Speed Sensorless AC Drive with Inverter LC Filter and Fault Detection Using Load Torque Signal

Abstract

The industrial development in recent years has seen a major increase in the use of induction motors, whereby the cost has to be as low as possible and the lifetime as long as possible. To follow up this desire, investigations in this area have become very intense. For that reason, this paper presents a solution for driving an induction motor and simultaneous fault detection with no need for additional sensors. In order to achieve this target, an observer system is implemented and a torque estimation procedure is used for torque detection. An LC filter was installed at the inverter output to provide better THD of the current. The validation of the drive operation was achieved through simulation and experiments. To investigate possible faults, an artificial unbalance was introduced to the test bench, whereby the experiment was validated by a comparison of physical vibrations and estimated torque.