DC Diaries: Day 4. D-Day.

I woke up with a sore throat this morning after only sleeping 5 hours. I was still practicing in the shower as I was getting ready. Then headed downstairs for the author's breakfast. I was feeling pretty awesome, not nervous, really perky, really excited, joking, being charming. My advisor even asked me what was wrong with me and said that even he gets nervous sometimes.
On the way to the lecture hall I saw Ryan and Jeff and told them how excited I was feeling.

L: (really excited) DUDE! this is going to be GRRREAT! I can't wait, I am so ready!! Man, I'm not usually this perky!
RYAN and JEFF: (at unison, while rolling their eyes in annoyance) Yeah actually, you are.
::laughter::

The session starts and I am the third presenter. By the end of the first presentation I was worried because the room was emp-tee. At 9:10am people start swarming in as the second presenter is answering questions. I am psyched, you don't even know, I was ready to take on the world and deliver this amazing talk, there are over 100 people in the room, I was really excited even as the session chair introduces me. Then I step up to the podium and... The fucking air escapes me, I can't breathe, I try to utter some words, I even had a joke prepared:

L: Good morning (shaking). I want to thank all of you for attending this session... (silence... I decide I need to put some effort into breathing, otherwise I will pass out in front of all this people) This is my first conference and I have to say it has been a wonderful experience. I wanted to congratulate the Organization Committee for doing such an amazing job, however I do have one suggestion: If you are going to gift a woman with a money clip, it should at least be pink.

(There is some minor laughter in the back of the room where all my friends are sitting, I had asked them to attend and be my official joke laughers. Other than that, the room is cold and silent)L:... And I am sure all the ladies in the room will agree with me... All three of you.

(Again some sort of mumbling, maybe somebody giggled or sneezed)

L: Ahem (still nervous, somebody do something!)... Well, that is not what I am here to talk about, I am very excited and grateful to be here today and have the opportunity to share with you my research... etc...

I had practiced the talk so much, I somehow managed to unconsciously spew out some intelligible English. Mid talk I can actually breath a little easier, and at the very end I was sort of "normal" again. Now it was time to answer questions, and they only let me have at three before the time ran out. Questions were easy, phew! All three people who asked their question congratulated me, said they were impressed with our results, and one of them even said that the implementation of pass-through mode (you need to read paper to know what that is) was "quite clever".
The next presentation was from my advisor, on microinverters for PV roof shingles. The room was full at this point, and afterwards there was a 30 minute break before the next talk. People swarmed around us, asking more questions, asking for my email, congratulating me, shaking my hand, asking me to kiss their babies, etc, etc. I felt like a million bucks! All kinds of people approached me saying they were working on very similar stuff (dc-dc solar module integrated converters) and they were from all over: Georgia Tech, MIT, U of North Dakota, some guy from India, Spain, Japan, it was AWESOME! I have always felt like my work is cool and relevant, but I also always wondered if other people think so as well. There are many solar power skeptics out there, and even I have my doubts about the future of solar power sometimes, so it is great to be reassured this way. I want to do a conference again!!!!

Afterwards I escaped to the Adams Morgan district looking for a cafe with free wifi to relax and get away from the engi-herds for a little while. I met up with some of the guys at a diner and we had lunch and beers.

I slept for the rest of the afternoon because I was really tired and the sore throat was coming back. In the evening we went to Chinatown for dinner. Then Ryan and I met up with Leah (Erin's college roommate, sweet girl, funny, works at NPR in Washington) at a bar. And we also met up with Alfredo! this is a friend from high school, he was a year older, in my brother's class. He found out I was in DC through Facebook and met us for beers! It was really fun and I was so happy to see him again. Ryan, being the eccentric he is, bough everyone some really fancy Belgium champagne beer, rested in French oak, /*insert more fanciness here*/ . Mmm, deliciosa...
Then I had one last beer at the hotel with the rest of the guys and now I am off to bed. Must wake up in 3 hours for the flight home and I am NOT feeling good.
Here is my paper and presentation by the way.

What I learned today: Engineers are robots! I am funny goddammit!
Currently feeling: Tipsy, tired, stuffy...
Currently listening to: "Reckoner" by Radiohead

DC Diaries: Day 3. I'm psyched.

