Double Qualification in Engineering Studies in Telematics and Computer Science

Double Degree in Engineering Studies in Telematics and Computer Science

Receive training to become an expert engineer in Network and Internet Technologies and get the CCNA and CCNP official qualifications

Power Electronics

Description
This course introduces the components and topologies commonly used in the implementation of the different types of switched-mode power converters. The first part of the course is aimed at developing the analysis techniques required to obtain the relevant converter parameters in steady state conditions (voltages, currents and efficiency) and at developing a first converter equivalent model. Both continuous and discontinuous modes of operation are considered. The basic DC-DC converter topologies (buck, boost and buck-boost), as well as other converter types (SEPIC, Cuk) are covered. Following lectures are devoted to the study of the power semiconductors (diode, MOSFET, IGBT) and its realization in switched-mode power converters. Equivalent circuit models developed previously are refined to include the efficiency losses derived from component non-idealities (conduction and switching losses). A basic introduction to the transformer for switching applications is given and a number of isolated converter circuit topologies are explored. The course addresses as well the converter control in closed-loop mode. Firstly, the converter AC model is derived and solved to find the important transfer functions of the converter and its controller. The closed-loop system is analyzed, and the controller designed to meet the design goals (line and load regulation, transient response, etc.). A whole chapter is dedicated to AC-DC converters or rectifiers, with special emphasis on low harmonic content rectifiers. The last set of lectures is devoted to motors and motor drivers. A brief description of the most common motor types is followed by a more detailed analysis of the associated motor drivers. LTspice simulator is extensively used along the course to illustrate the concepts introduced in the theoretical sections and to analyze the performance of the different circuits and devices. A basic understanding of electronics components and semiconductor devices, electrical circuit analysis and control systems are assumed prerequisites for this course.
Type Subject
Optativa
Semester
First
Credits
4.00

Titular Professors

Previous Knowledge

Electronic components and semiconductor devices, basic electronics, analysis of circuits and fundamentals of control systems.

Objectives

After completing successfully this course, the student will acquire the knowledge and the skills needed to:
• Understand what a switched-mode converter is, its operating principles and the different topologies used to implement them.
• Use different analysis techniques to derive an averaged equivalent circuit model and solve for the relevant converter parameters in steady-state.
• Use transformers to implement isolated DC-DC converters.
• Implement the converter switches using power semiconductors.
• Determine the critical parameters and ratings of both passive and active components used in converter circuits and select commercial devices fulfilling them.
• Design low and medium complexity DC-DC converters using commercial controllers.
• Evaluate the efficiency of the converter circuits, and identify and analyze options to improve it.
• Develop simple thermal models for the converter components.
• Develop an AC model of the converter and use it to analyze and design the converter controller.
• Simulate switched-mode converters in open and closed-loop mode using their equivalent DC and AC models.
• Understand the different types of electric motors and the circuits used to drive them.

Contents

1. INTRODUCTION TO POWER ELECTRONICS
1.1 Introduction

2. DC-DC CONVERTERS
2.1 Introduction and objectives
2.2 Analysis techniques
2.3 Volts-second and charge balance
2.4 Basic DC-DC converter topologies: buck, boost and buck-boost
2.5 Output voltage ripple
2.6 Efficiency
2.7 DC model of the converter
2.8 Other topologies: Ćuk, SEPIC
2.9 Transient mode

3. ELECTRONIC SWITCHES
3.1 Switch implementation
3.2 Diode
3.3 MOSFET
3.4 Implementation of switches using semiconductor devices
3.5 Bipolar transistor
3.6 IGBT
3.7 SOA
3.8 Effect of the switch on efficiency
3.9 Thermal analysis

4. DC-DC ISOLATED CONVERTERS
4.1 Introduction
4.2 Transformers for switching applications
4.3 Asymmetric isolated converters
4.4 Symmetric isolated converters

5. MODEL AC AND DESIGN OF THE CONTROL SYSTEM
5.1 Converter control in closed loop
5.2 Converter averaged and AC models
5.3 Transfer functions
5.4 System design

