17.7 A 0.03mV/mA Low Crosstalk and 185nA Ultra-Low-Quiescent Single-Inductor Multiple-Output Converter Assisted by 5-Input Operational Amplifier for 94.3% Peak Efficiency and 3.0W Driving Capability

2021 ◽  
Author(s):  
Tzu-Hsien Yang ◽  
Yong-Hwa Wen ◽  
Yu-Jheng Ouyang ◽  
Chun-Kai Chiu ◽  
Bo-Kuan Wu ◽  
...  
Keyword(s):  
Operational Amplifier ◽  
Peak Efficiency ◽  
Driving Capability

Ground Transportation: Road and Rail

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Internal Combustion Engines ◽  
Energy Use ◽  
Rolling Resistance ◽  
Electrical Energy ◽  
Combustion Engines ◽  
Peak Efficiency ◽  
Railroad Tracks ◽  
Air Resistance ◽  
Thin Structure ◽  
Main Disadvantage

Everything that rolls along the ground uses energy to overcome both rolling resistance and air resistance. Air resistance is more significant at higher speeds. Repeated accelerations dominate energy use in stop–start city driving. Not surprisingly, heavy, large SUVs use more energy to go a given distance than lighter, more streamlined cars. Due to the mismatch between the torque required and the rotation rate of the drive wheels, internal combustion engines in cars or trucks do not operate at their peak efficiency. Trains are the most efficient form of ground transportation due to both the lower rolling resistance of steel wheels on railroad tracks and the lower air resistance of its long and thin structure. A further advantage is that rail with fixed tracks can take advantage of the efficient generation of electrical energy. This is also obviously the main disadvantage; trains can only go where tracks have been laid.

scholarly journals Simulation of 2-Coil and 4-Coil Magnetic Resonance Wearable WPT Systems

Proceedings ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 13
Author(s):  
Yixuan Sun ◽  
Stephen Beeby
Keyword(s):  
Power Efficiency ◽  
Power Transmission ◽  
Rotation Angle ◽  
Wireless Power ◽  
Peak Efficiency ◽  
Frequency Splitting ◽  
At Resonance ◽  
Higher Power ◽  
The Impact ◽  
Proper Frequency

This paper presents the COMSOL simulations of magnetically coupled resonant wireless power transfer (WPT), using simplified coil models for embroidered planar two-coil and four-coil systems. The power transmission of both systems is studied and compared by varying the separation, rotation angle and misalignment distance at resonance (5 MHz). The frequency splitting occurs at short separations from both the two-coil and four-coil systems, resulting in lower power transmission. Therefore, the systems are driven from 4 MHz to 6 MHz to analyze the impact of frequency splitting at close separations. The results show that both systems had a peak efficiency over 90% after tuning to the proper frequency to overcome the frequency splitting phenomenon at close separations below 10 cm. The four-coil design achieved higher power efficiency at separations over 10 cm. The power efficiency of both systems decreased linearly when the axial misalignment was over 4 cm or the misalignment angle between receiver and transmitter was over 45 degrees.

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