• Journal of Institute of Control, Robotics and Systems
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• v.6 no.5
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• pp.367-375
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• 2000

It is proposed that the rotor time constant and inductance are compensated at the same time in the indirect vector control method of an induction motor. The proposed scheme compensates the rotor time constant using the difference between the Q-axis real stator current and estimated current that is calculated from the terminal voltage and current, and compensates inductance by using the difference between the D-axis real stator flux and estimated stator flux in the synchronous rotating reference frame. Although the rotor time constant and inductance vary at once, the proposed method compensates the rotor time constant and inductance with accuracy. In addition to, two variables can be compensated not only at the steady state condition, but also at the transient state, where the torque varies in a rectangular pulse waveform. Therefore, the performance of vector control is greatly improved as verified by experiment.

• Journal of electromagnetic engineering and science
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• v.17 no.4
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• pp.228-232
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• 2017

The radiation properties and fabrication precautions of a 3D printed, electrically small folded spherical meander wire monopole antenna are investigated. The antenna is self-resonant and shows sufficiently high radiation efficiency at an electrical size ka of 0.4, with the radiation quality factor Q approaching the lower physical bound. In antenna fabrication, the possible structural deformation due to gravity is examined before the antenna frame is 3D-printed. The required conductivity is achieved by multiple manual paintings of a silver paste. The radiation efficiency and pattern show very good agreement with the computed expectations, whereas the resonant frequency deviates by 11.8%. The method to minimize such a fabrication error when using 3D printing technology for wire antennas is discussed.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.173-176
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• 2004

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(SPMSM) drive without mechanical sensor. A adaptive fuzzy controller is applied for speed control of SPMSM drive A adaptive state observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of SPMSM, that employs a d-q rotating reference frame attached to the rotor. A adaptive observer is implemented to compute the speed and position feedback signal. The validity of the proposed sensorless scheme is confirmed by various response characteristics.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.56-61
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• 2000

The precise and reliable loss model for induction motor and converter system is very important in order to predict the efficiency performance of variable speed drives. This paper proposes an accurate loss model of induction motor and converter system. The motor losses, such as stator and rotor copper loss, core loss and stray loss, are considered for fundamental and harmonic frequencies. Also considered are the skin effect on rotor resistance, temperature effect on bath stator and rotor resistance, magnetizing inductance saturation, and friction and windage loss. All the above features are incorporated in a synchronous frame dynamic d-q equivalent circuit. The converter system, consisting of a diode rectifier and PWM transistor inverter, is modeled accurately for conduction and switching losses. Validity of the models, in both steady state and transient conditions, is verified by simulations.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.739-742
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• 2002

This paper is to see the availability of electrical signatures as a means for evaluating performance of MOVs which are extensively used in safety-related systems in nuclear plants. To estimate motor torque, two methods such as d-q frame conversion and air-gap method are suggested and estimated results are compared with measured values. The error between measured and estimated torques is within acceptable error bound with below $1\%$ under varied load. Frequency domain analysis of calculated torque has been done as well. It is shown that monitoring of peak frequency could give useful clues to detect anomalies of MOV.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.186-189
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• 2003

This paper is proposed to position and speed control of interior permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. A gopinath observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor, A gopinath observer is implemented to compute the speed and position feedback signal. The validity of the proposed scheme is confirmed by various response characteristics.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.502-505
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• 1998

In this paper, the new vector control scheme of BLDCM producing loss-minimized ripple-free torque based on the d-q-Ο reference frame is presented including 3 phase unbalanced condition. The optimized phase current wave-forms that are obtained by the proposed method can be a reference values and the motor winding currents are forced to track it by delta modulation technique. As a results, it can be shown that the proposed work provides a simple and clear way to obtain an optimal motor excitation current.

• Journal of Power Electronics
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• v.18 no.3
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• pp.817-825
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• 2018

In this paper, a current hysteresis control with good decoupling properties for doubly-fed brushless induction machines (BDFIMs) has been proposed based on a generalized vector model. The independent control of the reactive power and speed for BDFIMs has been achieved by controlling the d-axis and the q-axis current of the control windings (CW). The proposed vector control method has been developed for the power winding (PW) flux frame. Experimental verification of a type Y180M-4 BDFIM prototype with 1/4 pole-pairs has been presented. Evidence of its good performance has been shown through experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.2
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• pp.98-106
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• 2006

This paper proposes to position and speed control of interior Permanent magnet synchronous motor(IPMSM) drive without mechanical sensor. Also, this paper develops a adaptive fuzzy controller based fuzzy logic control for high performance of PMSM drives. In the proposed system, fuzzy control is used to implement the direct controller as well as the adaptation mechanism. A Gopinath observer is used for the mechanical state estimation of the motor. The observer was developed based on nonlinear model of IPMSM, that employs a d-q rotating reference frame attached to the rotor. A Gopinath observer is implemented to compute the speed and position feedback signal. The validity of the proposed scheme is confirmed by various response characteristics.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.482-489
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• 2006

This paper presents the generalized dynamic modeling of self-excited induction generator (SEIG) using state-space approach. The proposed dynamic model consists of induction generator; self-excitation capacitance and load model are expressed in stationary d-q reference frame with the actual saturation curve of the machine. An artificial neural network model is implemented to estimate the machine magnetizing inductance based on the knowledge of magnetizing current. The dynamic performance of SEIG is investigated under no load, with the load, perturbation of load, short circuit at stator terminals, and variation of prime mover speed, variation of capacitance value by considering the effect of main and cross-flux saturation. During voltage buildup the variation in magnetizing inductance is taken into consideration. The performance of SEIG system under various conditions as mentioned above is simulated using MATLAB/SIMULINK and the simulation results demonstrates the feasibility of the proposed system.