Low-Cost Sensorless Induction Motor Speed Control

This paper presents direct field oriented control sensorless speed servo for induction motors where the main contribution is the use of low-cost electrical sensors. It is possible due the use of a linear Kalman filter. The current estimates are used in a recursive least-square speed estimator. Moreover, estimated rotor flux provided by Kalman filter helps to keep the flux and torque decoupling. As it is presented in this paper, with both techniques working together is possible to obtain good speed estimation with low noise level and computation effort, in spite of use current transducer that cost just some cents. Some experimental results are presented to evaluate this proposal