Uninterruptible power supply and control method thereof

Abstract

An uninterruptible power supply comprises an energy storage battery, a monitoring circuit, a controllable switch, a grid-connected control circuit, an off-network control circuit, a mode changeover switch and a converter, wherein the grid-connected control circuit comprises a harmonic and reactive current extraction circuit and a current ring control circuit, and the off-network control circuit comprises a voltage outer ring circuit and a current inner ring circuit. When the above uninterruptible power supply is in grid connection, the grid-connected control circuit extracts a harmonic and reactive compensation instruction signal according to harmonic and reactive components in a mains supply and carries out reactive and harmonic compensation through current closed-loop control so as to reduce electric energy loss; the off-network control circuit does not take participate in controlling in a grid-connected mode while still is in a running state, and an off-network control signal can be generated according to a given voltage value of a voltage ring, an output voltage feedback signal and an output current feedback signal; and when the system is switched to an off-network mode from a grid-connected mode, the converter controls the output according to the off-network control signal so as to achieve seamless switching between the grid-connected mode and the off-network mode. The invention also relates to a control method of an uninterruptible power supply system.

Description

technical field [0001] The invention relates to the technical field of power supply, in particular to an uninterruptible power supply system and a control method thereof. Background technique [0002] With the rapid growth of power loads in data centers in recent years, the requirements for energy efficiency indicators are getting higher and higher. For the uninterruptible power system (UPS) used in high-density data centers, it is not only necessary to supply power to IT equipment, but also to ensure the power supply of auxiliary equipment such as air conditioners for the operation of IT equipment, and the demand for power will continue to increase. Since the high density of data centers is an inevitable trend, new requirements are put forward for the UPS that provides power guarantee for it. In the traditional data center power supply mode, an online UPS power supply based on double conversion technology is generally used. The main disadvantage of this kind of online UPS...

AI Technical Summary

Problems solved by technology

The main disadvantage of this kind of online UPS is that the power loss in the strong grid power supply environment is large, and the operating cost is high. Moreover, the traditional UPS cannot effectively improve the power quality of the grid when the power quality is poor, so it cannot meet the requirements of high-quality data centers. power supply needs

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