新型自耦变压器耦合桥式固态限流器及其拓扑改进

A Novel Auto-transformer Coupling Bridge-type SSFCL and Its Topology Improvement

变压器耦合桥式固态限流器的体积与成本取决于串联耦合变压器、整流桥和限流电感等限流器各组成部分。为减小串联耦合变压器的体积与成本,提出一种新型自耦变压器耦合桥式固态限流器,详细分析了其工作原理和限流过程。针对整流桥晶闸管无法控制关断从而导致限流电感必须设计得较大的缺点,进一步提出一种基于全控电力电子器件的限流器二次侧改进拓扑结构,缩短故障后整流桥和限流电感承受冲击电流的时间并降低冲击电流幅值和上升率,从而可减小整流桥电力电子器件和限流电感相关参数设计值,进一步降低限流器成本。仿真研究验证了相同限流目标下,相比串联耦合变压器,采用常规非自耦变压器,上述限流器具有更好的经济性。最后,对改进拓扑结构进行样机实验,验证了改进拓扑的有效性。

The volume and cost of the transformer coupling bridge-type solid-state fault current limiter(SSFCL)depend on the components of the fault current limiter including the series coupling transformer, rectifier bridge and current-limiting inductance.To reduce the volume and cost of the coupling transformer,a novel auto-transformer coupling bridge-type SSFCL is proposed with a detailed analysis of its working principle and current-limiting process.For the problem of large current-limiting inductance due to the inability of rectifier bridge thyristor to control the turn-off,the topology of the secondary side of SSFCL is improved by using full-controlled power electronic devices.The improved topology has the ability to shorten the time for the bridge and current-limiting inductance to withstand the inrush current while reducing the amplitude and the slope of inrush current.Thus,the related parameters of power electronic devices in rectifier bridge and current-limiting inductance can be decreased and the cost of SSFCL further cut.Simulation results show that SSFCLs with auto-transformer are more efficient and cost-effective than those with normal transformer with the same current-limiting objective.The effectiveness of the improved SSFCL is validated by experiment.