Suitable Transistor - 01/19/05 09:40 PM
Hi all
first thread and all that, it's gonna have to be a question
here is my problem. I want to control an AC induction motor using PWM, so far i think i will Rectify the AC so it becomes a nice DC voltage then generate 20KHz or higher PWM pulse using a PIC16 or PIC18, and an oscilator to control the speed (manual control). then the PWM goes onto the Switches which are going to be a Half Bridge Transistor Bridge. and hopefully it will work like a treat.
Now questions: 1) Are there an Tansistors out there thats say about $10 and can do high power (600watts or so) and can they be switch at 20KHz? 2) if i can avoid it, i really don't want to use MOSFET due to their prices, unless you can find me some really cheap ones. and lastly 3) do i need full bridge? as the motor only really need to go forward and stop.
thanks for any sort of help.
cheerio
first thread and all that, it's gonna have to be a question
here is my problem. I want to control an AC induction motor using PWM, so far i think i will Rectify the AC so it becomes a nice DC voltage then generate 20KHz or higher PWM pulse using a PIC16 or PIC18, and an oscilator to control the speed (manual control). then the PWM goes onto the Switches which are going to be a Half Bridge Transistor Bridge. and hopefully it will work like a treat.
Now questions: 1) Are there an Tansistors out there thats say about $10 and can do high power (600watts or so) and can they be switch at 20KHz? 2) if i can avoid it, i really don't want to use MOSFET due to their prices, unless you can find me some really cheap ones. and lastly 3) do i need full bridge? as the motor only really need to go forward and stop.
thanks for any sort of help.
cheerio