Rotor Resistance Uncertainty Research Articles

Adaptive backstepping control of a speed-sensorless induction motor under time-varying load torque and rotor resistance uncertainty

A new global adaptive backstepping controller is designed for induction motor speed control based on measurements of stator current and estimation of rotor speed. The designed partial state feedback controller is singularity free and guarantees asymptotic tracking of smooth reference trajectories for the speed of the motor under time varying load torque and rotor resistance uncertainty. The new control algorithm generates estimates for unknown time varying load torque, rotor resistance and rotor speed, which asymptotically tracks and converges to their true values. The rotor flux modulus asymptotically tracks a desired reference signal which allows the motor to operate within its specifications. As in the field-oriented control scheme; the control algorithm generates references for the magnetising flux component and for the speed component of the stator current. The control strategy yields decoupled rotor speed and rotor flux amplitude tracking control goals which allow the selection of an appropriate flu...

Adaptive backstepping control of an induction motor under time-varying load torque and rotor resistance uncertainty

A new global adaptive controller is designed for induction motor speed control based on measurements of speed and stator current. The designed partial state feedback controller is singularity free, and guarantees asymptotic tracking of smooth reference trajectories for the speed of the motor under time-varying load torque and rotor resistance uncertainty, for any initial condition. The new control algorithm generates estimates for unknown time-varying load torque, rotor resistance and unmeasured state variables (rotor fluxes) which asymptotically tracks and converges to their true values. The rotor flux modulus asymptotically tracks a desired reference signal which allows the motor to operate within its specifications. The control strategy yields decoupled rotor speed and rotor flux amplitude tracking control goals which allows the selection of an appropriate flux modulus for the rotor to maximise efficiency.

Design of H∞ Position Tracking Controllers for Current-Fed Induction Motors Used in Articulated Mechanical Loads

This paper describes a systematic procedure to design H∞ position and flux-norm tracking controllers for current-fed induction motors. The designed controllers achieve convergence to zero of both position and flux-norm tracking errors while ensuring robustness with respect to unknown load torque disturbances. The proposed procedure offers the possibility of a simple development of the controllers’ design; in particular, it does not require a numerical solution of the Riccati matrix equation. A case study has been set up which considers the application of the proposed control scheme to a two-link robot manipulator system actuated by two induction motors. Numerical simulation results confirm the validity of the proposed design methodology, even in the presence of rotor resistance uncertainty.

Bandwidth vs. gains design of H∞ tracking controllers for current-fed induction motors

This paper describes a systematic procedure for designing speed and rotor flux norm tracking H ∞ controllers with unknown load torque disturbances for current-fed induction motors. A new effective design tool is developed to allow selection of the control gains so as to adjust the disturbances’ rejection capability of the controllers in the face of the bandwidth requirements of the closed-loop system. Application of the proposed design procedure is demonstrated in a case study, and the results of numerical simulations illustrate the satisfactory performance achievable even in presence of rotor resistance uncertainty.

Two Adaptive Nonlinear Control Schemes for an Induction Motor

Two adaptive nonlinear control schemes are presented for an induction motor: tuning function and modular design approaches. The objective here is to control the speed and flux in an independent manner despite rotor resistance uncertainty. In most existing adaptive schemes with this objective, load torque is regarded as a constant but unknown parameter to be estimated rather than a disturbance. On the other hand, this paper uses an integrator to deal with the low-frequency load torque instead of trying to estimate it. Simulations show that the proposed adaptive schemes lead to uniform closed-loop performance despite the uncertainty of the rotor resistance.

Adaptive control of induction motor systems despite rotor resistance uncertainty

We present an adaptive, partial-state feedback, position tracking controller for the full-order, nonlinear dynamic model representing an induction motor actuating a mechanical subsystem. The proposed controller compensates for uncertainty in the form of the rotor resistance parameter and all of the mechanical subsystem parameters, while yielding asymptotic rotor position tracking. The proposed controller does not require measurement of rotor flux or rotor current; however, it does exhibit a singularity when the magnitude of the estimated rotor flux is zero. Simulation results are provided to verify the effectiveness of the approach. Copyright © 1996 Elsevier Science Ltd.

Optimal design of flux observer in induction machines

Abstract Flux estimation is essential in most advanced control schemes of induction machines like indirect field‐orientation control and feedback linearizing approach. In this paper, optimal control theory and Lyapunov stability analysis are applied to design the full‐order flux observer of induction machines. The observer refers only to measurable quantities which are composed of terminal voltages, currents and rotor speed. The time‐invariant and time‐varying portions of the error dynamics of the observer are minimized separately. The degree of relative stability of the observer can be prescribed at the beginning of the design and is independent of speed variations. In the presence of uncertainty in rotor resistance, a sufficient condition for the design with bounded estimation errors is derived and the resultant residual can be formulated explicitly. Results from computer simulations show that the method exhibits excellent convergent characteristics and robustness to rotor resistance uncertainty.