Planes, trains, automobiles and AI — what does the future hold for power electronics?

Can you explain what power conversion is? 

IL: Power conversion generally is about converting electricity from one combination of voltage and current to another. 

Our devices can operate at high or low voltages and can also be supplied by low or high voltages from a power source. That power source can also be AC or DC. So there are a lot of conversion combinations that need to happen to deliver power to a device. 

The basic principle of power conversion is to chop up the incoming power into small portions and then redistribute the small portions to your device. This is how we change the voltage level or convert electric current from one form to another, and we need semiconductors to do this.    

When the semiconductor device chops up the power, it is essentially turning the electric current on and off really quickly. So there will be successive periods where the device is conducting power and then not conducting power. 

When conducting power, we want to limit the amount of conduction loss. When transitioning from conducting power to not conducting power, we want that to happen as fast as possible so no energy is lost in the transition.  

Compound semiconductors are much more efficient at this switching process than silicon-based semiconductors. 

And what is the impact of this improved efficiency?  

IL: Roughly 45% of all electricity globally is used by various electric motors. There are many applications that use motors across lots of different sectors, and both semiconductor and compound semiconductor devices are critical for making these motors work.   

Some of these systems are already very efficient and have low power losses. For argument’s sake, let's say they are 95% efficient. If they can be increased to 97.5% efficiency, you are basically halving the power loss. 

If you extend this small efficiency gain across all of the applications consuming 45% of our electricity around the world, the total amount of losses avoided becomes enormous. 

That's lots of energy saved and lots of carbon emissions reduced as a consequence. 

And are there other emerging materials or compound semiconductors showing promise that we need to keep an eye on?  

IL: Yes, there's a lot of academic research looking into alternative materials. One of them is gallium oxide. That is an interesting material as it has an even wider bandgap than silicon carbide and gallium nitride, but it has some thermal conductivity limitations.  

There is also early-stage research looking into aluminium nitride, which can operate at extremely high temperatures, for example at 1000°C. That's amazing and would reduce the need for cooling in many applications, which would also significantly reduce the weight of the application. This material also has potential, but it is quite far from the market. 

Are there any future applications or trends within power electronics that are particularly exciting? 

IL: The overriding trend in power electronics for many decades has been what we call SWaP-C — minimising size, weight, power (loss) and cost and trying to optimise each one. Up until now, this has been done in a non-organised way with lots of trial and error. 

What we’re seeing now is a move towards automating this process by taking advantage of machine learning and artificial intelligence (AI) techniques. This will allow us to design power converters in a more systematic and automated way so that the right components are chosen for optimised circuit topology for each specific application. Ultimately, we will be able to make power converters more efficient using less materials and at a lower cost than before. 

We call this multi-objective optimisation. It’s really exciting and something that we’re heavily involved in at CSA Catapult.

What are the challenges or obstacles facing the industry, and how might they prevent us from reaching our Net Zero targets? And what are we doing to solve them? 

IL: One big challenge for power electronics, especially in the energy distribution market, is the required lifetime of a power converter. 

The big and bulky passive transformers we currently use have been doing a good job for 40 or 50 years. Trying to replicate that longevity with power electronics is challenging because these devices are much smaller and contain many, many individual components to make a system. And just from a probability point of view, components can fail, so this is a really big challenge. 

Staying competitive is also a challenge, especially with many different sectors requiring power electronics and developing so quickly. This is where AI will have the biggest impact, allowing us to search and simulate different solutions and combinations in just a matter of minutes compared to weeks and months. 

Looking to the future, what does the UK need to do to capitalise on our expertise and push us towards our Net Zero targets? 

IL: It’s positive to see the UK government is aligned with the UK's strength in compound semiconductors, and that provides many opportunities for the sector in the UK. The UK is very strong in academic research in compound semiconductors as well.  

We can use this to our advantage and position the UK as leading the world in compound semiconductors, from the design and manufacturing of devices, the packaging and the power converters for many different markets.

All of this will help to grow the UK economy and achieve Net Zero targets. 

However, to fully develop the industry at scale, future investment in the overall supply chain will be required.  

And what role can CSA Catapult play in this? 

IL: The CSA Catapult supports the UK industry in developing the technical innovations required. We also convene and influence for the industry.   

In the power electronic sector, we have been working very closely with our packaging team at CSA Catapult and together we've had over 20 collaborative research and development projects that have supported the industry in evaluating different solutions for the transportation, energy and data centre markets to fully exploit what compound semiconductor components can do. 

And finally, how optimistic are you that the UK can reach its Net Zero targets and how important will compound semiconductors and power electronics be to achieving this? 

IL: I'm very optimistic based on the technical strengths in the UK, within academia and industry.

I’m also optimistic about future government investment into this area to build a supply chain that can establish the UK as a global leader in compound semiconductors.