Method and apparatus for line power monitoring for uninterruptible power supplies

Patent · Tue Jul 20 04:00:00 EDT 1993

OSTI ID:6411117

Baxter, Jr, R V; Stich, F A

AC line waveform monitoring apparatus is described for detecting AC line power faults and providing a fault signal for control of an uninterruptible power supply comprising: (a) means for sampling an AC line power signal at times synchronized with the cycle of the AC line waveform; (b) means for producing a reference waveform at selected sample times during the period of the AC line signal given previous reference waveform values and a prior cycle wherein a reference waveform value at each sample time comprises a selectively weighted average of value at that sample time in the prior cycle of the AC line signal and the previous reference waveform value at that sample time; (c) an uninterruptible power supply including an auxiliary power supply battery, the uninterruptible power supply receiving the AC line power and normally providing the AC line power to a load and responsive to a fault signal to switch to provide power to the load from the battery; (d) means for comparing the AC line signal waveform with the reference waveform at corresponding times in the reference waveform and the signal waveform and providing the fault signal to the uninterruptible power supply so that it provides power to the load from the battery when a selected difference condition is exceeded.

• Assignee: Best Power Technology, Inc., Necedah, WI (United States)
• Patent Number(s): A; US 5229651
• Application Number: PPN: US 7-404902
• OSTI ID: 6411117
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
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Transmission & Distribution-- AC Systems-- (1990-)
AVAILABILITY
CAPACITY
DEMAND
ELECTRIC BATTERIES
ELECTRICAL EQUIPMENT
ELECTRICAL TRANSIENTS
ELECTROCHEMICAL CELLS
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
POWER CONDITIONING CIRCUITS
POWER DEMAND
POWER DISTRIBUTION SYSTEMS
POWER SUPPLIES
RELIABILITY
TRANSIENTS
VOLTAGE DROP