新型不对称接线三相变两相平衡变压器

平衡变压器具有消除零序电流和抑制负序电流的重要功能。不同于现有的平衡变压器两相或三相绕组对称结构,提出了一种新型三相绕组互不对称接线的平衡变压器。阐述了该变压器的基本原理和接线方案,并建立数学模型。在此基础上,得出一次侧和二次侧绕组的电流关系,导出了一次侧中性点电流为零时的平衡条件和两相解耦条件。该变压器具有满足平衡条件后两相自然解耦的优点。通过仿真分析和1kW模型机实验,证明了理论分析的正确性和可行性。该变压器采用三相三柱式通用铁心,每相仅2~3个绕组,绕组和铁心结构简单,材料利用率高;同时两相系统中有公共点和3次谐波电流流通的回路,综合性能良好,适合于作为电气化铁道牵引变压器等需要两相或单相电源供电的应用场合。

A Novel Asymmetrical Connection Three-phase to Two-phase Balance Transformer

A balance transformer has the function of eliminating zero sequence current and suppressing negative sequence current.Different from the traditional balance transformer with two-phase or three-phase symmetrical windings,a novel balance transformer with three-phase asymmetrical windings was presented.The basic principle and the connected scheme of the transformer were clarified.The mathematical model was established.On this basis,the current relationships of the primary windings and second windings were derived.The balance condition(when the neutral current in the primary side is zero),and the two-phase decoupling condition were deduced.The transformer has the advantage that the two-phase decoupling condition is naturally satisfied if the balance condition is matched.Correctness and feasibility of the theoretical analysis were verified through the simulation analysis and experimental results of a 1kVA model transformer.The three-phase three-leg core is adopted and each phase has only two or three windings in this transformer.The transformer has a simple structure of iron and windings with a high material utilization ratio,while the two-phase system has a public point and a loop in which the third harmonic currents can flow.The transformer has good performance and may be utilized for two-phase or single power supply such as traction power supply in electric railways.