급전선로 손실 최소화를 위한 PWM컨버터 차량의 무효전력 제어

PWM converter trains exhibit excellent load characteristics in comparison with the conventional phase controlled trains since they can be operated at near unity power factor by using the voltage vector control. However, in case of high track density or extended feeding, here as elsewhere, the line loss and the voltage drop can appear significantly. Instead of operating the trains at the fixed unity power factor, this paper suggests the continuous control of the power factors of each train according to the varying load conditions to minimize the line loss and improve the voltage drop optimally. The proposed method utilizes the steepest descent algorithm targeting all the cars in a feeding section to set the optimal reactive power compensation that minimize the line losses. The results from the simulation to the sample system show that the voltage drop also can be improved.