动车组用网压过零点快速检测装置设计

Design of Rapid Detection Device for Zero Crossing of Network Voltage for EMU

兰新高速铁路玉门南站附近(公里标2440~2499区间)网压波动一直较大(范围在28~31 kV上下),且存在较大谐波,动车组途径此地容易发生牵引离线、闪红、自动切除及主断跳开故障。为保证动车组运行正常,设计了一种动车组用网压过零点快速检测装置,系统包括采集网压信号的网压采集电路、将模拟网压信号转换为数字网压信号的模数转换器、FPGA。FPGA对模数转换器发送的数字网压信号进行采样,并对采样的数字网压信号进行滑动窗口滤波和FIR滤波得到频率50 Hz的正弦波网压信号;FPGA内设过零点检测模块,过零点检测模块被设置为:当连续达到预设阈值T个网压数据大于零时,标记Flag=1;当连续达到预设阈值T个网压数据小于零时,标记Flag=0;当连续预设阈值N包网压数据小于零时,则输出过零中断信号。该装置已成功应用到高速动车组牵引控制单元,能够实时快速精确地检测动车组用网压过零点,使动车组在网压畸变严重的情况下依然保持正常运行。

The network voltage fluctuations near Yumen South Station of Lanzhou-Xinjiang High-speed Railway(kilometer sign 2440~2499)have been large(ranging from 28~31 kV)and contain a large number of harmonics.The EMU is prone to traction offline,flashing red,automatic cutting and main break tripping.In order to ensure the normal operation of EMU,a fast detection device for zero crossing of network voltage for EMU is designed.The system includes a network voltage acquisition circuit for collecting network voltage signals,an analog-to-digital converter for converting analog network voltage signals into digital network voltage signals,and FPGA;The FPGA samples the digital network voltage signal sent by the analog-to-digital converter,and performs sliding-window filtering and FIR filtering on the sampled digital network voltage signal to obtain a sinusoidal network voltage signal with a frequency of 50 Hz;The FPGA is internally provided with a zero-crossing detection module,which is set as follows:when T network voltage data continuously reaching a preset threshold value is greater than zero,the Flag=1;When T network voltage data continuously reaching the preset threshold is less than zero,Flag=0 is marked;and when the network voltage data of continuous preset threshold N packets is less than zero,a zero-crossing interrupt signal is output.The device has been successfully applied to the traction control unit of high-speed EMU,which can quickly and accurately detect in real time the zero crossing point of the network voltage of EMU,and make the EMU still run normally under the condition of serious network voltage distortion.