Uninterruptible power supply learning type load current estimation system

Abstract

The invention discloses an uninterruptible power supply learning type load current estimation system, which comprises a main inverter circuit, a filter inductor, a fixed three-phase current sensing group, a filter capacitor, an inverter controller, a three-phase rectifier and a storage battery, wherein the input end of the main inverter circuit is connected with the three-phase rectifier through the storage battery, and the output end of the main inverter circuit is sequentially connected with the filter inductor and the fixed three-phase current sensing group in series; one end of the filtercapacitor is arranged on a three-phase line of the output end of the fixed three-phase current sensing group, and the other end of the filter capacitor is grounded; one end of the inverter controlleris connected with the fixed three-phase current sensing group and the filter capacitor, and the other end of the inverter controller is connected with the main inverter circuit. In the embodiment of the invention, the number of current sensors in UPS is reduced, and the accuracy of inverter model parameters can also be improved so as 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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