交直流系统暂态仿真中换流器的改进准稳态模型

Modified quasi steady state model of converters in transient simulation of hybrid AC/DC systems

当交流系统发生三相不对称故障时,忽略直流系统负序分量的准稳态模型将给交直流混合系统的仿真带来较大的误差。文中考虑了整流器、逆变器的具体差异,给出了换相电压不对称情况下的直流电压计算方法,编制了换流器的仿真程序,并应用到考虑直流系统负序分量的换流器改进准稳态模型的混合系统暂态计算中,取得了令人满意的结果。

The QSS (Quasi Steady State) model of converter which neglects the negative impedance of DC system will bring some errors when three phase unbalanced fault occurs in AC system. This paper takes into account the differences between rectifier and inverter and provides the computation method for DC voltage under the unbalanced commutation voltage. This model is applied in the transient simulation program of hybrid AC/DC systems with the modified QSS converter model , which pays attention to the negative impedance of DC system and acquires satisfying results.