Quang Dich Nguyen

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Stress sensing test chips are a powerful tool for measuring in-situ stresses in electronic packages. In this study, we have applied (111) silicon test chips to perform a variety of measurements of moisture and thermally induced die stresses in flip chip on laminate assemblies. The developed chips incorporated optimized eight-element sensor rosettes that(More)
Magnetic bearing motors have many advantages such as no friction loss, no abrasion, lubrication-free quality, very high speed and so forth. However, they are not widely used due to their high cost, complex control and large size. In order to solve these problems, a self-bearing motor is a reasonable trend in current researches. This paper will introduce an(More)
This paper presents an improvement of sensorless speed vector control for a nonsalient type axial gap self bearing motor (AGBM), in which rotor speed and position are estimated by using sliding mode observer with full mathematical model. The approach is based on the estimation of the motor back-EMF (or induced voltage) through a sliding mode observer with(More)
The goal of this paper is utilization of the state observer to research a new capability of controlling the axial gap self-bearing motor. Analytical and experimental evaluation for a sensorless speed vector control of a salient axial gap self-bearing motor is presented. The approach is based on the estimation of the extended electromotive force (EEMF)(More)
In this study, an investigation has been performed on effects of moisture on die stresses in 240 pin Quad Flat Packs (QFPs). Stress sensing test chips were used to experimentally measure the complete state of stress at the die surface. The samples were exposed to a harsh high temperature and high humidity environment (85 C, 85% RH) for various time(More)
Moisture is a significant contributing factor to the failure of microelectronic packaging including phenomena such as popcorn cracking, delaminations, and interfacial fracture. While the effects of moisture have been examined extensively in plastic encapsulated packages (e.g. DIP and PBGA), there have been no published studies on the effects of underfill(More)
This paper presents the study on displacement valveless micropump which is actuated by electromagnetic force on a permanent magnet embedded in PDMS diaphragm. The network channel of the present pump includes two inlets and one outlet channels forming an intersection in front of a pump chamber. Two designs of the pump with different structure of the inlet(More)
Electronic packages absorb moisture when exposed to uncontrolled humid conditions during manufacturing processes and service life. At high temperatures, the effects of moisture absorption on electronic packages become even more significant. A number of failure modes are caused by moisture effects such as popcorn cracking, delamination, and electrochemical(More)
This paper will introduce an inset-type axial-gap self-bearing motor (AGBM), which is an electrical combination of an axial thrust-bearing and an axial flux motor. A method for controlling the axial position and the rotating speed of the AGBM without the influence of reluctance torque is also discussed. First, the axial force and the motoring torque are(More)
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