Development of an Early Diagnosis System for External Faults on Three Phase Inverter Fed Induction Motor Drive

Abstract

ABSTRACT newline newlineOwing to the rugged construction, low maintenance cost, sustainability in the harsh operating conditions, availability of advanced control techniques, Induction motor drives have been dominating deployment across the industry verticals and horizontals. Due to the popularity of the induction motor drives, there is continuous research in academia as well as the industry to improve entire design of the drive and control systems. After considerable work, the Rectifier Inverter has come out as a winner and has become the most sought-after induction motor drive system. Simultaneous Speed and torque control could be achieved by varying the frequency and input voltage of the motor electronically within the inverter by employing sinusoidal Pulse Width Modulation (PWM). newlineApart from meeting the speed control requirements, reliability and fault tolerant operation of Rectifier-Inverter system is extremely important for industrial drives and this research explains the variable-frequency variable-voltage operation of a three-phase induction motor for common external faults of a three-phase Rectifier-inverter. newlineThe inverter faults, such as base drive open and transistor short-circuits, the protection system is designed to shut down the drive and protect the power circuit, resulting in inadvertent shut down. So, under fault condition, exploring the option of reconfiguration the drive circuit to operate under reduced operating conditions while in running is critically important for applications that cannot afford to shutdown abruptly. For example: for a fault in the 3-phase inverter system, isolating the faulty leg and continue to operate the in 1-phase mode with reduced torque will be much more beneficial than shutting down the system. There are many such other faults which can be reconfigured into single phase mode if the fault has been diagnosed sooner. newlineAmong the diagnostic methods studied, employing the Digital Signal Processing techniques would be suitable for effective and efficient early fault detection. FFT and W