It doesn't really work that way. A capacitor of the same capacitance but with a 40% higher voltage rating may well be more than twice the size mechanically. No matter how you do it, you have to hunt around for the capacitor with the most energy per unit volume for your application.
Which is not so difficult if you use a microcontroller to control the PWM. I've built a similar circuit (far less power though). I use a $3 ARM controller from NXP which measures the capacitor voltage and switcher current to determine the PWM pulse width. A switching frequency of 300kHz is not a problem (uses about half the controller's CPU time).
On Jul 11, 5:46=A0am, Michael wrote: =2E.. Any suggestions =A0how to
You just want an oscillator at 10V, transformer coupled, with a capacitor/rectifier/capacitor/rectifier ladder type of doubler/tripler rectifier. Inhibit the oscillator when it gets to full charge.
This uses the ladder capacitors to limit the current, but just pushes current at full rating all the time.
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