Importance

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Abstract

A boost-input backed-up uninterruptable power supply from an input voltage source, such as a 60 cycle 120/240 Vac service, provides an uninterrupted output voltage to a load connected to a return. The backed-up power supply has an input rectifier and low energy storage filter coupled to the input voltage source for converting the input voltage source into at least an unregulated positive dc voltage source, and an unregulated negative dc voltage source. Each respective unregulated source has a respective unregulated dc voltage value with respect to the return. Two 120V battery stacks provides respective positive and negative battery voltages at corresponding positive and negative battery output terminals. A diode isolates the unregulated positive and negative dc voltage sources from their respective battery voltages for unregulated voltage source values equal to or greater than their respective battery voltages and clamps the unregulated dc voltage values to their respective battery voltages in response to loss of the sinusoidal input voltage source. A boost regulator receives power from the unregulated positive and negative dc voltage sources and provides a positive and a negative regulated dc voltage with respect to the return. A dc-to-ac converter receives a reference signal and converts the positive and negative regulated dc voltage into at least a first uninterrupted output voltage for application to the load.

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First Claim