基于变压器延边三角形接法的城轨24脉波整流机组的研究

Research on simulation of urban rail 24-pulse rectifier unit based on transformer extended delta connection

分析了城轨交通牵引供电系统中基于移相整流变压器网侧绕组延边三角形接法的24脉波整流机组工作机理,对移相变压器的移相及其对网侧电流谐波相消进行了公式推导。基于Matlab/Simulink构建城轨24脉波整流机组模型并仿真。对整流机组网侧和直流侧的电流谐波进行FFT分析,得出其分布规律,验证了所推导的谐波电流相消公式的正确性。最后对整流机组输出的直流电压纹波系数进行计算,计算结果表明其输出的直流电压能够满足牵引网直流母线电压所需的供电质量要求。

At present,most of domestic urban rail transit traction substations adopt 24-pulse rectification unit to rectify the AC power which is lead in from the step-down transformer substation. The working mechanism of 24-pulse rectifier and the basic principle of the modulation theory are presented. Starting from the three-phase full bridge rectifier circuit of the pulse wave,the 24 pulse rectifier voltage and current switching functions are derived gradually without considering the commutation angle. Basing on the modulation theory and FFT analysis method of time domain,the harmonic characteristic of 24 pulse rectifier at the DC side is analyzed. Finally,the correctness and the reliability of the characteristic harmonics distribution at the DC side are proved by simulation with Matlab /Simulink,which provides a new method for the harmonic analysis of 24-pulse rectifier unit.