Browsing by Author "Chao, Paul C. P."

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A Hula-Hoop Energy-Harvesting System
(2011-10-01)
Lu, C. H.
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Wang, Y. J.
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Sung, C. K.
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Chao, Paul C. P.
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影像與生醫光電研究所
This paper proposes a hula-hoop energy-harvesting system that integrates a hula-hoop motion transformer with an electromagnetic generator. The hula-hoop motion transformer converts the linear motion from environment, machinery, or even human body into rotational one under specifically designed dynamic conditions. Then, the system can generate power through electromagnetism after combining the electromagnetic generator with the rotational motion. The equations prescribing the relation between induced voltage and power for the system are derived according to Faraday's theory. Meanwhile, the physical model of energy-harvesting system is established and the governing dynamic equations are derived as well via the Lagrange's equations. Good agreement of induced voltage and power between theoretical and experimental results is obtained. The maximum power that the system can generate is approximately 5 mW when the frequency and amplitude of the external excitation are 8 Hz and 11.2 N, respectively.
A new single inductor bipolar multi-output (SIBMO) DC-DC converter driven by constant on-time with improved performance
(2016-06-01)
Chao, Paul C. P.
;
Chang, Chun-Kai
;
Cheng, Chun-Kai
;
Trong-Hieu Tran
;
Sauter, Thilo
This study is dedicated to design and realization of a new single inductor bipolar multi-output (SIBMO) DC-DC converter with performance improvement. A bandgap is first designed to offer a stable input bias with capability to work against inevitable input voltage variations for avoiding possible p-n breakdowns. A new drive technique based on constant on-time (COT) is developed for the designed SIBMO with assistance from level shifters and zero current detection circuits to drive MOS devices. The designed circuit is capable of boosting input voltage 2.8 V to four bipolar outputs of +6, -6, +12 and -12 V. The COT proposed herein adopts a new technique of time multiplexing to offer stable multi-outputs with an off-chip inductor for fast switchings. This new COT is different from the conventional pulse width modulation which usually operates with fixed frequencies. The COT is particularly favorable in regards of crossing regulation and high transfer efficiency in cases of unbalanced loads. The proposed SIBMO and COT are applicable to drive systems of organic light-emitting diodes, optical sensors, and portable electronic devices, displays, etc. The designed on-chip SIBMO and COT are fabricated via the TSMC 0.25 A mu m high-voltage CMOS process. Experimental results clearly show the capability of the designed SIBMO chip to offer four bipolar, stabilized output voltages with a total power consumption minimized to 320 mW and the switching frequency varying from 650 to 500 kHz. Most importantly, the maximum efficiency reaches 83.1 %.
A new single inductor bipolar multi-output (SIBMO) DC-DC converter driven by constant on-time with improved performance
(2016-06)
Chao, Paul C. P.
;
Chang, Chun-Kai
;
Cheng, Chun-Kai
;
Trong-Hieu Tran
;
Sauter, Thilo
This study is dedicated to design and realization of a new single inductor bipolar multi-output (SIBMO) DC-DC converter with performance improvement. A bandgap is first designed to offer a stable input bias with capability to work against inevitable input voltage variations for avoiding possible p-n breakdowns. A new drive technique based on constant on-time (COT) is developed for the designed SIBMO with assistance from level shifters and zero current detection circuits to drive MOS devices. The designed circuit is capable of boosting input voltage 2.8 V to four bipolar outputs of +6, -6, +12 and -12 V. The COT proposed herein adopts a new technique of time multiplexing to offer stable multi-outputs with an off-chip inductor for fast switchings. This new COT is different from the conventional pulse width modulation which usually operates with fixed frequencies. The COT is particularly favorable in regards of crossing regulation and high transfer efficiency in cases of unbalanced loads. The proposed SIBMO and COT are applicable to drive systems of organic light-emitting diodes, optical sensors, and portable electronic devices, displays, etc. The designed on-chip SIBMO and COT are fabricated via the TSMC 0.25 A mu m high-voltage CMOS process. Experimental results clearly show the capability of the designed SIBMO chip to offer four bipolar, stabilized output voltages with a total power consumption minimized to 320 mW and the switching frequency varying from 650 to 500 kHz. Most importantly, the maximum efficiency reaches 83.1 %.
Dorsolateral subthalamic neuronal activity enhanced by median nerve stimulation characterizes Parkinson\'s disease during deep brain stimulation with general anesthesia
(2015-12-01)
Tsai, Sheng-Tzung
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Chuang, Wei-Yi
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Kuo, Chung-Chih
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Chao, Paul C. P.
