output 220DC from 220 AC with variable value

hi i want to output 220 DC from 220 AC and i want that this value would be variable, how can i do this ?

do you need isolation?

How much power do you wish to draw from the 220VDC?

It can be done with a thyristor but all depends on the above 2 qu's

the process of getting DC voltage from Ac Voltage is called "Rectification" so what you need first is to rectify the ac voltage through a bridge rectifier and smooth it through capacitors to get a good and smooth Dc voltage o/p without distortion. but take in advice that the output from the bridge will not = 220 volt! no its 220*Sqrt(2). which gives you approx. 311.12 volt.

for the voltage control part; i guess the best choice is using PWM (Pulse Width Modulation) now we have two choices! (control the Ac side Or control The Dc Side)
both got advantages and disadvantages and both depends on your knowledge in control systems
the advantage of the Ac is its low cost compared to the cost of controlling the dc side since you'll need High Power Transistor and many components to isolate (also you may need to use more that one power supply to separate grounds) but it is easier than the Ac). the control of the Ac side (which i recommend) can be done through many ways

1) micro controller and triac , the task of the micro will be the determination of zero crossing and enabling the triac based on the desired duty cycle and frequency
2) if you are not familiar with programming and micro controllers you can calculate the average voltage you need on the ac side and use timer555 for enabling the triac
3) if 1 & 2 are not suitable you can use TCA785 phase control ic from Siemens hich is avery very good IC with built-in zero crossing detector you can use it to enable the triac and check the examples written in its datasheet.
4) if 1,2,&3 are not suitable for you. i'll come do it for you myself.

no i did not isolation, the power is 2200 watt, what do you think ?

Sorry what I ask. Can You tell me purpose of this device and what load will use this ?