| Electronics > Beginners |
| VFD to control 3 phase AC induction motor 400V 6000 rpm |
| (1/1) |
| 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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