Advanced Cophase Traction Power Supply System Based on Three-Phase to Single-Phase Converter

Abstract

An advanced cophase traction power supply system is proposed to solve the power quality problems of the traditional traction power supply system, such as unbalance, reactive power, and harmonics to three-phase industrial grid. The three-phase to single-phase converter-based substation is adopted in this system, which can transfer active power from three-phase grid to singlephase catenary and compensate reactive power and harmonics of the locomotives. One catenary section could be utilized in the advanced cophase system instead of the multiple split sections in traditional system. The neutral sections and problems caused by them in traditional system could be avoided. In this paper, the characteristics of the advanced cophase system and the automatic current-sharing control algorithm of three-phase to single-phase converter are studied and analyzed. The simulation and experimental results verify the viability and effectiveness of the proposed system.Index Terms-Automatic current-sharing control, multilevel converter, power quality, three-phase to single-phase converter, traction power supply.

Research on the circulating current suppression strategy of parallel operation of multiple cophase supply devices

“…Corresponding to Figure 2, when CS 1 works normally, CS 2 implements the control strategy of active circulating current suppression, accurately calibrate output currents, and ultimately make output voltages of CS 2 and CS 1 completely equal to those of u o2 and u o1 , so as to achieve active circulating current suppression. At the moment, out currents of the two power supply devices are all 0.…”

“…Due to the use of this power supply mode, there are four major problems existing in the power supply system, including negative sequence, reactive power, harmonic wave and electric phase separation [1], which have serious impact on power quality of the electric power system and the traction power supply system, and restrict heavy-load, high-speed and economical operation of electric locomotive in the meantime [2]. However, the problems above can be effectively solved by replacing the traction transformer with the new cophase supply device in the cascaded multilevel structure.…”

Research on Control Strategy of AC‐DC‐AC Substation Based on Modular Multilevel Converter

“…Although the neutral section at the exit of the substation was canceled in cophase system, that between adjacent SS still exists. To connect all catenaries from different substations, a new traction power supply system is proposed in [6] that is based on a three-phase to single-phase converter as the critical piece of equipment in the substation, as shown in Figure 1(c). The system transfers active power from the isolated three-phase grid to a one-phase traction line and provides the output voltage with a controlled frequency, phase, and amplitude.…”

“…It is important to analyze the effect of asymmetric grid voltage on the operation characteristics of the system. In [6,7], the classical dq decoupling control is used in the rectifier side. However, this control is only applicable to the balanced grid voltage.…”

A Traction Three-Phase to Single-Phase Cascade Converter Substation in an Advanced Traction Power Supply System

“…In [7], the advanced traction power supply system (ATPSS) based on a three-phase to single-phase converter is proposed, of which the system structure is shown in Figure 1c. There is a step-down transformer on the input side and a step-up transformer on the output side in a traction substation, respectively.…”