Browsing by Author "Cheng, Stone"

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A Novel Seesaw Swivel Actuator Design and Fabrication
(2010-07-01)
Chou, Po-Chien
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Lin, Yu-Cheng
;
Cheng, Stone
;
機械工程學系
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Department of Mechanical Engineering
Many small form factor optical pickup heads based on the swing arm design utilize piezoelectricity or slim plate of metal to perform focusing action. The seesaw type actuator is a new driving mechanism used for swiveling the entire optical pickup heads devices. The configuration of the seesaw swivel actuator has unique features including a rotary actuator for coarse and fine tracking and a seesaw arm for swiveling along a pivot instead of a hinge to permit a tilt focus movement. In this paper, a biaxial voice coil motor (VCM) combining the swing type tracking VCM and seesaw type focusing VCM in the rear of the swing arm is proposed. This seesaw swing arm actuator is fabricated and evaluated in dynamic experiments. The performance of the biaxial VCM is verified through simulation by finite-element methods, and the effectiveness is confirmed by experimental procedures and parametric design optimization.
Adaptive on-line parameters identification of nonlinear behavior in vector-controlled permanent magnet synchronous motors
(2017-01-01)
Ting, Chia-Min
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Chou, Hsin-Hung
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Cheng, Stone
;
機械工程學系
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Department of Mechanical Engineering
This paper addresses the problem of nonlinear dynamic of system parameters to specify the design of adaptive parameters identification algorithm with respect to a globally converged feedback control of permanent magnet synchronous motor drives. In this paper, synchronization of separated physical and analytical system of similar dynamic structures is proposed for solving online parameter estimation for nonlinear permanent magnet synchronous motors (PMSM) models. The Lyapunov function analysis is used to assure the convergence of the proposed system performance. Simulations are presented and discussed to validate the proposed identification method. The results demonstrate that the proposed method can achieve more accurate parameter identification.
Adaptive ZPETC Method for Dual-Stage Actuator Controller Design In Miniaturized Optical Disc Drive
(2008)
Cheng, Stone
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Chou, Po-Chien
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機械工程學系
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Department of Mechanical Engineering
A swing-arm/PZT dual-stage actuator is designed to provide high performance solution to realize precise tracking and focusing operation of miniaturized optical disc drive (mini-ODD). Because of its dual-stage mechanical characteristics can perform the focusing action smoother and more precise for better fault and error tolerance, the servo system to control such a dual-stage system tends to be more effective than a conventional single-stage ODD system. However, it is not enough to restrain the unwanted outside disturbance. Therefore, the zero phase error tracking controller (ZPETC), as proposed by Tomizuka (1987), which is very sensitive to improve the modeling error in motion control is used for this dual-stage miniaturized actuator. This paper presents an adaptive ZPETC method in dual-stage actuator design to achieve better focusing performance.
All GaN-on-Si High Power Module Design and Performance Evaluation
(2013)
Cheng, Stone
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Wang, Chieh-An
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Chou, Po-Chien
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Chieng, Wei-Hua
;
Chang, Edward Yi
This paper presents a 270-V, 56-A GaN power module with three AlN substrates are prepared for the module. Each substrate is composed of three parallel connected GaN chips which incorporates six 2-A AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) cells. The substrate layout inside the module is designed to reduce package parasitic. The devices are wire-bonded in parallel connection to increase the power rating. The packaged GaN HEMTs exhibit the pulsed drain current of 0.435 A/mm. Both DC and pulsed current-voltage (ID-VDS) characteristics are measured for different connection and sizes of devices, at various of power densities, pulse lengths, and duty factors. The other static parameters like threshold voltage and leakage currents were extracted to show how these parameters would scale as the devices are paralleled. Performance of multiple chip GaN power module package is studied. Experimental results demonstrated the ability to parallel nine GaN HEMTs die together and to verify the current sharing during the dynamic switching to attain high-current capacities.
