集成电压平衡功能的三绕组LLC谐振变换器

Three-winding LLC Resonant Converter with Integrated Voltage Balancing

  • 摘要: 当正负极母线之间功率不平衡时,双极直流配电系统面临着电压不平衡的挑战,需要电压平衡器进行均压。然而,额外电压平衡组件的引入增加了设备体积与成本,降低了变换器转换效率。提出一种用于两极直流配电系统集中式电压平衡的三绕组LLC谐振变换器,采用频率和移相的调制方式来传输功率。重要的是,它可以自动均衡两极电压,并且对负载侧的不平衡电流进行重新分配。对于所提变换器,分析其工作特性,包括均压原理、不平衡电流分配过程、软开关、损耗和器件应力。除此之外,还提出了预防变压器饱和的磁通平衡控制策略。最后,通过仿真验证变换器均压能力以及磁通平衡控制的有效性。

     

    Abstract: When the power is unbalanced between the positive and negative buss, the bipolar DC distribution system faces the challenge of voltage imbalance, and a voltage balancer is required for voltage equalization. However, the introduction of additional voltage balancing components increases the size and cost of the device, and reduces the conversion efficiency of the converter. A three-winding LLC resonant converter for centralized voltage balancing in two-pole DC distribution system is proposed. The proposed converter uses frequency and phase shift modulation to transmit power. Importantly, it automatically equalizes the voltage at the two poles and redistributes the unbalanced current on the load side. For the proposed converter, the operating characteristics are analyzed, including the voltage equalization principle, the unbalanced current distribution process, soft switching, losses, and device stresses. In addition, a magnetic flux balance control strategy is proposed to prevent transformer saturation. Finally, the pressure equalization capacity of the converter and the effectiveness of the magnetic flux balance control are verified by simulation.

     

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