• International Journal of Aeronautical and Space Sciences
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• v.17 no.2
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• pp.167-174
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• 2016

Even though the differential drag type machines of the vertical wind turbines are a bit less efficient than the lift type machines such as Darrieus type machines, they have an advantage of low starting torque. The flapping blade type wind turbine is a specific type of the differential drag machines, and it has no need for orientation as well as quite low starting torque. This work is to develop an innovative 5kW class flapping type vertical wind turbine system which will be applicable to a hybrid power generation system driven by the diesel engine and the wind turbine. The parametric study was carried out to decide an optimum aerodynamic configuration of the wind turbine blade. In order to evaluate the designed blade, the subscale wind tunnel test and the performance test were carried out, and their test results were compared with the analysis results.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.930-939
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• 2009

A bimodal tram is being developed to combine the flexibility of a bus with the punctuality of a train. The propulsion system is a series hybrid type using a set of CNG engine generator and Li-polymer battery. This paper presents the experimental results of the series hybrid propulsion power unit using an active loader which can simulate powering and regenerative braking conditions of the propulsion equipments continuously. The power sharing scheme between PWM converter and a battery pack has been observed. The measurement results of DC link voltage and SOC(State Of Charge) of battery pack are presented.

• Journal of Power Electronics
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• v.5 no.3
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• pp.218-223
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• 2005

A simple construction, low cost, and a fault tolerant power electronic drive have made the switched reluctance drive a strong contender for many applications. But the switched reluctance drive exhibits higher levels of vibration and acoustic noise than most competing drives. The main source of vibration in the switched reluctance drive is generated by the rapid change of radial magnetic force when the phase current is extinguished during commutation. In this paper, some excitation methods are proposed to reduce the vibration and acoustic noise of the switched reluctance drive. The excitation strategies considered in this research are 1-phase, 2-phase and hybrid excitation methods. The 1-phase method is the conventional approach, while in the 2-phase method, the two phases are excited simultaneously. The hybrid excitation has 2-phase excitation using a long dwell angle as well as conventional 1-phase excitation. The vibration and acoustic noise are compared and tested. The suggested 2-phase and hybrid strategies reduce acoustic noise because the schemes reduce the abrupt change in excitation level by using distributed and balanced excitation.

• Journal of Power Electronics
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• v.11 no.5
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• pp.704-712
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• 2011

This paper describes a hybrid induction motor drive system incorporating DTC-hysteresis and Direct Self Control (DSC) schemes to achieve excellent dynamic performance. The control scheme is switched from a circular to a hexagonal flux locus whenever a dynamic condition is encountered. On the other hand, when the motor operates under steady state conditions, a circular flux locus is used. Without major modifications to the simple structure of a basic DTC, hexagonal flux locus operation is established by modifying the flux error status, before it is fed to the look-up table. The feasibility of the proposed hybrid scheme to achieve excellent control performance is verified by experimental results.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.390-398
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• 2014

The systematic optimal tuning of power system stabilizers (PSSs) using the dynamic embedded optimization (DEO) technique is described in this paper. A hybrid system model which has the differential-algebraic-impulsive-switched (DAIS) structure is used as a tool for the DEO of PSSs. Two numerical optimization methods, which are the steepest descent and Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithms, are investigated to implement the DEO using the hybrid system model. As well as the gain and time constant of phase lead compensator, the output limits of PSSs with non-smooth nonlinearities are considered as the parameters to be optimized by the DEO. The simulation results show the effectiveness and robustness of the PSSs tuned by the proposed DEO technique on the IEEE 39 bus New England system to mitigate system damping.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.249-253
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• 2006

Because of the high cost for the active power filter, passive filters have been widly used to absorb harmonic currents of nonlinear loads and can also improve the power factor. They are not often optimal filters because the passive filters are designed with the fixed load conditions. In this paper we proposed the method which only the necessary harmonic filters are operated by detecting the various harmonic current components. By the experimental results using the proposed system for the 500VA rectifier load, we concluded that the researched hybrid filter is cost effective and the performance is better than the passive filter.

• Transactions on Electrical and Electronic Materials
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• v.18 no.3
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• pp.129-135
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• 2017

This paper introduces a design and a simulation of a hybrid active power filter (HAPF) for harmonics reduction given an ideal supply source. The synchronous reference frame method has been used here to identify the reference currents. The proposed HAPF uses a new artificial- intelligence technique called Particle Swarm Optimization (PSO) for tuning the parameters of a proportional and integral controller called PI-PSO. The PI-PSO controller is used to archive optimality for the DC-link voltage of the HAPF-inverter. The hysteresis non-linear current control method is used in this approach to compare the extracted reference and the actual currents in order to generate the pulse gate required for the HAPF. Results obtained by simulations with Matlab/Simuling show that the proposed approach is very flexible and effective for eliminating harmonic currents generated by the non-linear load with the HAPF based PSO tuning.

• Ocean Systems Engineering
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• v.13 no.1
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• pp.21-41
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• 2023

Decarbonization and energy transition can be considered as a main concern even for the oil industry. One of the initiatives to reduce emissions under studies considers the use of renewable energy as a complimentary supply of electric energy of the production platforms. Wind energy has a higher TRL (Technology Readiness Level) than other types of energy converters and has been considered in these studies. However, other types of renewable energy have potential to be used and hybrid concepts considering wind platforms can help to push the technological development of other types of energy converters and improve their efficiency. In this article, a preliminary hydrodynamic assessment of a new concept of hybrid wind and wave energy conversion platform was performed, in order to evaluate the potential of wave power extraction. A multiple OWCs (Oscillating Water Column) WEC (Wave Energy Converter) design was adopted for the analysis and some simplifications were adopted to permit using a frequency domain approach to evaluate the mean wave power estimation for the location. Other strategies were used in the OWC design to create resonance in the sea energy range to try to maximize the potential power to be extracted, with good results.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.490-496
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• 2023

Unmanned aerial vehicles (UAVs) research is recently actively underway. Especially, fuel cell battery hybrid systems are widely used to overcome the limitations of continuous operation. However, fuel cell systems must be operated in combination with a battery due to their low specific output characteristics. Therefore, a hybrid power system model for UAVs is developed. The rule-based strategy is applied to the model to properly distribute power to batteries and fuel cells. As a result, the designed rule-based power distribution control operates UAVs while maintaining battery state of charge(SOC) at an appropriate level.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.325-326
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• 2005