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This paper presents a module-integrated isolated solar micro-inverter. The studied grid-tied micro-inverters can individually extract the maximum solar power from each photovoltaic (PV) panel and transfer to the AC utility system. A harmonic suppression technique is used to reduce the DC-bus capacitance. Electrolytic capacitors are not needed in the studied solar micro-inverter. High conversion efficiency, high maximum power point tracking accuracy and long lifespan can be achieved. The operation principles and design considerations of the studied PV inverter are analyzed and discussed. A laboratory prototype is implemented and tested to verify its feasibility. This paper presents a grid-tied isolated solar micro-inverter. A harmonic suppression technique is used to reduce the DC-bus capacitance. E-Cap is not needed, and the lifetime of the studied module-integrated solar inverter can be then prolonged. High conversion efficiency, high MPPT accuracy and low THD characteristics can be also achieved. In the experimental verifications, the MPPT accuracy of the developed solar micro-inverter is around 0.99, while the measured CEC efficiency can be up to 92.18%. 582H.-J. CHIU ET AL.

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Insulating liquids in transformers experience the transformer operational temperature rather than the ambient temperature that is often used in discharge studies in laboratories. This paper presents the effects of temperature on partial discharge (PD) and streamer characteristics of a synthetic ester liquid under AC stress. A needle-toplane electrode configuration was employed to perform the PD and streamer measurements. The PD pattern, streamer images, current signals were chosen to explore the PD and streamer characteristics at temperatures of 20, 40, 60 and 80 ºC. It was found that both PD and streamer characteristics of the synthetic ester are temperature dependent. As the temperature increased, the magnitude and repetition rate of positive PDs increased slightly, but both the magnitude and repetition rate of negative PDs dropped dramatically. In addition, it was observed that when the temperature increased, the stopping length of positive streamers did not change appreciably while a significant reduction of negative streamer length and area was witnessed. A mechanism based on the electrohydrodynamics (EHD) phenomenon and the space charge theory has been used to explain the different effects of temperature on positive and negative PDs.

Enhancement of the Stark effect in AlInAs/GaInAs coupled quantum wells and their application to tunable midinfrared photodetectors

Abstract:The aim of the present study was to investigate the effects of hip thrust (HT) training on the strength and power performance of lower extremities. In total, 20 male collegiate baseball players participated in this study and were divided into a HT training group (HTT) and a control group (CON). Participants in the HTT group added HTT movements to a regular baseball training regimen (3 times per week for 8 weeks), whereas participants in the CON group only performed the regular baseball training regimen. Before and after the training sessions, strength performance was assessed via tests of squat strength and 3 repetition maximum (3RM) HT strength; power performance was assessed via vertical jump height, standing long jump distance, and 30-m sprint time. The results indicated significant improvement in squat strength (31% ± 15%) and 3RM HT strength (36% ± 16%) (P < 0.05), but not in vertical jump height, standing long jump distance, and 30-m sprint time. Furthermore, the improvement in squat strength highly correlated with 3RM HT strength (r = 0.83, P < 0.05). In conclusion, HTT plays a role in developing squat strength but does not appear to improve power performance.

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