Flyback transformer rating selection

Hello Sir,
I am designing flyback boost converter, and done required calculation. But not able to select flyback transformer current rating.

Specification required after calculation:

• Output power : 120 watt
• Primary peak current : 16 Amps
• Secondary peak current : 2.2 Amps
• Primary RMS current : 9.2 Amps
• Secondary RMS current : 0.53 Amps
• Primary inductance value : 11 micro henry
• Turn Ratio : 1:10 (Np:Ns)
• Input voltage : 24v
• Output voltage : 200v to 600v
• Output current : 200mAmps

A push pull ckt might be better for this step up ratio, with flyback you will indeed have 20A peak in the pri switch (for fully DCM) compared to 5A in a push pull, I note 600V to 200V o/p, so you would reduce the PWM for the lower o/p voltges.

Turning off 20 A in a flyback with give you quite the volt overshoot above 84V (for 600Vout) unless your Tx is very low leakage. Your output diode needs to be 1kV min ( 240V + 600V) and these will be slower devices (unless you series 2 x 600v ultra -fast) so you will need to keep the freq down. From your above it will take 9.2uS to ramp up to 20A on the pri - so the max freq is 54kHz for the above Tx design. Snubbers needed on the o/p diode(s)

You have the rms currents in the windings which is all you need to know to calc the dissipation in the windings of a given Tx.

good luck ...

yes, or otherwise you could try a flyback converter with two secondaries...each one giving 100 to 300v...then stack the output of one onto the other one.
..Because the leakage inductance ring onto your output diode will be high and need a lot of snubbing to keep it from overvoltaging the output diode. So use the split technique and then you can use more common lower voltage diodes.
Yes the power dissipation in your primary clamp will be trouble some though, as EasyPeasy says esp if not well coupled.

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Another rough way to do it is to have a boost converter followed by a 1:1 LLC converter operating at the upper resonant frequency and in on/off mode . Then you regulate vout by regulating the output of the booster. LLC converters which switch at the upper resonant ffrequency give an output which is their input voltage multiplied by their turns ratio of their transformer. And of course, the LLC sufferes no overvoltage ringing of its output diodes. Another point is that the LLC is most efficient when switching at its upper resoannt frequency.