Power Electronics Europe Issue 4 - November 2022

26 WBG DATACENTER www.wolfspeed.com Issue 4 2022 Power Electronics Europe www.power-mag.com Finding the Right Technology to Solve Datacenter Power Challenges Although Silicon (Si) is the most familiar technology, its smaller bandgap limits operating temperature, its low breakdown electric field restricts its use to lower voltages, and its low thermal conductivity limits power density compared to wide bandgap (WBG) materials, like gallium nitride (GaN) and Silicon Carbide (SiC). Digitization and the rapid deployment of cloud services have boosted the growth of datacenters worldwide. WBG helps to reduce their power consumption. Anuj Narain, Director Power Platforms and Applications, Wolfspeed, USA Datacenters consume close to one percent of global electricity, a number that is only expected to grow. Industry trends, such as metaverse and augmented and virtual reality, will continue to demand more energy than the planet can sustainably produce. While increasing renewable energy contribution is a step in the right direction, it is not enough, and energy efficiency is another area of focus that targets the nearly 40 percent of datacenter operational costs due to energy consumption by servers and their cooling systems (Figure 1). Global standards for datacenter power supplies also continue to evolve toward higher efficiencies. The Open Compute Project (OCP) 3.0 offers further optimization of hardware that lowers energy consumption, and the 80 Plus Platinum and Titanium certification requirements as well as EU’s Ecodesign in Europe (ErP) Lot 9 regulations continue to evolve (Table 1). The next update to Lot 9 is already scheduled for January 2026. Power architecture evolution As processor and server power is increasing, datacenters are using more power per rack. They now need 2-4 kW discreet blocks with the industry trending toward even higher power densities. Distributing this power at the first- generation 12 V levels means having to handle much higher currents. To provide 1 kW to a server rack, the traditional 12-V architecture needs to deliver 83 A of current. To control I?R losses and address safety concerns, more copper would be needed in the wiring harness of such a system. A one-percent efficiency improvement can result in saving kilowatts at datacenter level and second-generation power architectures, using 48 V (Figure 1), result in 16-times lower I?R losses while still being below the UL-60950-1 standard 60 V DC Safety Extra – Low Voltage (SELV) limit beyond which additional insulation, spacing, and testing are required. To meet new energy efficiency requirements, the LEFT Figure 1: Global energy savings from Gen2 power architectures can be equivalent to 27 1- GW nuclear power plants (Source: Fred Lee, Power Architecture for the Next Generation of Datacenter) Table 1: Lot9 and 80Plus have similar requirements with 80Plus Titanium applications demanding a greater 98.5 percent PFC efficiency