Indirect Field Oriented Control of an Induction Motor Sensing DC-link Current

This paper describes an analysis method for achieving control torque and speed with vector control for induction motors. An indirect field-oriented output feedback motor controller is presented; it is suitable for low-cost applications. A current model control is used to sense back electromotive force (back-EMF) by means of an analog to digital converter (ADC); its simulation and filtering are discussed. A Current model is the core of this work, but other system modules are analyzed such the proportional-integrative (PI) controller, the space vector with pulse width modulation (SVPWM), and others. Their implementations on a digital signal processor (DSP) along with the electrical power stage are shown. The cascaded structure of the controller allows performing a constructive tuning procedure for position and speed control loop.