David J Layden, 45154799 Rd S, Mosinee, WI 54455

5182518, Jan 26, 1993

Apr 11, 1991

7/685068

Frederick A. Stich - Wisconsin Rapids WI
Richard V. Baxter - Neenah WI
Herbert A. Podewils - Sparta WI
David L. Layden - New Lisbon WI

Best Power Technology, Inc. - Necedah WI

G01R 3102
G01R 3136
H02J 904

324511

The inverter of an uninterruptible power system is tested by turning on switches in the inverter at a selected test phase in each half-cycle of the AC input waveform so that the inverter provides a voltage which opposes the AC input voltage waveform during part of each half-cycle of the waveform. The resulting current drawn from the inverter battery, if any, is measured and its peak may be found. The peak battery current during each half-cycle is compared to maximum allowable peak currents to determine if an inverter failure has occurred. If the peak currents are lower than a maximum acceptable value, the test is repeated on a subsequent AC input waveform at a decreased test phase (a shorter time delay from the zero crossing of each half-cycle of the waveform) until the peak current in the first half-cycle is at a selected value, at which time the peak in the second half-cycle is checked to determine if it is within an acceptable range. If not, an inverter test failure is indicated. Inverter test failure is also indicated if repeated cycles during which the test phase is reduced fail to cause the first peak to reach the proper value and the test phase is finally reduced to a minimum allowable test phase.

5602462, Feb 11, 1997

Feb 21, 1995

8/391761

Frederick A. Stich - Wisconsin Rapids WI
Thomas G. Hubert - Necedah WI
David L. Layden - New Lisbon WI
Donald K. Zahrte - Necedah WI

Best Power Technology, Incorporated - Necedah WI

G05F 116
H02J 700
H02J 900

323258

An uninterruptible power system has a transformer with a primary connected to input terminals, a secondary connected to output terminals, a static switch connected between the input terminals and the primary, and an auxiliary primary connected to an inverter which is supplied by a battery to provide output voltage to the output terminals when a main AC power system connected to the input terminals has failed. The primary has multiple taps at different voltage levels and a buck-boost winding. The taps of the transformer are switched and the buck-boost winding is controlled to provide either buck, boost, or pass-by to allow control of the output voltage from the transformer to within a few percent of a desired voltage level despite large changes in the input voltage. A battery charger coupled to the auxiliary primary operates as a boost converter to provide current to charge the battery at a current level which tracks the input voltage from the AC power system, thereby providing a substantially unity power factor to the AC power system. The voltage control of the output voltage also controls the voltage at the output of the auxiliary primary to which the battery charger is connected, whereby the voltage applied to the charger is substantially regulated and the output power of the charger itself is substantially regulated.