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Hig Voltage transistor switching 230V Arduino PWM Control Hig frequency Answered

Hi all :) 

My name is Karlo Kasupovic and ay come from Croatia.

I need a way, to control a microwawe transformer whit a arduino and a mosfet ay wona use a 230v AC input and rectifier to 200-230V DC then whit a opto isolator control a POWER Mosfet (the signal generator its a Arduino.) I wanna play with different frequencies

Code for the Arduino signal genergenerator already hawe.

Ay need  schematic and explanations.

thanx a lot all :D

10 Replies

user
iceng (author)2014-09-22

230 VAC will peak at 1.414 x 230 = 325 VDC after it is rectified.

Good idea to opto isolate for safety and use a 600 V mosfet..

How fast do you want to PWM that XFMR ?

Most opto isolators are slow to drive a mosfet.

Maybe there is a fast mosfet driver made by Linear semi.

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karlok1 (author)iceng2014-09-23

Hi iceng, no problem for the opto-isolator ay hawe a hig Swiching Opto isolator ay want PWM the XFRM at 0-1KHz Its the shematic ok ? And ay will use a difrent dridge rectifire 6A And ay dont anderstent the 2 caps and zener diod ?

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iceng (author)karlok12014-09-23

The rectified power the mosfet switch sees the 325 volt peak pulsed DC.

While the Gate control must be smooth DC and no more then 10 volts to operate the mosfet, that is where the zener keeps regulating the C1 lower voltage from increasing when the opto-isolator is off.

This is further complicated because when the mosfet is turned on there is basically zero voltage to feed the gate supply.

Diode D6 keeps the mosfet from draining its gate storage capacitors.

This circuit only works if you occasionally turn the BUZ41 OFF ie PWM allows recharging the gate supply for the next ON period.

The gate uses no continues current at all, but that 22K R2 resistor uses much more current and it does guarantee a rapid zero gate voltage when the opto-iso turns off...

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karlok1 (author)iceng2014-09-23

what do you suggest ? What ay cant i change ?in dis shematic so ay get a rapid zero gate voltage when the optp-iso turns off. Do i need a larger resistor value R2 or i do not use the diode D6 And tppppp and sory abaut my poor understanding

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iceng (author)karlok12014-09-23

I only wanted to point out that the momentary charging of the capacitance of the transistor gate is tiny compared to the steady 1/2 ma of R2.

You must use D6 for the circuit to work.

Start with the values to begin then a scope can help you get better results later.

This is a complicated circuit for a beginner to try..

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user
karlok1 (author)iceng2014-09-24

Ok inceng and tenx a lot :)

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user
iceng (author)karlok12014-09-25

Your welcome.

You can always click the "Best Answer"

A...

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karlok1 (author)karlok12014-09-23

And a difrent Mosfet abaut 1500v and the gate is on 5V

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iceng (author)karlok12014-09-23

Good safe voltage, you can run a 5V gate with 10V no problem.

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