Research On Uninterruptible Auxiliary Power Supply For Electrified Railway Vehicles

With nearly a decade of rapid development of China railway. HXD series AC drive electric locomotive and CRH series EMU has gradually become the main force of electrified railway transport. Compared to the traditional electric locomotive, the towing capacity, reliability and comfort of passengers of new AC drive electric locomotive have been significantly improved. The auxiliary power supply system is an important part of AC drive electric locomotive, its reliable and uninterruptible work is an important prerequisite to ensure the reliability of locomotive and comfort of passengers. However, there are many neutral sections in single-phase AC power supply electric railway traction power supply system inevitably, which affects the continuous work of train auxiliary power supply system to a certain extent. This thesis focuses on how to achieve auxiliary power supply system working uninterruptedly without over-voltage and over-current when train passes neutral section, and researches common auto-passing neutral section with power supply and without power supply. The research includes the converter control in auto-passing neutral section without power supply, and also includes the system solutions, train pantograph position detection technology and over-current suppression in auto-passing neutral section with power supply.In this thesis, the main circuit structure of auxiliary system in HXD series AC drive electric locomotive and CRH series EMU are compared, the influence of passing neutral section without power supply to train is discussed, the existed auto-passing neutral sections are compared. Based on it, the existed auto-passing neutral sections are modified, new auto-passing neutral sections with uninterruptible auxiliary power supply system are proposed.This thesis researches the problems of auxiliary power supply system without power supply, proposes the auto-passing neutral sections with uninterruptible auxiliary power supply system represented by HXD3type AC drive electric locomotive based on the existed auto-passing neutral sections technology without power supply. Through the research on working condition of traction converter in auto-passing neutral section without power supply, this thesis proposes the control strategy before and after the main breaker is closed or open, and achieves the train auxiliary power supply system uninterrupted without over-voltage and over-current in auto-passing neutral section without power supply. In connection with the shortage of existed auto-passing neutral section technology with power supply, this thesis researches the auto-passing neutral section with power supply through electronic switch, analyzes the generation mechanism of over-voltage and over-current, proposes the control strategy to suppress over-voltage and over-current using characteristic of electronic switch. This solution can effectively shorten the dead time and achieve the train auxiliary power supply system uninterrupted without over-voltage and over-current in passing neutral section. Through the research and analysis on the structure of catenary, this thesis proposes the train pantograph position detection technology applied in auto-passing neutral section system with power supply.This thesis also establishes a test bench of ground auto-passing neutral section of uninterruptable auxiliary power supply system with electronic switch, which simulates locomotive load by single-phase transformer and four quadrant rectifier, and achieves control strategy of electronic switch. The result verifies the theoretical analysis of this thesis, and indicates that ground auto-passing neutral section technology with electronic switch can achieve the uninterrupted train auxiliary power supply system without over-voltage and over-current in passing neutral section.