Powerware Corporation

Exide Electronics Corporation

Eaton Power Quality Corporation

William J Raddi

Robert William Johnson, Jr

Joseph Charles Paulakonis

George William Oughton, Jr

Haroon Inam

James Thommes

Blazej W Sonnenberg

An uninterrupted power supply (UPS) device with uninterrupted neutral from input to output utilizes the same converter for converting rectified AC power and battery power to positive and negative high voltage (HV) rails. A simple circuit is utilized for connecting the battery to the conversion components of the PFC circuit without adverse affect on the performance of the PFC circuit, and while holding the battery substantially connected to neutral. In a first embodiment, the circuit comprises a simple combination of four diodes and a pair of high pass capacitors arranged so that in both power line and battery supply modes the battery is balanced around neutral. In a second, preferred embodiment, one terminal of the battery is connected directly to neutral.

Power factor corrected UPS with improved connection of battery to neutral

Power factor corrected UPS with improved connection of battery to neutral and methods of operation thereof

A power converter includes first and second voltage busses and a neutral bus. A first switching circuit, e.g., a rectifier circuit, is operative to selectively couple an input node thereof to the first and second voltage busses. A balancer circuit is operative to selectively couple the neutral bus to the first and second voltage busses such that relative magnitudes of respective first and second voltages on the first and second voltage busses are controlled responsive to respective first and second rates at which the balancer circuit couples the first and second voltage busses to the neutral bus. A second switching circuit, e.g., an inverter circuit, is operative to selectively couple the first and second voltage busses to a load connected at an output node thereof. The balancer circuit preferably includes first and second switches operative to selectively couple respective ones of the first and second voltage busses to the neutral bus through an inductance such that the relative magnitudes of the first and second voltages are controlled responsive to respective first and second duty cycles of the first and second switches. The power converter is capable of multiple operating modes and suitable for use in uninterruptible power supplies (UPSs).

Multi-mode power converters incorporating balancer circuits and methods of operation thereof

Power factor corrected UPS maintaining neutral integrity and methods of operation thereof

An uninterruptible power supply (UPS) includes an AC source port configured to connect to an AC power source, a DC source port configured to connect to a DC power source and a load port configured to connect to a load. A rectifier circuit is operative to selectively couple the AC source port to first and second voltage busses through a first inductance. An inverter circuit is operative to selectively couple the load port to the first and second voltage busses through a second inductance. A bidirectional DC source coupling circuit is operative to couple the DC source port to the first and second voltage busses to provide bidirectional power transfer therebetween, preferably such that a voltage at the DC source port is maintained in a substantially fixed proportion to first and second DC voltages at respective ones of the first and second voltage busses. In one embodiment, the bidirectional DC source coupling circuit includes a transformer having first and second inductively coupled windings, the first winding having first and second end taps and a center tap coupled to the neutral bus. A switching circuit is operative to selectively couple the first end tap of the first winding to the first and second voltage busses. A rectifying circuit couples the second end tap of the first winding to the first and second voltage busses. A bidirectional DC-AC converter circuit is coupled between the second winding and the DC source port. Related operating methods are also discussed.

Uninterruptible power supplies with dual-sourcing capability and methods

A UPS device adapted for parallel connection to a load along with one or more other UPS devices, having circuitry for sharing of the load, including load harmonics. A feedback network has an error signal circuit which generates an error signal representative of the difference between the actual current provided by the device and the designated share of current it should provide. The error signal is transformed by a value representative of the effective output impedance of the UPS inverter, whereby the inverter is controlled to share the fundamental of the load current as well as the harmonics.

Power supply with improved circuit for harmonic paralleling

An uninterrupted power supply (UPS) systems is provided comprising a rectifier circuit, an inverter circuit and a battery boost circuit. One of the input terminals of the rectifier circuit is for connection to the ungrounded conductor of an AC power source and the other input terminal of the rectifier circuit is for connection to the grounded conductor of the AC power source. The UPS has a pair of load terminals for connection to a load. The input terminal of the rectifier circuit for connection to the grounded conductor is connected to one of the pair of load terminals by an electrical conductor whose electrical continuity is maintained from this input terminal to the one of the pair of load terminals without any isolation device such as a 50 or 60 Hz transformer being disposed between the input terminal and the one of the pair of load terminals.

Uninterrupted power supply having no low frequency power magnetics

An uninterruptible power supply including a transformer having a first input winding normally coupling an inverter AC source with a critical AC load, which transformer also includes a second input winding operable to supply power from a bypass source to the load in the event of malfunction of the inverter circuit. The inverter is of the four-quadrant pulse-width-modulated type, thereby to permit recharging of the battery which serves as the DC source to the inverter. An inductance is provided for varying the phase relationship between a utility voltage source and the inverter voltage to produce minimum real inverter current and the 'break-even' operating conduction, and a step-up device is provided for increasing the utility voltage to further minimize the break-even inverter current required during normal operation, and to maximize the through-put efficiency.

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Raleigh, NC, United States of America

William J Raddi