A secondary phase-shifted dual-bridge converter with semi-active rectifier is able to perform buck–boost dc–dc conversion with soft-switching. However, it can not maintain zero-voltage switching (ZVS) operation for all switches in a wide load range. Besides, the root mean square/peak tank current increases inversely with the decreasing of load in the light load region. To alleviate these problems and extend its load range, a hybrid varying-frequency phase-shift (VFPS) control is proposed to manipulate the power for a semi-dual-bridge converter with the primary half-bridge and secondary semi-active rectifier topology. Steady-state analysis of the converter under VFPS control is performed using the fundamental harmonic approximation approach. A detailed design procedure is given then to find a full ZVS trajectory with a fixed ZVS margin at light load. Experimental results proved that the VFPS control can effectively extend the operation range with full ZVS and maintain high efficiency at light load for the semi-dual-bridge resonant converter.

中文翻译：

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变频相移控制的半双桥谐振变换器的宽ZVS操作

具有半有源整流器的次级相移双桥转换器能够通过软开关执行降压-升压型dc-dc转换。但是，它不能在较宽的负载范围内为所有开关维持零电压开关（ZVS）操作。此外，在轻负载区域中，均方根/峰值储能电流与负载的减小成反比。为了缓解这些问题并扩展其负载范围，提出了一种混合式可变频率相移（VFPS）控制，以控制具有初级半桥和次级半有源整流器拓扑的半双桥转换器的功率。使用基本谐波逼近方法对在VFPS控制下的转换器进行稳态分析。然后给出详细的设计过程，以找到轻载下具有固定ZVS裕度的完整ZVS轨迹。实验结果证明，VFPS控制可以有效地扩展全ZVS的工作范围，并在轻负载下保持半双桥谐振变换器的高效率。