Alternating current-direct current electric locomotive traction device and system

Abstract

The invention discloses an alternating current-direct current electric locomotive traction device and a system, wherein the alternating current-direct current electric locomotive traction device comprises a pulse-width modulation (PWM) converter unit and a step-down chopping unit, an input end of the PWM converter unit is connected into a power grid, an output end of the PWM converter unit is connected with a traction motor through the step-down chopping unit, the PWM converter unit converts an alternating current power supply which is connected into the power grid and stabilizes voltage to output direct current, and the step-down chopping unit reduces voltage and chops direct current which is output from the PWM converter unit to be required direct current by controlling switching of a chopping switch pipe, and supplies the required direct current for the traction motor. The system comprises more than one traction converter, wherein each traction converter is provided with a traction controller and more then two sets of traction devices which are respectively connected with the traction controller, and each set of traction device is corresponding to the traction motor. The alternating current-direct current electric locomotive traction device and the system can achieve traction power supply with simple structure, low making cost, steady output of traction energy and high power factor on the basis of that locomotive circuit structures do not need to change.

Description

technical field [0001] The invention relates to the technical field of AC and DC electric locomotives, in particular to a traction device and system for AC and DC electric locomotives. Background technique [0002] At present, the traction device of AC and DC electric locomotives usually adopts thyristor phase-controlled rectification and voltage regulation technology, and most of them use unequal three-stage semi-controlled bridge rectification and voltage regulation technology, such as SS3B, SS4G, SS4B, SS6B, SS7D, SS7E AC / DC electric locomotives represented by , SS8, SS9G, etc., and a few other locomotives (such as SS7, SS7C electric locomotives) adopt the "full control + half control" second-stage bridge rectification and voltage regulation technology. [0003] Although the thyristor phase-controlled rectification and voltage regulation technology is widely used, its power factor is low, harmonics are large, and the utilization rate of electric energy is not high. Take ...

AI Technical Summary

Problems solved by technology

Although the thyristors of each bridge section are in a state of large opening angle as much as possible through the sequential input of the three sections of bridges, that is, at low speed and low voltage, the thyristors of one section of the bridge can be fully opened; Insufficiency of bridge phase-controlled rectification circuit in power factor and harmonic components

Taking the SS4B type electric locomotive as an example, its AC voltage harmonic component index is less than 10%, and its AC current harmonic component index is above 10%. The power factor of the locomotive is greater than 0.9 only when the power compensation device is put in. However, due to the power compensation device The reliability of the locomotive itself is low, and its actual normal utilization rate on the SS4B electric locomotive is lower, and the actual power factor of the locomotive is far less than 0.9

In order to further improve the power factor of the locomotive, the AC / DC electric locomotive using the above-mentioned traction device usually needs to be equipped with a power factor compensation device, so that the power compensation device can be put into operation in a timely manner during traction to improve the power factor of the locomotive, and this will further increase the cost input and overhaul strength

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