# Report & Presentation¶

Your work during this lab is evaluated with:

• a report
• a presentation

## Report¶

First, you can look at some general guidelines on writing a Lab report: Lab_report HOWTO.pdf and Clean Matlab plots.pdf. It contains general guidelines on content selection and on formatting (in particular formatting of results and figures).

### Content of the report¶

The report cannot contain everything discussed during the lab sessions (even more true for the 15’ presentation). After an introduction which briefly summarizes the context and objectives of the lab, these are the keys aspects that should appear in the report.

#### Principle of AC power flow¶

• relation between Id, Iq currents and P,Q powers
• approximate relation showing the effect of the inverter voltages Vd, Vq on P and Q.

#### Inverter modeling¶

• explain (and show with some experiment), for one inverter leg, the relation between the PWM input and the “running average” voltage of that leg. Define precisely this “running average”
• explain the modeling process to go from the circuit in the natural abc reference frame to the abstrac dq reference frame. State the hypothesis of your model.

#### Inverter control¶

Control structure

• Discuss first why it is not appropriate to control the inverter in open loop (by inverting the “inverter voltage → power” relations)
• Present and explain the overall structure of the control.
• big picture: which variables are measured, which are set by the controller ? Any interface blocks needed between the plant and the controller? (for this, drawing a functional block diagram may help!)
• why dq control?
• why some feedforward terms?

Control tuning

• State and explain your choice of requirements for the control loop
• Explain your method for PI control tuning. Either algebraic like [Sko2003] or frequency based design.
• Check the performance of your controller, using models of increasing realism (from the single channel block diagram to the three phase switched model). This validation should look in particular at:
• overshoot (and relate it to the phase margin of the open loop frequency response)
• rejection of perturbations (e.g. grid voltage changes)
• robustness against modeling assumptions (I suggest you focus on one of the proposed topics)

#### Conclusion¶

Finally, you can conclude on what you believe you have learned in this lab (think of both technical topics but also methodolical ones). You can comment about the difficulty you faced and if you believe this lab will in the future help you facing similar situations. You are welcome to suggest improvements to this lab for the next students of the Smart Grids program (you can also do it orally if you prefer).

### Technical files¶

You don’t need to submit your “technical files” (Matlab scripts), although your report can include code extracts if you think it’s appropriate.

## Presentation¶

Useful document: checklist Presentation evaluation.pdf.

### Format of the presentation¶

15 minutes presentation + 15 minutes discussion

You may want to rehearse in advance to respect the allocated time (neither too short, nor too long). If you rehearse alone (without an audience), keep in mind that we usually take more time when facing an audience.

Each group member should be the speaker for part of the presentation and the transition between the parts and the speakers should be smooth.

#### Slides¶

In order to be more comfortable during the presentation, it is highly recommended preparing slides (PowerPoint, Impress, LaTex/Beamer…), instead of scrolling through the report.

Rule of thumb: 1 slide/minute (important detail: slide should be numbered)

Slides should be designed with readability in mind:

• big enough font size (including on figures and diagrams)