• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.5-8
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• 1988

A digital simulation method for Hysteresis motor using Preisach model is proposed. From this, the instantaneous torque, hysteresis loss of rotor can be calculated, considering slot and winding distribution and current harmonics.

• 전자공학회논문지A
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• 제31A권9호
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• pp.10-17
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• 1994

In this paper, a priority schedling and a flow control algorithm with hysteresis effect are proposed for high-speed networks. A mathematical model for the flow control is proposed and a cell transition probability from this model is found. And the performance of the proposed algorithm is analyzed by a computer simulation. According to the simulation results, it can be shown that the priority scheduling and the flow control with hysteresis effect get the cell loss probability 0.061 better and the average delay 100ms better and the average delay 100ms beter than those of single threshold.

• Smart Structures and Systems
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• 제9권4호
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• pp.373-392
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• 2012

Tracking control of systems with variable stiffness hysteresis using a gain-scheduled (GS) controller is developed in this paper. Variable stiffness hysteretic system is represented as quasi linear parameter dependent system with known bounds on parameters. Assuming that the parameters can be measured or estimated in real-time, a GS controller that ensures the performance and the stability of the closed-loop system over the entire range of parameter variation is designed. The proposed method is implemented on a spring-mass system which consists of a semi-active independently variable stiffness (SAIVS) device that exhibits hysteresis and precisely controllable stiffness change in real-time. The SAIVS system with variable stiffness hysteresis is represented as quasi linear parameter varying (LPV) system with two parameters: linear time-varying stiffness (parameter with slow variation rate) and stiffness of the friction-hysteresis (parameter with high variation rate). The proposed LPV-GS controller can accommodate both slow and fast varying parameter, which was not possible with the controllers proposed in the prior studies. Effectiveness of the proposed controller is demonstrated by comparing the results with a fixed robust $\mathcal{H}_{\infty}$ controller that assumes the parameter variation as an uncertainty. Superior performance of the LPV-GS over the robust $\mathcal{H}_{\infty}$ controller is demonstrated for varying stiffness hysteresis of SAIVS device and for different ranges of tracking displacements. The LPV-GS controller is capable of adapting to any parameter changes whereas the $\mathcal{H}_{\infty}$ controller is effective only when the system parameters are in the vicinity of the nominal plant parameters for which the controller is designed. The robust $\mathcal{H}_{\infty}$ controller becomes unstable under large parameter variations but the LPV-GS will ensure stability and guarantee the desired closed-loop performance.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.78-90
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• 2017

This paper presents the design of closed loop controllers operating a single-phase AC-DC three-level converter for improving power quality at AC mains. Closed loop inhibits outer voltage controller and inner current controller. Simulations of three level converter with three different voltage and current controller combinations such as PI-Hysteresis, Fuzzy-Hysteresis and Fuzzy tuned PI-Hysteresis are carried out in MATLAB/Simulink. Performance parameters such as input power factor and source current total harmonic distortion (THD) are considered for comparison of the three controller combinations. The fuzzy-tuned PI voltage controller with hysteresis current controller combination provides a better result, with a source-current THD of 0.93% and unity power factor without any source side filter for the three level converter. For load variations of 25% to 100%, a THD of less than 5% is obtained with a maximum value of only 1.67%. Finally, the fuzzy-tuned PI voltage with hysteresis controller combination is implemented in a Xilinx Spartan-6 XC6SLX25 FPGA board for experimental validation of power quality enhancement. A prototype 100 W, 0-24-48 V as output converter is considered for the testing of controller performance. A source-current THD of 1.351% is obtained in the experimental study with a power factor near unity. For load variations of 25% to 100%, the THD is found to be less than 5%, with a maximum value of only 2.698% in the experimental setup which matches with the simulation results.

• 한국자동차공학회논문집
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• 제25권1호
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• pp.66-73
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• 2017

In this work, graphene platelets were introduced into wax in an automotive electronic controlled thermostat for the purpose of enhancing its thermal-conductive property and improving response performance. Graphene content ranging from 10 % to 20% was added into and mixed with the wax to investigate the effect of graphene amounts on the performance of an automotive electronic controlled thermostat in terms of response time, hysteresis and melting temperature. The experimental results revealed that graphene in wax contributed to a reduction in the response time and hysteresis of an automotive electronic controlled thermostat. As a consequence, important improvement in thermal sensitivity, full lift, melting temperature and hysteresis were obtained. The thermal response of wax with graphene content of 20 % was improved by 25 %, as compared to that of wax with Cu content of 20 %. Hysteresis of wax with graphene was reduced by $0.6^{\circ}C$ as compared to that of wax with Cu content. The melting temperature of wax is lowered and hysteresis is also improved with increased graphene content of wax in an electronic controlled thermostat. We hope that this study can help further the transition of nano-fluid technology from small-scale research laboratories to industrial application in the automotive sector.

