Mosfet DC to DC converter problem

[alec_t]

Sounds as though the coils are high impedance. The slightest load (even a test meter) is dropping their output volts considerably.

 

[schmitt trigger]

"Sounds as though the coils are high impedance. The slightest load (even a test meter) is dropping their output volts considerably."

My same thoughts.

What is driving those coils?

 

[ronsimpson]

I agree with alec_t. It looks like the coil can not support the load.

 

[MikeMl]

I'll bet that the 1n4007s are going into reverse breakdown, and the high-impedance source keeps from blowing them. The 650V may be due to the reverse breakdown of the diodes....

 

[ronv]

There are all kinds of things that could contribute to the confusion. But trying to make a linear regulator go from 1000 volts to 17 volts at 200 ma is probably not going to be a good idea. 200 watts in to get 3.5 watts out just doesn't make sense.
Best to describe how you want everything to work and what the input is.
At best it could be a buck regulator, but maybe a wall wort would work just as well.

 

[RobertEagle]

There are not 200W. What I get from the coils in total is just 3.82W. The impedance is high due the small current. As I said 2.04mA/ch.
Well, what I'm trying is somehow transform this energy, into some useful form.
i.e: 17Volts DC at 0.224A (17 times 0.224 equals 3.82W minus efficiency loses). This voltage is going to power up some electronics. That's all.

 

[alec_t]

Well, what I'm trying is somehow transform this energy, into some useful form.

The obvious method would be to use a conventional transformer. Why not?

 

[ronsimpson]

There are not 200W. What I get from the coils in total is just 3.82W.
Well, what I'm trying is somehow transform this energy, into some useful form.
i.e: 17Volts DC at 0.224A (17 times 0.224 equals 3.82W minus efficiency loses).

You want 17V @ 0.224A = 3.82W. You wrote 1000V on the schematic and 224mA from 1000V is 200W.
What you are missing is that the current in you 17V supply must come from the 1000V supply.
Your 1000V falls to 200V or did you say 67V. So the watts lost is 67V X 0.224W=15W

Also when your 1000V supply falls to 67V the Zener will not function correctly.

 

[RobertEagle]

I wanted to go from high voltage and low current to low voltage and high current.
You're right. I can't do it with this schematic, it's linear. I just want to convert that energy, just as I said earlier, not dissipate it.

One solution came from alec_t, with a transformer.
I'm wondering if there's another solution of doing this.
I've been thinking. Wouldn't a buck converter solve this problem? Might the voltage be to big? And if it's a solution, how a circuit would look like?

Best regards,
RobertEagle

 

[ronsimpson]

A transformer will work. I noticed transformer appears repeatedly above.

A buck switching power supply will work. I don't understand what your voltage is, but as you approach 1000 volts parts are hard to find.
Bucking from 600V to 17V is a long way. Using a switching power supply with a transformer can do the 600 to 17.

You complaint about transformers "it radiates EM waves", a buck converter uses a coil (or transformer) and will "it radiates EM waves".