Research on Control Strategy of Power Electronic Traction Transformer Based on LLC Resonant Converter
Liu Jianqiang1, Zhao Nan1, Sun Bangcheng2, Wang Yang1, Qi Hongfeng2
1. School of Electrical Engineering Beijing Jiaotong University Beijing 100044 China; 2. Technical Research Department CRRC Industry Research Institute Co. Ltd Beijing 100070 China
Abstract The goal of miniaturization and lightweight for high-speed train traction transformers can be achieved by replacing traditional power frequency transformers with power electronic traction transformers (PETT). For the PETT composed of a cascaded H-bridge converter and an LLC resonant converter, the outer voltage loop and inner current loop control strategy of the cascaded H-bridge converter is studied. The working principle of the power reverse flow and the gain characteristics of LLC resonant converter are analyzed. A control method for power bidirectional flow by adjusting frequency is proposed. In order to solve the power balance problem of the system, a power balance control strategy based on LLC resonant converter is proposed. In this method, the pre-stage cascaded H-bridge converter only uses basic control, and the power balance of the system can be achieved by voltage balance control of the LLC resonant converter. The PETT simulation model and experimental prototype were built. The simulation and experimental results show that PETT can realize bidirectional power flow, and the transmission power of each power unit remains consistent, which realizes the power balance of the system.
Liu Jianqiang,Zhao Nan,Sun Bangcheng等. Research on Control Strategy of Power Electronic Traction Transformer Based on LLC Resonant Converter[J]. Transactions of China Electrotechnical Society, 2019, 34(16): 3333-3344.
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2019, Vol. 34 
