2013年2月5日 星期二

Buck-Boost DC voltage transformation principle

principle

DC-DC is the acronym of the English DC to DC,Grid tie inverter, and the DC-DC circuit is a DC power supply was changed to a different voltage values ​​of the circuit. DC-DC is a branch of the switching power supply techniques include AC-DC, DC-DC ff branch. DC-DC circuit divided by function
low voltage is converted into a high voltage circuit.
a high voltage is converted to a low voltage circuit.
reverse the polarity of the voltage shift circuit, a positive power supply becomes negative power, the negative power supply becomes two types of positive supply.
three important branches of
, of course, take advantage of in a unified circuit will boost reverse, buck-boost, and other effects at the same time.
DC-DC converter circuit is a boost converter, a buck converter, the step-up/step-down converter three kinds.
buck converter schematic diagram shown in Figure 1, when the switch is closed, applied to the inductor voltage (Vi-Vo), the excitation of the inductor by the voltage (Vi-Vo), inductance increase the magnetic through (Vi-Vo) * Ton.
When the switch is turned off, because the output current is sustained, http://www.gridtieinverter.de/,  diode VD becomes conduction the inductor cut magnetic inductance to reduce the flux of (Vo) * Toff of,power inverter.
when unsealing closed with switching off condition reaches equilibrium (Vi-Vo) * TON = (Vo) * Toff of the duty ratio D <1, so Vi> Vo, antihypertensive efficacy.
a buck converter schematic
schematic
boost converter shown in Figure 2, when unsealing is closed, the input voltage across the inductor, the inductor inductance flux additions by the excitation voltage (Vi), (vi) * TON.
When the switch is turned off, because the output current is sustained, diode VD becomes conduction the inductor cut magnetic inductance to reduce the flux of (Vo-Vi) * Toff of.
When the switch is closed and the switching off condition reaches equilibrium, (vi) * TON = (Vo-Vi) * Toff of the duty ratio D <1, so Vi .
the Figure 2 boost converter

schematic
buck converter, into and out of the opposite polarity principle shown in Figure 3, when the switch is closed, the inductor inductance flux added by the excitation voltage (Vi), (Vi) * Ton; When the switch is off , the inductor cut magnetic inductance to reduce the flux of (Vo) * Toff of. When the switch is closed and the switch-off state to reach equilibrium, the growth of the magnetic flux is reduced the magnetic flux, (vi) * TON = (Vo) * Toff of, may in Vi Vo.
Figure 3 Buck converter schematic

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