EMU overvoltage control method and system

Abstract

The invention provides an EMU overvoltage control method and system. The EMU overvoltage control method includes: collecting the intermediate DC voltage of the EMU and the network voltage of the EMU in multiple consecutive time periods; performing modal analysis on the network voltage in each time period to obtain the Harmonic energy amplitude; detect the fluctuation of the intermediate DC voltage, calculate the voltage fluctuation peak value of each voltage fluctuation cycle of the intermediate DC voltage; judge whether the network voltage has a high-order harmonic resonance trend according to the multiple harmonic energy amplitudes; Multiple voltage fluctuation peaks determine whether the intermediate DC voltage has a low-frequency oscillation trend; when the grid voltage produces a high-order harmonic resonance trend, control the inertial operation of the EMU; when the intermediate DC voltage produces a low-frequency oscillation trend, output low-frequency oscillation warning information. The invention can identify faults effectively and in time, reduce the evolution trend of fault deterioration, avoid the influence caused by faults to the greatest extent, and ensure the safety of the EMU operation.

Description

technical field [0001] The technical field of EMUs of the present invention, in particular, relates to an overvoltage control method and system for EMUs. Background technique [0002] The AC-DC-AC transmission system is widely used in my country's electrified railways, and its grid-side converter adopts pulse width modulation technology, which has the characteristics of wide harmonic spectrum and non-negligible high-order harmonics. Harmonic current not only affects the performance of the traction drive system of high-speed trains, but also becomes the excitation source of traction network resonance, resulting in harmonic resonance overvoltage phenomenon in the vehicle network system. Harmonic resonance will cause serious distortion of traction network voltage and current, further Increase the harmonic current of the electric locomotive / EMU, resulting in the formation of resonance overvoltage between the EMU and the traction power supply system, causing equipment burnout. ...

AI Technical Summary

Problems solved by technology

Harmonic current not only affects the performance of the traction drive system of high-speed trains, but also becomes the excitation source of traction network resonance, resulting in harmonic resonance overvoltage phenomenon in the vehicle network system. Harmonic resonance will cause serious distortion of traction network voltage and current, further Increase the harmonic current of the electric locomotive / EMU, resulting in the formation of resonance overvoltage between the EMU and the traction power supply system, causing equipment burnout

[0003] When multiple electric locomotives / EMUs are in the state of no-load / light load, the electrical quantities of electric locomotives / EMUs and traction power supply systems have obvious low-frequency oscillation overvoltage phenomena, and low-frequency oscillations are generally caused by nonlinear loads. Induced, the unstable electrical quantity further affects the flow of the EMU through the traction drive control system, resulting in further aggravation of fluctuations, which eventually leads to the traction blockade of the EMU and affects the traffic order

[0004] At present, in view of the above two fault phenomena, the EMUs in operation are protected by the method of threshold judgment. Although this method can finally realize the isolation under the fault, but at the cost of the power loss of the EMU and the tripping of the substation, it is harmful to a certain extent. Traffic order has caused irreparable impact

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