The Research Of Cophase Traction Power Supply Control System

The singe-phase power frequency power supply system of the now available electrified railways in our country have problems like three-phase imbalance, phase separation, low energy feedback efficiency, inject reactive current and harmonic current into the public supply network, etc. To solve these problems, large amount of manpower and material resources needed to be cost by the national power system on power quality management. Parallel connect electric energy quality compensation device on traction transformer is the available solution at present. But this is a passive compensation method which can not abolish phase separation thoroughly. In this article,it focuses on the study of series of key questions,that this novel topology faces in the application of the electrified railway traction power supply system, based on a non-traction power transformer Cophase system topology.Non-traction transformer cophase power supply system, it is the single phase supply voltage with the contact wire formed directly by power electronics converter that realize the initiative management of the quality of electric energy; This paper points out the advantages of this topology from aspects of harmonic current, reactive current, negative sequence current and parallel connection, etc. and gives the superiority that it is used in electrified railway traction power supply system.H-H single-phase power unit is the basic unit of the new phase power supply topology that this subject researchs. Regarding to Megawatt power single-phase PWM Rectifier unit, PWM Rectifier unit Control strategy is put forward in this paper baised on the full feedforward control strategy of input voltage, DC bus current and DC bus voltage,which aims at solving the contradiction between stability and dynamic response of high power conversion system to satisfy the characteristics of frequent and rapid change of locomotive load; a new type PWM modulation strategy is put forward in this paper to solve the universal problem of low switching frequency in places where high-power is used that influence control performance to short system control period and modulate lag, and the application range of this control strategy is also given in this paper; To solve oversized ripple input current question caused by the switching action in the low switching frequency switching system,it puts out the numbers of power units rectifier carrier phase-shift control strategy; Finally, the proposed method is puts out for optimizing digital lock and inhibition of single-phase system instantaneous power fluctuations of the digital filter design methods, in order to form a complete unit control strategy.To cancel electricity phase link, it must enable the output of the Traction power supply device can be achieved power supply through parallel catenary, the core goal of the same phase power supply system is to achieve penetrating parallel power supply in multiple-phase power supply units.In this paper, it dose depth analysis in parallel circulation problem that presents in electrified railway phase power supply system, points out reasons that Electricity Phase can not be completely canceled electrified railway power supply system; establishes a circulation models used in parallel system, and clearly puts forward the special problems and control objectives in the same phase power supply; based on non-interconnect control thought, a Multi-phase power supply units parallel control strategy,which could provide voltage support and inhibite Current circulationin the same, is gived; to supply requirements of uninterruptible power supply in Electrified railway system, it dose fault tolerance analysis and design.Then, this paper presents a complete system parameters and main circuit design,a complete control system including modules like human machine interface, master control unit, peripheral processor, lower computer, and sampling plates, etc. is established in this paper. To the IGCT application in high-power system, it points out the key issues, and gives solutions to the absorption circuit, dead time compensation, drive protection and other special problems. Power unit rectification side experiment and cophase power supply experiment with triple unit in series are also done in this paper, the experimental results totally satisfy design index and the equipmental device runs steadily and reliably which lay the foundation for the further study of non-traction transformer cophase power supply system and its use in industry.