• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.50-56
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• 1999

This paper presents consideration on validity of instantaneous correlation power theory. The proposed power theory is defined and analyzed by time domain approach, thus it is easy to understand and instrument. The power is decomposed into active, fundamental reactive and harmonics components based on the autocorrelation and crosscorrelation signal techniques between voltage and current waveforms. On the compensation property, active power filter deal with three components only. Also, for real time control of active power filter, the power models with difficult concept are not cost effective. To verify the validity of the instantaneous correlation power theory, experimental work for voltage type DSP based active power filter is achieved. The power of thyristor controlled motor drives is decomposed into three orthogonal components by proposed power theory. From compensation results, validity of proposed theory is confirmed. feedback controller needs the information on some motor parameters. New recursive adaptation algorithms for rotor resistance and mutual inductance which can be applied to our nonlinear feedback controller are also presented in this paper. The recursive adaptation algorithms make the estimated values of rotor resistance and mutual inductance track their real values. Some simulation and experimental results show that the adaptation algorithms are robust against the variation of stator resistance and stator inductance.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.213-215
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• 2003

This paper presents an instantaneous space vector modulated voltage source type three-phase soft-switching PFC rectifier using a single auxiliary resonant DC Link snubber for alternative energy utilizations. in the first place, the operating principle of an active auxiliary resonant DC link snubber circuit is described including its unique features. In the next place, the simulation analysis of three-phase soft-switching PWM rectifier is implemented, and the operating performances or the three-phase voltage-fed PWM rectifier treated here, which can operate under the conditions of sinewave line current shaping and utility power factor are evaluated and discussed on tile basis of this simulation results.

• Journal of Power Electronics
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• v.2 no.3
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• pp.162-170
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• 2002

Voltage sag detection algorithm for voltage sag corrector is proposed in this paper. To quantify the standard of voltage unbalance under the faulted conditions, the 3-phase unbalanced voltages are decomposed into two balanced 3-phase symmetrical components of the positive and negative sequence voltages, which is defined by the magnitude factor (MF) and unbalance factor (UF). It is analyzed that MWF and UF values are given as the dc constant values even though under the voltage unbalance condition. This paper also proposes the control scheme of the instantaneous voltage sag corrector based on this detection algorithm. The validity of the proposed algorithm is verified through the EMTDC simulation and experiments.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.73-76
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• 2002

In this paper, we consider an algorithm for effectively providing data services for mobile users with different levels of priorities in a DS-CDMA system. The priority level of a user is specified by a factor that is a weighting on the instantaneous data throughput of the user. We define tile weighted instantaneous aggregate data throughput and use it to characterize the performance of the prioritized data service. Our prioritized data service is implemented so that the weighted instantaneous aggregate data throughput is maximized via efficient power and spreading gain allocation. We present efficient algorithms for computing tile optimal power and spreading gain allocation.

• Journal of Power Electronics
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• v.9 no.3
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• pp.491-498
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• 2009

The hydraulic-oil pump is widely used for building machinery, brake systems of vehicles and automatic control systems due to its high dynamic force and smooth linear force control performance. This paper presents a novel direct instantaneous pressure control of the hydraulic pump system with SRM drive. The proposed hydraulic pump system embeds the pressure controller and direct instantaneous torque controller. Due to the proportional relationship between pump pressure and torque, pressure can be controlled by the motor torque directly. The proposed direct torque controller can reduce inherent torque ripple of SRM, and develop a smooth torque, which can increase the stability of the hydraulic pump. The proposed hydraulic pump system has also fast step response and load response. The proposed hydraulic pump system is verified by computer simulation and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.576-584
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• 2003

This paper presents a new control method of single-phase active power filter(APF) for the compensation of harmonic current components in nonlinear loads. Constructing a imaginary second-phase giving time delay to load currents, making single-phase system into the system that has two phases, complex calculation is possible. In the previous method, it made a imaginary-phase lagged to the load current T/4(here T is the fundamental cycle), but in proposed method, the new signal, which has the delayed phase through the filter, using the phase-delay property of low-pass filter, was used to the second phase. Instantaneous calculation of harmonic current is possible, because two phase have different phase. In this paper, it was done with instantaneous calculation using the rotating reference frames(RRF) that synchronizes with source-frequency, a reference of compensation currents, not applying to instantaneous reactive power theory which uses the existed fixed reference frames. The simulation and experiment about R-L loads using the current source were carried out, and the effect of the proposed method was preyed through the result of this experiment.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1454-1470
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• 2014

This paper propose a new power conditioner topology with intelligent power management controller that integrates multiple renewable energy sources such as solar energy, wind energy and fuel cell energy with battery backup to make best use of their operating characteristics and obtain better reliability than that could be obtained by single renewable energy based power supply. The proposed embedded controller is programmed for maintaining a constant voltage at PCC, maximum power point tracking for solar PV panel and WTG and power flow control by regulating the reference currents of the controller on instantaneous basis based on the power delivered by the sources and load demand. Instantaneous variation in reference currents of the controller enhances the controller response as it accommodates the effect of continuously varying solar insolation and wind speed in the power management. The power conditioner uses a battery bank with embedded controller based online SOC estimation and battery charging system to suitably sink or source the input power based on the load demand. The simulation results of the proposed power management system for a standalone solar/WTG/fuel cell fed hybrid power supply with real time solar radiation and wind velocity data collected from solar centre, KEC for a sporadically varying load demand is presented in this paper and the results are encouraging in reliability and stability perspective.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.27-33
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• 1997

In this paper, instantaneous controller of a single-phase PWM converter is realized using DSP. The stable PI gain of the input current and the DC link voltage control system is designed. The DC link voltage control system can be designed in continuous-time domain. But as for the input current control system, the descretizing effect cannot be ignored so it must be designed in descrete-time domain considering the calculation time. The capacitance estimating algorithm which can be acquired through the ripple voltage is proposed. By this algorithm the DC link capacitance can be estimated even under the transient state. Experimental results show the input power factor of 99.1% and the voltage variation rate of $\pm$5% according to the load variation.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1055-1059
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• 1992

Instantaneous Voltage Control of inverter for uninterruptible power supply(UPS) is presented. In order to improve the transient response, the authors propose a control scheme based on a double regulation loop with sinusoidal hysteresis band. And also, using 8097 single chip microprocessor, software synchronization and static switch control scheme is impremented with minimal hard ware structure.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.934-935
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• 2015

This paper presents the sensorless control method that employs the adaptive back-EMF(Electromotive Force) and current model observer of interior permanent magnet synchronous motor(IPMSM). The estimated back EMF considering a saliency is obtained by using the adaptive control method. The estimated EMF is inputted to the current model observer which is connected in series with adaptive back EMF estimator and is used to estimate the position and speed of the rotor. In order to improve the shortcomings of conventional method using the current error components multiplied in the compensation constant, the modified instantaneous reactive power compensator is applied. The validity of the control system presented is verified by the simulation.