A novel Multilevel Power Quality Compensator for electrified railway

Connected to high-voltage power system directly, electrified railway is a particular user to power system, and its loads have the characteristics such as non-liner, asymmetry and volatility and so on. Researched on Chunshen traction substation which belongs to Shanghai-Hangzhou Electrified Railway, and accorded to the requirements and characteristics of comprehensive management to harmonics, reactive power and negative sequence currents in electrified railway, this paper proposes a novel Multilevel Power Quality Compensator (MPQC). This novel MPQC is composed of two single-phase cascaded inverters by sharing the DC capacitors. Each cascaded inverter is made of two cascaded H-bridge inverters and the ratio of the DC voltage is 3:1, then, connects to traction power system via grid-transformer. By analyzing the working principle of the MPQC, researching the Multilevel Direct Pulse Width Modulation (MDPWM) method, this work presented multilevel inverter control strategy based on energy balance. Simulation and Experimental results proved this novel MQPC was reliable, could compensate the both feeders in traction power system simultaneously, and also could manage the power quality of the electrified railway comprehensively to achieve satisfactory compensation effects.

[1]  Shu-Guang Sun,et al.  Study of two detection methods for harmonics and reactive currents , 2008, 2008 International Conference on Machine Learning and Cybernetics.

[2]  Lu Zhi-hai.  The impact of electrified railway on electric power system , 2004 .

[3]  A.K. Gupta,et al.  A general space vector PWM algorithm for multilevel inverters, including operation in overmodulation range , 2007, IEEE International Conference on Electric Machines and Drives, 2005..

[4]  Fang Zheng Peng,et al.  Multilevel inverters: a survey of topologies, controls, and applications , 2002, IEEE Trans. Ind. Electron..

[5]  Chandan Chakraborty,et al.  A Direct PWM Technique for a Single-Phase Full-Bridge Inverter Through Controlled Capacitor Charging , 2008, IEEE Transactions on Industrial Electronics.

[6]  Xinjian Jiang,et al.  A novel active power quality compensator topology for electrified railway , 2004 .

[7]  Poh Chiang Loh,et al.  Optimal impedance termination of 25-kV electrified railway systems for improved power quality , 2005, IEEE Transactions on Power Delivery.

[8]  A.K. Gupta,et al.  A Space Vector Modulation Scheme to Reduce Common Mode Voltage for Cascaded Multilevel Inverters , 2007, IEEE Transactions on Power Electronics.

[9]  Zhang Jianhua,et al.  Approach on Detection of Reactive and Harmonic Currents in Single-phase Circuit , 2006, IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics.

[10]  Ashwin M. Khambadkone,et al.  A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM , 2006, IEEE Transactions on Industrial Electronics.