中压配电网用10kVac-750Vdc/1MVA电力电子变压器功率密度影响因素研究

Power density analysis of 10kVac-750Vdc /1MVA power electronic transformer/ solid-state transformer for medium voltage distribution grid

对面向10k V配电网的电力电子变压器(PET/SST)来说,其主要功能是在完成高低压侧电气隔离的前提下实现对电能/电功率的双向流动控制。为了提高功率密度,目前10k V配电网用PET/SST主要通过高频电力电子变换器+高频变压器的方案实现。本文结合研制的10k Vac-750Vdc/1MVA电力电子变压器样机实测数据,详细分析了影响中压配电网PET/SST功率密度的多种因素,指出了影响PET/SST功率密度提高的关键瓶颈问题——功率模块数量多是限制PET/SST功率密度提高的主要因素。而通过提高高频变压器工作频率的方法难以显著提高10k V配电网用PET/SST的功率密度。

For the 10 k V medium voltage distribution grid applications,power electronic transformer / solid-state transformer（ PET / SST） is mainly adopted as the voltage and electric power flow regulator with galvanic isolation.In order to increase the power density,the existing PETs / SSTs for 10 k V distribution grid usually employ high-frequency converter with high-frequency transformer. This paper analyzes the factors that influence the power density of PETs / SSTs based on the prototype of 10 k Vac-750 Vdc /1MVA PET / SST. The main obstacle that restricts the improvement of the power density of PETs / SSTs is also pointed out,i. e. the large number of the power modules in the high-voltage power converter in PET / SST. Meantime,analyses also show that it is not valid to improve the power density of 10 k V grid oriented PETs / SSTs by increasing the operation frequency of the transformers.