René Raaijmakers
10 November

For years, a dozen engineers within Next Level Electronics developed power converters outside office hours, while most of them worked part-time for Lightyear. Lightyear’s acquisition of NLE straightens this out.

In 2016, a dozen engineers started to meet on Monday evenings and sometimes Saturdays to work on power converters in their own time. They knew each other from the student team that had participated in the 2013 and 2015 World Solar Challenges, where they had built a motor controller that was more reliable than the ones commercially available at the time. Their hobby became serious and after a year, the group decided to found the company Next Level Electronics (NLE).

All the while, most of the engineers also worked part-time for Lightyear, which had started in 2016 as well, as a spinoff of the same student team. Over the years, the activities got ever more entangled. Arjo van der Ham co-founded both companies and doubled as the CTO of Lightyear and the director of NLE. In 2020, the NLE team extended its efforts to the development of circuit board-based motors, with Lightyear as its customer. Supported by funding from the Dutch SME Innovation Stimulus for Regional and Top Sectors (MIT), granted just last year, this project was completed successfully, but it failed to interest other takers. These wrinkles are now ironed out by Lightyear’s acquisition of NLE.

Lightyear NLE power converter
Lightyear’s inverter design is based on the IP first licensed from NLE and recently purchased.

Mission

With the takeover, NLE is throwing in the towel and stopping its activities completely. Lightyear points out that the acquisition is only about the technology and not the employees, as they weren’t officially employed by NLE. The Helmond-based automaker speaks of “a strategic decision to strengthen the intellectual property of Lightyear’s powertrain inverters to support the efficiency of the entire powertrain platform.”

The specific inverters are crucial for the two models Lightyear is working on. “With the acquisition, Lightyear secures its technology and can further progress in the development and production of a more efficient drivetrain platform for its solar electric vehicles,” the press release reads.

All assets, including the PCB motor, are now owned by Lightyear. This gives its design team more freedom. The company sees the acquisition as an opportunity to further improve its technology to get one step closer to its mission of clean mobility for all. After validating the technology for its first car model, the Lightyear 0, the powertrain will continue to be developed for the mass-market model, the Lightyear 2.

Silicon carbide

Electric cars need an inverter to convert DC voltage from batteries into three-phase AC voltage for the motor. The design for the Lightyear 0 differs from other electric cars in this regard, as it has an internal motor in each of the wheels – so four in total. By powering not centrally but locally, its 0 model is about a factor of two more efficient than current electric cars, Lightyear claims.

The approach has implications for the inverter design. Each of the four inverters only needs to provide one-eighth the power compared to inverters in a centrally powered electric car. This give rise to different requirements and architectures. NLE and Lightyear chose silicon carbide power ICs in their designs, which have a 6 percent higher efficiency than silicon-based alternatives.

Virtually everyone involved in power conversion agrees that silicon carbide power ICs are the future. Tesla gave the silicon carbide chip market a big boost in 2017 when it decided to become the first automotive manufacturer to use SiC Mosfets in its Model 3. The higher the voltages, the more efficient SiC chips are. Besides Si and SiC, there’s another flavor in power chips, gallium nitride, which BMW opted for.

Europe plays an important role in power conversion chips. Infineon and STMicroelectronics are among the world leaders in SiC chips and announced hefty investments in the technology last year. French-Italian ST even decided to start its own wafer production to secure the supply of the expensive SiC wafers. Bosch announced early this year that it was going to invest 3 billion euros in power microelectronics production, including 250 million for silicon carbide ICs and MEMS production in Reutlingen.