Jeff overheard me saying I would love some chocolate over lunch and bought me a gigantuous chocolate bar depicted below. It was supposedly my good-luck-at-your-first-talk present. What a nice guy.

I just found out today the total number of registered people for this conference is 1900. It is pretty huge and admittely they have done a fairly good job of organizing it. The food was great, the exhibits thorough, some of the papers were not as exciting but the all the special presentations and rap sessions were really good.

My advisor gave a presentation on the future of power electronics for photovoltaics (PV) and it was a nice introduction to the subject, I hope that it encouraged people to attend mine! There was a dinner, with free flowing wine and beer and some entertainment after it. The Capitol Steps, a political satire/musical group, kind of funny, but mostly... not, only a couple of their numbers really made me laugh.

I am writing to you from my room and I will not be going out tonight because my presentation is in the morning. I practiced it a couple of times, took a bath, relaxed and I feel really good about it. I have to be at the author's breakfast tomorrow bright an early. Please channel all your good vibes towards Washington DC, tomorrow morning at 9:20am Eastern time :-)

Currently feeling: psyched!!

Currently listening to: nothing, I am practicing!

DC Diaries: Day 2. Moving on.

Something I learned today: If you ever want to publish anything in the field of Electrical Engineering, and I can only speak for the area of power electronics, there are a few keywords that MUST be present in your publication title. A bad title may be the sole reason your paper gets rejected from a conference or journal. These keywords are: "novel", "new", "improved", "sensorless", "optimized", "optimization", "superior", "cost-effective', and etc, etc. You get the idea. Though I'll admit if I ever see a paper titled "Cheap, inefficient, inaccurate something that gets really hot yet does the bare minimum of what you need" I would definitely go see that talk an read that paper. Funny thing is my paper has the word "improved" in it, which I chose before learning about this trend.
Something else I learned today: I don't always realize how famous/accomplished the people I work for are. Power electronics is big, and the fact that everyone I meet knows the names of my professors feels kind of weird, though admittedly pretty cool.
Today the morning was a bit slow. I attended some good talks and schmoozed with companies. We had the afternoon off and so we went sight seeing. We visited the Capitol Building, the Library of Congress (LOC), the National Mall and the Space and Air Museum. The LOC was my favorite, they had a special exhibit on Abraham Lincoln, which was really interesting, but I mostly fell in love with the architecture and paintings of the building. The ceilings, the details, the finishes, arches, the frescoes, it was all awe-inspiring. We went back to the hotel and while everyone decided to attend a talk on the future of electric vehicles, which sounded awesome, I decided to be responsible and retire to my room to do homework :-(

I have said it a million and times and I'll say it once more. I HATE homework. Despise it. I have been a student for too long, and I know it was my choice, and I am working with it. But honestly, I'm so sick of it. Siiiiick!

In the evening we had thai food for dinner, then some beers at an Irish Pub, called "Murphy's", which has to be the most common name for an Irish Pub in the world. We met some Canadian and Spanish students at dinner, but they were being lame and didn't want to drink with us. All and all a pretty good day, laid back, not too much to report.
I think I will practice my presentation once tonight and then go to bed. The big day is on Thursday. Peace.


Currently feeling: At ease
Currently listening to: "Comtine D'un Autre Ete: L'apres Midi" by Yann Tiersen

DC Diaries: Day 1. It was all going so well...

