• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.916-922
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• 2014

Diode rectifiers have been widely used for an AC to DC converter. But a big problem is that they include large harmonics components in the input currents. A 12-pulse configuration with phase shifting transformer is useful for reducing them. however, it still includes the ($12{\pm}1$)th (m; integer) harmonics in the input currents. In this paper, we propose a single-phase square wave auxiliary voltage supply which is inserted in the middle DC bus. It reduces harmonics especially the 11th and 13th and the harmonic characteristic becomes almost equivalent to a 24-pulse rectifier. Theoretical analysis of the combined 12-pulse diode rectifier with the auxiliary supply is presented and a control method of the auxiliary supply is proposed. The reduction in the input current harmonics is verified by simulation using software PSIM.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.304-309
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• 1999

In this paper, a new 24longleftarrowpulse diode rectifier system based upon the conventional series-connected 12-pulse rectifier is p proposed with the least number of switching devices and low VA rating of the additional passive components. The p proposed approach does not employ any active switching devices. Therefore, the system is rugged and simple to i implement. Detailed analysis with VA rating calculation of the components is presented and experimental results from a a 220V, 3kV A rectifier system verify the proposed concept.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.346-349
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• 1999

This paper proposes a new series-connected diode rectifier which draws sinusoidal input currents. The proposed rectifier system is configured by adding an auxiliary circuit to the conventional 12-pulse series-connected diode rectifier and employing a current injection technique. A low kVA (0.02Po (PU) ) active current source injects a triangular current results in near sinusoidal input current from the utility with less than 1% THD. The resulting system is suitable for high voltage and high power applications. Experimental results is provided from a 220VA rectifier system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.759-769
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• 2015

Diode rectifiers are very popular in industry. However, they include large low-order harmonics in the input current and do not satisfy harmonic current content restrictions. To reduce the harmonics to the power system, several methods have been introduced. It is heavy and expensive solution to use passive filters as the solution for high power application. Another solution for the harmonic filter is utilization of active filter, but it is too expensive solution. Diode rectifiers with configurations using switching device have been introduced, but they are very complicated. The combined 12-pulse diode rectifier with the square auxiliary voltage supply has been introduced. It has the advantages that auxiliary circuit is simple and inexpensive compared to other strategies. The advanced auxiliary voltage supply in this thesis is presented as a new solution. When the square auxiliary voltage supply applied, the improvement of THD is 6~60[%] in whole load range. But when the advanced auxiliary voltage supply applied, it shows stable and excellent reduction effect of THD as 57~71[%]. Especially, for the case with 10[%] load factor, reduction effect of THD has little effect as 6[%] in the case of inserting a square auxiliary voltage supply. But when the proposed new solution applied, reduction effect has excellent effect as 71[%]. Theoretical analysis of the combined 12-pulse diode rectifier with the advanced auxiliary voltage supply is presented and control methods of the auxiliary supply is proposed. The reduction in the input current harmonics is verified by simulation using software PSIM.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.207-216
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• 2017

Wind energy conversion systems (WECS) which consist of wind turbines with permanent magnet synchronous generator (PMSG) and full-power converters have become widespread in the field of renewable power systems. Generally, conventional diode bridge rectifiers have used to obtain a constant DC bus voltage from output of PMSG based wind generator. In recent years, together advanced power electronics technology, Pulse Width Modulation (PWM) rectifiers have used in WECS. PWM rectifiers are used in many applications thanks to their characteristics such as high power factor and low harmonic distortion. In general, L, LC and LCL-type filter configurations are used in these rectifiers. These filter configurations are not exactly compensate current and voltage harmonics. This study proposes a hybrid passive filter configuration for PWM rectifiers instead of existing filters. The performance of hybrid passive filter was tested via MATLAB/Simulink environment under various operational conditions and was compared with LCL filter structure. In addition, neuro-fuzzy controller (NFC) was preferred to increase the performance of PWM rectifier in DC bus voltage control against disturbances because of its robust and nonlinear structure. The study demonstrates that the hybrid passive filter configuration proposed in this study successfully compensates current and voltage harmonics, and improves total harmonic distortion and true power factor.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.11
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• pp.640-645
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• 1999

This paper proposes a new series-connected diode rectifier which draws sinusoidal input currents. The proposed rectifier system is configured by adding an auxiliary circuit to the conventional 12-pulse series-connected diode rectifier and employing a current injection technique. A low kVA($0.02P_{\circ}$(PU) ) active current source injects a triangular current into the interphase reactor of the diode rectifier. The current injection results in near sinusoidal input current from the utility with less than 1% THD. The resulting system is suitable for high voltage and high power applications. Experimental and simulation results are provided from a 220V, 3kVA prototype rectifier system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.1
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• pp.66-70
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• 2013

The input current of three phase rectifier which is mainly used in the propulsion system of the electric propulsion ship includes a variety of low order harmonics. To reduce these harmonics, the power conversion system, used in the large vessels which high power is required, is currently used the rectifiers of 12-pulse output, but it still has a problem that occurs $12{\pm}1$ harmonics. Also, in the case of the direct torque control technique which is widely used for the speed and torque control, the torque ripple is severe and the input current of motor has greatly included harmonics by the switching of the inverter. In order to reduce harmonics and improve the performance of torque control, this paper presents that the auxiliary supply assisted into the 12-pulse rectifier of the electric propulsion system using direct torque control technique. We confirm the validity of the proposed method through the simulation under the environment of a real vessel system.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.705-711
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• 2005

In DC traction substation with 12-pulse diode rectifiers, the DC line voltage tends to rise above noload voltage because it can't absorb the regenerative power caused by electric brakes of train. To solve this problem, an IGBT regenerative inverter should be installed and recycles the surplus regenerative power by delivering it. to the supply grid. In this paper, the DC traction substation equipped with a IGBT regenerative inverter is studied using computer simulation. Matlab/simulink is used to simulate the operation of regenerative inverter which injects the regenerative power into the supply grid and stabilizes the DC line voltage. It is confirmed that the high quality regenerative power is delivered to the supply grid thorough computer simulation.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.279-281
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• 2005

In DC traction substation with 12-pulse diode rectifiers, the DC line voltage tends to rise above noload voltage because it can't absorb the regenerative power caused by electric brakes of train. To solve this problem, an IGBT regenerative inverter should be installed and thus recycles the surplus regenerative power by delivering it to the supply grid. In this paper, the DC traction substation equipped with a IGBT regenerative inverter is studied using computer simulation. Matlab/simulink is used to simulate the operation of regenerative inverter which injects the regenerative power into the supply grid and stabilizes the DC line voltage. It is confirmed that the high quality regenerative power is delivered to the supply grid thorough computer simulation.