill Education, 2012.
A. Emadi, “Advanced Electric Drive Vehicles (Energy, Power
Electronics, and Machines)”, CRC Press; 1st edition (2014).
Mehrdad Ehsani, Yimin Gao, Sebastien E .Gay, and Ali Emadi: "Modern Electric, Hybrid Electric, and Fuel Cell Vehicles Fundamentals, Theory, and Design", CRC Press.
C. Rahn, C.Y. Wang, “Battery Systems Engineering”, Wiley, 2013.
B. Scrosati, J. Garche, “Advances in Battery Technologies for Electric
Vehicles”, Woodhead Publishing, 2015
N. Mohan, T. M. Undeland, W. P. Robbins: “Power Electronics:
Converters, Applications and Design”, John Wiley & Sons Inc;
D. Grahame Holmes, Thomas A. Lipo: “Pulse Width Modulation for Power Converters: Principles and Practice“;
On the TEAMS of the course (in compliance with copyright)
- The notes used by the professor during the lectures and numerical exercises
- the slides of the lessons
- The mathematical models introduced for numerical modeling and computer simulation with Matlab / Simulink and PLECS