Learning objectives
1) Knowledge and understanding
Attending classes and individual study will allow students to acquire knowledge and understanding of:
- advantages, potential and problems of renewable energy for electricity generation
- main issues connected with meeting electricity demand
- circuit topologies of the most relevant circuits for static energy conversion
- principles of operation of the most relevant circuits for static energy conversion
- need for protection circuits (snubbers), their structure, operation and design
- examples of driver circuits
- transformer operation and design
- electro-mechanical energy conversion
- asynchronous and synchronous AC electrical machine operations
- technologies, technics and circuits of photovoltaic and wind systems
- simulation software by mathematical and/or functional modelling
2) Applying knowledge and understanding
Attending classes and individual study will allow students to acquire the capability of:
- describing the main characteristics of systems by renewables
- analyzing the energy use and power demand statistics data
- analyzing the operation of power converter circuits for static energy conversion
- analyzing voltage and current waveforms and evaluating the main power converter figures of merit.
- solving simple design exercises involving the hand calculation of required active and passive components specifications.
- solving simple problems involving the analysis and design of transformers
- solving simple problems involving the analysis of electrical machines
- applying the knowledge on components and circuits for energy conversion provided during the course, to power systems based on renewable energy
- using a simulation software (beginner level), by mean of mathematical and/or functional models
Prerequisites
Students should be familiar with the concepts taught in the physics courses of year 1 and 2 (Fisica generale 1, Fisica generale 2), with electricity and electrical circuit theory (Principi ed applicazioni dell'ingegneria elettrica), and basic electronic concepts (Elettronica 1 and Elettronica 2).
Course unit content
1) Introduction: consumption and generation of energy and electricity
2) Conventional and renewable generation
3) Introduction to power electronics
4) AC/DC converters (rectifiers)
5) Dissipative regulators and switching DC/DC converters
6) DC/AC converters (inverters)
7) Snubber circuits for power switches
8) Drivers for BJTs e MOSFETs
9) Single-phase transformer
10) Three-phase transformer
11) Asynchronous AC electrical machines
12) Synchronous machines
13) Electric power distribution
14) Photovoltaic and wind systems
15) Models for simulations of power electronic converters
Full programme
1) Introduction: consumption and generation of energy and electricity
Environmental sustainability. World, European and Italian energy consumption. Energy regulations.
2) Conventional and renewable generation
basic principles of the hydroelectric, geothermal, wind, solar thermal and photovoltaic, tides and waves, biomass and biogas, conversion systems.
3) Introduction to power electronics
Basics of semiconductor power switches. Power converter classification. Figures of merit: input and output distortion, efficiency, regulation.
4) AC/DC converters (rectifiers)
Single-phase half-wave rectifier. Single-phase full-wave rectifier with center-tapped transformer. Single-phase full-wave bridge rectifier. Lowpass filters. Single-phase full-wave bridge rectifier with RLE load. Three-phase full-wave bridge rectifier.
5) Dissipative regulators and switching DC/DC converters
Dissipative regulators. Switching DC/DC converters: Buck; Boost; Buck-Boost; Cuk converter; H-bridge. PWM modulation.
6) DC/AC converters (inverters)
Single-phase half-bridge inverter. Single-phase full-bridge inverter. Three-phase full-bridge inverter: 180° and 120° operation. Full-bridge inverter modulation: single-pulse PWM, multiple-pulse PWM, sinusoidal PWM; space vector modulation.
7) Snubber circuits for power switches
Turn-off, overvoltage, and turn-on snubbers.
8) Drivers for BJTs e MOSFETs
Examples of driver circuits for BJTs and MOSFETs. Driver isolation.
9) Single-phase transformer
Equations, equivalent circuits, operation as impedance adapter, operation in converter circuits, variable-frequency operation, design concepts.
10) Three-phase transformer
Connection between phases, operation in converter circuits.
11) Asynchronous AC electrical machines
equations, electrical and mechanical characteristics, rotational speed regulation.
12) Synchronous machines
excited by current, with permanent magnets, equations, grid operation, voltage-frequency regulation.
13) Electric power distribution
Distribution with centralized electricity generation. The current state of the electric grid. The impact of renewable resources. Distributed generation. Smart Grid. Energy storage. Reference technical rules for the connection of active and passive users to the low-voltage electrical utilities (CEI 0-21).
14) Photovoltaic and wind systems
Solar spectral irradiance. Photovoltaic and wind power systems: technologies, components and architectures.
15) Models for simulations of power electronic converters
Laboratory activities to show models of power converter using MATLAB-Simulink.
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.
• M. Guarnieri & M. Stella, "Principi e applicazioni dell'elettrotecnica" Vol. II, Ed. Progetto Padova
• Instructor’s notes.
Teaching methods
Classroom lectures by the instructor. Classroom exercises solved by the instructor. Laboratory exercises for software use learning.
Assessment methods and criteria
Oral exam.
Students will have to show that they:
• know the main problems due to energy balance and consumptions, 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 determination of active and passive component specifications.
• know the basic theory of transformers and electric machine presented during the lectures. It is also expected that students will be able to show how to design a transformer for 50 Hz applications.
• know how to model a power converter for simulations, using mathematical and logical functions.
Other information
Supporting material available for downloading at https://didattica.unipr.it