An Empirical Study on a Variety of Solar Panels in BIPV Power Conversion Applications
(2012)
Sung, Hsien-Chao
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Cheng, Stone
;
Huang, ChaoYang
;
Chan, Chi-Chang
;
機械工程學系
The dynamic nature of building integrated photovoltaic (BIPV) power conversion applications has given rise to the performance evaluation issues of power capacity and generation. We present an empirical study of four solar panel types including polysilicon double-sided glass light through modules; single side color polysilicon opacity glass modules; amorphous silicon thin-film modules; and stack-type mu-crystalline silicon membrane modules, which are located at four different sites of a construction. We have (1) designed BIPV experimental platform (housing) with a four-person office and a showroom, that allows us to specify and detect different kinds of solar panel structure power flows, (2) implemented four solar panel structures to explore the accuracy of PV simulation results, and (3) used the monitoring system to conduct a large-scale empirical study over the 12 months power generation of four individual power flows. Our survey shows that system performance ratio at the sloping roof is 80.60%; at the right side of the building wall is 65.49%; at the facade electric windows site is 73.62%; and at the facade awning site is 56.43%. Thus, the installation of a PV module associated with direction, azimuth, and shading are the essentially influencing factors on the power generation of photovoltaic solar panels, and those factors can be useful design parameters in order to optimize a PV system for an architectural BIPV application.
Analysis and Suppression of Torsional Vibrations for the Permanent Magnet Synchronous Motor-Load System
(2009)
Fu, Shiang Chih
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Cheng, Stone
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機械工程學系
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Department of Mechanical Engineering
In motor transition system, different components, such as coupling, gears, and shaft are having different stiffness; they may be high or low. The low stiffness component will cause torsional vibration in the system, this phenomenon results in defect of products. In this paper, how the affection the parameters of a shaft caused to torsional vibration was discussed, and an adaptive notch filter is utilized to suppress the torsional oscillation, and then improve the bandwidth of the speed control loop. The adaptive notch filter can auto-identify the vibration frequency and auto-tune the parameters of the notch filter, achieving the objective of auto-suppressing torsional oscillation.
Channel temperature measurement in hermetic packaged GaN HEMTs power switch using fast static and transient thermal methods
(2017-08-01)
Chen, Szu-Hao
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Chou, Po-Chien
;
Cheng, Stone
;
機械工程學系
;
Department of Mechanical Engineering
A GaN-based power device is a superior component for high-frequency and high-efficiency applications and especially for applications that involve megahertz power conversion. In this work, a fast process of static thermal resistance (R (th)) and transient thermal impedance (Z (th)) measurements are made and analyzed to determine the thermal characteristics of the channel temperature of a hermetically packaged GaN power device. Five temperature-sensitive parameters (TSPs) are measured at temperatures from 20 to 160 A degrees C. Measurements and statistical analyses included variations with temperature of on-resistance (R (on)), saturation drain current (I (Dsat)), drain conductance (g (d)), threshold voltage (V (th)), and knee voltage (V (knee)). The statistical analyses revealed the relationships between the heating curve parameter (R (on)) and the cooling curve parameters (V (knee), I (Dsat), g (d), and V (th)). The average thermal resistance values are extracted as follows: Maximum R (th) is 2.99 A degrees C W-1, minimum R (th) is 2.92 A degrees C W-1, and the variation among the five TSPs is < 3%. Conventional optical-based techniques such as infrared (IR) and micro-Raman thermography are destructive to packaged devices. Therefore, this study developed the two reliable and fast non-destructive methods for estimating channel temperature with the following features: (1) They elucidate static and transient characteristics; (2) they involve heating and cooling; and (3) they evaluate transient thermal impedance (TTI) and safe operating area (SOA). The heating curve method has advantages over cooling curve method in terms of capturing time (40 vs. 400 s, respectively), and a lower power excitation is required to obtain the transient channel temperature response.
Comprehensive dynamic on-resistance assessments in GaN-on-Si MIS-HEMTs for power switching applications
(2018-05-01)
Chou, Po-Chien
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Hsieh, Ting-En
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Cheng, Stone
;
del Alamo, Jesus A.
;
Chang, Edward Yi
This study comprehensively analyzed the reliability of trapping and hot-electron effects responsible for the dynamic on-resistance (Ron) of GaN-based metal-insulator-semiconductor high electron mobility transistors. Specifically, this study performed the following analyses. First, we developed the on-the-fly Ron measurement to analyze the effects of traps during stress. With this technique, the faster one (with a pulse period of 20 ms) can characterize the degradation; the transient behavior could be monitored accurately by such short measurement pulse. Then, dynamic Ron transients were investigated under different bias conditions, including combined off state stress conditions, back-gating stress conditions, and semi-on stress conditions, in separate investigations of surface-and buffer-, and hot-electron-related trapping effects. Finally, the experiments showed that the Ron increase in semi-on state is significantly correlated with the high drain voltage and relatively high current levels (compared with the off-state current), involving the injection of greater amount of hot electrons from the channel into the AlGaN/insulator interface and the GaN buffer. These findings provide a path for device engineering to clarify the possible origins for electron traps and to accelerate the development of emerging GaN technologies.