6. AC-DC CONVERTERS
6.1 Basic concepts of rectifiers
6.2 Uncontrolled rectifiers
6.3 Rectifiers with low harmonic content
6.4 Polyphase rectifiers
6.5 Thyristors and Triacs
6.6 Controlled rectifiers

7. MOTOR DRIVERS
7.1 Introduction
7.2 Brushed DC motors
7.3 Step Motors
7.4 Brushless DC Motors
7.5 AC motors

Methodology

The subject is taught by lectures where the theoretical contents are combined with the demonstration of concepts through the use of simulation programs and other visual tools (models, animations, etc.).

The consolidation of the acquired concepts is achieved through the realization of individual exercises that allow to develop and to extend the theoretical concepts and to use simulation tools for its application and validation
.
A practice, in the form of a small project that covers all the phases of design and that the student develops throughout the course, allows him to apply and consolidate additionally the knowledge acquired.

All the teaching material (presentations, simulation models, etc.) is available on the Moodle platform.

Evaluation

The course grading is based upon the following information:
• the continuous assessment assignments (homework),
• the final exam and
• the practical part.

The score of the continuous evaluation exercises (NAC) is calculated as the arithmetical average of the individual scores of the exercises proposed.

In the ordinary examination session, the score of the theoretical part is calculated from the score of the continuous assessment assignments and that of the final exam, using the following weighting factors:
NT = 0,45 x NAC + 0,55 x NEF(ORDINARY)

The final course grade is calculated from the scores of both the theoretical and the practical parts using the following formula:
N = 0,8 x NT + 0,2 x NPR

In order to pass the course, the student must:
• Achieve a score of the final exam (NEF) equal to or greater than 4 and
• Achieve a score of the theoretical part equal to or greater than 4 and
• achieve a score of the practical part (NPR) equal to or greater than 5 and
• achieve a final course score, calculated from the theory score (80%) and that of the practical part (20%), equal to or greater than 5.

Failure to deliver the practical part entails a final grade of NP.

In the extraordinary examination session, the theory score is that of the final exam:
NT = NEF(EXTRAORDINARY)

The final course grade is calculated from the scores of both the theoretical and the practical parts using the following formula:
N = 0,8 x NT + 0,2 x NPR

Failure to deliver the practical part entails a final grade of NP.

Delivery of homework assignments is compulsory. A delivery date for each of them is set. Homework assignments delivery before the deadline will be scored over 10 (standard scoring). Late delivery of assignments conveys a scoring penalty that is calculated multiplying this standard scoring by the coefficient:
K = 1 – (0,2 x d)
Where d is the delay in delivering the assignment expressed in days.

Thus, the scoring of an exercise delivered with a delay of two days is obtained multiplying the standard scoring by 0.6. Each student has a pool of 6 days that can be “consumed” to avoid late delivery penalties. The maximum number of days that can be used for a single exercise is 4 (even if a bigger number of days remain available yet).

Evaluation Criteria
Basic Bibliography

Robert W. Erickson, Dragan Maksimovic, Fundamentals of Power Electronics, 2nd ed., Kluwer Academic Publishers, New York, 2004.
N. Mohan, T. M. Undeland, and W. P. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed.,Wiley, New York, 2003.
D. W. Hart, Power Electronics, McGraw-Hill, New York, 2011
M. H. Rashid, Electrónica de potencia – Circuitos, dispositivos y aplicaciones, 3ª edición, Pearson-Prentice Hall, México, 2004

Additional Material

[1] PRESSMAN, ABRAHAM. Switching and linear power supply, power converter design . 1998
[2] KASSAKIAN, JOHN G. Principles of power electronics. 1991
[3] Maxon Motors. www.maxon.com
[4] Linear technology www.linear.com
[5] Texas Instruments www.ti.com
[6] Analog devices www.analog.com
[7] National Semiconductor www.national.com
[8] Maxim www.maxim-ic.com
[9] Intersil www.intersil.com