Performance Analysis of Wound Rotor Induction Motor by Dsp Based Rotor Dynamic Capacitor Control

The paper presents a novel secondary reactance control technique in the rotor circuit of a three phase wound rotor induction motor (WRIM). The problem associated with the conventional rotor capacitive reactance control is the demand of exceptionally large capacitance requirement for enhancing the performance of the motor in wide operating range. In the proposed technique, a three phase bridge rectifier with a dynamic capacitor is used in the rotor circuit. The dynamic capacitor is H-bridge circuit with a capacitor in which the duty cycle of switching elements is varied for emulating the capacitance value dynamically and to be used as capacitive reactance control. A TMS320F2407 Digital Signal Processor (DSP) controller is used for delivering Pulse Width Modulation (PWM) pulses for appropriate switches. The performances such as speed, torque, power factor, efficiency, harmonics of the motor are analyzed for different speed and loading conditions. The feasibility of the proposed system is verified by simulation and experimental results.