Adaptive Partial State Feedback Control of the Induction Motor
Elimination of Rotor Flux and Rotor Velocity Measurements

Background:

In recent years, researchers have methodically attacked and surmounted many of the difficulties indigenous with high performance tracking control of the induction motor such as i) control singularity elimination, ii) rotor flux/rotor velocity measurement elimination, and iii) compensation of selected parametric uncertainty. In light of the previous success, many researchers have now focused their efforts on the compensation for rotor resistance effects while also removing the need for rotor flux/rotor velocity measurements in the control algorithm.

Research Objective:

Our objective is to design a partial-state feedback, singularity free controller for the full-order, nonlinear dynamic model of an induction motor to obtain rotor position tracking despite parametric uncertainty in the rotor resistance and mechanical subsystem. The control algorithm requires only measurement of rotor position and stator current (i.e., rotor flux and rotor velocity measurements are not required).

Approach:

In the control development, we construct two nonlinear observers for stator current and rotor flux. In additon, two nonlinear filters are developed to provide a proper method for compensating for the rotor resistance effects. We then develop desired stator current and rotor flux trajectory signals to achieve rotor position despite parametric uncertainty in the mechanical subsystem and without rotor velocity measurements. Finally, voltage control inputs are constructed to guarantee stator current tracking.

The Experimental Setup:

An experiment was conducted on a three phase induction motor (Baldor Electric Co., Model M3541) powered by three linear amplifiers (Techron, Model 7570-60) to test the performance of the proposed controller. The rotor position was measured using a 10,240 line shaft-mounted encoder (BEI Inc.). Three hall effect sensors (Microswitch, Model CSLB1AD) were used to measure the phase currents. A QNX based real time environment developed in-house serves as the user-interface required to implement the control algorithm. The control algorithm is computed on a Pentium processor thus eliminating the need for a separate DSP board. The sampling frequency was selected to be 1300 Hz. The MultiQ board (8 A/D, 8 D/A, and 6 encoder channels) manufactured by Quanser Consulting was used to output the three phase voltages to the induction motor.

The Mechatronics Workstation - Union Camp Laboratory

Some Experimental Results:

Select and click to view some of the experimental plots:



Publication:

For more information concerning this research, please refer to the following publication:

P. Aquino, M. Feemster, D. M. Dawson, and A. Behal, "Adaptive Partial State Feedback Control of the Induction Motor: Elimination of Rotor Flux and Rotor Velocity Measurements," International Journal of Adaptive Control and Signal Processing, accepted, December 1998, to appear.