I arrived in Washington DC around 1:20pm this afternoon. The group proceeded to the hotel, and because I am the only female out of 10 students from our group at this conference, I was given the option to get a room for myself, which I took. For some odd reason my room ended up being in the far end of the building, an old wing of the hotel where nobody else was staying. This turned out to my advantage because my room is so much nicer than everyone else's. It is very cozy and quaint and I feel like am staying at a fancy bed and breakfast in upstate New York.
Immediately after arrival we proceeded to the Conference registration, where they already had my name and there was a goody bag waiting for me. The goody bag contained a CD with all the technical session presentations, a program with the schedule for the week, and oh goodness there was freebie in there too! A gift, if you will, something to make this week even more unforgettable. What could it be? well if it isn't a money clip!!! How lovely no? I opened it in front of the registration personnel (all women) and said out loud "are you serious? a money clip? how feminine!" And of course, I was right, so the ladies in the registration staff laughed out loud. I promised to myself and my colleagues I would write a serious note recommending a more unisex gift for the future, and I will drop my money clip with note attached in the suggestion box at the end of the conference.
The afternoon went on, I found a few of my friends that I used to work with/for at the University of Illinois. I invited them to my talk, though also admitted to them I was quite nervous because green energy is a hot topic right now, so I can foresee a lot of people attending it. Anyway, some of us decided to ditch the plenary session and go grab some food and drinks. We ended up at a sushi restaurant across the street, sat on the floor, ate some sushi, drank some beer, it was a lot of fun!
After dinner we decided to head to he corporate exhibit where corporations strut their stuff by showing all the latest technology/products. There was free beer and wine at the exhibit, one of the main reasons we were so inclined to attend. I grabbed a beer and started walking around. At some point I start talking to a French man from a certain semiconductor company I will not mention. I thought we were having what I would call a competent discussion on his flyback converter controller chip, that in this case was being used to drive the circuit of an LED lamp. He asks me where I am from, and I say Venezuela, I ask him where he is from he says France. He also introduces me to his other French colleague standing nearby and all of a sudden says "Are you over 21?" I looked at him, a bit offended and said "Yes, of course I am over 21, I am in gradschool, why do you ask?" he says "well, I just see you with this beer..." Now don't get me wrong, everybody was walking around with a beer, and mine was mostly full!! His other French colleague steps in and says "please don't mind him, it's a little French humor" and proceeded to ask me some off the topic question about my work, I politely answered it and then I said "right, well it was nice to meet you both, thank you for sharing with me about your chip" I shook their hands and left.
What... the... f*ck? This would NEVER, EVER, happen to a man no matter how young he looked like. This is the kind of attitudes that make me want to strangle people!!!
I went back to my friends and told them about it, they said the French man was a douche and suggested I forget the whole ordeal. Then they started a joke out of it, which made me laugh, bless their souls for making me laugh. Now every time someone does something seemingly dumb we ask "Are you over 21?"
I just came back from a game of darts at an Irish Pub and even though I already let it go, it still makes me kind of uneasy to know that I will always encounter this sort of disrespectful sexist attitudes in my workplace. I honestly don't know how to interact with these people and would love to hear some suggestions. I don't need you to agree or disagree with me, I just want to know what you would do.

Currently feeling: frustrated, still a bit angry, or maybe just annoyed
Currently listening to: "All Alright" by Sigur Ros

DC Diaries: Day 0

The date is finally here! We get to go to Washington DC!!!1! By we I mean Aaron, Barry, FuZen, Jeff, Luca, Quing, Raj, Ryan, Thurein, Xu and I!! Woo-hooo!!!! partaaay! It's going to be madness!... not. Are you kidding me? We're going to a power electronics conference people! in Washington DC, not in Rhodes, Greece (where PESC was last held), it'll be nerdy as hell!
I have low expectations. During the day it will be mostly boring and tiresome, but I do hope to make it interesting for myself by exploring the city a bit and who knows? maybe I'll actually meet some interesting engineers! and who knows?! maybe someone will give me job! ::sigh:: Scott, my offer to be your personal shopper/assistant is still up.
I will be keeping an online diary through this blog, where I'll try to post everyday for... erm... 5 days. I will report on how I am feeling, what I did, who I met and what I learned about. If you intend to follow along daily... good luck to you. I don't own a digital camera of any sorts, my toy phone ($14.99 at target) doesn't even have one. My laptop has a webcam which I intend to use as often as possible, when appropriate. Other than that, I may be stealing SD cards from people.
We leave tomorrow bright and early, Ryan is picking me up at 3am, we take the bus to the airport, flight leaves at 6:15am. And what am I doing right now?? well I am trying to write a half-decent blog post, and immediately after I promise to start packing. For progress on packing, see figure below.
This is my room! (as seen by my shitty laptop webcam) It looks ten times worse when I am packing for a real trip, but this is how it starts... We have here a hair-dryer, straightener, hair product, face lotion (SPF 15!) and body lotion. This is really all a girl needs, I could live on this for weeks. I think the lotion has natural organic ingredients, so I could eat it for survival. On the right side there is a pile of fresh new laundry that I will have to sort through for undies and socks. On the far left is my bookcase, or as I like to call it "the library". In the background is my closet, you can't see much of what's in there either, just clothes and enough shoes to feed a small African country. I kid! I kid!!! I don't have that many shoes... anymore.
And what am I up to? if not getting ready for my trip, you ask. Well, I was watching the news, following in on the referendum happening in Venezuela, where the people get to decide on presidential term limits. I am sad to announce that the referendum passed 54.4% to 45.6% allowing Hugo Chavez to be re-elected indefinitely. Sad faces all around. I don't have a good conclusion for this post, it took a sad turn somewhere... Ok, I guess I go pack now.

