Three-phase UPS (Uninterruptible Power Supply) control system for restraining disequilibrium of output voltage and harmonic wave

Abstract

The invention discloses a control system for restraining three-phase output voltage of an uninterruptible power supply (UPS) from disequilibrium and harmonic wave. Imbalance output voltage is decomposed to be a positive-sequence component, a negative-sequence component and a zero-sequence component, which pass three groups of PI controllers; the first group of PI controllers primarily controls the output voltage by a proportional controller P under Clarke coordinate to calculate margin of error; the second group of PI controllers adjusts the positive-sequence component by an integral controller I in a positive rotary coordinate system; and the third group of PI controllers restrains the negative sequence by an integral controller in a contra-rotation coordinate system; if the negative sequence is restrained 5 times and the harmonic wave is restrained 7 times, PI control is respectively carried in a reverse 5 times based wave angular velocity rotary coordinate system and a forward 7 times based wave angular velocity rotary coordinate system. Three-phase balance output voltage can be acquired after summing up the output of the five groups of PI controllers, and carrying out the space vector modulation, thus harmonic distortion is greatly reduced.

Description

Technical field: [0001] The invention relates to a UPS power supply control system which effectively suppresses the imbalance of ground three-phase output voltage and compensates harmonics. Background technique: [0002] With the increasing demand for high-quality power supplies in important departments and large-scale electrical equipment, and in order to reduce the harmonic pollution of the power grid caused by the extensive use of power electronic equipment and the continuous increase of non-linear loads, UPS (Uninterruptible Power Supply, uninterruptible power supply) has been increasingly widely used. Its function is mainly reflected in two aspects: on the one hand, it provides uninterrupted power supply for the load when the mains power is cut off, which usually uses the battery energy storage on the UPS to invert DC into AC to supply power to the load; on the other hand, Let the UPS play the role of isolation, always provide high-quality stable voltage and frequency ...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the three-phase unbalance problem cannot be solved in the prior art, or even if it is solved, but the hardware cost is large, only using figure 2 The circuit shown does not add any peripheral circuits, realizes three-phase decoupling control, and solves the problem of three-phase unbalance

Images