I need to design a circuit for controlling the speed of a single phase induction motor. I need to design this without using any microcontroller but it need to be efficient.
But I am not getting any idea that how should I do it. Most of the designs I have seen so far is using microcontroller which is not compatible with me.

So,It would be a great help if anyone can give me a starter, can give me any idea that what concept should I use or can you please refer links which have useful instructions or process.

 

A single phase induction motor locks onto the frequency of the AC, so you must design and build a variable frequency supply. So the first step is to get a DC source that is big to supply the motors current and be at least 1.5 times the AC voltage rating of the motor. Then you must use a "H" bridge driver stage for the motor and drive this from a variable frequency source.
Frank