UPS (uninterrupted power supply) parallel output system, master and slave units of UPS parallel output system and UPS parallel output voltage control method and device

Abstract

The invention relates to a UPS (uninterrupted power supply) parallel output system. In order to ensure that UPS inverters in the UPS parallel output system output uniform voltages Vo, a corrector of each UPS adjusts its own corrected value A in real time so that corrected voltages Ve of the UPSes are uniform. A master unit (0) of the UPS parallel output system transmits, in real time, its own corrected voltage Ve0 to a slave unit parallelly connected with the master unit, the corrector of the slave unit adjusts, in real time, its own corrected value A1 according to the corrected voltage Ve0 of the master unit, and thus, following corrected voltage Ve1 of the slave unit is closer to the corrected voltage Ve0 of the master unit; the slave unit receives, in real time, the corrected voltage Ve0 of the master unit (0) and then immediately adjusts the corrected value A1 of the corrector of the slave unit (1) so that the following corrected voltage Ve1 of the slave unit (1) is closer to the corrected voltage Ve0 of the master unit (0). Voltage controlling of the UPS parallel output system is implemented through a computer program.

Description

technical field [0001] The present invention relates to a UPS parallel output system and the UPS therein, and also relates to a voltage control method in the system. The steps in the voltage control method can correspond to the establishment of functional modules, combined into a functional module framework, mainly by storing in a computer-readable storage medium computer program to achieve. Background technique [0002] In the UPS parallel system, it is required that the output voltage Vo of the inverters of each UPS in parallel be equal or limited within a certain error range, so that current sharing between each UPS can be achieved during parallel connection, and the system can run stably. If there is a large difference in the output voltage Vo of each UPS, when they are connected in parallel, the circulating current between the UPSs will be large, and the system will fail and cannot operate normally. [0003] Each UPS internal circuit such as figure 1 , the controller ...

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Problems solved by technology

[0004] But in reality, because the sampling ratio R of the sampling circuit changes due to the influence of the environment, in a certain environment, the operator adjusts the correction value A=1 / R of the calibrator, and when the environment changes, the sampling ratio R of the sampling circuit will immediately At this time, if the original correction value A is still used for correction, it will cause a deviation of the obtained correction voltage Ve relative to the output voltage Vo of the inverter. Under the inherent control of the controller, the output voltage of the inverter Vo will deviate from the reference voltage Vf

In the UPS parallel system, the sampling ratio R of the sampling circuit of different UPSs is affected by the environment in different degrees, which leads to different deviations of the output voltage Vo of each UPS inverter, and a large Circulation, causing system failure

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