Girth gear/common shaft AC drive for cement rotary kiln

Investigation, realization and analysis of load parameters and how these affect the operation of a kiln drive system consisting of two AC motors 315 kW size each, on common tooth gear. Two separate inverter units with common rectifier control the motors. Backlash problems of tooth gear due to machinery wear cause rapid torque changes which leads to rapid and unpredictable regenerative operation to any motor, since the one (motor) pulls the other. These electrical energy returning effects and relevant machinery vibration are solved by direct torque control and dynamic performance in controlling all IGBTs switching procedure, based directly on the electromagnetic state of the motor since the total drive system is not regenerating.