• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.8-15
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• 2000

In this paper, we realize the active PFC(Power Factor Correction) system of BF(Boost Forward) converter with PWM-PFM(Pulse Width Modulation-Pulse Frequency Modulation) control technique to control DC output voltage, to remove the noise like harmonics at output voltage, and to control the input current with sinusoidal wave synchronized by the source voltage.To achieve the desired load voltage and improved PFC, we first implement current shaping control at the inverting stage and make the converted output DC voltage with forward converter. After making the ratio of output voltage to current as 50V/1A and the duty ratio greater than 0.5. When input voltage is 30V and boost inductance is 1.1mH. we control the voltage changing rate according to the variation of load resistance using a PWM-PFM control technique. And finally we prove experimentally, we attenuated its harmonics and improved PF up to 0.96 using the current shaping technique.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.31-38
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• 2000

Wide operating range and speed control is needed for wind power generating and a Doubly Fed Induction Generator(DFIG) has good adaptivity for that purpose. This paper deals with the speed, power, and power factor control using the Grid connected DFIG in the super-synchronous speed regions, by controlling frequency and voltage fed to the rotor. Power flow of the DFIG and steady-state algebraic equations of the equivalent circuit are analyzed. The wind turbine speed and constant stator power were controlled by the rotor exciting frequency. For a normal operating region, in which the generator ratings were not exceeded, rotor exciting frequency. For a normal operating region, in which the generator ratings were not exceeded, the rotor current was either less than or equal to the rated value. Accordingly, the optimal power factor can be selected relative to the permissible rated current at the rotor coil which controls the magnitude of the injected rotor voltage to the rotor according to a given rotor frequency. Consequently, it is possible to determine the optimal drive of a DFIG for wind power generation application.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.3
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• pp.53-61
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• 2006

This paper is proposed adaptive fuzzy-neuro controller for high performance of induction motor drive. The design of this algorithm based on fuzzy-neural network controller that is implemented using fuzzy control and neural network. This controller uses fuzzy nile as training patterns of a neural network. Also, this controller uses the back-propagation method to adjust the weights between the neurons of neural network in order to minimize the error between the command output and actual output. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive fuzzy-neuro controller is evaluated by analysis for various operating conditions. The results of experiment prove that the proposed control system has strong high performance and robustness to parameter variation, and steady-state accuracy and transient response.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.40-49
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• 2008

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications and so of due to their excellent power to weight ratio. To obtain maximum efficiency in these applications, this paper proposes the neural network control method. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the error back propagation algorithm(EBPA) of neural network. The minimization of loss is possible to realize eHciency optimization control for the IPMSM drive. This paper proposes high performance and robust control through a real time calculation of parameter variation such as variation of back emf constant, armature resistance and d-axis inductance about the motor operation. Proposed algorithm is applied IPMSM drive system, prove validity through analysis operating characteristics con011ed by efficiency optimization control.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.40-47
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• 2007

High speed electric trains have nonlinear loads including converters and inverters for the control synchronous motors. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probablistic approach is the most commonly used method to solve time varying harmonics. Harmonic simulations are performed to evaluate the harmonic voltage and current distortions throughout the system. This paper provides an in depth analysis on harmonics field measurement of the high speed electric train loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519-l992, and harmonics simulation using EDSA program for the case study.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.55-64
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• 2007

This paper represents characteristics and design example of series loaded LCC type high frequency resonant DC-DC converter with variable parallel capacitor in the secondary side of inductive power transformer. In this converter, ZVS(zero voltage switching) technique is applied to reduce turn-off switching losses, and the applied converter used the PFM switching pattern to control output voltage. The operating characteristics of the proposed converter is analyzed using nomalized parameter such as switching frequency and load factor with varing the secondary parallel resonant capacitor. The results of analysis show the operating characteristics and design method of the proposed converter using characteristic values. And the proposed converter can be applied for the contactless power supply with linear transfer system such as dean room facilities of semiconductor and Flat Panel Display.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.48-56
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• 2012

The object of this paper is the controller for supplying stably power in a separate house in which a hybrid electrical storage system with a stand-alone photovoltaic/wind power generation system and a small generator is applied. In the photovoltaic/wind hybrid power system used in the separate house, when only the battery is used in sunless days, the capacity of the battery is become larger. In particular, as in recent days, if cloudy days are frequent due to anomaly climate, it is difficult to estimate the number of sunless days. Accordingly, it is preferable to build the electrical storage system that numbers of sunshineless days are to be controlled and a shortage amount of the power generation capacity is to be handled by a small generator system. In order to supply stably power of new renewable energy such as solar to any separate houses, it is preferable to reduce the capacity of battery by decreasing the number of sunless days when estimating the capacity of battery and to drive the small generator for compensation of the power shortage. Such system needs components including inverters for photovoltaic and wind power generation system, batteries and controllers for automatically driving the small generator, based upon the nature of the stand-alone house, and it is preferable to use the controller having a simpler and higher stability by adopting the all-in-one scheme to facilitate its maintenance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.145-151
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• 2010

Voltage unbalance is regarded as a power quality problem of significant at the user application. Although the voltages are quite well balanced at the transmission system, the voltage level of utilization can be unbalanced due to the unequal system impedances and the unequal distribution of single phase loads. Capacitor is generally used for power-factor compensation and reducing harmonics of non linear load with reactor. If voltage unbalance exists, current unbalance is generated and it will be reflected in the capacity variance. When the reactor and condenser are used at the same location, generally its trouble rate is high. And it is very important checking out that how the variance of voltage, current and capacity of condenser is proceeded by the voltage unbalance. In this paper, we calculated that voltage, current and capacity of condenser are within the tolerance limit of official regulations in the event of voltage unbalance with/without reactor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.122-128
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• 2010

This paper presents the characteristics for ground impedance of combined three rods according to distance of current probe and frequency using the fall-of-potential method and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position of auxiliary probes. In order to analyze the effects of ground impedance due to the distance of the current probe and frequency, ground impedances were measured in case that the distance of current probe was located from 5[m] to 20[m] and the measuring frequency was ranged in 55~513[Hz]. The results could be help to determine the position of current probe and the measuring frequency when the ground impedance was measured at grounding system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.94-105
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• 2010

To detect faults in an inverter-fed permanent magnet synchronous motor (PMSM) drive under the circumstance having faults in a stator winding and inverter switch, an on-line basis fault detecting scheme during operation is presented. The proposed scheme is achieved by monitoring the second-order harmonic component in q-axis current and the fault is detected by comparing these components with those in normal conditions. The linear interpolation method is employed to determine the harmonic data in normal operating conditions. As soon as the fault is detected, the operating mode is changed to identify a fault type using the phase current waveform. To verify the effectiveness of the proposed fault detecting scheme, a test motor to allow inter-turn short in the stator winding has been built. The entire control algorithm is implemented using DSP TMS320F28335. Without requiring an additional hardware, the fault can be effectively detected by the proposed scheme during operation so long as the steady-state condition is satisfied.