• Journal of Power Electronics
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• v.13 no.6
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• pp.928-938
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• 2013

This paper proposes a novel control method for a multi-output switched-resonant converter. Output voltage can be regulated against variations in the supply voltage and load by controlling the voltage of the resonant capacitor (pulse amplitude control). Precise control is possible when pulse amplitude control is combined with pulse number control. The converter is analyzed, and design considerations are explained by using examples. Control implementation is described and load regulation and ripples are analyzed by simulation and hardware results. The topology is modified to obtain an additional negative output without any additional hardware other than a diode. The analysis of such a triple output converter with two positive outputs and one negative output is conducted and confirmed. The topology and control scheme are scalable to any number of outputs.

• Steel and Composite Structures
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• v.27 no.1
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• pp.89-94
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• 2018

Uniaxial ratcheting behavior of Z2CND18.12N austenitic stainless steel used nuclear power plant piping material was studied. The results indicated that ratcheting strain increased with increasing of stress amplitude under the same mean stress and different stress amplitude, ratcheting strain increased with increasing of mean stress under the same stress amplitude and different mean stress. Based on least square method, a suitable method to arrest ratcheting by loading the materials was proposed, namely determined method of zero ratcheting strain rate. Zero ratcheting strain rate occur under specified mean stress and stress amplitudes. Moreover, three dimensional ratcheting boundary surface graph was established with stress amplitude, mean stress and ratcheting strain rate. This represents a graphical surface zone to study the ratcheting strain rates for various mean stress and stress amplitude combinations. The graph showed the ratcheting behavior under various combinations of mean and amplitude stresses. The graph was also expressed with the help of experimental results of certain sets of mean and stress amplitude conditions. Further, experimentation cost and time can be saved.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.54-57
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• 1998

This paper describes a digital implementation of a pulse amplitude modulation(PAM) method for a unity-power-factor buck-booster converter. A digital controller is designed and implemented by a Digital Signal Processor(DSP) to replace the analog control circuit for PAM. Experimental results are presented and compared with simulations.

• International Neurourology Journal
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• v.22 no.4
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• pp.268-274
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• 2018

Purpose: To describe a technique for urodynamic diagnosis of detrusor sphincter dyssynergia (DSD) using urethral pressure measurements and examine potential associations between urethral pressure and bladder physiology among patients with DSD. Methods: Multiple sclerosis (MS) and spinal cord injured (SCI) patients with known DSD diagnosed on videourodynamics (via electromyography or voiding cystourethrography) were retrospectively identified. Data from SCI and MS patients with detrusor overactivity (DO) without DSD were abstracted as control group. Urodynamics tracings were reviewed and urethral pressure DSD was defined based on comparison of DSD and control groups. Results: Seventy-two patients with DSD were identified. Sixty-two (86%) had >20 cm $H_2O$ urethral pressure amplitude during detrusor contraction. By comparison, 5 of 23 (22%) of control group had amplitude of >20 cm $H_2O$ during episode of DO. Mean duration of urethral pressure DSD episode was 66 seconds (range, 10-500 seconds) and mean urethral pressure amplitude was 73 cm $H_2O$ (range, 1-256 cm $H_2O$). Longer (>30 seconds) DSD episodes were significantly associated with male sex (81% vs. 50%, P=0.013) and higher bladder capacity (389 mL vs. 219 mL, P=0.0004). Urethral pressure amplitude measurements during DSD were not associated with significant urodynamic variables or neurologic pathology. Conclusions: Urethral pressure amplitude of >20 cm $H_2O$ during detrusor contraction occurred in 86% of patients with known DSD. Longer DSD episodes were associated with larger bladder capacity. Further studies exploring the relationship between urethral pressure measurements and bladder physiology could phenotype DSD as a measurable variable rather than a categorical observation.

• Journal of Power Electronics
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• v.12 no.1
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• pp.193-200
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• 2012

Previous publications regarding the design and specifications of the interface inductor and the DC side capacitor for a STATCOM usually deal with the interface inductor and the DC side capacitor only. They seldom pay attention to the influences of the interface inductor and capacitor on the performance of a STATCOM system. In this paper a detailed analysis of influence of the interface inductor and the DC side capacitor on a STATCOM system and the corresponding design considerations is presented. Phase and amplitude control is considered as the control strategy for the STATCOM. First, a model of a STATCOM system is carried out. Second, through frequency domain methods, such as transfer functions and Bode plots, the influence of the interface inductor and the DC side capacitor on the stability and filtering characteristics of the STATCOM are extensively investigated. Third, according to this analysis, the design considerations based on the phase margin for the interface inductor and the DC side capacitor are discussed, which leads to parameters that are different from those of the traditional design.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.363-366
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• 2007

A new current control technique called Amplitude Shift Modulation (ASM) for cold cathode fluorescent lamps (CCFL) has been developed. This new technique sets and continuously controls the current of each individual CCFL in an LCD backlight lamp array.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.9-12
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• 2001

An active control of the vibration transmitted by longitudinal load in flight control system is investigated numerically. The flight control system is modeled as a finite, thin shell cylinder with constant thickness. A vibration source is generated by exterior monopole source. Distributed piezoelectric actuator is used to control of the vibration. Thin shell theory is used to formulate the numerical models. The amplitude of vibration at discrete location and power transmission are minimized by analytical optimization method. Genetic algorithm is used as numerical optimization method to search optimal actuator position and size which amplitude of vibration is minimized.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.1950-1959
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• 2001

An active control of the vibration transmitted by longitudinal load in flight control system is investigated numerically. The flight control system is modeled as a finite, thin shell cylinder with constant thickness. A vibration source is generated by exterior monopole source. Distributed piezoelectric actuator is used to control of the vibration. Thin shell theory is used to formulate the numerical models. The amplitude of vibration at discrete location and power transmission are minimized by analytical optimization method. Genetic algorithm is used as numerical optimization method to search optimal actuator position and size which amplitude of vibration is minimized.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1189-1191
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• 1999

This paper deals with the real and reactive power control of BESS(Battery Energy H Storage System) interconnected to power system. The real and reactive power control of proposed customer side BESS are performed by controlling the amplitude and the phase of inverter output voltage via power flow equation. Also in order to control the amplitude and phase of output voltage of proposed BESS, single-pulse width control method is used. The BESS and controller is implemented and the active and reactive power control is simulated by using the PSCAD/EMTDC simulation program.

• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.61-69
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• 2002

In the actual control systems, there exist many kinds of restrictions or nonlinearities. However, due to the nonlinearities in actuators and sensors, the designed controller may not be applicable in some practical situations. One such nonlinearity is amplitude saturation in actuators. Although sometimes it may be ignored, in other cases failure to consider actuator saturation may severely degrade closed-loop system performance and even lead to instability. On the other hand, limiting the controller gain to avoid saturation sacrifices control effort and may lead to loss of performance. Consequently, in some cases, the actuator saturation must be explicitly taken into account to ensure desired performance. However, in this paper, an anti-windup control system design method is introduced to suppress the windup due to the amplitude saturation of the actuator. The proposed control system has very simple design process and guarantees the good control performance. The validity of the proposed control system will be shown by comparing with the results of a reported paper.