• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.326-329
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• 2002

In this paper, a single-phase inverter using a diode bridge-type resonant circuit to implement ZVT(Zero Voltage Transition) switching is presented. The current control algorithm is analyzed about how to design the circuit with auxiliary switch which can ZVT operation for the main power switch. The simulation and experimental results would be shown to verify the proposed current algorithm, because the main power switch is turn on with ZVT and the hi-directional inverter is operated.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.123-126
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• 2003

This paper proposes a speed-sensorless induction motor control system using the rotor flux error. The rotor flux observer uses the reduced- dimensional state estimator technique instead of directly measuring the rotor flux. The estimated rotor speed is obtained directly from the electrical frequency, the slip frequency, and the rotor speed compensation with the estimated q-axis rotor flux. To precisely estimate the rotor flux, the actual value of the stator resistance, whose actual variation is reflected, is derived. For fast calculation and improved performance of the proposed algorithm, all control functions are implemented in software using a digital signal processor (DSP) with its environmental circuits. Also, it is shown through experimental results that the proposed system gives good performance for the speed-sensorless induction motor control.

• Journal of Power Electronics
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• v.11 no.4
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• pp.551-560
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• 2011

This paper proposes a grid-tied power conditioning system for the fuel cell power generation, which consists of a 2-stage DC-DC converter and a 3-phase PWM inverter. The 2-stage DC-DC converter boosts the fuel cell stack voltage of 26-48V up to 400V, using a hard-switching boost converter and a high-frequency unregulated LLC resonant converter. The operation of the proposed power conditioning system was verified through simulations with PSCAD/EMTDC software. Based on the simulation results, a laboratory experimental set-up was built with a 1.2kW PEM fuel-cell stack to verify the feasibility of hardware implementation. The developed power conditioning system shows a high efficiency of 91%, which is a very positive result for the commercialization.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.324-330
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• 2005

The complex sensorless control scheme is not practical for use in the field of home appliance systems because it is not economical. Therefore, it is necessary to introduce a simplified sensorless control scheme that is composed of least calculation to estimate the rotor position. This paper presents the principle of the rotor position estimation with comparison of the estimated flux linkage and reference flux linkage. In order to verify the feasibility of the control scheme, ACSL is used for the simulation and TI DSP TMS320F240 is used for the experiment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.254-256
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• 2012

본 논문에서는 MPEG-D 오디오 서브그룹에서 진행 중인 Unified Speech and Audio Coding (USAC) 표준의 Linear Prediction Domain (LPD) 복호화기 모듈을 고정소수점 알고리즘으로 제안한다. USAC 부호화기는 두 개의 최신 음성-오디오 부호화기가 융합된 형태로, 음성 및 오디오 신호에 대하여 우수한 성능을 갖는 부호화기이다. USAC의 표준 완료와 본격적인 서비스화에 앞서서 USAC LPD 복호화기의 구조적인 특성을 분석하고, Digital Signal Processor (DSP)구현을 위한 LPD 복호화기의 고정소수점 알고리즘을 구축하는 동시에 모듈의 복잡도를 측정하고자 한다. 또한 고정소수점 알고리즘으로 구현된 LPD 복호화기와 기존의 부동소수점 복호화기의 성능을 비교하고, LPD 복호화기의 두 가지 부호화 모드에 따른 복잡도 이슈를 다루도록 한다.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2057-2059
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• 1998

In order to maintain a high quality output voltage, conventional UPS systems use complex filters with large passive components. To overcome this drawback, real time feedback control schemes have been invested. However, these techniques require a high inverter switching frequency to dynamically adapt to changing load conditions reduce harmonics of the output voltage, thereby rendering the system inadequate for high power applications. This paper presents real time digital signal processor(DSP) control of a large capacity UPS system feeding nonlinear loads to provide a sinusoidal inverter output voltage, unity input power factor, low bus voltage ripple, and excellent transient response.

• Journal of Power Electronics
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• v.2 no.1
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• pp.55-66
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• 2002

A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuit and off-line experimental measurement, disturbance voltages in the synchronous reference dq frame caused by the dead time and non-ideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Simulations and experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.534-535
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• 2013

본 논문은 당사에서 개발한 5Mvar급 STATCOM(static synchronous compensator)의 제어 시스템에 대해 기술한다. 제작된 5Mvar급 STATCOM은 한 상당 12대의 HBI(H-Bridge Inverter)로 구성이 가능하도록 25-Level로 제작되었다. 제안된 제어시스템은 DSP(digital signal processor)를 이용하였으며, 하나의 Main Controller와 다수의 Cell Controller, FPGA 보드 등으로 구성되어 있다. Controller 간의 상호 정보를 교환하기 위해 eCAN 통신을 이용하였고, HBI의 스위칭을 위한 보드는 각각에 연결되어 있으며, Cell Controller보드와는 절연을 위해 광신호로 연결하였다. 본 논문에서는 개발한 제어시스템의 신뢰성을 검증하기 위한 실험을 진행하였다.

• 전기의세계
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• v.43 no.2
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• pp.4-10
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• 1994

산업현장에서 사용되고 있는 산업용로보트와 CNC 공작기계에 부착된 AC 서보모타는 아직까지 대부분 아나로그소자들로 구성된 아나로그제어기에 의해 구동되고 있으나, 최근들어 몇몇 선진업체가 고속의 DSP(Digital Signal Processor)를 채택하여, 전류(토오크), 속도, 위치를 디지틀제어하는 디지틀제어기를 개발하여 산업용로보트와 CNC 공작기계의 운동축을 구동하는 AC 서보모타를 제어하고 있다. 디지틀 AC 서보모타제어기는 아나로그 제어기로는 실현 할 수 없거나, 실현에 한계를 가지는 기능과 성능의 확보를 가능하게 하며, 산업용로보트와 CNC공작기계 제어기의 컴팩트(compact)화, 용이한 유지보수, 제어기가격의 절감등을 실현할 수 있게 한다. 본고에서는 산업용로보트와 CNC 공작기계의 고성능 동특성, 고정밀 제어를 가능하게 하는 AC 서보모타의 디지틀 제어기 개발시 고려해야 하는 사항과 실제 개발 및 적용사례를 소개한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.529-535
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• 2000

In this paper, a current control system of a single phase PWM AC/DC converter using a reduced-order Luenberger observer without source voltage sensors is proposed. The sinusoidal input current and unity input power factor are realised based on the estimated source voltage performed by the reduced-order Luenberger observer using actual currents and DC link voltage. The poles of the reduced-order Luenberger observer are placed in the left half plane of s-plane by the pole-placement method in order to acquire the stability of the observer. The magnitude and the phase of the estimated source voltage are used to accomplish the unity power factor. The proposed method is implemented by DSP(Digital Signal Processor). Experimental Results verify that the reduced-order observer estimates the source voltage without the estimation error and the control system accomplishes the unity power factor, and constant DC link voltage.