International Business Machines Corporation

Steven William Steele

Neil Clair Berglund

Timothy Charles Daun-Lindberg

Patrick Kevin Egan

Todd Jon Rosedahl

Gary Allen Thompson

Steven Dennis Keidl

Christopher John Kimble

Vernon J Kleve

Jeffrey Scot Rotter

Jon Anton Veer

John V Swenson

Charles J Pentek

Willard J Olson

An AC transfer switch (ATS) is provided for switching a system load between at least two AC lines. A first bridge rectifier is connected to a first AC line for providing a first full wave rectified AC waveform. A first pair of oppositely poled silicon controlled rectifiers (SCRs) is coupled to the first bridge rectifier and to the system load. A second bridge rectifier is connected to a second AC line for providing a second full wave rectified AC waveform. A second pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to the second bridge rectifier and to the system load. Control logic is coupled to a gate input of the first pair of oppositely poled silicon controlled rectifiers (SCRs) and a gate input of the second pair of oppositely poled silicon controlled rectifiers (SCRs) for applying one of the first full wave rectified AC waveform or the second full wave rectified AC waveform to the system load. The control logic includes a first AC line sense circuit for sensing the first AC line input and a second AC line sense circuit for sensing the second AC line input. A first optical isolator is responsive to an output signal provided by the first AC line sense circuit sensing the first AC line input within a predefined AC line tolerance for activating the gate input of the first pair of oppositely poled silicon controlled rectifiers (SCRs) and applying the first full wave rectified AC waveform to the system load. A second optical isolator is responsive to an output signal provided by the first AC line sense circuit sensing the first AC line input outside the predefined AC line tolerance and an output signal provided by the second AC line sense circuit sensing the second AC line input within the predefined AC line tolerance for activating the gate input of the second pair of oppositely poled silicon controlled rectifiers (SCRs) and applying the second full wave rectified AC waveform to the system load.

AC transfer switch using semiconductor devices

A battery backup system has a number of batteries and number of switches interconnecting the batteries to either a high-power load or a low-power load. The batteries are selectively connected in series with each other, or in parallel with each other by the switches. When the batteries are in the parallel configuration they are also connected to power the low-power load, and when in series, to power the high-power load. Between switching from the high-power series configuration to the low-power parallel configuration, a transition phase is provided during which a transition battery powers the low-power load.

Series-parallel battery array conversion

A power supply includes a rectifier which receives alternating current as an input, and which provides an output of direct current pulses at a positive polarity output line thereof with respect to a negative polarity output line thereof. A back-up circuit is coupled between the positive and negative polarity output lines of the rectifier. The back-up circuit includes the series connection of a switching device, a current blocking device, at least one electrical energy source device, and a current measuring device. A circuit protection device may also be provided in the series connection. The back-up circuit can be tested while the rectifier is providing the direct current output pulses by closing the switching device and detecting at least one pulse of a test current flowing through the back-up circuit and/or a terminal voltage of the at least one electrical energy source device during the testing.

Path test for a DC battery back-up system

A power system includes a battery back-up unit (BBU) having back-up battery circuitry which provides battery back-up support for a plurality of power supplies each having a respective power factor correction circuit front-end with a boost stage. The voltages output from the boost stages of the power supplies are monitored and compared with respective reference threshold voltages to derive a signal which is used to bring battery back-up power on-line when a monitored voltage falls below a threshold voltage, which may be indicative of a loss of AC mains input voltage. AC mains input voltage is also monitored to detect a restoration and disconnect the battery back-up power. In the event that battery back-up is brought on-line due to a faulty power supply rather than a loss of AC mains input voltage, the faulty power supply can be masked and reported for repair.

Method of controlling battery back-up for multiple power supplies

A battery capacity test and electronic system implementing the same tests both the high and low discharge capacities of a back-up battery to ensure that the battery is capable of handling both a short term, high discharge load and a long term, low discharge load. The battery capacity test is particularly suitable for use in an electronic system which, upon occurrence of a power outage, converts from an operational mode to a power saving mode during a conversion time. High discharge capacity testing is performed using a 'safety net' where the primary power source of the electronic system is switched to a reduced testing voltage output, rather than shut off or disconnected, so that the primary power source can take over quickly in the event of a back-up power supply failure during the test.

Battery capacity test and electronic system utilizing same

A back-up power supply includes a fixed charger fixably mounted in an enclosure of a computer system and having a charging circuit electrically coupled to the computer system. The charger is mounted in a case which houses the charging circuit and provides EMC shielding. A removable battery pack is docked with the charger through cooperative blind docking connectors to electrically couple a pair of batteries with the charging circuit. The batteries are enclosed within a case to substantially restrict external access to the batteries. Preferably, the batteries together form an 'L' shape, and the charging circuit is disposed on a circuit board having low and high profile areas. The batteries in the battery pack are disposed adjacent the low profile areas of the circuit board, such that the overall space required for the power supply is reduced.

Back-up power supply with replaceable battery pack

A battery charging aparatus and method are provided for charging a battery using current control with a switching power supply charging circuit coupled to the battery. During a first charging phase, a predetermined constant charging current is applied to the battery. The battery voltage is monitored and a second charging phase is started when the battery voltage reaches a predetermined threshold voltage. During a second charging phase, a sequence of stepwise decreasing-amplitude current pulses are applied to the battery. The envelope for the decreasing current pulses is exponential which is characteristic of the current for voltage controlled charging methods. The battery voltage is maintained at a temperature compensated target with a 1% tolerance. The charging current is compared to a predetermined minimum amplitude value and a third charging phase is started when the sequential charging current pulse equals the predetermined minimum amplitude value. During a third charging phase, predetermined charging current pulses having the predetermined minimum amplitude value are applied to the battery. The battery voltage is maintained at a temperature compensated target with a 1% tolerance.

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Rochester, MN, United States of America

Steven William Steele