Needed to shunt a research on High Voltage Supply that gives output to orders of KiloVolts, based on Voltage multiplier ckts. But we have to start with basic definition and theory of AC-DC conversion.
In HVDC traction rotary converter or mercury arc rectifiers were used, now a days are replace by SCR modules consists aries of series and parallel SCRs, required current and voltage are controlled by increasing parallel for current and series for voltage (modules) in operation. Detailed circuit, theory and derivation you can find in book of DC traction.