直流固态变压器新型均衡解耦控制策略  

A Novel Decoupling Strategy of Balancing Control for DC Solid State Transformer

作　　者：付超[1] 孙贺 张建成[1] 孙玉巍[1] FU Chao;SUN He;ZHANG Jiancheng;SUN Yuwei(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources （North China Electric Power University）, Baoding 071003, Hebei Province, China)

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6期1945-1953,共9页Power System Technology

基　　金：国家自然科学基金项目(51177047);中央高校基本科研业务费专项资金资助(2017MS099)~~

摘　　要：直流固态变压器（DC solid state transformer,DCSST）由双有源全桥（dual-active-bridge,DAB）变换器以输入串联输出并联（input-series output-parallel,ISOP）的方式组合而成,其运行时不仅要控制输出端电压稳定,还需控制各DAB子单元输入电压均衡,并且均压控制与输出电压控制需实现解耦。基于DCSST小信号模型的传统均衡解耦控制方法在输入电压受不均衡扰动较大的情况下会产生解耦误差,影响输出电压控制。针对该问题,文章深入分析了以往均衡控制策略产生解耦误差的原因,由此提出一种新型均衡解耦控制策略。通过定义虚拟控制量实现DCSST模型的完全线性化,进而通过令均压控制量之和为零以及对输出电压控制量进行补偿,消除了耦合影响。仿真与实验结果表明,所提控制方法在DCSST承受较大程度输入电压不均衡扰动时,能够较好地消除输入均压控制对输出电压的耦合影响,其解耦效果明显优于传统控制方法。DC solid state transformer（DCSST） is based on input-series output-parallel（ISOP） connection of dual-active-bridge（DAB） converters. Stability control of output voltage and balancing control of input voltages for each DAB unit are necessary when DCSST is operated, and coupling effect between input and output voltage controllers should be eliminated. Conventional DCSST balancing control methods are based on small-signal analysis and would cause decoupling error when big imbalance of input voltages occurs, affecting output voltage control. Aiming at this problem, this paper analyzed the reason of decoupling error for previous control method, and proposed a novel balancing and decoupling control strategy. In the new method, DCSST dynamic model was completely linearized by employing virtual control inputs. By setting summation of the balancing control inputs to zero and adding compensation to output voltage control input, the coupling effect was eliminated. Simulation and experimental results show that the proposed strategy can eliminate coupling effect of input voltage control on output voltage when the input voltages suffer great imbalance disturbance, and the decoupling effect is obviously superior to that of the conventional method.

关 键 词：直流固态变压器 双有源全桥 输入串联输出并联 解耦控制 

分 类 号：TM46[电气工程—电器]