In low-voltage and high-current wireless power transfer systems (LVHC WPTSs), the loss of power loop is usually large due to the high current. More critically, the equivalent load resistance (ELR) is usually much lower than the optimal load resistance, which leads to serious heating and low system efficiency. This article proposes a new technology, which employs the current-double synchronous rectifier (CDSR) to replace the traditional diode rectifier and dc/dc converter on the secondary side, and thus, the ELR can be adjusted in a large range by regulating the duty cycle of CDSR and the system can always work at the maximum efficiency point. In addition, the traditional dc/dc converter and inverter are replaced by the quasi-Z source inverter (q-ZSI) on the primary side, which can boost the dc-link voltage of inverter and reduce the current of power loop, so as to reduce the heating and improve the system efficiency further. Furthermore, the cooperative working mechanism of q-ZSI and CDSR for high-efficiency and constant power (CP) charging is analyzed thoroughly. Finally, the viability of the proposed topology is verified in a 1-kW prototype with 48-V input and 24–33.6-V output voltage, and the maximum efficiency of the prototype achieves 87.4%.

中文翻译：

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采用准 Z 源逆变器和双电流同步整流器的高效无线功率传输系统，适用于低电压和高电流应用


在低电压高电流无线功率传输系统（LVHC WPTS）中，由于电流大，功率环路的损耗通常很大。更关键的是，等效负载电阻（ELR）通常远低于最佳负载电阻，从而导致发热严重、系统效率低下。本文提出了一种新技术，采用电流双同步整流器（CDSR）代替传统的二极管整流器和次级侧的dc/dc变换器，从而可以通过调节占空比来大范围调节ELR。 CDSR循环，系统始终工作在最大效率点。此外，原边采用准Z源逆变器（q-ZSI）取代传统的DC/DC变换器和逆变器，可提升逆变器直流母线电压并降低功率环路电流，从而以减少热量并进一步提高系统效率。此外，还深入分析了q-ZSI和CDSR高效恒功率（CP）充电的协同工作机制。最后，在具有 48V 输入和 24-33.6V 输出电压的 1kW 原型中验证了所提出拓扑的可行性，原型的最大效率达到 87.4%。