• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.4
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• pp.349-356
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• 1990

In order to control DC motors for electric cars by chopper system, four quadrant operations - forward powering, forward regenerative braking, reverse powering, reverse regenerative braking - are needed. For the four quadrant operations, the separately - excited DC motors are used in this study. The conversion of each quadrant operation has been obtained by 1) adopting the two phase chopper system with combined output for the armature control, and 2) the single phase chopper system for the field control.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.473-475
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• 1996

In this paper, bilateral variable-ratio dc chopper system for electric vehicle is proposed. We present the method which is able to simplify the main synthetic chopper circuit by selecting among the forward powering, forward regenerative braking, backward powering, and backward regenerative braking only by control signal. By conducting the experiment with separately excited dc motor, it is confirmed that two quadrant chopper can drive four quadrant operation.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.91-97
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• 2012

This paper presents a state space model of a two quadrant chopper and PWM inverter-fed Interior Permanent Magnet Synchronous Motor (IPMSM) drive system and its application to hybrid vehicles. The drive system has two different state equations for motoring and regenerating action. This paper presents a common state equation by using State Space Averaging method. Using this model of the IPMSM drive system, detailed simulation and controller design of the drive system, including PWM inverter switching, are given. The validity of this model and usefulness, according to a comparison among Maximum Torque/Ampere control, Maximum Torque/Flux control, and Maximum Efficiency optimization, are confirmed from simulation results.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.547-551
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• 1987

New chopper circuits for decoupled operation of the dc series motor are presented. These new choppers are capable of controlling field current completely separately, while offering capability of bidirectional armature energy flow. To develop the chopper circuit, with minimum number of switching elements, the complete family of possible conduction circuits are systematically investigated. Then one or two quadrant chopper circuits which offer the desired operations are synthesized from the resulting conduction circuits. Finally, the developed chopper circuits are completely analyzed. The details of operation of the chopper circuits are also fully described.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.10
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• pp.832-839
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• 1989

New chopper circuits for decoupled operation of the dc series motor are presented. These new choppers are capable of controlling field current completely separately, while offering capability of bidirectional armature energy flow. To develop the chopper circuit with minimum number of swithcing elements, the complete family of possible conduction circuits are systematically investigated. Then one or two quadrant chopper circuits which offer the desired operations are synthesized from the resulting conduction circuits. Finally, the developed chopper circuits are analyzed in the steady state. The details of operation of the chopper circuits are also fully described and experimented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.11
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• pp.22-27
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• 2009

This paper presents a two-paralleled four quadrant DC chopper type PWM power conversion circuit in order to generate a gradient magnetic field in the Magnetic Resonance Imaging (MRI) system. This circuit has 8-IGBTs at their inputs/outputs to realize further high-power density, high speed current tracking control, and to get a low switching ripple amplitude in a controlled current in the Gradient Coils (GCs). Moreover, the power conversion circuit has to realize quick rise/fall response characteristics in proportion to various target currents in GCs. It is proposed in this paper that a unique control scheme can achieve the above objective DSP-based control system realize a high control facility and accuracy. It is proved that the new control system will greatly enlarge the diagnostic target and improve the image quality of MRI.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.569-574
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• 1998

This paper presents a two-paralleled 4 quadrant DC chopper type PWM power conversion circuit in order to generate a gradient magnetic field in the Magnetic Resonance Imaging (MRI) system. This power amplifier is connected in parallel with the conventional 4-quadrant DC chopper using IGBTs at their inputs/outputs to realize further high-power density, high speed current tracking control, and to get a low switching ripple amplitude in a controlled current in the Gradient Coils (GCs). Moreover, the power conversion circuit has to realize quick rise/fall response characteristics in proportion to various target currents in GCs. It is proposed in this paper that a unique control scheme can achieve the above objective. DSP-based control systems realize a high control facility and accuracy. It is proved that the new control system will greatly enlarge the diagnostic target and improve the image quality of MRI.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1119-1124
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• 2014

High temperature superconducting magnetic energy storage (HTS SMES) is known as an effective solution to significantly decrease the voltage and power fluctuations of grid connected wind power generation system (WPGS). This paper implements an effective control scheme of a back-toback converter with shunt-connected HTS SMES for the frequency regulation of an islanded microgrid. The back-to-back converter is used to connect the WPGS to the grid. A large-scale HTS SMES is linked to the DC side of the back-to-back converter through a two-quadrant DC/DC chopper. An adaptive control strategy is implemented for the back-to-back converter and the two-quadrant DC/DC chopper to improve the efficiency of the whole system. The performance of the proposed control system was evaluated in a test power system using PSCAD/EMTDC. The simulation results clearly show that the back-to-back converter with shunt-connected HTS SMES operates effectively with the proposed control strategy for stabilizing the power system frequency fluctuations.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.816-819
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• 1987