基于磁路并联的单极式AC/DC电力电子变压器

电力电子变压器PET(power electronics transformer)是电力电子化电力系统的关键设备之一。传统拓扑的PET功率密度和转换效率较低,应用受到限制,因此本文对传统PET拓扑进行改进。首先将传统模块化结构中子模块的低压侧电路移出,再利用磁路并联,使三相功率在变压器上相互补充。通过等效电路法进行分析,利用原边脉冲宽度调节来控制交流侧电流保持正弦波,并采用移相角来控制功率。该方案降低了子模块内部的绝缘要求,省去传统PET中用于滤除工频纹波的母线电容,从而减小模块体积,提高功率密度。通过1 MV·A的单级AC/DC PET方案进行仿真验证,并在小功率样机上进行实验,仿真和实验结果验证了本方案的有效性。

Single-stage AC/DC Power Electronics Transformer Based on Parallel Magnetic Path

A power electronics transformer(PET)is one of the key equipment in the power electronics electric system.Due to the low power density and low conversion efficiency of the traditional topology,its applications are limited.To solve this problem,the traditional PET topology is improved in this paper.First,the low-voltage side circuit is removed from the sub-module in the traditional modular structure.Then,the three-phase power on the transformer can compen?sate for each other using parallel magnetic path.The equivalent circuit method is analyzed,and the AC-side current is controlled by adjusting the pulse width on the primary side to keep the current to be sinusoidal.In addition,the power is controlled by means of phase shift angle.The proposed scheme reduces the insulation requirement from the sub-mod?ule and eliminates the bus capacitor in the traditional PET which is used to filter out the power frequency ripples,there?by reducing the module volume and improving the power density.A 1 MV·A single-stage AC/DC PET scheme was vali?dated by simulations,and it was tested on a low-power prototype.Simulation and experiment results verified the pro?posed scheme.