级联双向变换器在多能源变流器中的应用

Application of Cascaded Bi-Directional Converter in Multi-Source Converter

纯并网型分布式发电已不能满足用户降低用电成本的需求,多能源变流器(multi-source converter,MSC)作为分布式发电的有效组织和管理装置,正逐渐被用户接受,其中,蓄电池用双向变换器作为核心部分,需满足宽电压输入、高升压比及隔离、高转换效率等技术要求,是MSC设计的难点之一。该文基于buck/boost双向电路和双向LLC电路级联方案对蓄电池用双向变换器进行了设计,首先对拓扑组合和工作原理及其特点进行了分析,并推导了谐振频率下双向LLC电路的小信号模型;然后,结合电压、效率等指标,对变换器的中间电压、LLC谐振网络等电路参数进行了优化设计;最后,采用实验验证了该级联双向变换器设计的正确性与可行性。

Grid-connected only distributed generation cannot satisfy the users＇ requirements of electricity costs saving.Multi-source converter（ MSC）,which can help manage the energy utilization in demand,is accepted by users. Bi-directional converter for battery,which is characterized in wide range input voltage,high rise ratio,electrical isolation and high conversion efficiency,is the core component of MSC and one of the difficult points in MSC design. This paper designs the bidirectional converter for battery based on the cascaded scheme of buck /boost bi-directional circuit and bi-directional LLC circuit. Firstly,we analyze the topology,the operation principle and its characteristics,and deduce the small signal model for the bi-directional LLC circuit with resonant frequency. Then,combining the voltage,efficiency and other indicators,we optimally design the intermediate voltage of converter,LLC resonance circuit and other parameters. Finally,we adopt experiments to verify the effectiveness and and feasibility of the design of the proposed cascaded bi-directional converter.