Equivalent Modeling Method for Fast Electromagnetic Transient of Non-isolated DC Transformers
Electromagnetic transient simulation is of great significance for mastering the operating characteristics of DC transformers.However,the current high-speed equivalent modeling methods for modular converters are rarely mentioned for non-isolated transformers.Meanwhile,the existing electromagnetic transient simulation models for non-isolated DC transformers suffer from complex switch-state calculation and a large number of internal nodes,leading to low system simulation efficiency.Therefore,a fast electromagnetic transient equivalent modeling method for non-isolated DC transformers based on switch-state prediction and Thevenin equivalence is proposed.Firstly,a switch-state prediction method for submodules of non-isolated DC transformers is proposed.Secondly,based on the switch states,an equivalent circuit for the bridge arms of the DC transformer is obtained,and the Thevenin equivalence is applied to obtain the two-node equivalent circuit model of the bridge arms.Then,the equivalent circuit model of the autotransformer is established,and the equivalent circuit of the bridge arm and autotransformer is combined to obtain the equivalent circuit of the DC transformer.Based on this,the node voltage equation of the DC transformer is established.Finally,based on the Gaussian elimination,the equation is simplified to achieve the internal node reduction of the simulation model of the non-isolated DC transformer.The case study shows that the proposed equivalent modeling method for fast electromagnetic transient of non-isolated DC transformers has similar accuracy to traditional detailed modeling methods,and the simulation efficiency is significantly improved.
DC transformerThevenin equivalenceelectromagnetic transient simulationequivalent modelingswitch-state predictioninternal node reduction
万方数据
维普
