Electronics

Ultra-high voltage transistors aim to boost EV range and efficiency

Ultra-high voltage transistors...
Hundreds of billions of power MOSFET transistors power our electric vehicles and electronics. A new gallium oxide design could make them more efficient
Hundreds of billions of power MOSFET transistors power our electric vehicles and electronics. A new gallium oxide design could make them more efficient
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Hundreds of billions of power MOSFET transistors power our electric vehicles and electronics. A new gallium oxide design could make them more efficient
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Hundreds of billions of power MOSFET transistors power our electric vehicles and electronics. A new gallium oxide design could make them more efficient

A University at Buffalo team has proposed a new form of power MOSFET transistor that can handle incredibly high voltages with minimal thickness, heralding an efficiency increase in the power electronics of electric vehicles.

Metal-oxide semiconductor field-effect transistors, or MOSFETs to their friends, are extremely common components in all sorts of consumer electronics, and particularly in automotive electronics. Power MOSFETs are a type of switch specifically designed to handle large power loads. Something like 50 billion of these things are shipped annually, if that gives you a sense of scale to work with.

Effectively, they're three-pin, flattish electronic components that act as voltage-controlled switches; when a sufficient (usually fairly small) voltage is applied to the gate pin, it creates a connection between the other two pins, completing a circuit. They can switch high-power electronics on and off extremely quickly, and they're an integral part of electric vehicles.

By creating MOSFETs based on gallium oxide, the team at Buffalo claims it has worked out how to handle extremely high voltages using paper-thin transistors. When "passivated" with a layer of SU-8, a common epoxy-based polymer, the gallium oxide-based transistor was able to handle over 8,000 volts in lab testing before it broke down, a figure the researchers say is significantly higher than similarly designed transistors made from silicon carbide or gallium nitride.

The key property in question is gallium oxide's impressive bandgap figure of 4.8 electron volts. Bandgap measures how much energy is required to jolt an electron into a conducting state; the wider the bandgap, the better. Silicon, the most common material in power electronics, has a 1.1 electron volt bandgap. Silicon carbide and gallium nitride have 3.4 and 3.3 electron volt bandgaps, respectively. So gallium oxide's 4.8 electron volt bandgap puts it in elite territory.

By developing a MOSFET that can handle extremely high voltages at a tiny thickness, the Buffalo team hopes its work can contribute to smaller, more efficient power electronics in the EV world, as well as in locomotives, aircraft, micro-grid technologies and potentially solid-state transformers.

“To really push these technologies into the future, we need next-generation electronic components that can handle greater power loads without increasing the size of power electronics systems,” says the study’s lead author, Uttam Singisetti. These high-efficiency systems could eventually help you squeeze more range out of an electric vehicle.

Further experimentation is required, particularly to test the field strength of these new transistors.

The study is available at IEEE Electron Device Letters.

Source: University at Buffalo

4 comments
moreover
Very well explained but I'm not clear on whether these efficiency gains come mainly from their smaller size or from - I'm guessing here - avoided losses compared to older designs.
paul314
The big question is how much resistance it has. That controls how efficiently it lets power through and how rapidly it heat up when all that current is coursing through it.
Signguy
Couple this with the Million Mile Batteries fro Tesla...
Juanjo
Answering to "moreover" the efficiency gain must come from TWO sides: increased voltage to switch AND less resistance at the joint, so heat dissipation is similar to older devices with the same size. If these two requirements are met, then you will handle much more power, basically increasing the voltage, as the article suggests.