Development of the sensorless digital control system of electric drive based on double inverter-fed induction motor

In the article the results of theoretical and experimental research of the electric drive based on double inverter-fed induction motor operation mode using a novel sensorless digital control system to improvement and elimination of previous control systems options disadvantages for this type of electric drive are presented. The structure of a speed observer for an electric drive based on double inverter-fed induction motor using PI-controller is proposed. Unlike well-known speed observers structures used in AC drive control systems, the proposed rotor speed observer for double inverter-fed induction motor is independent on the base machine parameters and isn’t contained it in the speed calculation algorithms, which are depending on the operating mode of the electric drive and has better dynamic characteristics from previous control system options. The evaluation of the angular rotor speed observation accuracy in the range from the initial to the nominal values is given.