Design and characterization of a 200 V, 45 A all-GaN HEMT-based power module
(2013-11-03)
Chou, Po-Chien
;
Cheng, Stone
;
機械工程學系
;
Department of Mechanical Engineering
Emerging gallium nitride (GaN)-based high electron mobility transistor (HEMT) technology has the potential to make lower loss and higher power switching characteristics than those made using traditional silicon (Si) components. This work designed, developed, and tested an all-GaN-based power module. In a 200 V, 45 A module, each switching element comprises three GaN chips in parallel, each of which includes six 2.1 A AlGaN/GaN-on-Si HEMT cells. The cells are wire-bonded in parallel to scale up the power rating. Static I-D-V-DS characteristics of the module are experimentally obtained over widely varying base plate temperatures, and a low on-state resistance is obtained at an elevated temperature of 125 degrees C. The fabricated module has a blocking voltage exceeding 200 V at a reverse-leakage current density below 1 mA/mm. Two standard temperature measurements are made to provide a simple means of determining mean cell temperature in the module. Self-heating in AlGaN/GaN HEMTs is studied by electrical analysis and infrared thermography. Electrical analysis provides fast temperature overviews while infrared thermography reveals temperature behavior in selected active regions. The current distribution among cells was acceptable over the measured operating temperature range. The characterization of electrical performance and mechanical performance confirm the potential use of the packaged module for high-power applications. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.
Development and characterization of the thermal behavior of packaged cascode GaN HEMTs
(2016-01-01)
Chou, Hsin-Ping
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Cheng, Stone
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Cheng, Chia-Hsiang
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Chuang, Chia-Wei
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機械工程學系
This study investigates the heat generation behavior of packaged normally-on multi-finger AlGaN/GaN high electron mobility transistors (HEMTs) that are cascoded with a low-voltage MOSFET (LVMOS) and a SiC Schottky barrier diode (SBD). By foremost carrying out electro-thermal simulation and related thermal measurements with infrared thermography and Raman spectroscopy for basic 5 mm GaN HEMTs, the location of hot spot in operating device can be obtained. Based on the outcome, further packaged cascode GaN HEMT is analyzed. A hybrid integration of the GaN-HEMT, LVMOS, and SiC SBD are assembled on a directly bonded copper (DBC) substrate in the four-pin metal case TO-257 package. The metal plate is used as both the source terminal and heat sink. The analytical results of thermal investigation are confirmed by comparing them with the infrared thermographic measurements and numerical results obtained from a simulation using Ansys Icepak. For a power dissipation of less than 11.8 W, the peak temperature of the GaN HEMTs is 118.7 degrees C, obtained from thermal measurements. (C) 2015 Elsevier Ltd. All rights reserved.
Development of Motion Rendering using Laban Movement Analysis to Humanoid Robots Inspired by Real-Time Emotional Locus of Music Signals
(2015)
Cheng, Stone
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Hsu, Charlie
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機械工程學系
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Department of Mechanical Engineering
This paper proposes a sequential framework to explore the possibility of human form robots motion rendering models to express emotions inspired by the mechanisms of real-time emotional locus of music signals. The music emotion system progressively extracts the features of music and characterizes music-induced emotions in an emotion plane to trace the real-time emotion locus of music. Five feature sets are extracted from the WAV file of music. Feature-weighted scoring algorithms continuously mark the trajectory on the emotion plane. The boundaries of four emotions are demarcated by Gaussian mixture model. A graphic interface represents the tracking of dynamic emotional locus. The music emotion locus and robot movement are integrated and analyzed by the modified Laban movement analysis. The robot controller organized with multi-modal whole-body awareness of music emotions gave rise to robot\'s autonomous locomotion.
Dual robust controller design for high power AC servo drive
(2008)
Cheng, Stone
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Huang, Yuan-Yong
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Chou, Hsin-Hung
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機械工程學系
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Department of Mechanical Engineering
High power AC motors have a highly interacting multivariable control structure, and it is difficult to design high dynamic performance AC drive with traditional PID-like controller for high power AC servo motor. This paper presents analysis, design and simulation of velocity, loop dual robust controller for 11kw permanent magnetic synchronous motor (PMSM) in the AC servo system. By combining PDFF-MA and H-infinity control algorithms with its own capability of achieving good performance criteria such as dynamic reference tracking and load torque disturbance rejection, The PDFF-MA controller is designed and analyzed in the forward loop to provide low frequency stiffness and overcome low-frequency disturbances like friction. To compensate the system response, moving average(MA) error filter is added. While in the feedback loop, H-infinity controller is designed to meet system robust stability with the existence of external disturbance and model perturbations. The proposed PDFF-MA and H-infinity controllers are designed based on the transfer function of the poly-phase synchronous machine in the synchronous reference frame at field orientation control (FOC). The parameter variations, load changes, and set-point variations of synchronous machine are taking into consideration to study the dynamic performance.
