1 / 20

Photovoltaic Power Systems Laboratory: Practical Experiments in Solar Energy

Explore direct energy transfer, maximum power point tracking, inverter integration, and mini-projects in photovoltaic power systems. Learn about PV cell models, energy conversion, and system optimization. Engage in hands-on learning experiences.

southall
Download Presentation

Photovoltaic Power Systems Laboratory: Practical Experiments in Solar Energy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ECEN 4517 ECEN 5517 POWER ELECTRONICS AND PHOTOVOLTAIC POWER SYSTEM LABORATORY http://ece.colorado.edu/~ecen4517 • Photovoltaic power systems • Power conversion and control electronics Prerequisite: ECEN 4797 or ECEN 5797 Instructor: Mr. Roger Bell

  2. Experiment 1 Direct Energy Transfer System • Model PV panel • Investigate direct energy transfer system behavior • Investigate effects of shading • Observe behavior of lead-acid battery

  3. Experiments 2 and 3Maximum Power Point Tracking • Design and construct dc-dc converter • Employ microcontroller to achieve maximum power point tracking (MPPT) and battery charge control

  4. Experiments 4 and 5Add Inverter to System • Build your own inverter system to drive AC loads from your battery • Step up the battery voltage to 200 VDC as needed by inverter • Regulate the 200 VDC with an analog feedback loop • Change the 200 VDC into 120 VAC

  5. Mini-ProjectECEE Expo Competition • Operate your complete system • Competition during ECEE Expo: capture the most energy with your system outside • Morning of Thursday, May 2 A previous year’s competition poster

  6. Development of Electrical Modelof the Photovoltaic Cell, slide 1 Photogeneration Semiconductor material absorbs photons and converts into hole-electron pairs if Photon energy hn > Egap (*) • Energy in excess of Egap is converted to heat • Photo-generated current I0 is proportional to number of absorbed photons satisfying (*) Charge separation Electric field created by diode structure separates holes and electrons Open circuit voltage Voc depends on diode characteristic, Voc < Egap/q

  7. Development of Electrical Modelof the Photovoltaic Cell, slide 2 Current source I0 models photo-generated current I0 is proportional to the solar irradiance, also called the “insolation”: I0 = k (solar irradiance) Solar irradiance is measured in W/m2 Full sun: irradiance is approximately 1000 W/m2

  8. Development of Electrical Modelof the Photovoltaic Cell, slide 3 Diode models p–n junction Diode i–v characteristic follows classical exponential diode equation: Id = Idss (elVd – 1) The diode current Id causes the terminal current Ipv to be less than or equal to the photo-generated current I0.

  9. Development of Electrical Modelof the Photovoltaic Cell, slide 4 • Modeling nonidealities: • R1 : defects and other leakage current mechanisms • R2 : contact resistance and other series resistances

  10. Cell characteristic • Cell output power is Ppv = IpvVpv • At the maximum power point (MPP): • Vpv = Vmp • Ipv = Imp • At the short circuit point: • Ipv = Isc = I0 • Ppv = 0 • At the open circuit point: • Vpv = Voc • Ppv = 0

  11. Direct Energy Transfer

  12. Maximum Power Point Tracking (MPPT) • MPPT adjusts DC-DC converter conversion ratio M(D) = Vbatt/Vpv such that the PV panel operates at its maximum power point. • The converter can step down the voltage and step up the current. • Battery is charged with the maximum power available from the PV panel.

  13. Series String of PV Cellsto increase voltage • To increase the voltage, cells are connected in series on panels, and panels are connected in series into series strings. • All series-connected elements conduct the same current • Problems when cells irradiance is not uniform

  14. Bypass Diodes • Bypass diodes: • Limit the voltage drop across reverse-biased cells or strings of cells • Reduce the power consumption of reverse-biased cells

  15. Apparent path of sun through sky Baseline Rd. is 40˚N Times are not corrected for location of Boulder in Mountain Time Zone Net panel irradiation depends on cos(j) with j = angle between panel direction and direction to sun So take your data quickly

  16. Experiment 1 • Experiment 1: Photovoltaic System • Characterize the SQ-85 PV panels, and find numerical values of model parameters for use now and later in semester • Test the inverter provided • Charge the battery from the panel, using the Direct Energy Transfer method • Hope for sun! • Experiment 1 to be performed this week • Final report for Exp. 1 due in Canvas dropbox by 5:00 pm as listed in schedule.

  17. Lab Format • Two-person groups, up to 10 groups per section • Parts kits: • Available from E Store • One kit needed per group • Cost: $180. Contains power and control electronic parts needed for experiments. • You will also need other small resistors etc. from undergraduate circuits kit • Lab: • Access via CUID card reader • Fill out Lab Policy • Computer login via CU Identikey • You may optionally store your parts in your own locked drawer in your lab bench. Lock and key deposit for the semester at E Store.

  18. Lab reports • One report per group. Include names of every group member on first page of report. • Report all data from every step of procedure and calculations. Adequately document each step. • Discuss every step of procedure and calculations • Interpret the data • It is your job to convince the grader that you understand what is going on with every step • Regurgitating the data, with no discussion or interpretation, will not yield very many points • Concise is good

  19. Upcoming assignments • Experiment 1: PV DET system • Do Exp. 1 in lab this week • Exp. 1 report due in Canvas dropbox by 5:00 pm. See in Schedule. • One report per group • Experiment 2: Intro to LAUNCHXL-F28027F • Do Exp. 2 in lab. See in Schedule. • Exp. 2 scoresheet initialed by your TA and uploaded to Canvas. See dates in Schedule. • Experiment 3: Buck MPPT converter • Exp. 3 prelab assignment due in Canvas dropbox by 12:00 pm. See dates in Schedule.: Buck converter power stage design. • Start Exp. See dates in Schedule.

  20. Required Work • Your course grade will be based on the following: • Prelab assignments • Lab final reports • Quizzes • Project proposal and report • Expo • Attendance and lab performance • Assignments are due in the appropriate Canvas dropbox at the times listed in the course schedule page. Late assignments will not be accepted. • Weightings for assignments are listed in the course Canvas site.

More Related