【摘要】 采用电力电子牵引变压器取代传统工频变压器可实现高速列车牵引变压器小型化、轻量化的目标。针对由级联H桥变换器和LLC谐振变换器组成的电力电子牵引变压器,首先研究级联H桥变换器的电压电流双闭环控制策略,分析LLC谐振变换器功率反向流动的工作原理及变换器增益特性,提出采用变频控制实现功率双向流动的控制方法。为解决系统的功率平衡问题,提出一种基于LLC谐振变换器的功率平衡控制策略。该方法前级级联H桥变换器只进行基本控制,通过对后级LLC谐振变换器进行电压平衡控制,从而实现系统的功率平衡。搭建电力电子牵引变压器仿真模型和实验样机,仿真和实验结果表明所提出的控制策略能够实现功率双向流动,且各功率单元的传输功率保持一致,实现了系统的功率平衡。更多还原

【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.更多还原