• Journal of Power Electronics
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• 제10권5호
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• pp.477-484
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• 2010

A pulse width modulation-voltage source inverter (PWM-VSI) is used for variable speed permanent magnet synchronous motor (PMSM) drives. The PWM-VSI fed PMSM has two major disadvantages. Firstly, the PWM-VSI DC-link voltage limits the magnitude of the PMSM terminal voltage. As a result, the motor speed is restricted. Secondly, in a low speed range, the PWM-VSI modulation index declines. This is caused by a high DC-link voltage and a low terminal voltage ratio. As a result, the distortion of the voltage command and the stator current are increased. This paper proposes an optimal pulse amplitude modulation (PAM) control which can adjust the inverter DC-link voltage by using a buck-boost DC-DC converter. At a low speed range, the proposed system can reduce the distortion of the voltage command, which improves the stator current waveform. Also, the allowable speed range is extended. In order to verify the proposed method, experimental results are provided to confirm the simulation results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.877-880
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• 2005

This paper describes a PLL frequency synthesizer for wireless LNA applications. The design is focused mainly on low-power and low-phase noise characteristics. A 128/129 dual-modulus prescaler has been designed using the proposed TSPC D flip-flops for high-speed operation and low-power consumption The designed synthesizer includes all building blocks for elimination of external components, other than the crystal. Its operating frequency can be programmed by external data. The frequency synthesizer has been designed using a $0.25{\mu}m$ CMOS process parameters. It operates in the frequency range of 2GHz to 3GHz and consumes 3.2mA at 2.5GHz from a 2.5V supply.

• 한국통신학회논문지
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• 제30권1A호
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• pp.104-112
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• 2005

본 논문에서는 고속, 저전력 8-비트 ADC를 설계하는 기법들을 제안하였다. 비교적 적은 전력 소모를 가지면서 고속으로 동작 시키기 위해 기존의 파이프라인 구조인 MDAC를 이용한 폐쇄형 구조 대신에 개방형 구조를 채택하였다. 또한 Distributed THA와 캐스캐이드 형태의 구조를 이용하여 높은 샘플링 속도에 최적화 하였다. 제안한 각 단의 크로싱 지점을 판별하는 기법은 증폭기의 개수를 줄일 수 있도록 함으로서 저전력과 좁은 면적의 ADC 구현을 가능하게 하였다. 모의 실험 결과 500-MHz의 샘플링 속도와 1.8V 전원 전압에서 테스트에 필요한 디지털 회로까지 포함, 210mW의 전력을 소비함을 확인 할 수 있었다. 또한 1.2Vpp(Differential) 입력 범위와 200-MHz까지의 입력 주파수에서 8-비트에 가까운 ENOB를 가짐을 볼 수 있었다. 설계된 ADC는 $0.18{\mu}m$ 6-Metal 1-Poly CMOS 공정을 이용, $900{\mu}m{\times}500{\mu}m$의 면적을 차지한다.

• Journal of Power Electronics
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• 제2권2호
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• pp.146-153
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• 2002

this paper presents an implementation of digital control system of speed sensorless for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The problem of DTC for high-dynamic performance RSM drive is generating a nonlinear torque due to a saturated nonlinear inductance curve with various load currents. The control system consists of stator flux observer, compensating inductance look-up table, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source unverter, and TMS320C31 DSP controller. The stator flux observer is based on the combined voltage and current model with stator flux feedback adapitve control that inputs are the compensated inductances, current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated rotor speed is determined by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operation area. It does not requrie the knowledge of any montor paramenters, nor particular care for moter starting, In order to prove the suggested control algorithm, we have simulation and testing at actual experimental system. The developed sensorless control system is showing a good speed control response characterisitic result and high performance features in 20/1500 rpm with 1.0Kw RSM having 2.57 ratio of d/q reluctance.

• Journal of Power Electronics
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• 제15권3호
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• pp.644-651
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• 2015

This paper introduces a novel digital one cycle control (DOCC) boost power factor correction (PFC) converter. The proposed PFC converter realizes the FPGA-based DOCC control approach for single-phase PFC rectifiers without input voltage sensing or a complicated two-loop compensation design. It can also achieve a high power factor and the operation of low harmonic input current ingredients over universal loads in continuous conduction mode. The trailing triangle modulation adopted in this approach makes the acquisition of the average input current an easy process. The controller implementation is based on a boost topology power circuit with low speed, low-resolution A/D converters, and economical FPGA development board. Experimental results demonstrate that the proposed PFC rectifier can obtain a PF value of up to 0.999 and a minimum THD of at least 1.9% using a 120W prototype.

• Smart Structures and Systems
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• 제29권5호
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• pp.653-660
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• 2022

Gravel scattering that is generated during operation of high-speed railway vehicle is cause to damage of vehicle such as windows, axle protector and so on. Especially, those are frequently occurred in winter season when snow ice is generated easily. Above all, damage of vehicle windows has not only caused maintenance cost but also increased psychological anxiety of passengers. Various methods such as heating system using copper wire, heating jacket and heating air are applied to remove snow ice generated on the under-body of vehicle. However, the methods require much run-time and man power which can be low effectiveness of work. Therefore, this paper shows that large-area heating system was developed based on heating coat in order to fundamentally prevent snow ice damage on high-speed railway vehicle in the winter season. This system gives users high convenience because that can remotely control the heating system using IoT-based wireless communication. For evaluating the applicability to railroad sites, a field test on an actual high-speed railroad operation was conducted by applying these techniques to the brake cylinder of a high-speed railroad vehicle. From the results, it evaluated how input voltage and electric power per unit area of the heating specimen influences exothermic performance to draw the permit power condition for icing. In the future, if the system developed in the study is applied at the railroad site, it may be used as a technique for preventing all types of damages occurring due to snow ice in winter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.298-302
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, UM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1,100kVA inverter with four 210kW traction motors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.852-855
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• 2003

The switched reluctance motor (SRM) is gaining much interest as a candidate for electric vehicle for its simple and rugged construction, ability of extremely high-speed operation. This paper is to design and investigate the capabilities of the SRM for low speed electric vehicle(LSEV)

• 전력전자학회논문지
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• 제22권5호
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• pp.397-403
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• 2017

This paper studies the voltage angle control of interior permanent magnet synchronous motors (IPMSMs). For voltage angle control, the optimum voltage angle trajectory according to the operating speed is researched while the voltage and current limit conditions are considered. Through research, two different optimum voltage angle trajectories that depend on the design of IPMSMs were found. The IPMSM drive based on a voltage angle control that follows such trajectory is proposed. Unlike the conventional voltage angle control method, which is applied only in the flux-weakening region, the proposed voltage angle control can be implemented in all operation ranges from low to high speed. The proposed method is verified by experiments using a DSC controller for 800 W IPMSM.

• 한국항행학회논문지
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• 제28권2호
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• pp.250-253
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• 2024

This paper proposes a low-power waveform for a long-range air-to-air data link. In the case of an air-to-air data link, data communication is performed in the air and high Doppler shift may occur depending on the flight speed, so a waveform based on the non-coherent method is suitable. In addition, since it is mounted on an aircraft, it must have low power characteristics. This paper proposes a waveform that combines a modulation technique based on frequency modulation and pulse position modulation that can turn on/off the transmission signal. As a result of the performance analysis, it was shown that the performance was suitable for air-to-air operation while showing low power characteristics.