Electronics > Beginners
VFD to control 3 phase AC induction motor 400V 6000 rpm
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dexterbot80:
Hello,
I want to control the speed of a woodcutter that is equipped with an asynchronous three-phase motor 400V 6000 RPM 6KW.
From the searches I came to the conclusion that a VFD would successfully solve my problem so I decided to build one.
Arduino DDS Sinewave Generator http://interface.khm.de/index.php/lab/interfaces-advanced/arduino-dds-sinewave-generator/ seems to me the simplest solution for adjusting the frequency - I tested this circuit and obtained a three-phase sinusoidal signal.
This is my control circuit:
https://www.dropbox.com/s/5qbsr6hkr6mztf4/CONTROLL%20BOARD.png?dl=0
This is my gate driver circuit:
https://www.dropbox.com/s/oacyodtjh10pahm/GATE%20DRIVE.png?dl=0

Please help me to better understand how the control circuit works and tell me if the electronic circuit is correct.
Basically, I have to get 6 Hi / Lo signals that will command the three-phase IGBT bridge.

Thank you
Zero999:
I admit, I haven't checked out the links. It seems like you're reinventing the wheel.

What not use an off the shelf inverter? Preferably one with a serial interface, allowing you to control it using an Arduino.
james_s:
Building stuff like this is fun, but if you just want to run your motor you can get an off the shelf VFD for a few hundred bucks, probably less if you're willing to gamble on a used one. These will offer far better performance and more features than you're going to get by building one.
jmelson:
Assuming a 2-pole motor, you would need 100 Hz, which almost any VFD today will do.  One issue is the motor may be a low-inductance motor, and may require some inductors between the VFD and motor.  I run a 60,000 RPM air bearing spindle from a VFD that will only go up to 400 Hz, so that limits me to 24,000 RPM, but it works.  I had to add inductors to each phase wire.  But, it works.

Designing a 400 V VFD is not for the beginner.  You need to use purpose-designed FET/IGBT gate drivers, and even still, trace inductance and layout issues can cause expensive explosions.

Jon
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