Transformer DC Bias Suppression Method for Locomotive AC-DC-DC Power Supply System

Abstract

The invention relates to an alternating current-direct current-alternating current power supply system with transformer power supply for a locomotive or a motor car, in particular to a transformer direct current bias suppression method for the alternating current-direct current-alternating current power supply system of the locomotive. The problems existing in an existing alternating current-direct current-alternating current power supply system of the locomotive in overcoming the transformer direct current bias are solved. When transformer direct current bias suppression method for the alternating current-direct current-alternating current power supply system of the locomotive works through four quadrants, positive accumulation processing and negative accumulation processing of a plurality of power grid cycles are carried out on the input voltage of the four quadrants in the positive and negative half cycle of the power grid voltage. According to the actual working conditions, after the positive and negative half cycle phase intervals of the fundamental wave of the input voltage are accurately calculated, positive accumulation processing and negative accumulation processing of thepower grid cycles are carried out on the input voltage of the four quadrants. Whether direct current bias occurs or not is judged through four quadrant input voltage and current, when the direct current bias occurs, PI regulation is carried out on the accumulated value of the positive and negative half cycle of the current to change the output result of a current loop so as to adjust the PWM pulse width and realize the compensation and suppression of the direct current bias.

Description

technical field [0001] The invention relates to an AC / DC / AC power supply system for a locomotive or a motor vehicle including a transformer for power supply, in particular to a transformer DC bias suppression method for the AC / DC / AC power supply system for a locomotive. Background technique [0002] Such as figure 1 As shown, the locomotive or motor car takes power through the 25kV catenary, and is stepped down by a single-phase traction transformer to meet the required voltage level to provide traction power. There are multiple groups of taps on the secondary side of the traction transformer, and each group of taps is connected to the rectification unit Provide stable DC power for the traction converter (inverter unit) in the locomotive. When multiple groups of converters are running at full power at the same time, due to a series of factors such as inconsistent switching characteristics of four-quadrant power devices, differences in main circuit structure and parameters, ...

AI Technical Summary

Problems solved by technology

[0005] The invention solves the problem that the existing locomotive AC-DC-DC power supply system cannot fundamentally eliminate the DC bias of the transformer in the aspect of overcoming the DC bias of the transformer and the influence of the dynamic response of the four quadrants by using software and hardware filtering methods in the control , providing a transformer DC bias suppression method for locomotive AC / DC power supply system

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