A vector control system for multiresonant loads

The paper proposes a simple vector control solution for the current of a multiresonant load consisting of a induction motor and a capacitive filter, without speed-sensor. The system controls the rotor flux magnitude, the motor speed, without speed sensor, it calculates the magnitude of the current absorbed by the capacitive filter and based on this signals it further calculates the magnitude and phase of the composed load induction motor - capacitive filter current vector. The system also ensures auto-conduction according to the flux rectangular components. As a result, the proposed vector control system allows continuous functioning below and above the main resonant frequency and diminishes significantly the effects of the secondary resonant frequency. Experimental results are presented.