Eaton Corporation

Eaton Power Quality Corporation

Keith Bauman

George Arthur Navarro

John Gaylord Tracy

Hans-Erik Pfitzer

John G Tracy

An uninterruptible power supply (UPS) system includes an AC input configured to be coupled to an AC power source, an AC output configured to be coupled to a load and a power converter circuit coupled to the AC input and the AC output and configured to selectively provide power to the load from the AC power source and an auxiliary power source. The UPS system further includes a control circuit operatively coupled to the power converter circuit and configured to generate at least one galvanically isolated neutral reference from the AC power source and/or from the AC output and to control the power converter circuit responsive to the generated at least one neutral reference. In particular, the control circuit may be configured to generate the neutral reference from a three-wire AC connection.

Uninterruptible power supply systems and methods using an isolated neutral reference

In a power converter apparatus, such as an uninterruptible power supply, a phase reference signal is generated responsive to a DC voltage on a DC bus. A magnitude reference signal may be generated responsive to a phase current of an AC bus and/or the DC voltage on the DC bus. Power is transferred between the AC and DC busses responsive to the phase reference signal and the magnitude reference signal. Generation of the phase reference signal may include generating a DC voltage error signal responsive to the DC voltage on the DC bus, generating a phase offset signal responsive to the DC voltage error signal, and generating the phase reference signal responsive to the phase offset signal. Generation of the magnitude reference signal may include generating a volt-amperes reactive (VAR) error signal responsive to the phase current and generating the magnitude reference signal responsive to the VAR error signal.

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Oxford, NC, United States of America

Keith Bauman