Currently listening to: "Between the Bars" by Madeleine Peyroux.

Thanks for your visit! Come again!

Whoever you are... :-)


Visits from the last 2 months.

Panama Vacation

I scribbled the following on the sick-bag in the plane ride back from Zurich:

(Yes, I went to Zurich)

(Yes, in Switzerland)

(Nuff said)

It was last summer when I decided to visit my parents' for the holidays in their new house in Boquete, in the Chiriqui Province in Panama. Now in order to guarantee sanity (or maybe insanity?) I also invited a few of my closest friends to come with me. It was particularly important to me that my friends met my parents, and that I got to share a bit of my culture with them. It is a side of me that doesn't show often but that I am very proud of. All in all, the house was beautiful, the food was superb and we have three really adorable neighbors that are 3, 5 and 7 years old and they say things like:

"My dog is a boy because he has a beard" and "No! you can tell he is a boy because his collar is blue"

I hope I speak for everyone when I say that we had a freaking blast. Panama is beautiful, there is lots of things to see and do. Overall my favorite was the unconditional hospitality and charm of Panamanian people. People that value and respect their land, their traditions. People that work hard and play hard. People that celebrate life for what it is and always carry a smile on their face.

To enumerate a few of the things we did in Boquete: swimming in waterfalls, relaxing in hot springs, dancing the old year off, rock climbing, hiking volcanoes, going to the beach, and there was a bit of drinking and dancing here and there to tie it all together. On the last day we also visited Panama City, the ruins of Panama Viejo, the Panama Canal and Las Bóvedas (el Casco Antiguo). Panama Viejo, a UNESCO World Heritage Site, consists of the ruins left of the original Panama City, which survived earthquakes and fires but was ultimately sacked in the year 1671 by the pirate Henry Morgan. The Panama Canal has some very interesting history and I must encourage you to read it, it is truly an amazing engineering feat. El Casco Antiguo is where Panamanians relocated the city after the pirate attack. It is also now a UNESCO World Heritage Site and all the buildings are undergoing major renovations. Unfortunately, the renovations have driven a lot of Panamanians to relocate to government housing, but it has also brought in a lot of foreign investment and stimulus to the tourism and service insdustry. All the buildings in el Casco Antiguo have a colonial feeling to them and inside there are apartments, shops, art galleries, hotels, cafes and restaurants.


Do check Steve's photostream for some fun trip documentation. Parisa stayed on her own through the last weekend and visisted Bocas del Toro, something I would love to do next time. She also took lots of great shots of the vacation, to be checked out here.

Sigh... Back in Boulder. Back to work. Dealines soon. I am feeling depressed.

22 days...

Now that the paper was submitted I can focus on really important things. Like my upcoming trip to Panama to spend Christmas with my parents and hang out with my favorite posse. I talked to my dad today for a while about things we could do while there and got really excited. So I spent most of the day researching Panama and Boquete, the town we'll be staying in.

I am a big dork (and maybe a bit of a control freak), and so I made up an itinerary. This is especially useful to me because everyone arrives and leaves at different times! So I wanted to make sure we all got to spend some quality time together, so this is my quirky (to put it gently) way of saying: I <3 you and can't wait to see you.

Note: Itinerary subject to change without notice

Saving the world, one solar panel at a time

If you saw my previous post you probably thought "wtf is this?". I'm sorry that I did such a poor job of labeling anything on the graph, but I was really excited and it was sort of a rushed post.

Anyhow, as all of you know I've been stressing out over my research project because I still hadn't gotten any solid results worth publishing (deadline is less than 2 weeks). But now we did! and I want to share the loooooooooove :-) Get ready for me finally getting technical.

