• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.520-521
• /
• 2014

본 논문에서는 3-Level NPC 인버터에서의 새로운 PWM 기법에 대해서 제안하였다. 3-Level NPC 인버터에서 각 상하의 스위치는 데드타임으로 인해 전압과 전류의 왜곡과 직류링크단의 전압 불균형의 원인이 된다. 제안하는 기법은 지령전압과 전류의 위상에 따라 출력전압과 전류의 왜곡성분을 감소시키며 상보동작을 하지 않는 PWM 기법을 이론적으로 검증하였고, 시뮬레이션을 통해 증명하였다.

• Proceedings of the KIPE Conference
• /
• 2015.07a
• /
• pp.59-60
• /
• 2015

본 논문에서는 3-Level NPC(Neutral Point Clamped) 인버터에서 ZDPWM(Zero Dead Time Pulse Width Modulation) 기법에 대해서 제안한다. 3-Level NPC 인버터에서 기존 PWM 기법은 각 스위치는 서로 상보적인 동작을 수행하고, 반도체 스위칭 소자 특성상 Rise Time과 Fall Time의 시간차이로 인하여 단락사고를 방지하기 위해 스위칭 신호의 Rising Edge에 데드타임을 인가하여 단락을 방지한다. 그러나 이러한 데드타임은 지령 스위칭 신호와 실제 스위칭 신호의 오차로 인하여 출력 전압 및 전류에 왜곡이 발생하고, 이러한 왜곡으로 인하여 시스템의 오작동 및 직류링크단 전압의 불평형의 원인이 된다. 제안하는 PWM기법은 지령전압과 출력전류의 위상에 따라 영역을 나눈 후 전류의 방향에 따라 옵셋 전압을 생성하여 새로운 지령전압을 만들어 각 스위치에 스위칭 신호를 인가한다. 제안한 기법에 타당성을 증명하기 위해 시뮬레이션을 통해 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.5
• /
• pp.432-437
• /
• 2001

This paper describes a new developed 3.3KV/4MW class three-level Voltage Source Inverter(VSI), which is equipped with IIMS(Inverter Information Management System) based on the world wide web and with the Virtual operation simulator. The algorithm for motor control is the stator oriented Direct Torque Control(DTC), which works without speed sensor and gives the physically fastest dynamic response. The IIMS have the functions of operation monitoring and data managements. Virtual operation simulator can analyze and tune the system characteristics without main power. Now, this system is under the field test to verify the confidence.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.11 no.2
• /
• pp.135-141
• /
• 2006

In this paper, LC output filters are designed to reduce output harmonics and harmonic analysis are peformed. Generally, multilevel inverters are used in high power application and operates with low switching frequency, which, in turn, generates large output harmonics. Output filters we used to reduce output harmonics. The design approach to reduce output harmonics of the 31eve1 multilevel inverter is discussed and DSP(TMS320C31) is used for the digital control of the system. The design example is given. The designed system is verified by simulation and experiment.

• Proceedings of the KIPE Conference
• /
• 2015.11a
• /
• pp.135-136
• /
• 2015

대용량 분산 발전원이 증가하면서 이러한 대용량 분산 발전을 효율적으로 운전하기 위한 많은 연구가 진행되고 있다. 본 논문에서는 멀티레벨 인버터 토폴로지 중 NPC와 T-type 인버터의 중성점 전압제어를 통해 두 개의 멀티레벨 인버터에서 발생하는 효율과 제어방식의 차이를 시뮬레이션하고 비교 분석하였다.

• Journal of Power Electronics
• /
• v.17 no.4
• /
• pp.923-932
• /
• 2017

This paper proposes a novel scheme which can compensate the common-mode voltage (CMV) for five-level active neutralpoint clamped (5L-ANPC) inverters, which is based on modifying the space vector pulse width modulation (SVPWM) and adding an auxiliary leg to the inverter. For the modified SVPWM, only the 55 voltage vectors producing low CMV values among the 125 possible voltage vectors are utilized, which varies over the three voltage levels of $-V_{dc}/12$, 0 V, and $V_{dc}/12$. In addition, the compensating voltage, which is injected into the 5L-ANPC inverter system to cancel the remaining CVM through a common-mode transformer (CMT) is generated by the additional NPC leg. By the proposed method, the CMV of the inverter is fully eliminated, while the utilization of the DC-link voltage is not decreased at all. Furthermore, all of the DC-link and flying capacitor voltages of the inverter are well controlled. Simulation and experimental results have verified the validity of the proposed scheme.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.5
• /
• pp.595-604
• /
• 2011

A three-phase three-level shunt active filter controlled by fuzzy logic current controller which can compensate current harmonics generated by nonlinear loads is presented. Three-level inverters and fuzzy controllers have been successfully employed in several power electronic applications these past years. To improve the conventional pwm controller performance, a new control scheme based on fuzzy current controller is adopted for three-level (NPC) shunt active filter. The scheme is designed to improve compensation capability of APF by adjusting the current error using a fuzzy rule. The inverter current reference signals required to compensate harmonic currents use the synchronous reference detection method. This technique is easy to implement and achieves good results. To maintain the dc voltage across capacitor constant and reduce inverter losses, a proportional integral voltage controller is used. The simulation of global system control and power circuits is performed using Matlab-Simulink and SimPowerSystem toolbox. The results obtained in transient and steady states under various operating conditions show the effectiveness of the proposed shunt active filter based on fuzzy current controller compared to the conventional scheme.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1334-1339
• /
• 2004

This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. Transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 5th harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1427-1432
• /
• 2004

This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. Transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 5th harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system

• Journal of Power Electronics
• /
• v.12 no.2
• /
• pp.285-293
• /
• 2012

Multilevel inverters have gained attention in high-power applications due to their numerous advantages in comparison with conventional two-level inverters. In this paper a simplified Space-Vector Modulation (SVM) algorithm for a three-level Neutral-Point Clamped (NPC) inverter is implemented on a Freescale$^{(R)}$ DSP56F8037. The algorithm is based on a simplification of the space-vector diagram for a three-level inverter so that it can be used with a two-level inverter. Once the simplification has been achieved, calculation of the dwell times and the switching sequences are carried out in the same way as for the two-level SVM method. Details of the hardware design are included. Experimental results are analyzed to validate the performance of the simplified algorithm.