应用于电力电子变压器的CLLC型高频隔离电路参数鲁棒性分析与优化设计

Parameter Robustness Analysis and Optimization Design of CLLC High Frequency Isolation Circuit Applied to Solid State Transformer

电力电子变压器(solid state transformer,SST)是实现配电网分布式能源、新型负荷/储能灵活接入的关键装备,针对应用于SST中高频隔离环节的CLLC型直流变压器开展了电路参数的鲁棒性分析与优化设计研究。CLLC型直流变压器可利用开环控制简化控制复杂度,实现宽范围下接近恒定的双向电压增益,并采用高频变压器的漏感作为谐振电感,降低电路设计难度。提出了一种用于CLLC直流变压器的参数设计方法,利用该方法,即使电感电容值出现设计偏差时,所设计的CLLC直流变压器也具有良好的电压调节能力与软开关特性。分析了高频隔离变压器与器件寄生参数对直流变压器轻载下电压增益的影响,最后开展了典型直流变压器设计,并在PSIM软件中进行了仿真验证。

Solid state transformer(SST) is the key equipment to realize the flexible access of distributed energy and new load/energy storage in distribution network.In this paper,the robustness analysis and optimal design of circuit parameters are carried out for CLLC DC transformer used in high frequency isolation link of SST.CLLC DC transformer can use open loop control to simplify control complexity,realize nearly constant bidirectional voltage gain in a wide range,and use the leakage inductance of high-frequency transformer as resonant inductance to reduce the difficulty of circuit design.In this paper,a parameter design method for CLLC DC transformer is proposed.Using this method,the designed CLLC DC transformer has good voltage regulation ability and wide range soft switching characteristics even when the inductance and capacitance value have design deviation.The influence of parasitic parameters of high-frequency isolation transformer and device on the voltage gain of DC transformer under light load is analyzed.Finally,a typical DC transformer is designed and verified by simulation in PSIM software.