| 摘要 |
An uninterruptible power supply provides for input sinewaves of an AC utility to be separated by diode rectifiers to apply positive half sinewaves on a plus d.c. line and negative half sinewaves on a minus d.c. line. A battery-powered high-frequency inverter forming a part of the power supply includes a full wave diode rectifier for applying bursts of positive going pulses having sinusoidally varying duty cycles on a plus d.c. bus and bursts of negative going pulses having sinusoidally varying duty cycles on a minus d.c. bus. The plus d.c. line and the plus d.c. bus are joined and connected by a first synchronous switch to a common junction and the minus d.c. line and the minus d.c. bus are joined and connected by a second oppositely phased synchronous switch to the same common junction. The inverter is driven by bursts of pulses having sinusoidally varying duty cycles generated by comparing the amplitudes of feedback output half sinewave signals and reference half sinewave signals. During brownout, the bursts of pulses applied on the plus and minus d.c. busses are respectively diode ORed with the positive and negative half sinewaves on the plus and minus d.c. lines to form positive and negative composite waveforms on the common junction which are passed through a low pass filter to provide regulated output sinewaves to the load.
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