• Journal of Electrical Engineering and Technology
• /
• v.4 no.2
• /
• pp.219-228
• /
• 2009

The growing application and the numerous qualities of induction motors (1M) in industrial processes that require high security and reliability levels has led to the development of multiple methods for early fault detection. However, various faults can occur, such as stator short-circuits and rotor failures. Traditionally the diagnosis machine is done through a sinusoidal power supply, in the present paper we study experimentally the effects of the rotor failures, such as broken rotor bars in function of the ac supplying, the load and show the impact of the converter from diagnosis of the machine. The technique diagnosis used is based on the spectral analysis of stator currents or stator voltages respectively according to the types of induction motor ac supplying. So, four different ac supplying are considered: ${\odot}$ the IM is directly by the balanced three-phase network voltage source, ${\odot}$ the IM is fed by a sinusoidal current source given the controlled by hysteresis, ${\odot}$ the IM is fed (in open loop) by a scalar control imposing through ratio V/f=constant, ${\odot}$ the IM is controlled through a vector control using space vector pulse width modulation (SVPWM) technique inverter with an outer speed loop.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.4
• /
• pp.405-411
• /
• 2012

This paper deals with direct torque control of an induction motor (IM) with constant switching frequency. The desired torque is obtained from the speed controller which is designed using the IP controller. Decoupling control of torque and flux is developed based on the energy model of IM using the IP controller strategies. The desired d-axis and q-axis stator voltage components are obtained from the designed controller, which decouples torque and flux. The constant switching frequency can be applied using space-vector pulse width modulation, since the desired stator voltage can be known from the decoupling torque and flux controllers. In order to achieve stable operation of the proposed IP controllers, the gains of the controllers are chosen by setting the poles in negative (left) half of s-plane and by choosing the rising time for the response of the step function. The proposed controller was verified in simulations using Matlab/Simulink and results have proven excellent performance. It was found that the proposed IP controllers can provide excellent performance to track the desired torque and speed and to reject the disturbance of load.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.394-398
• /
• 1999

Direct Torque Control method for an Induction Motor is presented which is quite different from field-oriented control. It carries out a precise and quick control of the stator flux and electromagnetic torque of an IM without calling for coordinate transformation, speed measurement, and stator current control. In principle, moreover, DTC operation requires only the knowledge of the stator resistance.

• Proceedings of the KIEE Conference
• /
• 1995.11a
• /
• pp.55-58
• /
• 1995

An optimum design method of electric machines using neural network is presented. In this method, two multi - layer perceptrons of analysis and design neural network are used in optimizing process. A preliminary model of linear induction motor for subway is designed by the electric and magnetic loading distribution method and then optimized by presented method.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.47-49
• /
• 2005

This paper presents a robust speed control method of induction motors(IM) using a Non-linear PI controller(NPI), NPI is high gain controller in region of small error, and low gain controller in region of large error. so in steady state, system will be robust against variation of load torque. The simulation and experiment results confirm the validity of proposed control scheme.

• Journal of Fisheries and Marine Sciences Education
• /
• v.7 no.1
• /
• pp.111-126
• /
• 1995

In general, the electromagnetic transient phenomenon always exists in induction motor(IM) with the torque change. The control performance of IM is very worse than that of D.C motor owing to this transient phenomenon. So many studies about the elimination methods of the transient phenomenon have been making progress. Interesting methods of them are the Field acceleration method(FAM) and the method of impulse addition on the input voltage at the time point of torque change. In this paper, first, the circuit equation of IM is derived from the phase segregation method. The torque equation consisted of the stator and rotor currents is derived from the solving of the circuit equation. As we well known, the transient terms exist in this the torque equation. The method of impulse addition on the input voltage at the instance of torque change is confirmed theoretically for the elimination of the transient phenomenon. With the base on it, the author proposed a real time algorithm to eliminate the transient terms. The control system is consisted of the PI controller with the feedforward of torque change. The author could confirm that the quick stepwise responses of torque and speed can be obtained from response simulations.

• Journal of Power Electronics
• /
• v.17 no.1
• /
• pp.149-160
• /
• 2017

To improve the performance of sensorless induction motor (IM) drives, an adaptive speed estimation method based on a strong tracking extended Kalman filter with a least-square algorithm (LS-STEKF) for induction motors is proposed in this paper. With this method, a fading factor is introduced into the covariance matrix of the predicted state, which forces the innovation sequence orthogonal to each other and tunes the gain matrix online. In addition, the estimation error is adjusted adaptively and the mutational state is tracked fast. Simultaneously, the fading factor can be continuously self-tuned with the least-square algorithm according to the innovation sequence. The application of the least-square algorithm guarantees that the information in the innovation sequence is extracted as much as possible and as quickly as possible. Therefore, the proposed method improves the model adaptability in terms of actual systems and environmental variations, and reduces the speed estimation error. The correctness and the effectiveness of the proposed method are verified by experimental results.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1649-1654
• /
• 2009

Induction motors widely use in industry because structure is simple and hard and cost is generally cheap and they are easy to control. In recently, because of saving steel, ventilation and benefit of frame fixing, rectangular core type induction motors use in industry more and more. This paper presents current characteristic according to stator core cutting degree in three-phase induction motor (IM) with rectangular stator core. According to stator cutting degree, magnetic saturation and paths of flux are changed. Because of these situations, phase currents are unbalance and are produced harmonic components and they cause decrease of efficiency. We analyze each $10^{\circ}$ from $0^{\circ}$ to $30^{\circ}$ using 2-D finite element analysis (FEA). Optimal stator cutting core degree selection supplies stable currents and efficiency improvement. In this paper, loss separation test was executed by IEEE Std. 112-98 Method B and we compare with the result of loss separation by Simulation using FEM and by Experiment.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.4
• /
• pp.546-557
• /
• 2012

In Conventional Combined Vector and Direct Controls (VC-DTC) of induction motor, stator current is very rich in harmonic components. It leads to high torque ripple of induction motor in high and low speed region. To solve this problem, a control method based on the concept of fuzzy logic approach is used. The control scheme proposed uses stator current error as variable. Through the fuzzy logic controller rules, the choice of voltage space vector is optimized and then torque and speed are controlled successfully with a less ripple level in torque response, which improve the system's performance. Simulation results trough MATLAB/SIMULINK${(R)}$ software gave results that justify the claims.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.10a
• /
• pp.547-552
• /
• 2000

This paper presents a developed squirrel cage induction motor for axial flow In. Nearly all of the induction motors for fan consists of two parts, rotor and stator, and the position of rotor is located inside of stator. This construction restricts the air flow rate, otherwise requires bending duct. But developed squirrel cage induction motor for axial flow fan exchanged the position each other. So, we can reduce the weight and size about 30%, and there are no bending duct to locate the fan motor.