不平衡负荷下输出并联型电力电子变压器的优化控制策略

The Research on the Control Strategy of PET under unbalanced Load

输出电压的对称性是评价电力电子变压器(PET)性能的重要指标,造成PET输出电压不对称的主要原因在于不平衡负荷的存在。针对模块化输出并联型电力电子变压器,提出基于其拓扑特点的不平衡运行优化策略。首先,简析PET输出级模块化并联的运行策略,建立输出级的控制模型。然后,分析不平衡负荷对电力电子变压器输出电压的不利影响,进而对经典的输出级主从控制策略进行改进,在不改变主电源模块运行的基础上,从电源进行功率跟随控制。最后,通过仿真和硬件在环实验共同验证了该文提出拓扑结构和控制策略的有效性及可行性。

The symmetry of the output voltage is an important indicator for evaluating the performance of a power electronic transformer(PET).The main cause of the asymmetry of the PET output voltage is the presence of unbalanced loads.This paper proposes an unbalanced operation optimization strategy based on its topological characteristics for modular output parallel power electronic transformers.First,this paper briefly analyzes the modular parallel operation strategy of PET output stage and establishes the output stage control model.Then,the adverse effects of unbalanced load on the output voltage of the power electronic transformer are analyzed,and then the classic master-slave control strategy of the output stage is improved.Based on the operation of the master power module,power follow control is performed through the slave power.Finally,the effectiveness and feasibility of the proposed topology and control strategy are verified by simulation and experiments.