The High Performance Tractive Force Control Method of Propulsion Control System for Electric Railway Vehicles

This paper proposes the high performance tractive force control method of propulsion control system for electric railway vehicles. Using the PWM method progressed in the propulsion control system for electric railway vehicles, the harmonics of output have been reduced. This led to the proposal of a PWM method with a superior variable speed control. This method combined the SVM (space vector modulation) over modulation method and the low frequency synchronous PWM method to form the operating switching frequency of under 500 Hz. Also, This paper presents a new vector control for induction motor drives in a one-pulse PWM mode of inverter. For traction drives the inverter usually operates in this mode in a high speed region. The amplitude of voltage is restricted constant in this mode. The conventional vector control is not applicable as it requires controllability of the amplitude and the phase of the voltage vector for all time. The proposed scheme provides quick torque response even in the one-pulse mode. To verify the validity of the proposed control method, experiment was carried out using a 1.65 MVA class railway vehicle propulsion control systems with a 3300 V/1200 A IGBT, the inertial load with an equivalent modelling of railway vehicles 80 tons and readhesion running test at field.