基于变频-移相混合控制的L-LLC谐振双向DC-DC变换器

随着储能系统的不断发展及其在直流分布式系统中的广泛应用,充当储能与直流分布式系统能量交互接口,调节范围宽、运行效率高的双向直流变换器得到深入的研究。提出一种基于变频-移相混合控制的L-LLC谐振双向直流变换器,具备宽泛的增益及功率范围,可实现输入侧开关管的零电压开通和输出侧整流管的零电流关断,运行效率高。对变频-移相控制下L-LLC的运行状态及特性进行了精确的描述分析,从理论层面论证采用变频-移相混合控制的合理性并提出一种简单的变频-移相混合控制实现方法。样机实验结果验证了L-LLC谐振双向直流变换器理论分析的正确性及其在运行效率和调节范围两方面性能的优越性。

A L-LLC Resonant Bidirectional DC-DC Converter Based on Hybrid Control of Variable Frequency and Phase Shift

Considering the development and application of the energy storage systems in DC distribution system, bidirectional DC-DC converters with high power conversion efficiency and wide adjustable range are required. According to the hybrid control of variable-frequency (VF) and phase-shift (PS), a L-LLC resonant bidirectional DC-DC converter was proposed in this paper. It not only has wide adjustable ranges of the DC voltage gain and the transmission power, but also can realize the zero-voltage switching for input switches and zero-current switching for output rectifiers simultaneously. That leads to a high overall efficiency. Operation behaviors and characteristics of the converter under single VF or PS control were described. Then the rationality of the hybrid control was proved in theory, and an easy implementation was given. The experimental results of the prototype confirmed the validity of the theoretical analysis as well as the superior performance of L-LLC converter in operational efficiency and adjustable range.