直流固态变压器控制技术研究  

Research on Control Technology of DC Solid State Transformers

作　　者：孙贺 张建成[1] 付超[1] 孙玉巍[1] 

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学)

出　　处：《电网技术》2018年第1期56-64,共9页Power System Technology

基　　金：国家自然科学基金项目(51177047);河北省科技计划项目(16214504D)~~

摘　　要：为解决作为中压直流配网与低压直流微网互联设备的直流固态变压器（DC solid state transformer,DCSST）子模块均压均流问题,同时实现微网直流母线电压的稳定控制及灵活双向功率运行能力,提出了一种以DCSST输出电压稳定为主控制环,输入电压均衡为附加控制环的双环解耦控制策略。针对其输入串联输出并联（input-series output-parallel,ISOP）结构及隔离型双向DC/DC变换器（isolated bidirectional DC/DC converter,IBDC）移相控制原理,对DCSST进行统一建模,并通过对其小信号线性模型及传递函数的推导,分析了两控制环路之间的解耦条件。仿真与实验结果表明,在所提出的控制策略以及控制参数下,DCSST双向功率运行时输出电压稳定与输入电压均衡控制效果良好,同时,各IBDC模块采用交错控制可有效减小输出电流纹波。In order to solve voltage and current sharing problem among sub-modules and meanwhile guarantee voltage stability control on DC microgrid side and flexible bidirectional operation for DC solid state transformer（DCSST）, acting as interface between MV DC distribution grid and LV DC microgrid, a double-loop decoupling control is proposed, consisting of a main control loop of DCSST output voltage and an additional control loop for input voltage balancing. Based on input-in-series output-in-parallel（ISOP） structure and phase shift control principle of isolated bidirectional DC/DC converter（IBDC）, unified DCSST modeling is carried out, and decoupling conditions between the two control loops are analyzed by deriving its small signal linear model and transfer function. Simulation and experiment results show that, with the proposed control strategy and control parameters, the output voltage stability and input voltage balance of DCSST can be effectively ensured under bidirectional power flow. Meanwhile, output current ripple is effectively suppressed with interleaving control between IBDC modules.

关 键 词：直流配网 直流微网 直流固态变压器 解耦控制 输入串联输出并联 均衡控制 交错控制 

分 类 号：TM46[电气工程—电器]