Effectiveness of holographic optical element module sensor in measuring blood prothrombin time
(2014-07-01)
Lin, Yu-Cheng
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Yen, Shih-Chieh
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Cheng, Stone
;
Huang, Tony
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機械工程學系
A small-form-factor holographic optical element (HOE) module, which was mounted on a dual-stage seesaw actuator, was utilized to evaluate blood coagulation in real time. The method involved assessing the decrease in transmitted light of the blood sample surface when the clotting is formed. The prothrombin time (PT) was measured by illumining and focusing a 635 nm laser beam onto the sample. As the fibrinogen turned into non-solute fibrin, the transmitted efficiency and total intensity of the reflected light from the reflector changed. A low-pass filter suppressed the noise in the coagulation-related transient response to yield accurate signals. Finally, the PT measurements were compared to those made classically using other optical sensors.
Effectiveness of holographic optical element module sensor in measuring blood prothrombin time
(2014-07-01)
Lin, Yu-Cheng
;
Yen, Shih-Chieh
;
Cheng, Stone
;
Huang, Tony
;
機械工程學系
A small-form-factor holographic optical element (HOE) module, which was mounted on a dual-stage seesaw actuator, was utilized to evaluate blood coagulation in real time. The method involved assessing the decrease in transmitted light of the blood sample surface when the clotting is formed. The prothrombin time (PT) was measured by illumining and focusing a 635 nm laser beam onto the sample. As the fibrinogen turned into non-solute fibrin, the transmitted efficiency and total intensity of the reflected light from the reflector changed. A low-pass filter suppressed the noise in the coagulation-related transient response to yield accurate signals. Finally, the PT measurements were compared to those made classically using other optical sensors.
Enhanced lateral heat dissipation packaging structure for GaN HEMTs on Si substrate
(2013-03-01)
Cheng, Stone
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Chou, Po-Chien
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Chieng, Wei-Hua
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Chang, E. Y.
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機械工程學系
This work presents a technology for packaging AlGaN/GaN high electron mobility transistors (HEMTs) on a Si substrate. The GaN HEMTs are attached to a V-groove copper base and mounted on a TO-3P leadframe. The various thermal paths from the GaN gate junction to the case are carried out for heat dissipation by spreading to protective coating; transferring through the bond wires; spreading in the lateral device structure through the adhesive layer, and vertical heat spreading of silicon chip bottom. Thermal characterization showed a thermal resistance of 13.72 degrees C/W from the device to the TO-3P package. Experimental tests of a 30 mm gate-periphery single chip packaged in a 5 x 3 mm V-groove Cu base with a 100 V drain bias showed power dissipation of 22 W. (c) 2012 Elsevier Ltd. All rights reserved.
Enhancement of Optical Adaptive Sensing by Using a Dual-Stage Seesaw-Swivel Actuator with a Tunable Vibration Absorber
(2011-05-01)
Chou, Po-Chien
;
Lin, Yu-Cheng
;
Cheng, Stone
;
機械工程學系
;
Department of Mechanical Engineering
Technological obstacles to the use of rotary-type swing arm actuators to actuate optical pickup modules in small-form-factor (SFF) disk drives stem from a hinge's skewed actuation, subsequently inducing off-axis aberrations and deteriorating optical quality. This work describes a dual-stage seesaw-swivel actuator for optical pickup actuation. A triple-layered bimorph bender made of piezoelectric materials (PZTs) is connected to the suspension of the pickup head, while the tunable vibration absorber (TVA) unit is mounted on the seesaw swing arm to offer a balanced force to reduce vibrations in a focusing direction. Both PZT and TVA are designed to satisfy stable focusing operation operational requirements and compensate for the tilt angle or deformation of a disc. Finally, simulation results verify the performance of the dual-stage seesaw-swivel actuator, along with experimental procedures and parametric design optimization confirming the effectiveness of the proposed system.
