Abstract: Impedance mismatches in a radio-frequency (RF) electrical transmission line cause power loss andreflected energy. Voltage standing wave ratio (VSWR) is a way to measure transmission line imperfections. Thistutorial defines VSWR and explains how it is calculated. Finally, an antenna VSWR monitoring system is shown.
PW1555 is a programmable current limit switch with input voltage range selection and outputvoltage clamping. Extremely low RDS(ON) of the integrated protection N-channel FET helps toreduce power loss during the normal operation. Programmable soft-start time controls the slew rateof the output voltage during the start-up time. Independent enable control allows the complicatedsystem sequencing control. It integrates the over-temperature protection shutdown andautorecovery with hystersis
It has been over a decade since the Chinese publication of Line Loss in Electric Power Systems. To keep pace
with technological developments, I started a revision as early as 2002, following the main principles that the
theoretical framework and characteristics of the first edition should be retained, with new contents added
according to new problems after the reform of electric power systems and the new requirements for line loss
management practices and in combination with practical experience.
Power Electronics is one of modern and key technologies in Electrical and
Electronics Engineering for green power, sustainable energy systems, and smart
grids. Especially, the transformation of existing electric power systems into smart
grids is currently a global trend. The gradual increase of distributed generators in
smart grids indicates a wide and important role for power electronic converters in
the electric power system, also with the increased use of power electronics devices
(nonlinear loads) and motor loadings, low cost, low-loss and high-performance
shunt current quality compensators are highly demanded by power customers to
solve current quality problems caused by those loadings.
設(shè)計功率MOSFET驅(qū)動電路時需重點考慮寄生參數(shù)對電路的影響。米勒電容作為MOSFET器件的一項重要參數(shù),在驅(qū)動電路的設(shè)計時需要重點關(guān)注。重點觀察了MOSFET的開通和關(guān)斷過程中柵極電壓、漏源極電壓和漏源極電流的變化過程,并分析了米勒電容、寄生電感等寄生參數(shù)對漏源極電壓和漏源極電流的影響。分析了柵極電壓在米勒平臺附近產(chǎn)生振蕩的原因,并提出了抑制措施,對功率MOSFET的驅(qū)動設(shè)計具有一定的指導(dǎo)意義。When designing the drive circuit of power MOSFET,the influence of parasitic parameters on the circuit should be concerned.As an important parameter of MOSFET device,Miller capacitance should be considered in the design of drive circuit.The variation of gate voltage,drain source voltage and drain source current during the turn-on and turn-off of MOSFET were observed.The influences of parasitic parameters such as Miller capacitance and parasitic inductance on drain source voltage and drain source current were analyzed.The reasons of gate voltage oscillation nearby Miller plateau were analyzed,and the restraining measures were put forward.This research was instructive for the drive design of power MOSFET.
