Analysis and Simulation of Variable Frequency Measurement for Induction Motor

Induction motors and Variable Frequency Drives (VFDs) are widely used in industry to drive machinery trains. However, some mechanical trains driven by VFD motor systems have encountered torsional vibration problems. This vibration can induce large stresses on shafts and couplings, and reduce the lifetime of these mechanical parts. Long before the designed lifetime, the mechanical train may encounter failure. This thesis focuses on VFDs with voltage source rectifiers for squirrel-cage induction motors of open-loop Volts/Hertz and closed-loop Field Oriented Control (FOC). Induction motor loss segregation and efficiency measurement requires loading dynamometers and other equipment such as a variable voltage sinusoidal power supply. These are expensive and not often available even when a loading device is accessible. Variable frequency drives are now widely used for operating induction machines and are more widely available and less expensive.