• 한국지능시스템학회논문지
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• 제24권2호
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• pp.193-200
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• 2014

압전 액추에이터(Piezoelectric actuator)는 빠른 응답 특성, 넓은 대역폭, 우수한 반복 정밀도, 그리고 높은 분해능의 특성으로 인하여 다양한 산업분야에서 폭넓게 사용되고 있다. 하지만, 압전 액추에이터에는 히스테리시스 효과(Hysteresis effect)가 발생되는 단점이 있으며, 이는 시스템의 성능을 저하시키는 주요한 원인으로 알려져 있다. Generalized Prandtl-Ishlinskii(GPI) model을 이용한 기존 연구에서는 히스테리시스 효과를 제거하기 위하여 히스테리시스를 수리적으로 모델링하고, 그 결과로부터 역 히스테리시스를 도출하였다. 하지만 모델링된 변수 값에 따라서는 역 히스테리시스 루프를 형성하지 못하는 치명적 문제점이 발생된다. 따라서 본 논문에서는 이러한 문제점을 해결하기 위하여 Inverse Generalized Prandtl-Ishlinskii(IGPI) model을 이용하여 역 히스테리시스를 직접 모델링하는 방법을 제안하였다. 또한 모델링 정밀도는 다양한 입력신호를 이용한 실험 결과를 기반으로 검증하였다.

• 전기학회논문지
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• 제65권4호
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• pp.586-592
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• 2016

The current control of Continuous Conduction Mode(CCM) can be implemented by several methods: peak current control; average current control; and hysteresis control. Among these methods, the hysteresis current control is popularly applied in various converter applications because of its simplicity of implementation, fast current control response and inherent peak current limiting capability. However, a current controller with conventional hysteresis band which multiplies the current reference has the disadvantage that the modulation frequency varies in one cycle of the input voltage and, as a result, generates high switching frequency in the low input voltage section. Also it is complicated to design the input filter due to varying switching frequency. This paper proposed an optimum hysteresis-band current control method where the band is generated by using both multiplication method and sum method to maintain the modulation frequency to be nearly constant. This approach can solve the high switching frequency in the low input voltage section, and achieve easy design of input filter. The performance of the proposed converter is verified with the simulation and the experimental works.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.812-815
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• 2003

Most of all, DTC drive is very simple in its implementation because it needs only two hysteresis comparator and switching vector table for both flux and torque control. The switching strategy of a conventional direct torque control scheme which is based on hysteresis comparator results in a variable switching frequency which depends on the speed, flux, stator voltage and the hysteresis of the comparator. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple and inverter switching frequency. In this paper the influence of the amplitudes of flux and torque hysteresis bands and sampling time of control program on the torque and flux ripples are investigated. Simulation results confirm the superiority of the DTC under the proposed method over the conventional DTC.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.609-611
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• 2017

최근 다양한 산업 및 공학 응용분야에서 히스테리시스 현상이 자주 발생하며, 이에 대한 많은 관심과 연구가 수행되었다. 이러한 현상은 주로 압력비가 일시적으로 변화하는 과정에서 발생되며, 초음속 풍동 시동과정에 영향을 미칠 것으로 예상되나, 이에 대한 연구가 미미한 실정이다. 본 연구에서는 초음속 풍동 내부에서 발생하는 히스테리시스 현상을 수치해석으로 조사하였다. 비정상, 축대칭, 압축성 Navier-Stokes 방정식을 유한 체적법으로 이산화 하였으며, Spalart-Allmaras 난류모델을 적용하였다. 본 연구의 결과로 초음속 풍동 시동과정에서 시동압력비와 작동압력비가 다른 원인을 히스테리시스 현상으로 설명하였다.

• 설비공학논문집
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• 제14권11호
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• pp.948-953
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• 2002

The electronic expansion valve (EEV) may be used to control the refrigerant flow rate for the multi-type heat pump. Stepping motor driven EEV may precisely control the refrigerant flow rate to meet each internal load requirement. To control the EEV, PI algorithm may be used. But the hysteresis of EEV deteriorates the performance of superheat control. To reduce the performance degradation, the PI algorithm along with the dither signal may be used. The dither signal, with about 10 times higher frequency than the system crossover frequency and about 10 times larger magnitude than the deadband of hysteresis, was selected for the superheat control of EEV. Experimental results showed the improvement of EEV control by adding the dither signal to the PI algorithm.