Locomotive traction power supply system, four-quadrant converter control method and system

Abstract

The invention discloses a locomotive traction power supply system as well as a control method and system of a four-quadrant current transformer. The control method comprises the following steps: obtaining a first sampling current and a sampling voltage at the input end of the four-quadrant current transformer; obtaining a direct-current bias voltage corresponding to an average current value of the first sampling current; overlapping the negative value of the direct-current bias voltage to the sampling voltage so as to obtain a first modulation voltage; controlling the control end of the four-quadrant current transformer according to a first modulation control signal generated by the first modulation voltage. According to the control method, the direct-current bias in a circuit of the four-quadrant current transformer can be removed, the direct-current magnetic bias phenomenon of a traction voltage transformer is avoided, and stable running of the traction voltage transformer and a locomotive traction power supply network is favorably protected.

Description

technical field [0001] The invention relates to locomotive traction technology, in particular to a locomotive traction power supply system and a control method and system for a four-quadrant converter. Background technique [0002] The electric locomotive traction power supply system is used to convert the single-phase AC power supply of the railway power supply network into locomotive traction power and auxiliary power suitable for locomotive operation. The electric locomotive traction power supply system generally includes: traction transformer, four-quadrant converter, inverter And the control system, etc., under the control of the control signal generated by its control system, the four-quadrant converter can realize the bidirectional flow of energy between the traction motor and the grid. [0003] figure 1 For existing four-quadrant converter control systems, such as figure 1 As shown, the control system first samples the DC voltage of the output voltage of the four-q...

AI Technical Summary

Problems solved by technology

However, in practical applications, due to the existence of the dead time of the switching tube of the four-quadrant converter, the positive and negative half cycles of the pulse modulation signal output by the control system are not completely symmetrical, so in the main circuit of the four-quadrant converter The DC voltage component is generated, and a DC bias voltage is introduced into the secondary winding of the traction transformer. The DC bias voltage will cause the traction transformer to generate magnetic saturation and cause DC bias phenomenon.

The traction transformer works under the condition of DC bias, which not only accelerates the permanent damage of the traction transformer, but also has an adverse effect on the grid connected to the traction transformer

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