How solar panels work
Your typical photovoltaic (PV) cell is made out of silicon, though there are many different types and technologies that are quickly gaining better reputation. In lamest terms (and because I actually don't know much more detail about it) a photon is capable of kicking off an electron from the silicon valence band, effectively creating an electron-hole pair that flows creating electric current (and power!). Sounds very simple but not all photons are capable of creating the e-h pair. For this to occur the photon must have at least the same amount of energy as silicon's bandgap energy. If the photon is higher in energy the excess transforms into heat, same thing with low energy photons, they don't produce e-h pairs but they are still absorbed by the material. This is the reason why solar panels get hot, very very hot.

The solar resource
In case you did not now, solar panels are extremely sensitive to shading. Shading from clouds, neighboring building, trees, birds, etc. The relation between solar irradiance and output power is linear, however the relation between shading and output current/voltage is not. We only care about this if we put several solar panels in series or parallel to form a system, because then all the panels interact with each other and the operating point of Panel 1 will heavily depend on the operating points of Panels 2, 3, 4... n.

The series string problem
Solar panels produce direct current (dc) power, while pretty much every appliance in the world uses alternating current (ac) power. In order to interface the two you need an inverter. Types, sizes, cost, efficiency of inverters varies widely depending on the application, but one thing is known: the smaller the inverter the higher its efficiency is. Inverters tend to be big because more often than not they need a large transformer to convert the output voltage to 120V-ac, and transformers just like any type of magnetics tend to be lossy.

Typically, in a residential or commercial installation you would like to build up the dc voltage of your system and maintain it relatively constant in order to maximize the efficiency of your inverter. Hence everybody would like to put their solar panels in series, but this brings on another challenge as well. If the panels are in series they all share the string current, which means that the panel with the lowest output current will dictate where the rest of the system operates. You can bet all your money that the PV panels will operate far from its maximum rated power, and your entire system efficiency goes to hell. A single cell out of hundreds in the system can cause malfunction of the entire string.

Module integrated converters (MIC)
To solve this problem many people have proposed inserting a high efficiency dc-dc converter at the output terminals of each solar panel before interfacing to the string. Each converter performs what is called Maximum Power Point Tracking (MPPT) to ensure that the panel is operating at the point of maximum rated power. This way each panel is effectively decoupled from the string and it is insensitive to any changes in the system. This solution has been proven many times before BY SIMULATION. So far there hasn't been any published research on a real system with actual hardware.... until now... And let me tell you why there isn't published research on real systems, BECAUSE BUILDING THIS STUFF IS HARD!@%#~!!!

Last Saturday Sara (from the building systems group in the Civil Engineering department), Scott (undergraduate EE working for my advisor) and I went outside for what I thought would be another failed experiment. But luckily I was wrong and the experiment went really, really well. What the graph from the previous post shows are performance results from the three cases we studied. The blue bars represent the series string without any converters, three solar panels in series, period. The green bars are the system with my converters and the red bars are the percentage power gained by integrating the converters in each case. The first set of three bars is when all three panels were at full sun, you can see the gain is negative because there is a tiny bit of power used by my converters, but this is still a kick ass efficiency. The next set of bars are the system under "medium" shading conditions. I can't tell you what "medium" is because we haven't defined it yet, but it implies significantly lower solar iiradiance. The important thing is that output power was improved by nearly 20%. In the last case, the system was under "heavy" shading conditions, and the converters helped increased the output power by almost 40%!!!! These are really excellent numbers and I was very pleased with them.

It has been 6 long months since I first started building the circuit. Some days were longer than others, but I'm glad that now I get to relax a little bit more. Not just that but when good things happen I tend to feel more motivated to work. This research will be published next year in the Applied Power Electronics Conference 2009 happening in Washington D. C. next February where yours truly will be presenting this work.

The day after making history
As you expected I went out last night to celebrate this moment of history-in-the-making. I drank waaaay too much, and to make matters worse the bar we went to had karaoke. It was pure anarchy, by the end of the night I wasn't seeing double, but triple. I was hugging strangers and talking to them about solar power, it was ridiculous and wonderful. Most of today was spent in bed feeling sick, *sigh*. This is going to be a great week.

:'-D

*sigh*