Enhancement of PZT embedded swing arm actuator using integrated read/write performance and actuation
(2012-04-01)
Lin, Yu-Cheng
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Chou, Po-Chien
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Cheng, Stone
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機械工程學系
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Department of Mechanical Engineering
The current technological challenges associated with the rotary-type seesaw arm actuator for small-form-factor (SFF) disk drives are the small skew focusing, which causes off-axis aberrations and reduces optical quality. This article develops a novel design for a seesaw arm actuator and suspension assembly that is based on a micro-PZT actuator to position pickup head. Dual-stage actuation relaxes the dynamic requirement on the focusing stroke. The proposed actuator with a tilt-compensation mechanism uses a PZT bender to drive pickup head focusing. This combined system, optical module and dual stage actuator, is effectively self-aligned the optical axis for read/write performance in both experiment and simulation result. Finite element modeling and dynamic measurements reveal significant improvements in the actuator bandwidth with and without micro-PZT actuator compensation.
Evaluation and Reliability Assessment of GaN-on-Si MIS-HEMT for Power Switching Applications
(2017-02-01)
Chou, Po-Chien
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Chen, Szu-Hao
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Hsieh, Ting-En
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Cheng, Stone
;
del Alamo, Jesus A.
This paper reports an extensive analysis of the physical mechanisms responsible for the failure of GaN-based metal-insulator-semiconductor (MIS) high electron mobility transistors (HEMTs). When stressed under high applied electric fields, the traps at the dielectric/III-N barrier interface and inside the III-N barrier cause an increase in dynamic on-resistance and a shift of threshold voltage, which might affect the long term stability of these devices. More detailed investigations are needed to identify epitaxy- or process-related degradation mechanisms and to understand their impact on electrical properties. The present paper proposes a suitable methodology to characterize the degradation and failure mechanisms of GaN MIS-HEMTs subjected to stress under various off-state conditions. There are three major stress conditions that include: V-DS = 0 V, off, and off (cascode-connection) states. Changes of direct current (DC) figures of merit in voltage step-stress experiments are measured, statistics are studied, and correlations are investigated. Hot electron stress produces permanent change which can be attributed to charge trapping phenomena and the generation of deep levels or interface states. The simultaneous generation of interface (and/or bulk) and buffer traps can account for the observed degradation modes and mechanisms. These findings provide several critical characteristics to evaluate the electrical reliability of GaN MIS-HEMTs which are borne out by step-stress experiments.
Evaluation of thermal performance of all-GaN power module in parallel operation
(2014-09-05)
Chou, Po-Chien
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Cheng, Stone
;
Chen, Szu-Hao
;
交大名義發表
;
機械工程學系
This work presents an extensive thermal characterization of a single discrete GaN high-electron-mobility transistor (HEMT) device when operated in parallel at temperatures of 25 degrees C-175 degrees C. The maximum drain current (I-D (max)), on-resistance (R-ON), pinch-off voltage (V-p) and peak transconductance (g(m)) at various chamber temperatures are measured and correlations among these parameters studied. Understanding the dependence of key transistor parameters on temperature is crucial to inhibiting the generation of hot spots and the equalization of currents in the parallel operation of HEMTs. A detailed analysis of the current imbalance between two parallel HEMT cells and its consequential effect on the junction temperature are also presented. The results from variations in the characteristics of the parallel-connected devices further verify that the thermal stability and switching behavior of these cells are balanced. Two parallel HEMT cells are operated at a safe working distance from thermal runaway to prevent destruction of the hottest cell. (C) 2014 Elsevier Ltd. All rights reserved.
Evaluation of thermal performance of packaged GaN HEMT cascode power switch by transient thermal testing
(2016-04-05)
Chen, Szu-Hao
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Chou, Po-Chien
;
Cheng, Stone
;
機械工程學系
;
Department of Mechanical Engineering
In this investigation, thermal transient measurements and analyses are used to study the thermal performance of a cascoded GaN power device. The method is based on the thermal characterization of the on-resistance (R-on) of the device and the synchronized current-voltage characteristics under continuous operation. The changes in R-on with temperature (25 degrees C-180 degrees C) are measured, statistically studied, and correlations investigated. The proposed method for estimating transient thermal impedance has the following characteristics: (1) it is robust and reproducible; (2) it yields a heating curve to prevent overheating for the device under test (DUT); (3) it provides in-situ current-voltage characterization; (4) it includes a transient offset correction for initial transient electrical disturbances (such as current collapse); (5) it optimizes a compact thermal model; (6) it is sensitive to package structure and design variables. This monitoring of thermal impedance variation provides a simple and fast non-destructive method for analyzing power switching devices during thermal testing. Satisfactory experimental results confirm the feasibility of in-situ current-voltage characterization and the real power varies with the thermal impedance. (C) 2015 Elsevier Ltd. All rights reserved.