Are solar airplanes reality?
Flying a commercial passenger airplane from point A to B takes a huge amount of energy and power. If these demands were translated to a sustainable solution based on current technology by replacing kerosene with batteries, the weight would be much higher and more surface would be needed (or more efficient solar cells) to yield sufficient energy.
So it may not be possible for commercial passenger flights yet, but there are several initiatives to prove that solar powered electric airplanes are indeed the future.
One example is the famous SolarImpulse initiative that aims to fly around world on solar energy. The Solar Stratos project takes it even one step further, demonstrating the potential use of renewable energy by taking on the challenge of flying a solar powered electric airplane all the way to the stratosphere (altitude of 20 km).
Apart from these special initiatives, there are a number of commercial manned and unmanned (drone) airplane projects with different goals. Google’s solar powered drone, for example, has the goal to spread internet all over the world, especially to remote areas. These so called atmospheric satellites also fly at an altitude of 20 km.
One thing alle these projects have in common is the need for solar energy to power their flight. This is where MG comes into play. The energy generated from a solar panel is only a small percentage of the available solar power, typically between 20% and 25%. On earth the average irradiation is around 1000 W/m2.
This means if a solar panel has an efficiency of 25% the generate solar power from the panel is 250 W per square meter. Because of the small amount of energy converted by the solar panel, it is important to convert this energy with the highest possible efficiency in order to use it for propulsion or charging batteries.
The Maximum Power Point Tracker (MPPT)
Converting solar power to charge batteries with the highest efficiency is one thing, but solar panels are not an ideal source of energy. Each solar panel has a so called IV-curve, demonstrating the relationship between current and voltage. Figure 1 shows a particular example.
The key to getting the maximum amount of energy from a solar panel is to ‘search’ for the Maximum Power Point, which is called ‘tracking’. A DC/DC convertor with a Tracking function is required to convert the energy from the solar panel to charge the battery or use it for propulsion. This type of converters is called Maximum Power Point Tracker (MPPT).
There are basically two types of MPPT’s: Boost (from a lower solar voltage to a higher battery voltage) and Buck (from a higher solar voltage to a lower battery voltage). The type of converter we developed is a Boost converter. The MG Solar MPPT is a highly efficient MPPT with a ultrafast tracking algorithm.
MG’s history of development
The development of our MPPT began when we started building a solar powered boat, to participates in several solar challenges all over the world. After successful usage in this project, it we further optimized the efficiency and Tracking algorithm.
Several other race participants noticed the existence of our converter, for example the TU Delft solar team, participating in the World solar challenge in Australia with their Nuna car
s. They tested their existing best MPPT and compared it to our newly developed one.
Upon concluding MG’s new MPPT had a higher efficiency, they began to use it in their solar cars. After their successful win, more and more teams took an interest.
Now over … teams use our Solar MPPT. Every team has their own configuration and the Solar MPPT’s are tailored to their needs.
It’s possible to customize on voltage range, maximum current, connections and CAN-Bus communication.
The use of MG Solar MPPT in Solar Airplanes
The use of our MG Solar MPPT for racing purposes was also noticed by several solar airplane initiatives. One of the companies, Elektra Solar, implemented it in their one seater solar airplane, to face ‘the challenge of stratospheric manned and unmanned flight with solar-powered and emission-free aircraft”.
MG’s Solar MPPT solution ensures the maximum energy yield from the solar panels while keeping the added weight as low as possible, as you can see on our product page.
Table 1 shows the specifications of the different configuration types now available. Note that customizations to meet your project specifications are possible. Don’t hesitate to contact us if you have any questions or need additional information.
|Input voltage range *1
||22 – 58 V
||22 – 120 V
||22 – 120 V
|Output voltage range *1
||25 – 58 V
||25 – 180 V
||25 – 180 V
|Output voltage limit
|Input power range
||5 – 450 W *2
||2 – 700 W
||2 – 700 W
|Input current range
||0.5 – 10 A
||0.5 – 7 A
||0.5 – 7 A
||0.5 – 3 A
|Input current limit
|Output to input ratio range *1
||1.0 – 3.5
|Max. input forward current ( VIN > VOUT )
|Isolated CAN transceiver supply voltage
||10 – 58 V
|Isolated CAN transceiver current draw
||16 mA at 12 V
|Off state current draw
||20 µA at 30 VOUT
50 µA at 60 VOUT
||-20°C to +55°C
||Max. 95% (non-condensing)
Solar airplanes in future
Even if we can’t fly a commercial passenger airplane yet, we are eager to see what tomorrow will bring and passionate to develop more technology to make the future a reality. If it’s up to us, rather sooner than later.