Speed estimation of induction motor using TMS320F28335 digital signal processor

Abstract

In the modern world, almost 90 percent of the motors used in the industry are induction motors. Induction motors are used in wide range of applications ranging from fans, pumps, compressors to their use in complex drives for critical application. As the world advances, newer applications come up which require robustness and complete operational control over an induction motor, when subjected to most adverse dynamic real time conditions. These applications need to be controlled using control techniques such as Field Oriented Control, which require the knowledge of induction motor. Use of sensors adds to the cost. If the machine parameters are known, it is possible to eliminate the use such costly hardware speed sensors and replace them with software speed estimators. Scope of this paper is design, simulation and implementation of speed estimation algorithm by estimating the rotor flux angle and slip in a Digital Signal Processor(DSP). The rotor flux angle and estimated speed can be used in sensor-less rotor field oriented control scheme. First, a code is developed for speed estimation of induction motor and is tested in MATLAB. Later, this code is ported to TMS320F28335 floating point DSP and is tested on a 415V, 3.3 HP 1430 RPM squirrel cage induction motor to estimate its speed in real-time.