Wednesday, September 22, 2021
GaN Systems has announced an agreement with BMW to secure GaN transistor capacity. The volumes offered are expected to ensure supply chain reliability for automotive suppliers. CEO Jim Witham noted in an interview that GaN Systems will provide capacity for multiple applications in series production.
The electric vehicle (EV) sector continues to face two major challenges: price and range. The latter is considered the most important in terms of full EV adoption. Integrating the powertrain and leveraging wide-bandgap semiconductors (GaN and SiC) are among the approaches being adopted to cut costs and improve system efficiency. By increasing switching frequency and exploiting other advantages of wide band-gap semiconductors, it is possible to miniaturize components for automotive applications while improving thermal performance.
Gallium nitride technology aims to increase the efficiency and power density of critical EV applications. “GaN can be designed in a wide range of EV applications from onboard battery chargers, DC/DC converters to traction inverters, wireless power transfer, LiDAR, and 12-volt audio amplifier applications,” said Witham.
Moving Forward with GaN
GaN power semiconductors are emerging as essential in the next generation of high-performance EVs for achieving size and weight reductions along with improve efficiency. Those factors address range concerns. In a statement, Witham said BMW’s contract valued in the hundreds of millions of dollars illustrates how automotive OEMs are focused on innovation and sustainability.
The deal with BMW also highlights advances in wide-bandgap semiconductors, particularly DC/DC converters and drive inverters that are growing smaller, lighter and cheaper.
“GaN enables engineers to create power electronics systems that are four times smaller, lighter, and generate four times less energy loss than silicon,” Witham asserted. Among the advantages are zero-reverse recovery, which provides lower switching loss in battery chargers and traction inverters, higher frequency and faster switching speeds. In addition, lower switching turn-on and turn-off losses can help reduce the weight and volume of capacitors, inductors and transformers for applications like EV chargers and inverters.
Those advantages can reduce the size of onboard battery chargers by 25 percent, reduce power loss in traction inverters by more than 70 percent while halving power conversion losses in lighter, more compact DC/DC converters, the company said.
GaN for EVs
As electric vehicles enter the fast lane, demand for critical semiconductor components is likely to increase. That makes strategic partnerships with GaN providers even more important.
The bandgap of GaN is 3.2 electron volts (eV), approximately three times that of silicon (1.1 eV), meaning it takes more energy to excite a valence electron in a silicon semiconductor’s conductive band. GaN semiconductors exhibit 1,000 times more electron mobility – they flow quicker – than silicon, providing better efficiency. One result is improved thermal management and smaller, less expensive cooling.
“Electrification is the pathway forward in the automotive industry, and there is much to do to expand the entire ecosystem,” said Witham. “For continued mass adoption of EVs to occur, issues such as lowering vehicle price, shortening charging times, extending driving range and increasing the network of the EV charging infrastructure must be addressed.”
GaN technology is touted as addressing size and weight constraints along with reducing component counts while increasing power and efficiency. Those attributes could help reduce EV costs while boosting power density, reducing vehicle weight and extending driving range, Witham added.
Lithium-ion batteries, for example, constitute up to 30 percent of an EV’s sticker price, according to industry analysts. Proponents say GaN-based components could help reduce those costs. In one example, GaN-based inverters could boost efficiency by as much as 70 percent compared to traditional insulated-gate bipolar transistor devices used in current EV inverters.
The result would be increased efficiency via smaller and lighter chargers, traction inverters and DC/DC converters that could help squeeze more driving range out of current battery capacity while simplifying component packaging.
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