• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.456-458
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• 1997

The phase-lock technique is applied to a three-phase semi-bridge type battery charger system. Using an inner fast dynamic loop, the phase-locked voltage control (PLVC) technique of three-phase semi-bridge converter is proposed to give a frequency synchronism and to reduce the subharmonics due to the unbalance of transformer or power line. To protect the power devices, the two stage soft-start, function with softly locking the phase and softly increasing the current is presented. As limiting the reference voltage of the inner voltage control loop, muti-lock phenomena are removed on the PLVC loop. A current limit function is also proposed to limit the current of battery and converter. The proposed controller is confirmed through experiment results.

• Journal of Korea Foundry Society
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• v.26 no.1
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• pp.27-33
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• 2006

Phase evolutions involving nucleation stages together with diffusional growth have been examined in order to provide a guideline for determining rate limiting stages during phase evolutions. In multiphase materials systems in coatings, composites or multilayered structures, diffusion treatments often result in the development of metastable/intermediate phases at the reaction interfaces. The development of metastable phases during solid state interdiffusion demonstrates that the nucleation reaction can be one controlling factor. Also, the concentration gradient and the relative magnitudes of the component diffusivities provide a basis for a phase selection and the application of a kinetic bias strategy in the phase selection. For multicomponent alloy systems, the identification of the operative diffusion pathway is central to control phase formation. Experimental access to the nucleation and growth stage is discussed in thin film multi layers and bulk samples.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.270-272
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• 2018

This paper proposes an open-phase fault control system using 3-phase neutral voltage. The proposed control system is designed as a new topology which uses the potential difference between neutral point and ground(G) of three phase. And the open-phase detection system is configured to three resistance devices(Y-wiring) of the same capacity to each line of three phase power source R,S,T. This paper also designs a mobile phone application for remote alarm of open-phase fault.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.939-945
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• 2009

This paper is described BLDC motor in the submarine propulsion system which is asked high power per unit area. This study analyzes the independent 6-phase BLDC motor a specific extended by existing the independent 3-phase BLDC motor and propose forward development direction. Independent 6-phase motor has a characteristics that phases of stator are independent electrically with each other and two's independence 3-phase BLDC motor are linked with each difference of 60 degree. Six-phase BLDC motor is simulated with Matlab-simulink, the simulation result has a high current and low torque pulsation than existent independence 3-phase BLDC motor.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.619-625
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• 1997

In this paper, we show that the rotor position of the bifilar-wound hybrid stepping motors for the closed-loop drives is detected by the phase current measurement. We propose an instantaneous phase current equation, which is the function of electrical angle, by modeling the stepping motor including motor driving circuits. We also analyze the relationship between phase current and rotor position from the computer simulation results. We show that the information about the rotor position is obtained from the phase current amplitude and its derivatives at the instance of ${\pi}/2$ electrical angle of excitation voltage.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.25-28
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• 2002

In this paper, 2 phase modulated SRPP-PWM(Separately Random Pulse Position PWM) is proposed. This PWM technique is based on the 2 phase modulated SVPWM(Space Vector Pulse Width Modulation). In according to the theory of SVPWM, 2 phase modulated SVPWM uses two pulses, not three pulses as in 3 phase modulated SVPWM. In the proposed SRPP-PWM scheme, each of two phase pulses is located randomly in each switching interval. The experimental results show that the voltage and switching noise harmonics are spread to a wide band area. Also, the performance of the proposed 2 phase modulated SRPP-PWM and the conventional SVPWM are compared to each other In result, the speed response is nearly similar to each other from the viewpoint of the v/f constant control.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.540-542
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• 2019

This paper proposes an open-phase fault control system using 3-phase neutral voltage. The proposed control system is designed as a new topology which uses the potential difference between neutral point and ground of three phase. The open-phase detection system is also configured to Y-wiring of three capacitance devices of the same capacity to each line of three phase power source R-S-T. This paper also designs a mobile phone application for remote alarm of open-phase fault.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.4-6
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• 2018

This paper proposes an open-phase fault control system using 3-phase neutral voltage. The proposed control system is designed as a new topology which uses the potential difference between neutral point and ground(G) of three phase. And the open-phase detection system is configured to Y-wiring of three capacitance devices of the same capacity to each line of three phase power source R-S-T. This paper also designs a mobile phone application for remote alarm of open-phase fault.

• Journal of Ocean Engineering and Technology
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• v.37 no.3
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• pp.122-128
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• 2023

Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.297-304
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• 2014

Due to the nonlinearity and complexity of the three-phase photovoltaic inverter, we propose an intelligent control based on fuzzy logic and the classical proportional-integral-derivative. The feedback linearization method is applied to cancel the nonlinearities, and transform the dynamic system into a simple and linear subsystem. The system is transformed from abc frame to dq0 synchronous frame, to simplify the state feedback linearization law, and make the close-loop dynamics in the equivalent linear model. The controls improve the dynamic response, efficiency and stability of the three-phase photovoltaic grid system, under variable temperature, solar intensity, and load. The intelligent control of the nonlinear characteristic of the photovoltaic automatically varies the coefficients $K_p$, $K_i$, and $K_d$ under variable temperature and irradiation, and eliminates the oscillation. The simulation results show the advantages of the proposed intelligent control in terms of the correctness, stability, and maintenance of its response, which from many aspects is better than that of the PID controller.