you mean that i can get output dc more than the ac-input?how can i use the capacitor filter to do that?Without some regulation, you can't rectify Ac and come out with a lower DC voltage. If you use capacitor filters, the output voltage is about 1.4 times the AC input.
in that the maximum dc-output isHe meant to say that DC is ~.707 times the AC
AC is ~1.4 times the DC
The 220VAC is the RMS value of the grid voltage. The peak value is 1.414 times greater (Vpeak = sqrt (2) x Vrms) and that is the voltage of the resulting rectified current.you mean that i can get output dc more than the ac-input?how can i use the capacitor filter to do that?
sure threr are regulation.
No. Its the opposite.He meant to say that DC is ~.707 times the AC
AC is ~1.4 times the DC
What are you planning on powering with it? Tube plates?
What will your minimum, maximum, and average expected current be?
Running off the mains is risky business. When there are failures, the operator can be exposed to the power of the mains. I say when, because sooner or later, something will break.
A transformer serves not only to isolate from the power mains, but to better match the voltage you need while limiting the maximum current.
If the amount of current you need is small, you might consider using a moderate voltage transformer, and then voltage doubler/tripler/quadrupler circuit(s) to reach the voltage you need.
When you're working with high voltage, even small currents can kill you. Be careful.
i will try it simulation.With a large capacitor to hold the peaK voltage until the next peak, the estimate of 1.4 times the RMS voltage is correct. The DC output will be in the neighborhood of 308 Volts. Dropping that to 200 volts without dissipating a ton of power will be a challenge. Good Luck.
It might be easier to get a 220 to 140 transformer then the rectified and filtered voltage will be in the neighborhood of 200 VDC
for safety i will use circuit braker before the rectifierh.d.,
Your simulation is quite frightening of what can happen when you don't understand the problem accurately. As most people have mentioned, AC outputs are specified as RMS. You are taking them as peak values! Be careful with all of that voltage and power, safety is a priority.
You should use a transformer to do this, since it is straightforward and safe to do. It is possible to power a high voltage H-bridge, then just PWM the input. This IC is a bit under-rated current-wise, but it might be a good starting point. It is meant for 3-phase operation, but it will be happy with only two half bridges in use.
http://www.irf.com/product-info/datasheets/data/irams06up60a.pdf
Steve
my project is to drive dc motor by PWM so i will use MOSFET in the output of rectifier as a chopper class AA sine wave is measured by the rms voltage. Which is the the Peak-Peakvoltage divided by the square root of 2.
So to get a 200V dc output, you first have to convert your ac voltage to an ac voltage of 141.42VAC, and then when you rectify it you will get a dc voltage of 200V.
An example of this we can use is your AC wall voltage of 115VAC.
The RMS value is 115VAC, however if i were to get P-P voltage it would be 163V.
If you dont want to use a transformer you have to rectify your AC voltage using a SCR bridge, but then you need to worry about adjusting your triggering point to capture exactly the right amount of the ac wave.
MOSFETs can and do short when they fail. This would subject your motor to 150% of rated voltage. (225% of rated power.) A standard breaker might not trip quickly enough to protect your motor. A fuse or breaker capable of tripping quickly enough might also open during motor start-up.for safety i will use circuit braker before the rectifier
and after the output of rectifier would use MOSFET with PWM controlling
is it good?