• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.207-209
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• 2006

A number of techniques have been developed for estimation of speed or position in motor drives. The accuracy of these techniques is affected by the variation of motor parameters such as the stator resistance, stator inductance or torque constant. This paper is proposed a neural network based estimator for torque and ststor resistance in IPMSM Drives. The neural weights are initially chosen randomly and a model reference algorithm adjusts those weights to give the optimum estimations. The neural network estimator is able to track the varying parameters quite accurately at different speeds with consistent performance. The neural network parameter estimator has been applied to slot and flux linkage torque ripple minimization of the IPMSM. The validity of the proposed parameter estimator is confirmed by the operating characteristics controlled by neural networks control.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.3-5
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• 2004

The single phase SRM has some demerits that has a torque ripple, noise and vibration because of being excited by switching pulse power source. Therefore, to make up for these demerits, it is realized many studies for the structure design used by computer and the operating methods by power electronic technique. On this paper, we will measure the accurate torque characteristics of the disk type single phase SRM, which is designed and manufactured for fan drive through the previous studies. With this results, we'll find the control elements to reduce the torque ripple and then design and manufacture the optimal drive circuit.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.571-573
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• 1988

A new ripple analog-to-digital converter(ADC) has been developed. It consists of two parallel ADCs and a switching network. The circuit operates on the input signal in two serial steps. First a coarse conversion is made to determine the most significant bits by the first parallel ADC. The results control a switching network to connect the series resistor segment, the analog signal is contained within, to the second parallel ADC. At second step, a fine conversion is made to determine the least signification bits by the second parallel ADC. The circuit requires 2(2$\frac{N}{2}$) comparators, 2(2$\frac{N}{2}$) resistors, and 2(2$\frac{N}{2}$) switches for N-bit resolution.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.135-137
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• 2001

In slotless synchronous motor for precise position and speed control, eccentricity of rotor mass cause torque ripple, speed ripple and harmonics of back emf. This paper deals with magnetic field and characteristic analysis for ring type slotless synchronous motor by using analytical method. And then, speed and back emf harmonics are analysed.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.929-930
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• 2006

This paper presents a direct instantaneous torque control (DITC) of Switched Reluctance Moto (SRM) with a novel 4-level converter to obtain smooth torque and dynamic performance improvement. The DITC method can reduce the high inherent torque ripple of SRM drive system, but driving efficiency and dynamic performance are somewhat low due to the slow excitation current build-up. Since the 4-level converter can obtain a addition high voltage to get fast excitation current and demagnetization current, so, it can improve dynamic performance easily. As a high performance SRM drive system with low torque ripple and high dynamic performance can be implemented. The validity of proposed method is verified by some computer simulations and comparative experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.7
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• pp.409-416
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• 2004

This paper presents the selection method o( the input current wave forms for the thrust force ripple of linear pulse motor (LPM). We have developed and tested a prototype 2-phase 4-poles LPM with the permanent magnet and its control driver. To obtain the thrust performance curve of LPM, the performance curve at the air gap and the thrust are calculated and estimated by the analytical method on the base of the magnetic equivalent circuit and the finite element method. And, the thrust characteristics at the static operation state are analyzed and experimented with the respect to the input wave forms such as the rectangular, the triangular micro-step and the sine micro-step wave forms to investigate the thrust ripple and the vibration effects of LPM.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.918-925
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• 2012

This paper proposes a control method for grid-connected inverter systems under unbalanced and distorted grid voltage. The proposed method can reduce the power ripple caused by the unbalanced condition and compensate for the low-order harmonics of the output currents caused by the distortion of grid voltage. To reduce the power ripple, our method replaces the two conventional PI controllers with one PR controllers in the stationary frame. PR controllers can implement selective harmonic compensation without excessive computational requirements; the use of these controllers simplifies the method. Both the simulated and experimental results agree well with the theoretical analysis.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.754-756
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• 1987

In this paper, a new Harmonic Torque Factor(HTF) that represents torque ripple of induction motor is proposed. Trapezoidal PWM is analyzed to torque ripple by HTF and than we obtain optimum triangular factor at some carrier ratio. Six-step, sinusoidal PWM and Trapezoidal PWM are compared and evaluated for choosing a good control strategy of PWM inverter. It turns out that six-step inverter is better than sinusoidal PWM and Trapezoidal PWM when their carrier ratio is 9, and Trapezoidal PWM is superior to sinusoidal PWM. At induction motor is driven by PWM inverter, torque ripples are investigated by computer simulation using d-q two axis model. It is proved that a new Harmonic Torque Factor ix valid.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.31-38
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• 2014

Maximum power point tracking method is very important to enhance efficiency of photovoltaic system. Meanwhile a lot of research about MPPT has been studied and developed new one better than a method of the past. This paper deals with Perturb and Observation that are most commonly used. Tracking parameter changed PV voltage for PV current and it was simulated with P-SIM program. The P&O tracking method to use current for parameter lows ripple rate of output and enhances response rate of tracking. Through this study, it has been demonstrated that method using current for tracking parameter is effective.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1063-1065
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• 1993

LDM, easy to minute position control, is using as X-Y plotter or other recording instruments. Brushless LDM has better properties than the conventional Brush type LDM in many aspects. This paper presents magnetic flux density distribution by FEM and a way to reduce thrust force ripple particurary in low speed drive. And we apply this method to a real mode of LDM. This LDM is operated by IBM-PC host computer and uses rotary encoder to make position signal.