Power Electronics Europe February/March 2022

OPINION 5 www.power-mag.com Issue 1 2022 Power Electronics Europe P assenger electric vehicle (EV) sales are set to jump over 80 % in 2021, to 5.6 million units. Improving battery technology and costs, faster roll-outs of charging infrastructure, a wider range of vehicle models on offer to customers, and longer range and faster charging speeds due to highly efficient power semiconductors and last but not least public incentives paves the way towards e-mobility – one of the major markets for power electronics in 2022. Owing to the EV market’s substantial demand for longer driving ranges and shorter charging times, automakers’ race towards high- voltage EV platforms has noticeably intensified, with various major automakers gradually releasing models featuring 800V charging architectures, such as the Porsche Taycan, Audi Q6 e-tron, and Hyundai Ioniq 5. According to TrendForce demand from the global automotive market for 6-inch SiC wafers is expected to reach 1.7 million units in 2025 thanks to the rising penetration rate of EVs and the trend towards high-voltage 800 V EV architecture. The 800 V charging architecture will bring about a total replacement of Si IGBT modules with SiC power devices, which will become a standard component in mainstream EV VFDs (variable frequency drives). As such, major automotive component suppliers generally favor SiC components. In particular, Tier 1 supplier Delphi has already begun mass producing 800 V SiC inverters, while others such as BorgWarner, ZF, and Vitesco are also making rapid progress with their respective solutions. SiC usage in OBC (on board chargers) and DC/DC converters has been relatively mature, whereas the mass production of SiC-based VFDs has yet to reach a large scale. Power semiconductor suppliers including STM, Infineon, Wolfspeed, and Rohm have started collaborating with Tier 1 suppliers and automakers in order to accelerate SiC deployment in automotive applications. The upstream supply of SiC substrate materials will become the primary bottleneck of SiC power device production, since SiC substrates involve complex manufacturing processes, high technical barriers to entry, and slow epitaxial growth. The inherent benefits of SiC-based power switches with regard to power density and efficiency are well understood, with key implications for system cooling and size. The evolution to SiC promises 3 smaller inverters at 800 V/250 kW, with additional significant size and cost savings on companion DC link film capacitors. Compared to conventional Silicon, SiC power switches can enable better range and/or a reduced battery pack, giving the switches a favorable cost comparison from the device level to the system level. At the intersection of these range and cost considerations, the traction inverter remains the epicenter for innovations aimed at unlocking further EV efficiency and range gains. For nearly two decades, SiC power devices rated from 650 to 1200 V have permeated the marketplace, at last allowing designers to make disruptive advancements to technologies and end equipment – simultaneously improving performance, reliability, size, weight, and even cost. The recent release of a 1700V SiC product family extends SiC’s benefits up the power food chain to help shift the power conversion paradigm into new end segments, such as electrified commercial and heavy-duty vehicles, light rail traction and auxiliary power, renewable energy, and industrial drives. GaN-on-Silicon devices have been in volume production since 2010 and have demonstrated very high reliability in both laboratory testing and customer applications, such as 4G base stations, vehicle headlamps, or lidar for autonomous cars. What is missing is the powertrain. But with GaN-on-GaN epiwafers the race for efficiency with SiC in the high-power devices market is opened. GaN epi-wafer is a material comprising multi-stacked III-N compound semiconductor films on a wafer. It is used in high-speed chargers, EV power conversion, and defense radars. SiC or Silicon wafers are used to stack III-N films depending on the application field, but GaN wafers are required in high-power devices such as EV powertrains. Saint- Gobain in France and some Japanese material companies, such as Sumitomo and Mitsubishi, are leading production technology of GaN wafers. With the acquisition of the GaN wafer business from Saint-Gobain, South Korean IVWorks has acquired state-of-the-art technology for mass production of 4- and 6-inch GaN wafers. Based on this acquisition, the start-up company claims that it will be able by supplying GaN-on-GaN epi-wafers in high-power application fields to compete with SiC materials in the EV market. And with synthetic single-crystal diamond the next generation technology for future power electronics is on the horizon – waiting for commerzializaton. Thus the power electronics industry never stops innovating – even in difficult times caused by the pandemic. Achim Scharf PEE Editor Innovation Never Stops