• 제어로봇시스템학회논문지
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• 제15권3호
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• pp.258-264
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• 2009

This paper presents two control algorithms for the frequency and amplitude of the resonator of a micro sensor. One algorithm excites the resonator at its a priori unknown resonant frequency, and the other algorithm alters the resonator dynamics to place the resonant frequency at a fixed frequency, chosen by the designer. Both algorithms maintain a specified amplitude of oscillations. The control system behavior is analyzed using an averaging method, and a quantitative criterion is provided for the selecting the control gain to achieve stability. Tracking and estimation accuracy of the natural frequency under the presence of measurement noise is also analyzed. The proposed control algorithms are applied to the MEMS dual-mass gyroscope without mechanical connecting beam between two proof-masses. Simulation results show the effectiveness of the proposed control algorithms which guarantee the proof-masses of the gyroscope to move in opposite directions with the same resonant frequency and oscillation amplitude.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.249-256
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• 2007

This paper presents a new circuit topology and its digital control scheme for a half-bridge resonant inverter. As the proposed half-bridge inverter can be operated in load-freewheeling modes, the pulse-width modulation (PWM) method can be used for the output power control. The proposed half-bridge inverter is based on the resonant frequency-tracking algorithm with the goal of maintaining the unity of the output displacement factor of the load impedance even in varying conditions. In this paper, the operation principle, electrical characteristics, and detailed digital control scheme of the proposed half-bridge resonant inverter are described. The experimental results of the prototype experimental setup to verify the validity of the proposed half-bridge inverter are presented and discussed.

• 전자공학회논문지SC
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• 제42권3호
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• pp.71-80
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• 2005

본 논문에서는 새로운 하프브리지 공진형 인버터 토폴로지와 디지털 제어회로를 제안하였다. 제안된 인버터는 부하환류 모드를 제공함으로써 펄스폭 변조방식을 통해 출력을 제어할 수 있다. 따라서 부하측 고유 공진주파수를 추종하는 PWM 제어가 적용될 경우, 부하측 임피던스가 변화하는 조건하에서도 인버터 출력단의 변위율을 항상 1로 유지할 수 있다. 본 논문에서는 제안된 하프브리지 공진형 인버터의 동작원리와 전기적 특성 및 통상의 하프브리지 인버터와 비교한 손실해석에 대하여 고찰하였고, 제안된 알고리즘을 구현하기 위한 디지털 제어회로를 제시하였다. 또한 제안된 인버터의 유효성을 확인하기 위한 실험을 통해서 얻은 결과를 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.153-156
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• 2004

This paper presents a new circuit topology of the half-bridge resonant inverter. As the proposed half-bridge inverter can be operated in the load freewheeling modes, pulse width modulation (PWM) control method can be used for the output power control. The proposed half-bridge inverter should keep unity output displacement factor under the load-impedance varying conditions, if a new PWM control scheme based on the resonant frequency tracking algorithm is adopted. In this paper, electrical characteristics, and losses analysis of the proposed half-bridge resonant inverter are described. Simulation and experimental results of the prototype experimental setup to verify the validity of the proposed half-bridge resonant inverter are presented and discussed.

• Journal of Power Electronics
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• 제17권5호
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• pp.1150-1159
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• 2017

Flexibility in the power control of ultrasonic transducers has remained a challenge for cleaning applications. This paper introduces a modification of the existing piezoelectric ceramic transducer (PCT) circuit to increase the range of operation through its impedance characteristics. The output power is controlled using the asymmetrical voltage-cancellation (AVC) method. Together with a phase-locked loop control, the switching frequency of the inverter is automatically adjusted to maintain a lagging phase angle under load-parameter variations during the cleaning process. With the proposed modification, the region of the zero-voltage switching (ZVS) operation is extended, which results in a wider range of output power control. A hardware prototype is constructed and the control algorithm is implemented using an STM32F4 microcontroller. Simulation and experimental results are provided to verify the proposed method for a 50-W PCT. The operating frequency and output power ranges under study are 37 - 41 kHz and 15.8 - 50 W, respectively.

• 전력전자학회논문지
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• 제5권2호
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• pp.192-199
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• 2000

본 논문은 고주파 유도 가열기의 전력조절을 위해 뉴로-퍼지 알고리즘을 이용하고, IGBT를 사용한 위상 전이 펄스변조(PSPM)와 주파수 추종 펄스변조(FEPM) 가 조절되는 공진 고주파 인버터를 응용한 유도가열기를 설명한다. 이는 실제로 산업 현장에서 20KHz~500KHz 유도 가열 및 유도 용해 전원장치용으로 쓰인다. 위상 전이 펄스변조 (PSPM) 정전력 조절 기술을 바탕으로 한 적응 주파수 추종기법은 스위칭 손실을 최소화하고 전력조절을 용이하게 하기 위해 소개되어졌다. 뉴로-퍼지제어기를 사용하여 만들어진 실험장치는 성공적인 논증과 토의가 되어졌다.

• Smart Structures and Systems
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• 제13권2호
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• pp.177-201
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• 2014

With the increased size and flexibility of the tower and blades, structural vibrations are becoming a limiting factor towards the design of even larger and more powerful wind turbines. Research into the use of vibration mitigation devices in the turbine tower has been carried out but the use of dampers in the blades has yet to be investigated in detail. Mitigating vibrations will increase the design life and hence economic viability of the turbine blades and allow for continual operation with decreased downtime. The aim of this paper is to investigate the effectiveness of Semi-Active Tuned Mass Dampers (STMDs) in reducing the edgewise vibrations in the turbine blades. A frequency tracking algorithm based on the Short Time Fourier Transform (STFT) technique is used to tune the damper. A theoretical model has been developed to capture the dynamic behaviour of the blades including the coupling with the tower to accurately model the dynamics of the entire turbine structure. The resulting model consists of time dependent equations of motion and negative damping terms due to the coupling present in the system. The performances of the STMDs based vibration controller have been tested under different loading and operating conditions. Numerical analysis has shown that variation in certain parameters of the system, along with the time varying nature of the system matrices has led to the need for STMDs to allow for real-time tuning to the resonant frequencies of the system.