Torque Control Of Induction Motor Research Articles

A robust torque controller for induction motors without rotor position sensor: analysis and experimental results

A robust controller, which tracks flux and torque commands is designed for an induction motor. It is based on a transformation to the estimate of the rotor flux. The speed of the rotor is estimated from the stator currents using a high-gain observer. The controller is robust with respect to variations of the rotor resistance. Analysis of the controller shows that the system is asymptotically stable in the motoring and braking regions and in the generating region for large enough torque reference. Simulations and experimental results show agreement with the analysis.

Quick-response torque control of induction motor with robustness against variations of primary and secondary resistances

This paper proposes a novel quick-response torque control strategy of an induction motor, which is robust against variations of primary and secondary resistances. Conventional field-oriented control originally is robust against the variation of the primary resistance, but has very high parameter sensitivity of the secondary resistance. To compensate for its effect, considerable research has been conducted by using a stator voltage model, a low-sensitivity flux observer, an adaptive system, and so on. It is assumed that successful results have not been made in practice because each method requires not only complicated configurations but also motor parameters. Therefore its compensation has to be carried out with no relation to the motor parameter, especially the primary resistance. In this paper, a robust parameter-identification technique is applied to a field-oriented control system with a flux simulator as a means to solve the problem. The technique is based on instantaneous reactive power which is never affected by the primary resistance. The authors describe the aforementioned control theory and practical implementation. As a result, excellence performance was confirmed by some computer simulations and experimental tests. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (2): 30–40, 1997

Quick‐response torque control of induction motor with robustness against variations of primary and secondary resistances

Quick‐response torque control of induction motor with robustness against variations of primary and secondary resistances

Quick-response torque-controlled induction motor drives using phase-locked loop speed control with disturbance compensation

This paper presents an excellent speed control scheme for induction motor drives. Phase-locked loop (PLL) techniques based on proportional-integral derivative (PID) feedback of the phase difference is employed to provide extremely accurate speed regulation. The quick-response torque control of an induction motor is used to provide better torque characteristics. In addition, a disturbance is estimated by a disturbance observer and the estimated value is fed back to eliminate the disturbance effect on the motor speed. The proposed system combines the precise speed regulation of PLL technique and the advantage of the quick-response torque control, with the insensitivity to disturbance by the disturbance compensation. A phase-plane analysis is used to evaluate the effects of gain coefficients of PID feedback of phase difference. Experimental results are presented to verify the characteristics of the proposed system.

Quick-Response Torque Control of Induction Motor with Robustness against Variations of Primary and Secondary Resistances.

Quick-Response Torque Control of Induction Motor with Robustness against Variations of Primary and Secondary Resistances.

Field oriented control of induction machines employing rotor end ring current detection

The usual method of induction motor torque control uses the indirect field orientation principle in which the rotor speed is sensed and slip frequency is added to form the stator impressed frequency. Unfortunately, the rotor resistance varies as the motor heats up under load thereby changing the rotor time constant which has a deleterious effect on the torque response. In this paper two new field oriented control schemes are presented which employ rotor end ring current detection and thereby remove the dependence of the controller accuracy on temperature so that the controller is entirely independent of rotor time constant variations. The field orientation schemes do not require an incremental encoder for rotor position sensing. The motor torque can be accurately controlled even down to zero speed operation. >

DSP-based secondary flux controlled high precision torque control of induction motor.

In the field of industrial drives, the vector control of the induction motor has been widely used to achieve the high performance torque control. In this paper, a new high precision torque control of the induction motor has been proposed. The control strategy proposed here is developed according to the conventional vector control law, but it has a feature that the secondary is controlled directly by selecting the appropriate voltage vector of the voltage-fed inverter.The prototype was constructed using a 2.2kW induction motor where the torque control was implemented by software of DSP-TMS 32010. All control processing including the identification of the rotor resistance could be executed within 100μs. From the experimental results, the linear relationship between torque and slip frequency was established for the wide frequency range from rotor rocked condition to 50Hz. Due to identification of rotor resistance, the accuracy of the torque control within ±2% was obtained regardless of the temperature change of the motor.

Performance of Feedforward Current Regulators for Field-Oriented Induction Machine Controllers

To achieve instantaneous control of induction motor torque using field-orientation techniques, it is necessary that the phase currents be controlled to maintain precise instantaneous relationships. Failure to do so results in a noticeable degradation in torque response. Most of the currently used approaches to achieve this control employ classical control strategies which are only correct for steady-state conditions. A modern control theory approach which circumvents these limitations is developed. The approach uses a state-variable feedback control model of the field-oriented induction machine. This state-variable controller is shown to be intrinsically more robust than PI regulators. Experimental verification of the performance of this state-variable control strategy in achieving current-loop performance and torque control at high operating speeds is included.

High performance induction motor torque control using digital signal processor.

High performance induction motor torque control using digital signal processor.

High Performance Torque-Controlled Induction Motor Drives

The way in which a practical control method using derived torque feedback signal has made it possible to obtain the same high bandwidth torque control with standard cage induction motors as can be achieved with dc motors is demonstrated. In contrast with previous torque control systems, this method does not require the angular position of a motor field vector to be determined for control purposes. The versatility of this torque controller is illustrated with measured torque responses obtained from a transitorized servo drive, a cycloconvertor, and a current source inverter.