Control of Wound Rotor Induction Machine for Indian Traction Applications

The heart of high-speed trains is the traction motor which provides the required tractive effort. The main objective of a traction motor is to achieve high-power density, which can be possible with higher motor speed. To attain extra speed, the best in the business motors like interior-permanent magnet (IPM) motors and switched reluctance motors (SRM) have to compromise with their efficiency. But the doubly fed wound rotor induction machine (WRIM) has the advantage of providing power from both sides, which can operate in both sub-synchronous and super-synchronous speed operations. With this arrangement the 1 pu load can’t be compromised even with the operating range of 2 pu speed. This can quickly address the nonlinear load behavior of high-speed trains. This paper discusses the doubly fed WRIM for high-speed traction applications. The doubly fed WRIM has the advantage of high-power density like IPMs, and also, the dynamics gets improved as the motor is controlled from both ends. The mathematical model of doubly fed WRIM with the high-speed traction load is simulated using MATLAB/Simulink. The results shows that in super-synchronous speed the total shaft power is shared by both stator and rotor side of the motor. Hence, the power density of motor will improve.