Liebert Corporation

Kevin Kim Eschhofen

Brian Paul Heber

Terry Dwane Bush

Mohammad Nanda Marwali

Mohammad Nanda Rahmana Marwali

Xian Chen

Suratkal Padmanabha Shenoy

Russell Edward Shetler, Jr

Kevin Jay Bell

Ramesh Subramanian

Farzin Kafaipour

Nelson John Norris

Andy Margraff

Ronald Richard Rautenstrauch

Jon Ross Funk

A multiple UPS system has a plurality of UPS subsystems with a separate UPS data communications bus coupling a controller of each UPS subsystem to an associated controller of an associated tie cabinet. The multiple UPS system further includes a data communications tie bus that couples the controllers of the tie cabinets to each other. The controllers of the tie cabinets arbitrate power line based coordinating signals between the UPS buses without the use of auxiliary signals.

Intelligent arbitration of power line based coordinating signals between multiple UPS buses without any auxiliary signals

An uninterruptible power supply (UPS) includes a plurality of UPS modules. Each of the UPS modules has a battery that provides power to a protected load in the event of a utility power failure. A plurality of controllers control how much power each of the batteries deliver to the protected load, and a communication bus allows the controllers to exchange information about the battery voltages. One of the controllers calculates the average battery voltage of the plurality of batteries and adjusts the amount of energy provided by an individual battery such that the battery voltage is about equal to the average battery voltage.

Maximized battery run-time in a parallel UPS system

A method for pulse width modulated pulse synchronization in a parallel UPS system uses the locally measured critical bus voltage to detect a zero crossing and adjust the PWM pulse to coincide with the zero crossing. No communication between the units is required to perform synchronization, and no 'master' and 'slave' relationship exists to thereby increase the total system reliability.

Method for pulse width modulation synchronization in a parallel UPS system

An uninterruptible power supply is disclosed that includes a digital controller comprising a plurality of microprocessors. These microprocessors are programmed and arranged to provide various control features heretofore unavailable using analog controllers of the prior art.

Uninterruptible power supply

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Lewis Center, OH, United States of America

Kevin Kim Eschhofen