1. I see in your Linkedin Bio that your background is in botany and chemistry; what inspired you to found OSU’s Solar Vehicle Team?
A: I was working with Hai Yue, who is Founder & Leader of the Oregon State University Solar Vehicle Team (OSUSVT) in the Chemistry Club at OSU, and he asked me to help host an Electrathon race comprised of high school students racing home-built electric go-carts. After working with the high school Electrathon race, Hai Yue asked me to help him start this cool new team at Oregon State. It has been a fun, challenging and fulfilling experience, which has resulted in three solar cars, me switching to chemical engineering degree for a Ph.D., one first place trophy, and me marrying the guy who talked me into this crazy business in the first place!
2. Is there any significance behind the solar car’s name, Phoenix?
A: Yes. Some parts of the car actually contain burnt remains from our last vehicle, which was destroyed in a fire in 2011. So the name Phoenix actually has quite a lot of significance; this car also represents our team's hard work and optimism after our last vehicle was destroyed.
3. Are there any governing ideas from your study of nature that stirred any of the design choices?
A: Not really, except that every time someone suggests that we engineer a solar cell based on plant photosynthesis, I tell them that if we wanted to do that we'd be racing a biodiesel-powered vehicle, not a solar-powered vehicle. What my background really has provided was experience in leadership in my extracurricular activities.
4. How has Phoenix’s design evolved from its previous two predecessors?
A: The Phoenix was designed to be have much better aerodynamics than the first car and more elegant simplicity and reliability than the second car. Our team's solar module production results have improved significantly with each new array and our electrical design has become more reliable and robust.
Solar cars sacrifice seating space for solar arrays
5. What impact has your participation in solar car racing had on your future aspirations?
A: I have completely changed my career path from plant genetics to chemical engineering with a focus on optics of solar module). I find that, in making my hobby into my career, I am much happier and more well-suited to my research and I will now have a much more marketable degree.
6. How is your team’s design set design apart from that of their competitors in the Formula Sun Grand Prix?
A: We had two big advantages in this race. First, we arrived with a reliable, previously tested vehicle. Second, we are using a battery technology that is safe and efficient- with high charging and discharging efficiencies, our lithium iron nano-phosphate technology enabled us to keep racing when other teams' battery monitoring systems were shutting off their cars to prevent an overheating event. Except for our motor, which has been somewhat unreliable, our vehicle has been very dependable. We are working hard to secure funding to replace it and refurbish our current motor, so we can have a spare and continue improving our vehicle.
7. What’s the biggest challenge that arose from the Formula Sun Grand Prix’s race regulations and how were these overcome?
A: The biggest challenge from the FSGP regulations is that each team is only allowed six square meters of solar cell area. Our team managed to purchase bare solar cells and solder and laminate our own array, and the students did a very good job producing those modules. However, since we were working with a new kind of solar cell, there was one change that we should have made to our module design that we intend to incorporate next time to get more power out of our array. Because of this, we had to be very frugal with our power usage. A combination of great driving from our four drivers, efficient aerodynamics, good organization during solar charging times, and careful strategy for speeds during the race allowed us to complete the most laps.
8. What’s the furthest distance Phoenix has ever traveled in one sitting and how frequent are maintenance checks performed?
A: I would have to check the racing history to answer this question absolutely accurately, but the Phoenix usually traveled around 100 miles between driver swaps during the road race. That distance is similar to the distances traveled between driver swaps for the FSGP this year, unless the car had a problem. During the race, we had two popped tires, one brake scraping, and one motor problem during the race, all of which required pit stops.
9. According to OSU Solar Vehicle Team FAQ, Phoenix’s top speed of 85mph has never been tested. With that said, what’s the fastest speed that was tested?
A: We have driven the car 65 mph, which is the top legal speed for solar cars in the ASC or FSGP, and is also the top legal speed of roads in Oregon. And if you speed during the races the officials will penalize the team.
10. How much power can the solar panels harness and what type of voltage regulators does the vehicle use?
A: The solar array outputs just over 1 kW in full sun. That power is sent to three maximum point power trackers (AERL MPPTs, one for each sub array). The voltage is stepped up from 70 V coming out of the array to 110 V going into the battery by these power trackers.
11. How did you balance structural integrity with the light weight requirement of an efficient solar car?
A: Our team is very fortunate to live close to a titanium producer. We were able to design for and build our frame and suspension with titanium. Though titanium can be difficult to machine and weld, our team has been practicing for years and is very pleased with our titanium components now. Also, the body is produced, thanks to our generous sponsors at Composites Universal, Lancair and Boeing, out of pre-impregnated carbon fiber, which is the lightest, strongest option available to us for making the shell of the car.
12. What role did National Instruments’ CompactDAQ and LabVIEW play in monitoring and maximizing the electrical system’s efficiency and how crucial was electrical systems’ maintenance in your design?
A: The NI CompactDAQ and LabVIEW system design software were essential to the lamination and testing of our solar modules. We used LabVIEW and an NI GPIB cable hooked to a source meter to test the solar modules before and after lamination, which revealed any problems with the solar modules, enabling us to fix them before laminating them permanently to a film of plastic. The lamination system is controlled entirely using the NI CompactDAQ. LabVIEW also enabled our team to design a simple state machine that steps the laminator through the different stages of our lamination protocol. Our CompactDAQ controls vacuum solenoids, a heater, and also reads a feedback thermocouple.
13. Do you foresee the proliferation of this technology in future consumer auto-mobiles?
A: We have already seen proliferation of this technology in consumer automobiles. In the 1990's GM participated in the SunRayce (now the American Solar Challenge). They used the research that went into developing their solar vehicle to develop the drive train for the EV1, the star of “Who Killed the Electric Car.” Also, about a decade ago Stanford's solar vehicle team wasn't doing well with their solar car, but they had an electric car laying around that needed some work. One of their teammates, JB Straubel, thought they should just put a ton of batteries into the car and make a long distance EV. He showed this to Elon Musk and they started Tesla motors. So, I predict we will continue seeing innovation and these types of technologies in consumer vehicles.
However, neither of those examples include solar modules and the transportation industry has a long way to go before developing completely solar-powered vehicles. Currently, highway-legal vehicles, including EVs, are too heavy with aerodynamics that don't quite allow for complete solar power. Most vehicles have less surface area where you could put a solar array than our solar vehicle does. Let's say you have half the space (3 square meters of solar area) and that you have 500 W of solar input in great sun. The energy draw per mile from most vehicles is about 0.1 weight in lbs. So if you have a 2,000 lb vehicle, you might use 200 Whr per mile. So, after an hour of charging from this array you would only be able to drive 2.5 miles. In order to fill up your 100 mile battery pack, you would need to sit it in the sun for four days. Also, if you get into a fender bender you would need to replace the entire integrated system.
So, for now, I think consumers can be more energy efficient by putting solar cells on their roofs and driving electric vehicles. Of course, there is still a lot of opportunity for growth and innovation with solar vehicle challenges. For example, these competitions challenge students to propel a car at highway speeds with less than the power of a hairdryer. This produces creative and experienced students that have learned to think critically about the balance of design required for strength, reliability, and efficiency in an electric vehicle. The talented students of OSUSVT have created a vehicle that can drive for days on end without charging and hopefully few breakdowns. They have managed to do this on a tiny budget in their spare time while also taking a full load of classes. These are the types of engineers that we want hired into the EV industry to help continue improving energy efficient vehicles. By founding the OSUSVT, Hai Yue and I believe that we're not just making solar-powered electric cars, but we're making smart, skilled engineers!
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