• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.84-89
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• 2005

This paper presents a control algorithm for a large salient-pole synchronous motor fed by a Load Commutated Inverter (LCI). Many papers have been presented in the past few years on the justification, design, and application of variable-speed drive. The focus of this paper is on high torque operation and the estimation of initial rotor position. The results of simulation indicate that it is possible to produce the maximum torque and estimate the initial rotor position.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.7
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• pp.49-56
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• 2009

A new class of electronically commutated brushless motors, the flux-switching motor (FSM), is gradually emerging for use in power tools and household appliances especially fan and pump application thanks to green policies, This motor offers such advantages as high-power density and relatively high efficiency compare to induction motors, and low cost and simple motor structure compare to the BLDC motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Test results of the prototype motor are provided to verify the validity of the fan application with a TMS320F2812 DSP and inverter.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.493-497
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• 1998

In this paper, a three phase voltage source inverter synchronous motor drive is introduced which is capable of producing an approximate to sine-wave currents in the stator windings. Compare to a conventional current forced synchronous machine drive, for the same machine loss, a gain in out put per unit overall volume of 125% at a 50Hz supply frequency has been achieved. In addition, the torque pulsation has been drastically reduced. These improvements are achieved by introducing new rotor windings which are capable of controlling the stator current waveforms an approximate to sine-wave. A computer program has been developed which can be used to predict the dynamic performance of this drive/system. The paper describes the design of rotor windings for cylindrical rotor motor but the theory is equally applicable to salient-pole designs.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.10
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• pp.1029-1036
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• 1990

This paper presents a systematic study for control loops in the induction motor drive system employing a load commutated current source inverter (LCCSI) which has appeared since the early 1980's, and their effects on the dynamic stability of the system. A set of dq equations which amalgamate the overall system is developed, and from the equations it is revealed that the steady state characteristics of the LCCSI-induction motor system are between VSI and ASCI. When the speed control loop is constructed without a speed sensor, the evaluation of the pole/zero locations and the assessment of the stability for the added loops are investigated. We also show that the V/F loop is essential in this type of drive without the speed sensor.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.91-96
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• 2011

In this paper, we propose a microstrip bandpass filter using stepped-impedance coupled-line hairpin resonators. The stepped-impedance coupled-line hairpin resonator has extended harmonic suppression in comparison with a conventional hairpin resonator due to transmission zero and the movement of harmonic frequencies resulting from the stepped-impedance characteristic. A high-pass type impedance/admittance inverter is employed in order to improve the lower frequency skirt characteristics of the passband. A 4-pole bandpass filter is designed and fabricated at 1.8 GHz. The measured results show the excellent attenuation performance at the stopband which is greater than 30 dB up to 10 GHz.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.98-107
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• 2002

The performance of a capacity controlled system, which are tandem, pole change, bypass and inverter driven compressor, has been compared with that of a con- ventional constant speed system. It has been found that capacity modulated system can offer more than 14 percent improvement in SEER over the conventional system. Comparative test results show that two compressor system can attain an improvement in SEER up to 42% over the conventional on/off system, and is feasible without additional investment.

• Journal of Power Electronics
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• v.9 no.4
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• pp.567-574
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• 2009

A linear transfer function for the output current control of frequency-controlled resonant inverters is proposed in this paper. The circuit of resonant inverters can be transformed into two coupled circuits through the complex phasor transform. The circuits consist of cross-coupled power sources and passive elements. The circuits are used to induce the state space equation, which is transformed into the $4^{th}$ order cross-coupled transfer function. The $4^{th}$ order cross-coupled transfer function is modeled into a $2^{nd}$ order linear transfer function based on a behavior analysis of the pole and zero locations that facilitate a simple and intuitive linear transfer function. The feasibility and validity of the proposed linear transfer function were verified by simulation and experiment.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.264-265
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• 2017

본 논문에서는 3상 220V/5kVA 소프트스위칭 인버터의 새로운 회로구성을 제안하고 그 동작과 성능을 분석한 내용을 기술하고 있다. 제안하는 소프트스위칭 인버터는 ARCP(Auxiliary Resonant Commutated Pole) 인버터의 회로구성과 유사한 구조이나 이와 달리 LC 공진회로와 Diode 클램프 회로로 구성되어 있다. 이론적인 분석과 실험을 통해 제안하는 인버터의 효율을 분석하고 이를 하드스위칭 인버터와 비교하여 약 1% 정도의 효율 개선이 가능함을 알 수 있었다. 제안하는 인버터는 소프트 스위칭을 위해 소프트스위칭 보조회로와 게이트 드라이버가 추가로 장착되는 점에서 비용적인 경쟁력이 떨어질 수 있다. 그러나 최근 수요가 급증하고 있는 인버터에서 1% 효율 차이는 전력수급의 효율화를 통해 비용 측면에서 경쟁력을 갖을 것으로 판단된다. 또한 소프트스위칭 회로의 컴팩트화와 하드웨어의 최적화된 물리적 배치를 통해 추가의 효율증대가 가능할 것으로 보인다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.311-312
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• 2015

본 논문에서는 Unipolar PWM 스위칭 (Totem pole) 방법을 사용하는 단상인버터에서 나타나는 common mode noise를 저감시키는 스위칭 방법을 제안한다. 제안하는 방법은 출력전압의 중성점(N)을 입력전압 양단에 항상 고정하도록 스위칭을 하여 Common Mode Noise를 저감했다. 이를 Matlab Simulink를 사용한 모의해석과 실험을 통하여 Noise의 원인과 효과를 입증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.4
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• pp.384-394
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• 1999

This paper deals with a fixed frequency full-bridge inverter type DC-DC high-power converter with high frequency high voltage(HFHV) transformer-coupled stage, which operates under quasi-resonant ZVS transition priciple in spite of a wide PWM-based voltage regulation processing and largely-changed load conditions. This multi-resonant(MR) converter topology is composed of a series capacitor-connected parallel resonant tank which makes the most of parasitic circuit reactive components of HFHV transformer and two additional quasi-resonant pole circuits incorporated into the bridge legs. The soft-switching operation and practical efficacy of this new converter circuit using the latest IGBTs are actually ascertained through 50kV trially-produced converter system operating using 20kHz/30kHz high voltage(HV) transformers which is applied for driving the diagnostic HV X-ray tube load in medical equipments. It is proved from a practical point of view that the switching losses of IGBTs and their electrical dynamic stresses relating to EMI noise can be considerably reduced under a high frequency(HF) switching-based phase-shift PWM control process for a load setting requirements.