• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.65-67
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• 2007

In this paper describes the design and characteristic analysis of a novel 2-DOF(Degree of Freedom) motor. For multi DOF actuating, several numbers of motors have been used. But the using of normal motors they connected each other in single joint, have necessary to a several type of complex power transmission devices. The 2-DOF motor can drive pan, tilt motion in only one unit and it is not necessary to use additional gears and links parts. Therefore by the using of 2-DOF spherical motor ran eliminate; combined effects of inertia, backlash, non-linear friction, and elastic deformation of gears. The validity of the analysis is confirmed by 3D finite element method.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.553-558
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• 2012

An effort for motion control of multi-axis in robot have been continued recently. In this paper, we propose implementation method for AC servo driver that can be easily motion control of multi-axis in robot. This proposed method implement EtherCAT communication technologies of bi-directional optical communication based on single optical core method that applied WDM for communication between control stage which is upper and AC servo drive stage.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.124-126
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• 1988

The induction motor is constantly operated by general source, thus its speed control is employed an inverter system which can convert DC into AC. The CSI(Current Source Inverter) which have a commutation capacitor in its circuit is liable to cause a voltage spike that it is due to charge and discharge of commutation capacitor. And six phases inverter makes a number of harmonics. These have a effect upon the induction motor badly. This paper aims to suggest a way to reduce such adverse effects by maximally cutting the voltage spike as well as by eliminating a number of harmonics through the operation of Multi-HFCSI.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.162-169
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• 2000

A Direct Drive Valve(DDV) hydraulic actuation system which is commonly used as an aircraft's control surface driving actuator has multi-loop control structure to ensure its safety operation. However, because of not perfect matching of one self channel characteristics with the others, the servo valve driving current of each channel can be widely different. Therefore, the long-time use of DDV actuator without any correction of these channel current offsets will cause the problem of performance or life expectancy degradation due to unwanted heats in the linear motor. A current equalization loop structure which can minimizes current offsets between channels is introduced and designed. The performance of the current equalization loop is investigated and verified through the analytic and experimental ways.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.95-99
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• 2001

In this paper, a drive system for multi-phase bipolar brushless DC (MPB BLDC) motor is presented. This drive system is used for an electric bicycle. In general, the maximum and minimum speed of electric bicycle are required by law. At first, the proposed controller is satisfied for the limited speed control. Secondly, the system has a technique of exited with modulation(EWM), bidirection control, and partial square wave control. Thirdly, the controller is designed for system stability Experimental results show the performance of the proposed controller of MPB BLDC motors for an electric bicycle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1362-1370
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• 2008

This paper describes the design and characteristic analysis of a novel 3-DOF(Degree of Freedom) spherical motor. For multi DOF actuating, several numbers of motors have been used. By the using of normal motors they connected each other in single joint, is necessary to a several type of complex power transmission devices. The 3-DOF spherical motor can drive roll, pitch, and yaw motion in only one unit and it is not necessary to use additional gears and links parts. Therefore the using of 3-DOF spherical motor can eliminate; combined effects of inertia, backlash, non-linear friction, and elastic deformation of gears. In this paper, we propose the novel structured 3-DOF spherical motor and derive its principles of operation. Firstly, we designed concept model of novel structured 3-DOF spherical motor. Next, we derive the control method by calculating the currents. Also, to have intuitive driving control, we express the rotor position in equivalent angle-axis system and determine the exciting period of currents from the calculation result of the currents. To verify the control method, we calculated the currents by the position of rotor. and then we analyzed the characteristics by 3D Finite Element Method when the calculated currents are excited.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.44-54
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• 2010

Optimal efficiency control of synchronous reluctance motor(SynRM) is very important in the sense of energy saving and conservation of natural environment because the efficiency of the SynRM is generally lower than that of other types of AC motors. This paper is proposed a novel efficiency optimization control of SynRM considering iron loss using multi adaptive fuzzy learning controller(AFLC). The optimal current ratio between torque current and exciting current is analytically derived to drive SynRM at maximum efficiency. This paper is proposed an efficiency optimization control for the SynRM which minimizes the copper and iron losses. There exists a variety of combinations of d and q-axis current which provide a specific motor torque. The objective of the efficiency optimization control is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. The control performance of the proposed controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.576-585
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• 2016

The current control methods of Y-connected 7 Phase BLDC motor are sine wave current control and square wave control. The sine wave current control method needs dq axis transformation of $7{\times}7$ matrix for current control and very complex. Also this method is not suitable for multi Phase BLDC motor of trapezoidal back emf wave. Therefore, in Y connected multi phase BLDC motor, the square wave current control methods are required. Generally, in the 3Phase BLDC system, Average current control method is used for current control. The average current is obtained that the summation of absolute value of each phase current magnitude is divided by the number of conduction phase. However, if average current control method is applied to multi-phase system, there is a problem that each phase currents are different. This problem affects unbalance of each phase torque and fluctuation of total torque. This paper proposed each phase current control method of Y connected 7Phase BLDC system. Proposed method is used for PI controller of each phase for each phase current control. This method can perfect square wave current control. Also, configuration of the method is easier than DQ axis transformation. Proposed method is verified through simulation and experiments.

• Journal of Power Electronics
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• v.13 no.4
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• pp.569-583
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• 2013

In this study, the simultaneous use of a multi-level converter (MLC) as a DC-motor drive and as an active battery cell balancer is investigated. MLCs allow each battery cell in a battery pack to be independently switched on and off, thereby enabling the potential non-uniform use of battery cells. By exploiting this property and the brake regeneration phases in the drive cycle, MLCs can balance both the state of charge (SoC) and temperature differences between cells, which are two known causes of battery wear, even without reciprocating the coolant flow inside the pack. The optimal control policy (OP) that considers both battery pack temperature and SoC dynamics is studied in detail based on the assumption that information on the state of each cell, the schedule of reciprocating air flow and the future driving profile are perfectly known. Results show that OP provides significant reductions in temperature and in SoC deviations compared with the uniform use of all cells even with uni-directional coolant flow. Thus, reciprocating coolant flow is a redundant function for a MLC-based cell balancer. A specific contribution of this paper is the derivation of a state-space electro-thermal model of a battery submodule for both uni-directional and reciprocating coolant flows under the switching action of MLC, resulting in OP being derived by the solution of a convex optimization problem.

• Journal of Drive and Control
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• v.11 no.1
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• pp.1-7
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• 2014

This paper presents a novel concept of wave energy converter for electric generation from the ocean wave energy. In this paper, a Multi-Point Absorbing Wave Energy Converter, shortened as MPAWEC by using Secondary Control Hydrostatic Transmission (SCHST) was proposed. The power take-off (PTO) system in the proposed MPAWEC includes multi heaving buoys to drive hydraulic pumps placed at different points. The application of SCHST in MPAWEC gives some advantages, such as longevity of hydraulic components; more energy is harvested; the variation of the pressure in the accumulator limited; therefore the accumulator volume is reduced and the output speed is more stable, etc. A PID controller was designed for speed control of the hydraulic motor. The simulation results indicated that the speed of the generator was ensured with the relative error as 0.67%; the efficiency of the proposed system was 71.4%.