April 11, 2017 by Jeff Schnabel
At this year’s Applied Power Electronics Conference (APEC) in Tampa, FL, I was pleased to note a heavy emphasis on addressing energy needs at the system architecture level. Several speakers, including Google’s Shuai Jiang, talked of the growing power challenges faced by data centers, while the latest annual study from the Power Sources Manufacturers Association cites that data centers in the United States now account for 2% of the country’s total electricity consumption, some 70 billion kWhrs annually.
Given this rapid rise in power consumption, improving the efficiency of the distributed power systems used in data centers continued to be a hot topic at this year’s show. Google presented a non-isolated 48 V distributed power solution that they claimed will increase system efficiency by 2%. Though the adoption of a 48 V direct to 1 V system has been proposed as an alternate architecture to further reduce distribution losses by eliminating the 12 V intermediate step, Google recognized the need for a two-stage approach with 48 V to 12 V converters in-place to power disk drives, etc.
Of course, at APEC there is no escaping the latest power semiconductor developments, especially those benefitting from wide band-gap technologies such as SiC and GaN. In past years, the focus has been mainly on the promises of this technology, but this time around there were many real-world applications being demonstrated. While these technologies certainly provide performance advantages in certain markets, they are still not delivering on their initial promises due to cost and technical limitations. SiC continues to be limited to high-voltage applications such as renewable energy, while GaN, which originally promised SiC performance at the price of Si, is being relegated to use in lower voltage designs.
In returning to the data center topic, we need to understand why efficient power conversion and management is becoming ever more important. The initial explosion in data usage that resulted from Cloud computing, when businesses and individuals decided it was more productive, more convenient and often safer to keep data online, is now being supplemented by growing demands posed by the Internet of Things (IoT) where potentially billions of ‘Things’ will be connected to servers in data centers, either via conventional networks or increasingly via 5G communications systems. Indeed, one of the potential drivers for 5G connectivity is likely to be for autonomous vehicle and virtual reality applications. What is interesting about this is that the need for low latency dictates a closer range between user and server, which may well require so-called “micro-datacenters” to fill the gaps. These in turn are likely to be more power-constrained and hence demand even more efficient power solutions.
This is where digital power and more particularly Software Defined Power® (SDP), come into play. Digital power, where power supplies are controlled digitally through a common interface, such as PMBus™, provides the ability to extend the feedback loop to embrace the full power distribution architecture, optimizing voltages at all stages. Where SDP goes significantly further is in the ability to provide system-wide control by adding intelligence outside of the power supply. This can be used to allocate power where it is needed, coping with the need for supply redundancy in mission-critical systems without dedicating back-up resources “just in case.” SDP can also be used to profile energy usage and even out load fluctuations using battery reservoirs and a technique that is commonly referred to as “peak-shaving.”
Virtual Power Systems (VPS) has pioneered SDP with its Intelligent Control of Energy (ICE) software that makes power an elastic resource across the whole data center and works in conjunction with the ICE Block hardware from CUI that comprises power switching and Li-ion battery storage modules. This partnering of hardware and software, which was on display by CUI at APEC 2017, can improve infrastructure utilization by up to 50% within the existing power footprint while also providing full visibility of available power, which, apart from the efficiency benefits, can potentially avoid unnecessary new capital equipment expenditures.
Inevitably, most of the new solutions presented at APEC continue to be hardware-driven, intended to solve a specific technical challenge at the board-level. However, I believe that the power industry needs to take a step back and “see the forest for the trees,” adopting a system-level approach to the data center power challenge. Hardware improvements will inevitably hit a ceiling due to the laws of physics, which leaves software as an untapped area that should be explored to improve efficiency and power utilization, especially in the data center.
For more information on our Software Defined Power solutions for the data center, visit: www.cui.com/sdp-infrastructure-solutions