A Learning Type Load Current Estimation System for Uninterruptible Power Supply

Abstract

The invention discloses an uninterruptible power supply learning type load current estimation system, wherein the system includes: a main inverter circuit, a filter inductor, a fixed three-phase current sensing group, a filter capacitor, an inverter controller, a three-phase a rectifier and a battery; wherein, the input end of the main inverter circuit is connected to the three-phase rectifier through the battery, and the output end is connected in series with the filter inductor and the fixed three-phase current sensing group; one end of the filter capacitor is set on the fixed One end of the three-phase line at the output end of the three-phase current sensing group is grounded; one end of the inverter controller is respectively connected to the fixed three-phase current sensing group and the filter capacitor, and one end is connected to the main inverter circuit is connected. In the implementation of the present invention, the number of current sensors in the UPS is reduced, and the accuracy of inverter model parameters can be improved to ensure the accuracy of output current estimation.

Description

technical field [0001] The invention relates to the technical field of uninterruptible power supplies, in particular to an uninterruptible power supply learning type load current estimation system. Background technique [0002] Uninterruptible Power Supply (UPS) is widely used in the field of guaranteed power supply; a traditional single three-phase UPS generally requires two sets of three-phase current sensors, one set is used to measure the current of the main inverter circuit (ie, the inductor current), Another group is used to measure the UPS output current. Due to the existence of filter capacitors, these two sets of capacitors are not equal, but differ in the transient current on the filter capacitors. It can be seen that a single three-phase UPS needs at least six current sensors. [0003] At present, some output current estimation algorithms have been proposed to reduce the number of current sensors used, thereby reducing costs. These algorithms are often based on ...

AI Technical Summary

Problems solved by technology

[0003] At present, some output current estimation algorithms have been proposed to reduce the number of current sensors used, thereby reducing costs. These algorithms are often based on observer theory, and the implementation is relatively complicated; on the other hand, no matter what kind of current estimation algorithm, its estimation accuracy Both depend heavily on the inverter parameters, that is, the filter capacitor and inductance parameters, and the actual values ​​of the inverter parameters are often different from the nominal values, and these parameters will also change with the aging of the inverter; UPS model and control Algorithm performance can be affected by inaccurate model parameters

[0004] In general, two problems can be summarized above: first, traditional UPS requires more current sensors, which need to be reduced to reduce costs; second, the proposed output current estimation algorithm is complex and relies on accurate inverters parameters, there needs to be a suitable method to ensure the accuracy of the model parameters

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