Uninterruptible power supply system

• Main Authors: ZHANG TAO, YU WEI, XU HAIBO
• Format: Patent
• Language: Chinese; English
• Published: 27.04.2018
• Subjects: CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERATION; REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGYGENERATION, TRANSMISSION OR DISTRIBUTION; SYSTEMS FOR STORING ELECTRIC ENERGY; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

The invention discloses an uninterruptible power supply system, which comprises an energy storage device, a converter, a grid-connected control circuit, an off-grid control circuit, a mode switching switch and a control circuit, wherein the off-grid control circuit comprises an outer voltage loop circuit, an inner current loop circuit and a load side current harmonic suppression circuit; and the load side current harmonic suppression circuit comprises a three-phase resonant filter and is used for extracting preset subharmonics in three-phase load current and generating a load current harmoniccompensation instruction signal. According to the uninterruptible power supply system, reactive power and harmonic compensation can be carried out on output in the grid connection process, so that thepower loss is reduced. The off-grid control circuit does not participate in control in a grid-connected mode, but generates an off-grid control signal, so that seamless switching of the grid-connected/off-grid mode is achieve