Learning objectives
1) Knowledge and understanding
Attending classes and through individual study, students are to acquire:
• Know how to use renewables to produce electrical energy;
• Knowledge of circuits topologies and understanding of the working principle of: (i) basic circuits of the most relevant of static power converters conversion applied to renewables applications;
• Knowledge of the devices sizing of basic converters;
• Knowledge of the working principle, construction and types of transformers;
• Knowledge of the working principle, construction and types of electric rotating machines;
• Knowledge of technologies, technics and circuits of photovoltaic and wind systems;
• Knowledge and basic skills in MATLAB-Simulink to simulate power converters and power plants by renewables, using mathematical and/or functional models.
2) Applying knowledge and understanding
The main goal of this course is to provide students with the ability to apply their knowledge of electrical engineering, electronics, power electronics, and power systems for electrical production from renewable sources.
Importance is also given to the ability in solving problems and exercises to size active and passive devices and to evaluate the main figures of merit of power converters, analyzing their working principle.
Prerequisites
Students should be familiar with the notions of mathematics, physics (electromagnetism), electrical engineering digital and analog electronics typically acquired in first-level degrees in Information engineering (class L-8).
Course unit content
- Part 1: Introduction
1) Consumption and generation of energy and electricity
2) Conventional and renewable generation
- Part 2: Basic principles of power electronics
3) Switching DC/DC converters (Cuk, SEPIC, full bridge)
4) AC/DC converters (3-phase rectifier)
5) DC/AC converters (3-phase inverter)
- Part 3: Electrical machines
6) Asynchronous AC electrical machines
7) Synchronous machines
- Part 4: Electrical power distributions systems and power generation from renewable energy sources
8) Photovoltaic and wind systems
9) Electrical power distribution
10) Smart grid and smart plugs
11) Models for simulations of power electronic converters
Full programme
1) Introduction (2 h):
Consumption and generation of energy and electricity.
Environmental sustainability. The carbon cycle. World, European, and Italian energy consumption. Energy regulations.
2) Conventional and renewable electricity generation (1 h):
Basic principles of the hydroelectric, geothermal, wind, solar thermal and
photovoltaic, tides and waves, biomass and biogas, conversion systems.
3) AC/DC converters (1 h):
Three-phase full-wave bridge rectifier.
4) Switching DC/DC converters (10 h):
Boost converter in discontinuous mode; Cuk converter; from buck converter to SEPIC; DC/DC converter with H-bridge; PWM modulation.
Simulink models of the presented converters.
5) Controlled converters (8 hours):
Frequency analysis; Open loop step response; Step response in a closed loop; Response to load variations of the switching model. This part will be done by implementing logical-functional models with MATLAB/Simulink.
6) Resonant Converters (7 hours):
LLC Converters; Transformers (equivalent circuit and technology); resonant converters; Dual Active Bridge converter; ZVS and ZCS. This part will be done with insights for design using MATLAB/Simulink.
7) DC/AC converters (3 h):
Three-phase full-bridge inverter: 180° and 120° operation. Full-bridge inverter modulations: single-pulse PWM, multiple-pulse PWM, sinusoidal PWM;
space vector modulation.
8) Rotating electric machines (3 h):
Working principle, construction of asynchronous and synchronous electric rotating machines.
9) Electric power distribution (4 h):
Distribution with centralized electricity generation. The current state of the electric grid. The impact of renewable resources. Distributed generation. Smart Grids. Energy storage. Reference technical rules for the connection of active and passive users to the low-voltage electrical utilities (CEI 0-21). Topology of a smart plug.
10) Photovoltaic and wind systems (10 h):
Technologies, components, and architectures of photovoltaic and wind power plants.
Bibliography
• L. Freris, D. Infield, “Renewable energy in power systems”, Wiley, 2008, ISBN 978-0-470-01749-4
• M. Rashid, “Power electronics”, 3rd ed., Prentice-Hall, ISBN 0-13-122815-3.
• Instructor’s slides and notes uploaded on the Elly website.
Teaching methods
The course (6 credits) is given with lectures, tutorials, and laboratory work including simulation exercises in a total amount of 48 hours:
• Classroom lectures by the instructor with the aid of slides (available for download to students) projection, web surfing;
• MATLAB-Simulink tutorials and exercises.
The instructor is available to answer specific questions on the lessons also by appointment (e-mail).
Assessment methods and criteria
Oral exam.
The student is typically required to answer three main questions on all the topics covered in the whole course. The students will have to show that they:
• know the main problems due to energy balance and consumption, with particular attention to the electricity sector. Among the skills that students must show, there is also their know-how about renewables (RE) technologies, benefits, and technical and economic problems resulting from the penetration of RE and the technical rules of reference. In addition, it is required that the students can describe the basic architectures of converters for photovoltaic and wind power plants, together with their main features.
• know the structure of the circuits analyzed in the lectures, and that they can describe their operation. Students will also have to demonstrate that they can evaluate the performance of power converters by calculating their main figures of merit based on the voltage and current waveforms. It is also expected that students will be able to solve simple design exercises involving the sizing of active and passive devices.
• know the basic theory of electric machines presented during the lectures.
• know how to model a power converter or a power plant for simulations, using mathematical and logical functions.
Depending on the shown knowledge and skills, to each answer given to the main questions will be assigned a maximum score of 10. The maximum score is given if the answer is exhaustively compared to what was shown in the course lessons. When the answer is not exhaustive, the score is assigned according to what was discussed correctly by the student, comparing it with the overall topic discussed during the lessons.
In the case of a test judged positive (when the student proves to know at least the basic concepts of the arguments related to each question), the final vote will be given by the sum of the three partial scores.
Praise is given in the case of achieving the highest score on each topic, which includes some in-depth knowledge of the topics discussed during the lessons and/or the mastery of disciplinary vocabulary.
Other information
The course web site can be found on the Elly platform.
