# US 9,882,422 B2 · Energy efficient electrical systems and methods for modular data centers and modular data pods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,882,422 B2 - Document ID: US9882422B2 - Status: Granted - Kind: B2 - Application number: 14/595,688 - Filed: 2015-01-13 - Published: 2015-07-09 - Granted: 2018-01-30 - Earliest claimed: 2012-07-13 - Assignees: Inertech IP LLC - Applicants: Inertech IP LLC - Inventors: Subrata K. Mondal - Web page: https://patentgrep.com/patent/US9882422B2 ## CPC - H02J 9/06: with automatic change-over {, e.g. UPS systems} - G06F 1/30: Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations (for resetting only G06F1/24) - H02J 1/10: Parallel operation of DC sources - H02J 9/04: in which the distribution system is disconnected from the normal source and connected to a standby source - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An efficient, modular, direct current (DC) uninterruptible power supply (UPS) for at least one server of a data center is disclosed. The single-conversion DC UPS includes an AC-DC converter, an energy storage device electrically coupled to the output of the AC-DC converter, and a single conversion server supply DC-DC converter electrically coupled to the AC-DC converter and the energy storage device, which may be a low-voltage lithium-ion battery or combined with an ultra capacitor. The DC UPS may be incorporated into a UPS system for a data center including a plurality of server rack assemblies and a plurality of cooling distribution units (CDUs). The UPS system includes an electric generator, an AC UPS electrically coupled between the electric generator and the plurality of CDUs, and a plurality of DC UPSs coupled between the electric generator and the plurality of server rack assemblies. ## Claims ### Claim 1 A system for supplying power to a data center including a plurality of server rack assemblies and a plurality of cooling distribution units (CDUs) in thermal communication with the plurality of server rack assemblies, the system comprising: an electric generator; an AC UPS electrically coupled between the electric generator and the plurality of CDUs; and a plurality of DC UPSs, each of which is electrically coupled between the electric generator and a respective one of the plurality of server rack assemblies. ### Claim 2 (depends on 1) The system according to claim 1, wherein each of the plurality of DC UPSs includes an AC-DC converter and an energy storage device electrically coupled in parallel to an output of the AC-DC converter. ### Claim 3 (depends on 2) The system according to claim 2, wherein the energy storage device is a low-voltage battery. ### Claim 4 (depends on 3) The system according to claim 3, wherein the low-voltage battery is a 12 V battery, a 24 V battery, or a 48 V battery. ### Claim 5 (depends on 2) The system according to claim 2, wherein the energy storage device is a lithium-ion battery or a combination of a lithium-ion battery and a ultra-capacitor. ### Claim 6 (depends on 2) The system according to claim 2, wherein each of the plurality of DC UPSs further includes a high-frequency DC-DC converter for a power supply of at least one server in a respective server rack assembly, and wherein the high-frequency DC-DC converter includes a plurality of MOSFETs and a zero-voltage switching controller electrically coupled to the plurality of MOSFETs to output a plurality of DC voltages from the high frequency DC-DC converter. ### Claim 7 (depends on 6) The system according to claim 6, wherein a single power conversion is performed between the energy storage device and the at least one server in the respective server rack assembly. ### Claim 8 (depends on 1) The system according to claim 1, wherein the AC UPS is configured in an offline energy saver mode such that power is supplied from the AC UPS to the plurality of CDUs if a disturbance occurs in a utility power source that normally supplies power to the plurality of CDUs. ### Claim 9 (depends on 8) The system according to claim 8, wherein the AC UPS includes: an AC-DC converter; an energy storage device and a bidirectional DC-DC converter electrically coupled in series with a positive terminal of the energy storage device, the series combination of the energy storage device and the DC-DC converter being coupled in parallel to the AC-DC converter; and a DC-AC inverter electrically coupled in parallel to the series combination of the energy storage device and the DC-DC converter. ### Claim 10 (depends on 9) The system of claim 9, wherein the energy storage device is a medium voltage battery. ### Claim 11 (depends on 10) The system of claim 10, wherein the medium voltage battery supplies voltage between 250 V and 450 V. ### Claim 12 (depends on 8) The system of claim 8, wherein each of the plurality of DC UPSs is connected to a respective load line of a plurality of load lines. ### Claim 13 (depends on 8) The system of claim 8, wherein one of the plurality of DC UPSs is connected to one load line of a plurality of load lines. ### Claim 14 (depends on 1) The system of claim 1, wherein each of the plurality of DC UPSs is connected to a respective load line of a plurality of load lines. ### Claim 15 (depends on 1) The system of claim 1, wherein one of the plurality of DC UPSs is connected to one load line of a plurality of load lines.