Triac control using PWM

[NASK]

I need to speed control a single phase AC motor by using Triac. Therefore I need to trigger the triac gate using PWM pulse. Here I draw sample circuit & test changing the pulse width but I couldn’t take proper triggering shape. I thing solution is Zero Crossing circuit but how design it for this sample circuit . 

[fcb]

Aside from a load of questions regarding the actual type of AC motor, you should read up on TRIAC triggering modes and techniques - it's really well worth getting your head round how they actually work.

[Zero999]

PWM is not used for TRIACs driving motors. It would require a much lower PWM frequency, than the mains frequency

Phase control is used, which is a totally different thing. A TRIAC is a latching switch and only needs a brief pulse at the gate to turn on, then it will remain on, until the AC cycle passes through zero. Phase control works by delaying the gate trigger pulse, for a certain length of time after the zero crossing point. The greater the delay, the lower the power.

What sort of motor is it? How is it being used?

Phase control is only really good for brushed universal motors. It it not suitable for induction motors, unless they're used to drive a light load, such as a fan. A variable speed drive, is the correct way to control the speed of an induction motor.

[danadak]

https://www.ab.com/support/abdrives/documentation/techpapers/DriveMotorBasics01.pdf


http://www.ecmweb.com/power-quality/basics-variable-frequency-drives


http://www100.abb.com/Drives_DE/fundamentals/basics/dc_drive_basics_01r0201/data/downloads/dc%20drive%20basics%2001r0201.pdf


https://www.google.com/search?q=motor+drive+basiscs&oq=motor+drive+basiscs&aqs=chrome..69i57j0l5.5628j1j4&sourceid=chrome&ie=UTF-8


Some useful ref material.


Regards, Dana.

[NASK]

Thank you for the support!  I think finally I am able to design the requirement and it wish to use for small Ac motors. Hear attached results & used circuit.