Electronics Protection - Spring 2016 - (Page 14)

Feature Reducing TCO with the Right UPS Architecture and Operating Mode Peter Panfil, Vice President, Global Power Emerson Network Power One of the most widely discussed issues throughout the world today is the rapidly increasing demand for energy within the computing industry. This is fueling interest in energy efficiency solutions worldwide. Many organizations are looking at their data center's UPS systems to optimize efficiency while protecting availability and maintaining flexibility to quickly meet growing demands. This article looks at two steps data centers can take with their power infrastructure to achieve that optimal performance. The combination of these two suggestions - utilizing a high-energy efficiency mode and moving to a reserve bus power system configuration. When done correctly with the appropriate considerations and planning, can help to significantly reduce total costs. High-Energy Efficiency Mode Many data center professionals are turning to some form of economization in an effort to increase efficiency. Today's high-availability, double-conversion UPS systems can achieve efficiency improvements through the use of active eco-mode. This mode of operation accomplishes improved efficiency by powering the bulk of the critical load through the bypass path. When power problems are detected, the UPS automatically switches back to double-conversion mode. In double-conversion UPS systems (Figure 1), the rectifier and inverter should be designed to run continuously with the rectifier directly powering the inverter. The incoming AC is rectified to DC, which is then converted back to AC by the UPS inverter, resulting in a low-distortion, regulated stable AC output voltage waveform. This process can be up to 97 percent efficient. Approximately three to six percent of the energy passing through a double-conversion UPS is lost in the conversion process. Traditionally, this has been accepted as a reasonable price to pay for the protection provided by the UPS system. Figure 1. Double conversion mode is the most widely deployed UPS topology in data center applications. The active eco-mode approach (Figure 2) pushes efficiency up above 97 percent in some cases. It keeps the inverter and rectifier in an active state, which means the inverter is providing output that matches the bypass and is ready to accept the load immediately. As a result, the transfer to the inverter can be accomplished almost seamlessly. When the UPS senses bypass power quality falling outside accepted levels, the bypass opens and transfers power immediately back to the inverter until bypass anomalies are corrected. Once bypass power anomalies end, the critical load returns to active eco-mode automatically. It is important to note that not all UPS economization modes are created equal. Due to technology limitations, some UPS systems have to turn off Figure 2. Active eco-mode offers a more seamthe inverter before turning on the bypass or turn off the bypass before less transfer and possible UPS efficiency in excess of 97 percent. turning on the inverter. This is commonly referred to as an interrupted transfer. In active eco-mode, the UPS controls the inverter to be in a zero power state but keeps the inverter synchronized and ready to take the load. It is due to this technique that going into or suspending active eco-mode operation can be made without any interruption to the load. 14 Spring 2016 * www.ElectronicsProtectionMagazine.com http://www.ElectronicsProtectionMagazine.com

Table of Contents for the Digital Edition of Electronics Protection - Spring 2016

Editor's Choice
Security Considerations for Data Center Intelligent Rack Power Distribution
Five Misconceptions about DRUPS Systems
Designing and Managing Custom Battery Pack Enclosures
Reducing TCO with the Right UPS Architecture and Operating Mode
Enclosures
Thermal
Power
Hardware
Industry News
Calendar of Events

Electronics Protection - Spring 2016