Device and method for detecting voltages of direct current bus of variable frequency speed regulator

Abstract

The invention relates to a device and method for detecting voltages of a direct current bus of a variable frequency speed regulator. The device comprises a voltage dividing and current limiting clamping circuit, a differential input amplification circuit and a proportional amplification circuit. The voltage dividing and current limiting clamping circuit is used for converting the voltages of the direct current bus to millivolt-level voltage signals through voltage dividing and current limiting, and then introducing the millivolt-level voltage signals to the differential input amplification circuit. The differential input amplification circuit is used for amplifying and restoring the introduced millivolt-level voltage signals to volt-level voltage signals and then introducing the volt-level voltage signals to the proportional amplification circuit. The proportional amplification circuit is used for restoring the introduced volt-level voltage signals to actual values of the voltages of the direct current bus, and outputting the actual values of the voltages of the direct current bus to a control panel of the variable frequency speed regulator. Through the redesign of the device for detecting the voltages of the direct current bus, a detection circuit for the voltages of the direct current bus of the variable frequency speed regulator is simplified, the real-time performance, the stability and the precision of detection are improved, and a deviation correcting function is also achieved.

Description

technical field [0001] The invention relates to the field of DC bus voltage detection, in particular to a DC bus voltage detection device and method for a frequency conversion governor. Background technique [0002] The DC bus voltage of the frequency converter is a very critical parameter in the signal detection system of the frequency converter. It directly participates in the control algorithm of the frequency converter, and the accuracy of the DC bus voltage detection determines the performance of the frequency converter. [0003] The DC bus voltage detection circuit commonly used in the prior art is completed through a secondary output of the switching transformer that supplies power to the control system. The principle is that the DC bus voltage is used as the input of the switching transformer, and a secondary voltage of the switching transformer and The DC bus voltage forms a corresponding ratio. The circuit structure of this detection mode is complex, the response ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a DC bus voltage detection device and method of a frequency converter, which is used to solve the problems of the existing DC bus voltage detection circuit of the frequency converter with complex structure, slow response, and low accuracy.

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