• The Transactions of the Korean Institute of Power Electronics
• /
• v.17 no.3
• /
• pp.238-245
• /
• 2012

This paper presents a sensorless speed control of a 2-phase switch reluctance motor(SRM). The proposed sensorless control scheme is based on the slide mode observer with parameter compensator to improve the estimation performance. In the stand still position, the initial rotor position is determined by pulse current responses of each phase windings and the current difference. In order to determine an accurate initial rotor position, the two initial rotor positions are estimated by the difference of the pulse currents. From the stand still to the operating region, a simple open loop control which determines the commutation sequence by the pulse current of the unexcited phase winding is used. When the motor speed is reached to the sensorless control region, the estimated rotor position and speed by the slide mode observer are used to control the SRM. The flux calculator used in the slide mode observer is designed by phase voltage and the voltage drops in the phase resistance of the winding. The accuracy of the flux calculator is dependent on the phase resistance. For the continuous update of the phase resistance, current gradient at the inductance break point is used in this paper. The error of the estimated rotor position at the current gradient position is used to update the phase resistance to improve the sensorless scheme. The proposed sensorless speed control scheme is verified with a practical compressor used in home appliances. And the results show the effectiveness of the proposed control scheme.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.2
• /
• pp.70-78
• /
• 2005

In this paper, a novel rotor flux estimation method of an induction motor using support vector regression(SVR) is presented. Two well-known different flux models with respect to voltage and current are necessary to estimate the rotor flux of an induction motor. Training of SVR which the theory of the SVR algorithm leads to a quadratic programming(QP) problem. The proposed SVR rotor flux estimator guarantees the improvement of performance in the transient and steady state in spite of parameter variation circumstance. The validity and the usefulness of proposed algorithm are throughly verified through numerical simulation.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.1039-1041
• /
• 2000

To obtain a high performance in a vector controlled induction machine, it is essential to know the instantaneous position of the rotor flux which depends on the rotor time constant. But the rotor time constant mainly varies due to the temperature rise in the motor winding, so real time compensating algorithm is necessary. This paper proposes that it uses short duration pulses added to the constant flux command current and then resultant torque command current produced by speed controller is utilized for the rotor resistance estimation. This method has advantages with a low computational requirement and does not require voltage sensors. The proposed method is proved by simulations.

• Journal of Power Electronics
• /
• v.10 no.4
• /
• pp.396-404
• /
• 2010

This paper presents simple schemes used to estimate the initial rotor position and the d- and q-axis inductances for effective Maximum Torque per Ampere (MTPA) operation in a wind-power system using an IPMSM (Interior Permanent Magnet Synchronous Machine). An IPMSM essentially requires an exact coordinate transformation and accurate inductance values to use a reluctance torque caused by the saliency characteristic. In the proposed high-frequency voltage testing method, there is no voltage drop caused by the resistance and the electromotive force. The initial rotor position and the inductance can be measured through an analysis of the stator current without turning the rotor. The experimental results are presented in order to illustrate the feasibility of the proposed method.

• Proceedings of the KIPE Conference
• /
• 2003.07b
• /
• pp.644-647
• /
• 2003

The predictive maintenance can help to avoid the serious plant breakdowns and catastrophies. This paper deals with the fault diagnosis of the rotor of the induction motor which is widely used in the plants. In order to detect the broken bar, the Extended Kalman Filter is adopted to estimate the rotor resistance on the base of model-based method. The proposed estimation method is simulated with the aid of Matlab.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.304-309
• /
• 1998

In this paper, authors introduce an application of a nonlinear rotor flux observer, known under the name of ELO(extended Luenberger Observer), for direct rotor field oriented control(DRFOC) of induction motor. ELO requires no solution of nonlinear partial differential equation for its coordinate transformation and linearization used for the nonlinear observer design. Its simulation results concerned to different level of unknown variables of load torque and rotor resistance show high accuracy on rotor flux estimation in steady state.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.2
• /
• pp.69-76
• /
• 2002

To obtain a high performance in a vector controlled induction motor, it is essential to know the instantaneous position of the rotor flux which depends on the rotor time constant. But the rotor time constant mainly varies due to the temperature rise in the motor winding, so real time compensating algorithm is necessary. This paper proposes that it uses short duration pulses added to the constant flux command current and then resultant torque command current produced by speed controller is utilized for the rotor resistance estimation. This method has advantage with a low computational requirement and does not require voltage sensors. The proposed method is proved by simulations and experimentals.

• Proceedings of the IEEK Conference
• /
• 2000.07b
• /
• pp.1013-1016
• /
• 2000

In this study, the estimate speed of rotor in the induction motor with Model Reference Adaptive control System (MARC) principle and to study that vector control system feedbacks speed estimated to speed control system and its result is as follows; Considering with explanation an influence of speed estimation mechanism depend on error about the second resistance size established, it estimates the deviation of the second resistance establishment and exhibits a compensation method, what is more, it designs a reparation program using the fuzzy algorithm and testifies the result with the computer simulation. And besides, it composes the load torque estimation and estimates the load torque, as the result, feedback-compensating the result of estimation, it improves the efficiency. In consequence, it makes a good result for more powerful vector control system about the outside trouble.

• Proceedings of the KIEE Conference
• /
• 2000.07e
• /
• pp.162-166
• /
• 2000

In this paper, a maximum efficiency control technique of real-time processing in which parameter variation is compensated in vector control of an induction motors(I.M.) is proposed. Based on equivalent model of I.M., a loss minimization factor(LMF) with the variations of speed is derived. To solve problem of inaccuracy of LMF curves due to machine parameter variation, rotor resistance estimation is performed by using instantaneous reactive power. The estimated rotor resistance values are applied to the maximum efficiency control with a LMF.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2057-2059
• /
• 2001

A nonlinear adaptive speed controller is designed for induction motors. Only the measurement of the stator current is used to design the controller and the observers. The sliding mode cascade observer is introduced to estimate the stator current and its time derivatives. The open-loop observer are designed to estimate the rotor flux and its time derivatives. The adaptive observer is also designed to estimate the rotor resistance. Sequentially, the rotor speed can be calculated using these estimated values. It is shown that the estimation errors of the corresponding states and the parameter converge to the specified residual set. It is also shown that the speed controller using these estimates is performed well. The experimental results are represented to investigate the validity of the proposed observer and controller.