• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1223-1231
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• 2018

The direct torque control (DTC) scheme features a simple structure thanks to stator flux-oriented control. It has the advantage of robustness against motor parameters variation since only the stator resistance is involved in the control scheme. On the other hand, the disadvantage of DTC is large torque ripple. To reduce the torque ripple, many studies on DTC-space vector modulation (DTC-SVM) schemes, which modulate the duty ratio with a fixed switching cycle, have been proposed. However, there is the difficulty in obtaining the duty ratio for DTC-SVM. Hence, this paper proposes a new duty ratio selection and stator flux calculation methods for reducing torque ripple. Simulations and experiments were carried out to determine the validity of the proposed method. The proposed scheme has simplified the duty ratio command and achieved the same control performance as the conventional duty ratio modulation method without using the information of motor parameters.

• 한국소프트웨어감정평가학회 논문지
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• 제15권1호
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• pp.103-107
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• 2019

최근 저전력 고속 디지털 데이터 통신을 구현 하기위해 많은 기술들이 개발되고 있는 추세이며 듀티사이클 보정에 관련된 기술도 그중 하나이다. 본 논문에서는 전압제어 링 발전기용 저-면적 듀티사이클 보정 회로를 제안하였다. 듀티사이클 보정 회로는 전압제어 링 발진기의 180도 위상차이를 이용하여 듀티사이클을 보정하는 회로이며, 제안된 저-면적 듀티사이클 회로는 기존의 플립플롭을 TSPC(True Single Phase Clocking) 플립플롭으로 변경하여 회로를 구성하였고 이로 인하여 저-면적 고성능 회로를 구현하였다. 일반적인 플립플롭을 대신하여 TSPC플립플롭을 사용하여 기존 회로 대비 저-면적으로 회로 구현이 가능하며 고속 동작에 용이하여 저-전력용 고성능 회로에 활용될 것으로 기대된다.

• 한국전자통신학회논문지
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• 제11권1호
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• pp.9-16
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• 2016

IEEE 802.15.4 LR-WPAN에서 대부분의 디바이스는 배터리에 의존해 동작하기 때문에 효율적인 에너지 소비기능을 갖추도록 설계되어야 한다. 본 논문은 LR-WPAN에서 에너지 절약을 위한 두 개의 알고리즘, DDC(Dynamic Duty Cycle)와 DBT(: Dynamic Beacon Tracking)를 제안한다. DDC 알고리즘은 채널 상태에 따라 듀티 사이클을 동적으로 조정한다. DBT 알고리즘은 트래픽 조건에 따라 비콘 트래킹 모드를 적응적으로 제어한다. 또한, DDC와 DBT 알고리즘을 결합함으로써 프레임 전달률과 평균 지연 시간을 만족할 만한 수준으로 유지하면서 광범위한 입력 부하에 대해 효과적으로 에너지를 절약할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1849-1876
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• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.3-3
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• 2000

Limit cycle analysis of attitude control system using gas jet thrusters is performed. Schmitt-Trigger and PD control laws are applied and solenoid valve time delay is considered. Phase plane method is used for calculation of characteristics of limit cycle. Important characteristics of resultant limit cycle such as frequency, amplitude, maximum rate, and duty ratio could be expressed analytically by proposed method.

• 전기의세계
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• 제28권9호
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• pp.51-59
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• 1979

The forming and design method of D.C thyristor chopper circuit for DC Series motor control is suggested, ard the computation method of thyristor commutaing element's, value which makes it all the more important, is possible. Also the trigger circuit was dealt with. In this paper, in order to control the duty cycle, the duty time is kept on constancy and variable chopping frequency was adopted. By above mentioned circuit design method, the D.C thyristor chopper circuit was implemented and tested. In this circuit, the result of D.C motor control was good and reliable. The relation between the $K_{d}$ and the ratio of input-output current, or the characteristic of speed was varied lineary at the range 0.1 ~ 0.9 of duty cycle. This confirms the fact that D.C to D.C power conversion which is the merit of chopper control is operated most likely a transformer.ormer.

• 센서학회지
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• 제25권1호
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• pp.65-70
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• 2016

We devised a method to control the temperature of a liquid bath as low as $-100^{\circ}C$ using the duty cycle control of a solenoid valve. The solenoid valve controls the flow of liquid nitrogen that we used as a cryogen in this system. By controlling the duty cycle of a solenoid valve using feedback from the measured temperature of the liquid bath, we were able to achieve temperature stability within ${\pm}19mK$ around $-100^{\circ}C$. We also demonstrated that by taking average values of the temperature readings for sequence of measurements from more than one thermometer, it is possible to use this system for the calibration of thermometers within 3 mK. This system and the control method can be used for the precise temperature control in the range between $0^{\circ}C$ and $-100^{\circ}C$, where commercially available precision baths are much expensive and hard to be built in customized configurations.

• Journal of Power Electronics
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• 제17권2호
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• pp.334-345
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• 2017

In order to meet the increasing needs of the hybrid energy source system for electric vehicles, which demand bidirectional power flow capability with a wide-voltage-conversion range, a bidirectional three-level DC-DC converter and some control strategies for hybrid energy source electric vehicles are proposed. The proposed topology is synthesized from Buck and Boost three-level DC-DC topologies with a high voltage-gain and non-extreme duty cycles, and the bidirectional operation principle is analyzed. In addition, the inductor current ripple can be effectively reduced within the permitted duty cycle range by the coordinated control between the current fluctuation reduction and the non-extreme duty cycles. Furthermore, benefitting from duty cycle disturbance control, series-connected capacitor voltages can also be well balanced, even with the discrepant rise and fall time of power switches and the somewhat unequal capacitances of series-connected capacitors. Finally, experiment results of the bidirectional operations are given to verify the validity and feasibility of the proposed converter and control strategies. It is shown to be suitable for hybrid energy source electric vehicles.

• 대한전자공학회논문지SD
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• 제46권10호
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• pp.9-15
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• 2009

본 논문에서는 고속 ATC(Automatic Threshold Control) 회로 구조를 고안하고 이를 이용하여 고속 ATC 기능을 갖는 버스트 모드 제한증폭기를 설계하였고, $0.8{\mu}m$ SiGe BiCMOS 상용 파운드리 기술을 이용하여 제작하였다. 제작된 버스트 모드 제한증폭기는 $PRBS=2^7-1$에서 무에러(error free)의 아이를 보였고, 160ps이내의 지터 특성과 95ps이내의 상승/하강시간을 보였다. ATC특성 측정결과 버스트 데이터의 신호의 초기부터 안정되게 파형을 잘 잡아낼 정도로 빠른 ATC동작이 이루어지고 있어 고안한 ATC회로의 고속특성을 확인할 수 있었다. 그러나 버스트 초기에서 듀티사이클 왜곡이 발생했고, 입력 신호의 크기가 커짐에 따라 듀티사이클이 59%까지 증가하는 특성을 보였다. 그러나 10 사이클이 지난 후에는 모든 입력 신호의 크기에 대해 듀티사이클이 52% 이내로 안정화되고 있음을 확인하였다

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.470-475
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• 2002

Instantaneous following PWM control technique is pulsed nonlinear dynamic control method. This new control technique using analog integrator is proposed to control the duty ratio D of do-dc converter. In this control method, the duty ratio of a switch is exactly equal In or proportional to the control reference in the steady state or in a transient. Proposed control method compensates power source perturbation in one switching cycle, and the average value of the dynamic reference in one switching cycle. There is no steady state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with buck converter have demonstrated the robustness of the control method and verified theoretical prediction. The control method is very general and applicable to all type PWM