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Chen, Tsung-Ying
OBJECT Deep brain stimulation (DBS) surgery under general anesthesia is an alternative option for patients with Parkinson\'s-disease (PD). However, few studies are available that report whether neuronal firing can be accurately recorded during this condition. In this study the authors attempted to characterize the neuronal activity of the subthalamic nucleus (STN) and elucidate the influence of general anesthetics on neurons during DBS surgery in patients with PD. The benefit of median nerve stimulation (MNS) for localization of the dorsolateral subterritory of the STN, which is involved in sensorimotor function, was explored. METHODS Eight patients with PD were anesthetized with desflurane and underwent contralateral MNS at the wrist during microelectrode recording of the STN. The authors analyzed the spiking patterns and power spectral density (PSD) of the background activity along each penetration track and determined the spatial correlation to the target location, estimated using standard neurophysiological procedures. RESULTS The dorsolateral STN spiking pattern showed a more prominent bursting pattern without MNS and more oscillation with MNS. In terms of the neural oscillation of the background activity, beta-band oscillation dominated within the sensorimotor STN and showed significantly more PSD during MNS (rho < 0.05). CONCLUSIONS Neuronal firing within the STN could be accurately identified and differentiated when patients with PD received general anesthetics. Median nerve stimulation can enhance the neural activity in beta-band oscillations, which can be used as an index to ensure optimal electrode placement via successfully tracked dorsolateral STN topography.
Dynamic Analysis of a Motion Transformer Mimicking a Hula Hoop
(2011-02-01)
Lu, C. X.
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Wang, C. C.
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Sung, C. K.
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Chao, Paul C. P.
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電機工程學系
Hula-hoop motion refers to the spinning of a ring around a human body; it is made possible by the interactive force between the moving ring and the body. Inspired by the generic concept of hula-hoop motion, this study proposes a novel motion transformer design that consists of a main mass sprung in one translational direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the center of the main mass. It is expected that the transformer is capable of transforming linear reciprocating motion into rotational motion. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A thorough dynamic analysis of the proposed transformer system is conducted in this study in order to characterize the relationships between the varied system parameters and the chance of hula-hoop motion occurrence. The governing equations are first derived with Lagrange's method, which is followed by the search for steady-state solutions and the corresponding stability analysis via the homotopy perturbation method and the Floquet theory. Direct numerical simulation is simultaneously performed to verify the correctness of the approximate analysis. In this manner, the feasibility of the proposed design and the occurrence criteria of hula-hoop motion are assessed. [DOI: 10.1115/1.4001839]
Friction effect on ball positioning of an automatic balancer in optical disk drives
(2012-09-01)
Chan, T. C.
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Sung, C. K.
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Chao, Paul C. P.
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影像與生醫光電研究所
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電機工程學系
This study was aimed at evaluating the perfect balancing position of an automatic ball balancer installed in optical disk drives taking into consideration the effects of the rolling friction, speed ratio, and scaling parameter on ball positioning. A mathematical model that is employed to derive the dynamic equations of the ABB system was constructed. Stability of the steady-state solutions was then analyzed. A numerical simulation and an experimental study were conducted to verify the mathematical model. The simulation and experimental results were in good agreement.
Non-linear suspension of an automatic ball balancer
(2011-03-01)
Chan, T. C.
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Sung, C. K.
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Chao, Paul C. P.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This study investigates the effects on ball positioning because of the non-linear suspensions of an automatic ball balancer (ABB) installed in a rotor system. A complete dynamic model of the ABB, focusing on the non-linearity of the suspensions, is presented. The elastic behaviour of these suspensions is assumed to be well characterised by equivalent non-linear springs. Herein, two Duffing-type non-linear springs are considered: stiffness-softening and stiffness-hardening. Four types of asymptotic solutions that represent the ball positions at steady state are obtained by employing the method of multiple scales. The stabilities of all four types of solutions were found using Floquet theory. In contrast to the perfectly balanced solutions (Type I), the other solution (Type II) is affected by non-linear stiffness suspension. After properly designing the avoidable level of non-linearity, the balancing balls of the ABB still resided at the positions required to reduce the expected vibrations in the steady state. Numerical simulations were performed to validate the theoretical results. The results were also used to predict the level of residual vibration, and design guidelines that would guarantee the desired performance of the ABB for high-precision applications were formulated. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.