control single phase AC-motor

Thread Starter

h.d

Joined Oct 22, 2007
150
hi
i want to design circuit to drive an speed control for single phase AC-motor
P=1.5hp
v=220 v
f=50hz

i want to control it using PWM . the signal of PWM come from PIC16F877A
that signal will trigger the power element that used(IGBT,MOSFET)
am need help in design that circuit also how to use the signal from PIC(5V,20mA) to trigger power element(high cureent)?
 

thingmaker3

Joined May 16, 2005
5,084
PWM control of a DC Motor is pretty easy. PWM control of an AC motor is challenging, as both frequency and voltage must change together. You should be able to write an algorithm to do such, but I do not envy you the task.

For your voltage and frequency requirements, I would choose MOSFET rather than IGBT.

For an AC motor, you'll want your MOSFETs in a push-pull arrangement, or possibly an H-bridge.

To drive MOSFETs from your PIC, you'll need drivers. Here is an excellent document to begin learning about driving MOSFETs: http://www.powersystems.eetchina.com/PDF/2007JUL/PSCOL_2007JUL26_DROP_TA_101.PDF?SOURCES=DOWNLOAD
 

Thread Starter

h.d

Joined Oct 22, 2007
150
PWM control of a DC Motor is pretty easy. PWM control of an AC motor is challenging, as both frequency and voltage must change together. You should be able to write an algorithm to do such, but I do not envy you the task.

For your voltage and frequency requirements, I would choose MOSFET rather than IGBT.

For an AC motor, you'll want your MOSFETs in a push-pull arrangement, or possibly an H-bridge.

To drive MOSFETs from your PIC, you'll need drivers. Here is an excellent document to begin learning about driving MOSFETs: http://www.powersystems.eetchina.com/PDF/2007JUL/PSCOL_2007JUL26_DROP_TA_101.PDF?SOURCES=DOWNLOAD

thnks man,
about PWM for ac-motor ,i agree with u
and thanks for the link u put it.
but if i use dc-motor 12V or 24 V 1.5 hp the current will arise to 20 A and thats an important problem?isnt it?
 

thingmaker3

Joined May 16, 2005
5,084
There are several MOSFETs which can handle 20 Amps or more. You can also parallel MOSFETs if you have trouble acquiring high current MOSFETs.
 
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