pulse width modulation 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 .

It's not really practical to control the amplitude of an AC signal using PWM. You might do better to try to control the RMS voltage by chopping the signal. But for simple light dimming, there are simpler methods. An SCR or triac that turns on at varying times after zero crossing does the job simply.

Thanks for your reply. Can you help to give me any ac chopper circuit if you have ? Or you can direct me to any link that you know . I'm really required to use an ac chopper with the pwm .
Thanks .