Design and Implementation of a Robust Controller for Single Inverter Dual Induction Motor Drives under Heavy Unbalanced Load in Electric Trains

Single inverter dual induction motor drives have gained wide currency among electric train manufacturers because of their economic advantages. Different methods have been proposed to improve system reliability in unbalanced load conditions and one of the best-presented methods is weighted vector control. Although this method performs efficiently in medium unbalanced load conditions, it doesn’t guarantee system stability under heavy unbalanced loads applied to the motors. This paper presents an advanced weighted vector control strategy based on Direct Torque Control using a Space vector modulation algorithm to develop this kind of drive system. In the proposed method, a hysteresis controller is added to prevent the instability of the stressed motor under a heavy unbalanced load. A laboratory setup was designed and implemented to test the performance of the proposed controller by using a DSP microcontroller. The efficiency of the proposed method is proved by simulation and experimental results.