基于结温反馈方法的模块化多电平换流器型高压直流输电阀损耗评估

Dissipation Analysis of MMC-HVDC Based on Junction Temperature Feedback Method

为了计算模块化多电平换流器(modular multilevel converter,MMC)的半导体器件在实际工作结温下的损耗,提出了基于结温反馈方法的MMC损耗计算方法。根据供应商数据及仿真得到的换流器实时电压电流值,在PSCAD/EMTDC中建立了考虑结温变化的损耗计算模块,分析了MMC子模块各部分的通态损耗和开关损耗。同时给出了不同散热器温度下MMC一端换流站的阀损耗比例。计算结果表明,由于器件的实际工作结温往往低于标准结温,因此采用结温反馈后计算得到的换流阀损耗值小于采用恒定结温方法得出的结果。同时证明了MMC的开关损耗较小,在不计吸收电路及驱动电路损耗的前提下,其单站阀损耗占额定直流功率的比例可以下降至<1%,这与二电平和三电平电压源换流器拓扑相比有明显的下降。

We evaluated losses of the converter power of modular multilevel converter { MMC） by a junction temperature feedback methr^d. Using the data provided by the manufacturer, we acquired the characteristic of semiconductor device, and calculated both the switching and conduction losses with the real-time voltage and current waveforms, which were derived from the detailed PSCAD/EMTDC model. Moreover, we applied the thermal circuit model to estimate the average junction temperatures of the semiconductors, and investigated the converter valve losses with different heat sink temperatures. Power losses evaluation results demonstrate that the power loss of MMC topology is lower than 1~ of the rated power, which is lower than that of the 2-level or 3-level VSC topologies.