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Despite what many may believe, the aviation sector's contribution to global CO\u2082 emissions is relatively small. Even so, it is clear that sustainability and efforts to reduce the environmental impact of all economic sectors are, and must be, a global objective. And those efforts involve decarbonisation.<\/span><\/p>\n\n\n\n Due to various circumstances, aviation is one of the most difficult sectors to decarbonise. For this reason, for some years now, various solutions have been promoted to help reduce the use of fossil fuels<\/strong>. A significant part of these efforts focuses on the use of alternative energy sources, notably sustainable aviation fuels (SAF), but also on greater efficiency and reducing the energy demand of aircraft. Essentially, this involves greater electrification of aircraft<\/strong>.<\/p>\n\n\n\n The objective is to promote the design of hybrid or electric aircraft<\/b>, especially, at least in the short term, as a solution for short and medium-range flights. This is undoubtedly a feasible mission, but it is not withoutseveral challenges<\/b>.<\/p>\n\n\n\n <\/p>\n\n\n\n Personally, whenever I hear any expression with the word \"electrification\" in it, I think of the scene in Jurassic Park with the 10,000 V wire fence around the T-Rex enclosure, where we all saw it coming that someone would be electrocuted... Although, in reality, the famous scene with the boy on the fence can be considered a failure that no electrical engineer would have accepted, as there was no earth faulty shunt to close the circuit.<\/span><\/p>\n\n\n\n Possible script errors aside, the trend over the last 20 to 25 years, especially in the automotive world, and with the aim of contributing to the decarbonisation<\/b> the economy, has been to progressively increase electrification<\/b>, and with it, the working voltage in vehicles. But why?<\/p>\n\n\n\n We will try to explain it in a simple way through the well-known formula of Ohm's law, and its corollaries in the form of power:<\/span><\/p>\n\n\n\n The first formula, Ohm's Law<\/b>, states that voltage (V) and current (I) are proportional to a constant (R) commonly known as resistance. This law can be used for both direct current (DC) and alternating current (AC) circuits. The second formula is simply the multiplication of both variables to see the quadratic dependence of voltage and current on power (doubling the voltage or current provides four times the power).<\/p>\n\n\n\n It can be seen that if we want to increase the power delivered by the electrical system (battery) of our car, we have two options: O <\/span>we increase V (voltage), or we increase I (current)<\/b>R is the load or resistance of our system, and is constant for a given car and conditions.<\/span><\/p>\n\n\n\n Between increasing V or increasing I, there are some pros and cons that make engineers opt for one or the other alternative. <\/span>Roughly speaking<\/span><\/i>The disadvantage of increasing V is that the conductors and sub-circuits need to be better insulated to prevent arcing or voltage discharges to the vehicle chassis, while increasing I has the disadvantage that the effective cross-section of the conductors needs to be increased in order to carry the higher current that has to reach the sub-systems.<\/span><\/p>\n\n\n\n This is where the <\/span>synergies between the aeronautical world and the automotive world<\/b>The ultimate aim of electrification in the very short term is to save fuel by carrying less weight, and to reduce the weight of the vehicle. <\/span>in the medium and long term, we want to be fuel-free in order to decarbonise our planet and reduce our carbon footprint as much as possible.<\/b>.<\/span><\/p>\n\n\n\n <\/p>\n\n\n\n Circuits at higher voltages than the classic 12 V that we found (and still find for the starter circuit) in our combustion or hybrid vehicles, fall short for this purpose. And that is why the automotive industry started to mobilise to look for <\/span>an optimum between the battery pack to be installed, the required insulation, the resulting operating voltages and the required <\/b>inverters<\/i><\/b> or inverters needed to switch from AC to DC during the charging, discharging and regenerative braking process.<\/span><\/p>\n\n\n\n Many manufacturers placed this optimum point at around <\/span>400 V for electric vehicles<\/b> (hybrid, plug-in hybrid or fully electric), since Silicon (Si) and IGBTs (Insulated Gate Bipolar Transistor) technology was well established thanks to previous work on soft starters for single and three-phase motors for HVAC (High Voltage Alternate Current) present in various industrial machines. The problem started when 100 km of autonomy was not enough, or a full charge in less than 1 hour was not achievable.<\/span><\/p>\n\n\n\n This is the birth of the <\/span>batteries of higher voltages<\/b> to achieve greater autonomy, accompanied by other types of technology that <\/span>can no longer be based on Silicon alone, but on Silicon Carbide (SiC) and Gallium Nitride (GaN).<\/b>which enable electronic developers to <\/span>work in the 400 - 900 V range with high efficiencies<\/b>This is understood as low heat dissipation in the delivery of the battery to the vehicle's electric motors, as well as high efficiency in the Wall Mount charger that will deliver power from the domestic mains to the battery for recharging when plugged in.<\/span><\/p>\n\n\n\n We won't go into too much detail about why SiC or GaN can work at higher voltages than Si, but we can comment that the main explanation is that they are <\/span>devices that are referred to as WBG (Wide BandGap)<\/b>. This higher value in SiC and GaN to pass an electron from the valence band to the conduction band is what makes it possible for them to have higher breakdown voltages and, therefore, to work at higher voltages than Si alone.<\/span><\/p>\n\n\n\n <\/p>\n\n\n\n And what is happening in the aeronautical world? Quite simply, the same thing that happened in the automotive world 24 years ago: <\/span>We want hybrid or electric planes to help us decarbonise and reduce our CO2 per trip.<\/b>. The challenge is that the power required to fly a light aircraft is not comparable to that needed to drive a car.<\/span><\/p>\n\n\n\n <\/p>\n\n\n\n For this decarbonisation of the aviation sector to be effective, i.e. for aircraft to be truly electrified without losing functionality and profitability, it will presumably be necessary to promote the <\/span>innovation<\/span> in various development pathways, including:<\/span><\/p>\n\n\n\n Again, the aviation industry will be able to take the concepts that the automotive industry has developed for the decarbonisation of its vehicles, adapting and improving them for electric aviation according to its boundary constraints. But what does seem clear is that, to electrify aircraft, it will be necessary to <\/span>design new inverters in the range 250 - 600 Vdc<\/b>The first stages (hybrid aircraft) bleed this inversion of the engines at 115 Vac @ 400 Hz, complying with all applicable aeronautical regulations (DO-160, MIL-STD-704, etc.), and then move on to a <\/span>all-electric model aircraft, perhaps at a voltage in excess of 900 Vdc,<\/b> where SiC technology has to be researched and polished as it was done decades ago with Si-based technology.<\/span><\/p>\n\n\n\n Companies such as <\/span>AERTEC<\/b><\/a> We are now ready to design and realise this new future that the decarbonisation of the aviation sector is leading to. Will you join us?<\/span><\/p>\n\n\n\nSeeking solutions for the decarbonisation of the aviation sector<\/span><\/h4>\n\n\n\n
Challenges in vehicle electrification for decarbonisation<\/span><\/h4>\n\n\n\n
Decarbonisation of the aviation sector through electrification <\/span><\/h4>\n\n\n\n
Particular features of electrification in aviation<\/span><\/h4>\n\n\n\n
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