• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.209-212
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• 2003

This paper proposes a soft-transition control strategy for a three phase ZCS(Zero Current Switching) inverter circuit. Each phase leg of inverter circuit consists of an LC resonant tank, two main switches, and one auxiliary switches. This paper presents design consideration via a study example of a three phase prototype inverter for motor drives. A simple device tester with zero current switching capability is proposed to select eligible auxiliary switches. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 2.2kW 5kHz IGBT based experimental circuit.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.429-430
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• 2020

2상 유도전동기를 구동하기 위한 2레그형 인버터에서는 직류링크 양단에 직렬로 연결된 2개의 커패시터에 걸리는 전압에 불균형이 발생하므로 이것이 전동기 상전류의 불평형과 토크리플을 야기한다. 본 논문에서는 이러한 상전류의 불평형을 간접 보상할 수 있는 PWM 제어 방법과 커패시터 전압의 균형을 제어함으로써 전동기 상전류의 평형을 유지할 수 있는 직접 보상 방법을 제안하였다.

• Journal of Power Electronics
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• v.7 no.2
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• pp.109-117
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• 2007

In this paper, a novel proposal for a utility-interactive three-phase soft commutation sinewave PWM power conditioner with an auxiliary active resonant DC-link snubber is developed for fuel cell and solar power generation systems. The prototype of this power conditioner consists of a PWM boost chopper cascaded three-phase power conditioner, a single two-switch auxiliary resonant DC-link snubber with two electrolytic capacitors incorporated into one leg of a three-phase V-connection inverter and a three-phase AC power source. The proposed cost-effective utility-interactive power conditioner implements a unique design and control system with a high-frequency soft switching sinewave PWM scheme for all system switches. The operating performance of the 10 kW experimental setup including waveform quality, EMI/RFI noises and actual efficiency characteristics of the proposed power conditioner are demonstrated on the basis of the measured data.

• Journal of Power Electronics
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• v.8 no.2
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• pp.156-162
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• 2008

This paper proposes a low-cost power converter for micro wind turbine systems using permanent magnet synchronous generators (PMSG). The proposed converter consists of a two-leg three-phase PWM inverter for the generator control and a single-phase half-bridge PWM converter which is connected to the utility grid. For the two separate DC-link voltages, a balancing control is added and the adverse effect of the DC-link voltage ripples on the inverter output voltage is compensated. The control performance of the proposed converter topology for the micro wind turbine system is shown by the simulation results using PSIM software.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.372-375
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• 2021

A three-leg inverter-type isolated DC-DC Converter that can use 220 and 440 V grid input voltages is introduced. The secondary circuit structure of the proposed topology is center-tap, which is the same as the conventional phase-shifted full-bridge converter. However, the primary circuit structure is composed of a three-leg inverter structure and a transformer, in which two primary windings are connected in series. The proposed circuit structure has a wider input voltage range than the conventional phase-shifted full-bridge converter, and the circulating-current on the primary-side is reduced. In addition, the voltage stress at the secondary rectifier is greatly improved, and high efficiency can be achieved at a high input voltage by removing the snubber circuit added to the conventional converter. Prototype converters with input DC of 311 V, output of 622 V, and 50 V and 6 kW class specifications were designed and manufactured to verify the validity of the proposed topology; the experimental results are presented.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1791-1801
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• 2016

This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.164-171
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• 2006

In this paper, the fault tolerant system for BLDC motor has been proposed to maintain control performance under an open switch fault of inverter. The fault identification is proposed to two methods, which are using the difference between reference and actual current, and adding voltage sensors across lower legs of inverter. The reconfiguration scheme is achieved by the four-switch topology connecting a faulty leg to the middle point of DC-link using bidirectional switches. The proposed fault tolerant system quickly recovers control performance by short fault detecting time and reconfiguration of system topology. Therefore, continuous free operation of the BLDC motor drive system after faults is available. The superior performance of the proposed fault tolerant system is proved by simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.2
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• pp.115-122
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• 2007

In this paper, a novel fault detection method for fault tolerant control is proposed when the NPC inverter has a open failure in the switching device. The open fault of switching device is detected by checking the variation of a leg-voltage in the neutral-point-clamped inverter and the two phases control method is used for continuously balance the three phases voltage to the load. It can be achieve the fault tolerant control for improving the reliability of the NPC inverter by the fault detection and reconfiguration. This method has fast detection ability and a simple realization for fault detection, compared with a conventional method. Also, this fast detection ability improved the harmful effects such as DC-link voltage unbalance and overstress to other switching devices from a delay of fault detection. The proposed method has been verified by simulation and experiment.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.260-262
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• 2013

본 논문에서는 2상 유도전동기의 가변속장치인 3-레그 2상 인버터의 PWM 방식을 공간벡터제어 방식으로 제안하였다. 기존의 3-레그 인버터의 PWM방식은 전형적인 SVPWM 방식을 적용하여 PWM 방식이 복잡하다. 본 논문에서는 3상 PWM 옵셋전압방식을 응용하여 2상 인버터에 적용하여 기존의 공간 벡터(space vector) PWM(SVPWM) 방식방식을 단순화 시킨 것이다. 제안된 3-레그 인버터의 PWM방식에 대한 타당성을 확인하기 위해 모의 실험과 실험이 실행되었다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.393-394
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• 2017

유도전동기는 속도 제어가 어렵기 때문에 이를 위한 고가의 벡터제어 인버터가 널리 사용되어 왔다. 이 때문에 최근에는 이를 저가화하기 위하여 제어 알고리즘이 단순하고 구현이 용이한 직접토크제어 방식에 대한 연구가 이루어지고 있다. 한편으로 소용량의 저전력 응용 분야에서는 기계적으로 구조가 단순하고 가격이 저렴한 2상 유도전동기를 적용하려는 노력이 활발해지고 있다. 2상 유도전동기용 인버터의 대표적인 토폴로지는 3상 IPM 소자를 그대로 이용할 수 있는 3레그형이다. 그러나, 3레그형 인버터에서는 출력 전압 벡터가 비대칭 육각형의 형태로 나타나므로 2상 유도전동기에 이러한 직접토크제어 방식을 적용하면 전동기의 발생 토크에 리플이 증가하는 문제가 있다. 본 논문에서는 3레그형 인버터를 사용하는 2상 유도전동기에 직접토크제어 방식을 적용하고 이때 문제가 되는 전동기의 토크 리플을 저감하는 방법에 관하여 연구하였으며, 이것의 유효성은 시뮬레이션을 통하여 유효성을 검증하였다.