Current bias adjusting method and device of direct-drive permanent magnet electric locomotive converter

Abstract

The embodiment of the invention provides a current bias adjusting method and device of a direct-drive permanent magnet electric locomotive converter, and the method comprises the steps of sampling analternating current inputted into a four-quadrant rectifier, and obtaining an alternating current in a sampling period, wherein the alternating current comprises a positive half-period current value and a negative half-period current value; obtaining a first sum value of the current values of the positive half cycle and a second sum value of the current values of the negative half cycle, and obtaining a current bias value according to the first sum value and the second sum value; inputting a first difference value between the current bias value and zero into a first PI controller to obtain a first output value outputted by the first PI controller; obtaining a pulse width modulation symbol according to the first output value and a second output value outputted by the PR controller; and controlling the on-off of an IGBT in the four-quadrant rectifier according to the pulse width modulation symbol. According to the method provided by the embodiment of the invention, the current bias at the transformer side can be fundamentally suppressed and eliminated, so that the influence of the current bias on the control of the four-quadrant converter is eliminated.

Description

technical field [0001] The invention relates to the electric locomotive converter technology, in particular to a method and equipment for adjusting the current bias of the direct-drive permanent magnet electric locomotive converter. Background technique [0002] The converter consists of two parts, a four-quadrant rectifier and an inverter. When the voltage bias of the four-quadrant rectifier occurs due to factors such as devices and controls, the four-quadrant converter will be unstable, and the IGBT device will deviate from its rated working area. At the same time, a large DC bias will be generated on the transformer, causing the transformer to work Point offset, temperature rise, etc. will seriously affect the normal operation of the rectifier and the normal operation of the electric locomotive, and at the same time cause damage to the transformer or reduce its service life. [0003] In the prior art, hardware filtering circuit design or software high-pass filter design ...

AI Technical Summary

Problems solved by technology

[0004] However, with the existing technology, the DC bias has not been fundamentally solved. The four-quadrant rectifier can operate stably, but the transformer still works at the bias point, and the temperature rise of the transformer and other problems caused by it have not been solved.

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