


Politecnico di Torino  
Academic Year 2017/18  
01OELMK, 01OELET, 01OELFJ, 01OELJM, 01OELLI, 01OELLM, 01OELLN, 01OELLP, 01OELLS, 01OELLU, 01OELLX, 01OELLZ, 01OELMA, 01OELMB, 01OELMC, 01OELMH, 01OELMN, 01OELMO, 01OELMQ, 01OELNX, 01OELOA, 01OELOD, 01OELPC, 01OELPI, 01OELPL, 01OELPM Photovoltaic and wind systems for electricity production 

1st degree and Bachelorlevel of the Bologna process in Energy Engineering  Torino 1st degree and Bachelorlevel of the Bologna process in Biomedical Engineering  Torino 1st degree and Bachelorlevel of the Bologna process in Mechanical Engineering  Torino Espandi... 





Subject fundamentals
The course is devoted to present both the Photovoltaic and Wind power systems, in which general aspects of power electronics are included, starting from their operating principle. The methods to correctly design the main components, to evaluate the energy production with the economic analysis of investment are the goals of the course.

Expected learning outcomes
At the end of the course students should know the main technologies about the photovoltaic plants and wind turbines, and should be able to calculate the productivity and to correctly design the main components of these power systems.

Prerequisites / Assumed knowledge
Basic knowledge about electric circuit theory and applied Mechanics.

Contents
PHOTOVOLTAIC POWER SYSTEMS (about 40 h)
Advantages and drawbacks of Photovoltaics. Manufacturing process of solar cells. Structure of the semiconductors: energy bands; doping; pn junction and electric field; electron – hole pairs; losses in the energy conversion. Spectral response and efficiency of the main technologies: single, multicrystalline and amorphous silicon, Cadmium Telluride, CopperIndium Diselenide. Surface covering per installed kilowatt. Equivalent circuit of the solar cell; currentvoltage characteristic( IV curve) at variable irradiance and temperature. Focus on an application problem: series/parallel connection of cells; IV curve mismatch and shading effect; hot spots and breakdown; bypass and blocking diodes. Structure of a PV module; qualification tests to simulate accelerated ageing. Datasheets of the commercial PV modules, thermal coefficients of the electrical quantities. DCAC converters for the grid connection: Maximum Power Point Tracking (MPPT); active/reactive power control; interface protections; protections against overcurrent and direct/indirect contacts. Optimal coupling PV array/inverter: checking of power/voltage/current. Conventional calculation of energy production: assessment of solar radiation, loss sources in the productivity, economic analysis by the Net Present Value (NPV) method. Automatic Data Acquisition System, experimental results on operating PV plants, typical testing procedure. Plant schemes; cost of installation and energy production. WIND POWER SYSTEMS (about 20 h) Characterization of the wind: speed and direction; power density; surface roughness; statistic distributions. Structure of a wind turbine: blades, hub, gearbox, electric generator, tower. Operating Principle of a wind turbine: lift and drag in a blade; pitch and yaw regulations; adjustment toward stall/feather. Equivalent circuits of induction and synchronous machines and power curve vs. wind speed. A solution for variable speed wind turbines: the doublyfed induction generator. Wind farms: interference among wind turbines, wind park effect. Environmental impact of wind turbines: noise. Power size, diffusion of wind installations in the world. Schemes, cost of installation and energy production. Advantages and drawbacks. 
Delivery modes
Classroom exercises for a total of about 15 h. Summary of electric circuits. Calculation of the electrical parameters of the PV modules in conditions different from STC by datasheet of the manufacturers. Calculation of reverse currents in PV strings connected in parallel. Optimum coupling between PV array and inverter. Calculation of the energy production in a PV system. Calculation of mechanical quantities in a wind turbine. Use of simplified equivalent circuit of induction machine: application to the Doubly Fed Induction Generator (DFIG). Calculation of energy production for a wind turbine.
Laboratories from videos for a total of about 5 h: Measurement of the IV curve of a PV module. Measurement of efficiency and power quality for an inverter in grid connection. 
Texts, readings, handouts and other learning resources
Teaching documents on the POLITO portal of the teacher. For deepening the book "M. Patel, Wind and Solar Power Systems, 2006, CRC Press, USA".

Assessment and grading criteria
Written exam, 2hduration, with theoretical questions for a total of 20 points (short discussions, drawings and formulas) and numerical exercises for a total of 10 points. During the written exam, it is possible to use electronic calculator, but using other material is not allowed. Oral exam is possible only above 24/30.

