This paper presents the hybrid control of a dc–dc resonant converter for a dc micro-grid. The hybrid control is the simultaneous variation of the frequency and the duty ratio, which can provide excellent voltage regulation and maintain zero-voltage switching (ZVS) over a wide load range. Hence, excellent conversion efficiency is also maintained over the wide load range using hybrid control. However, the conventional control methods for a dc–dc resonant converter using either variable switching frequency or duty ratio have their own limitations. The frequency control requires wide variation in switching frequency for output voltage regulation, which leads to higher switching losses at turn-off of switches and lower efficiency particularly at light loads. The duty ratio control has a limitation of loosing of ZVS at light loads. The simulation and experimental results of hybrid control of resonant converter operating above 100 kHz with maximum duty ratio of 0.48 for 3 kW are presented from full load to no load. The maximum efficiency of the resonant converter is found to be 98%, which was achieved at 75% of the full load.

中文翻译：

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可再生能源系统的高效谐振变换器的混合控制

本文介绍了用于直流微电网的直流-直流谐振转换器的混合控制。混合控制是频率和占空比的同时变化，可以提供出色的电压调节并在较宽的负载范围内保持零电压开关（ZVS）。因此，使用混合控制在宽负载范围内也可保持出色的转换效率。但是，使用可变开关频率或占空比的DC-DC谐振转换器的常规控制方法有其自身的局限性。频率控制要求开关频率有很大的变化以调节输出电压，这会导致开关关断时的开关损耗更高，特别是在轻负载时效率更低。占空比控制在轻负载时具有ZVS松动的限制。从满载到空载，给出了谐振变换器的混合控制的仿真和实验结果，该变换器在100 kHz以上，最大占空比为3 kW时为0.48。发现谐振转换器的最大效率为98％，这是在满负载的75％时实现的。