• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1206-1212
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• 2001

The kinematic analysis of Stewart platform manipulator(SPM) is carried out in order to reduce the calculation time for its forward kinematic solution when the iterative numerical method is employed. The kinematic equations for three substructures of the 6-3 SPM are newly derived by introducing Denavit-Hartenberg link parameters and using kinematic constraints associated with the SPM and substructure kinematics. It is shown that the forward kinematics can be easily solved from three nonlinear equations with three unknown variables only, leading to a great reduction in calculation time.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.97-99
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• 2009

In this paper, a new type of electromagnetic actuator, an electro magnetic force driving actuator (EMFA) is developed and analyzed, applicable to air circuit breaker (ACB). Transient analysis is performed in order to obtain the dynamic characteristics of the EMFA. The distribution of static magnetic flux is obtained using the finite element method (FEM). The coupled problems of electrics and mechanics governing equations are solved using the time difference method (TDM). Also according to interception rate of each contactor, investigation about load condition of contactor spring is conducted, applied it to three-link system. And comparison about dynamic characteristics of three-link simulation and experiment data are performed.

• 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.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.316-317
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• 2018

This paper propse the DC link capacitor voltage balancing control for three level neutral point clamped converter with harmonic component injection method. The injcetion voltage consists of harmonic component and DC link capacitor voltage difference. Theoretical analysis is provided to balance the DC link voltage, and it shows that harmonic component compensates the unbalanced condition between the capacitors. Both simulations and experiments are carried out to show that the voltage unbalance have been decreased by the proposed method.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.68-71
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• 2020

As a T-type three-level PWM converter has several intrinsic advantages, it has been widely studied for many applications. However, it requires an additional voltage control loop for balancing each DC link voltage. Generally, satisfying this requirement involves the use of an offset voltage to provide a neutral point current without affecting other variables, such as the total DC link voltage and three-phase input current. In this study, the theoretical relationship between the offset voltage and the neutral point current is analyzed. The results can be beneficial for effective voltage balancing controller design. The effectiveness of the analytical modeling is verified by simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.55-59
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• 2002

This paper presents a novel three-phase current-fed Pulse Width Modulation converter with switched capacitor type resonant DC link commutation circuit operating PWM pattern strategy under a design consideration of low-pass filter, which can operate on the basis of the principle of zero current soft switching commutation. In the first place, the steady state operating principle of this converter with a new resonant DC link snubber circuit is described in connection with the equivalent operation circuit, together with the practical design procedure of the switched-capacitor type resonant DC link circuit is discussed from a theoretical viewpoint on the basis of a design example for high-power applications. The actively delayed time correction method to compensate distorted currents due to a relatively long resonant commutation time is newly implemented in the open loop control scheme so as to acquire the new optimum PWM pattern. Finally, the experiment of set-up in laboratory system of this converter is concretely demonstrated herein to confirm a zero current soft-switching commutation of this converter. The comparative evaluations between current -fed hard switching PWM and soft-switching PWM converters are carried out from a viewpoint of their PWM converter characteristics.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.613-617
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• 2011

In the present paper, a new type of electrical actuator, an electromagnetic force driving actuator (EMFA), applicable to air circuit breaker is developed and analyzed. Transient analysis is performed to obtain the dynamic characteristics of EMFA. The distribution of static magnetic flux is obtained using the finite element method. The coupled problems of electrics and mechanics governing equations are solved using the time-difference method. According to the interception rate of each contactor, investigation of the contactor spring load condition is conducted and applied to the threelink system. Comparisons of the dynamic characteristics of the three-link simulation and experimental data are performed.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.65-74
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• 2002

A three dimension(3D) link analysis is peformed considering multipath effects caused by a reflected signal and the difference angle between the antenna bore-sight and Line-Of-Sight(LOS). In addition, a direction of a receive antenna is determined for a receiver to get maximum signal strength in a telemetry situation. For a fixed receive antenna, the angle is determined to maximize the average Carrier to Noise Ratio(CNR) over the interested part of a trajectory. For a tracking antenna, the angle at every position is selected to give maximum CNR or to direct the boresight to the flying projectile.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.170-175
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• 2000

A new quasi-parallel resonant DC link inverter is proposed for three phase soft switching application. By i inserting only one additional switch, the proposed inverter excludes both voltage stresses and restricted PWM p problems, which are demerits of the conventional resonant inverter. In this paper, the circuit operations are e explained in detail using the operational mode analysis of the proposed inverter and design methods of the r resonant components are suggest('x:l. Lastly, the applicable possibility of the proposed inverter is vel예fied t through the experimental results.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.143-146
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• 2002

This paper proposes a new auxiliary resonant DC link(ARDCL)snubber circuit and deals with its power loss on the basis of actually-measured conduction loss characteristic of switching device module. Voltage-ed soft switching three-phase inverter using proposed ARDCL snubber circuit is presented along with its performance evaluations. And, the power loss analysis of three-phase hard and soft switching inverter are carried out from the point of simulation and experimental results.