Control method for uninterrupted power supplier

Abstract

The invention provides a controlling method of an uninterrupted power supply unit. The uninterrupted power supply unit at least comprises an AC input voltage, a DC input voltage and a single-phase alternating current-alternating current adaptor. The single-phase alternting current-alternating current adaptor consists of an AC inductor, a busbar capacitor, a boosting bridge arm, a public bridge arm and a decompression bridge arm. The controlling method comprises the following steps. The busbar voltage is controlled to involve a DC element and a biphase rectification element; a busbar voltage parameter K is set, and the K is more than or is equal to 0, and is less than or equal to 1 so that when K approaches to 0, the bus bar voltage approaches to an AC voltage; when K approaches 1, the busbar voltage approaches to a biphase rectification voltage.

Description

technical field [0001] The present invention relates to a control method for an uninterruptible power supply, in particular to a line-interactive uninterruptible power supply using a single-phase AC-AC converter with three bridge arms. Background technique [0002] see figure 1 , which is a circuit diagram of an existing online interactive uninterruptible power supply. exist figure 1 Among them, the online interactive uninterruptible power supply 1 mainly includes an AC input voltage AC, a switch group composed of diodes D1 and D2, a single-phase AC-AC converter 11, and a filter composed of a filter inductor Lo and a filter capacitor Co. An AC filter 12 and a load R are formed. [0003] In the single-phase AC-AC converter 11, there are AC inductance Li, bus capacitor Cs and three bridge arms, wherein the bridge arm formed by switches S1 and S2 is called boost (boost) bridge arm, and the bridge arm formed by switch S3 The bridge arm formed by S4 and S4 is called a common ...

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Problems solved by technology

[0012] On the contrary, its main disadvantages are poor dynamic characteristics, large input reactive current, and large ripple current on the bus capacitor Cs

Since the current flowing to the load R is very small at light load and no-load, in order to maintain the full-wave rectified voltage waveform on the bus capacitor Cs, the bus capacitor Cs must be charged and discharged ineffectively, but this will cause the converter 11 to Large losses at light load or no load

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