pulse width modulation (PWM) AC voltage regulator

Hi friends ,
Can anyone help me to tell how i can implement this work ?
I want to build a circuit for a pulse width modulation AC voltage regulator . This cicuit is to vary the amplitude of an AC voltage using pwm technique. The ac chopper should use bidirectional switches . The load could be a light dimmer, ac heater or an induction motor. I have not really got a clear knowledge about this work .Please,assist !

Thanks .

How would YOU do it?

Yes, i want any suggestion on how to go about that. Possibly, circuit diagrams for the ac chopper (using bidirectional switches) and the pwm . If you know any link, you can direct me . Thanks .

I belive that IGBTs have a diode built in to allow for bidirectional switching. And for the PWM signal just use a 555 timer.

Hi,
Thanks for your help.I got one simple pwm power controller on discovercircuits.com . Can you help to tell me how to interface the ac chopper output and the pwm input ? The input and output should be AC voltage .I mean, the load has to be an ac load , not dc . The circuit input voltage is +6V, so should i first step down the voltage from the 240V supply to 6V before feeding the ac chopper ? The frequency has to be a fixed 50HZ.

Do you have any link where i can get an ac chopper schematic, using bidirectional switch ?

Thanks for your help .