Re: DIY AC Servo Drive - ATMega based
X axis is ready!
https://www.youtube.com/watch?v=jlnwZzAQRMw
The max speed you see there is 12 meters per minute. Pretty good!
All alu parts you see there are made by myself on my Chinese 3040! I would say they made some good devices for the money...
Enjoy!
Mihai
Re: DIY AC Servo Drive - ATMega based
Great project. It would be nice to replace the AVR circuit with one of these:
STM32F103C8T6 ARM STM32 Minimum System Development Board Module FOR Arduino Erus | eBay
Same size. Lower cost. Much higher performance. Free tools. The circuit on the left can be eliminated.
Re: DIY AC Servo Drive - ATMega based
I have been looking at those same ARM boards, and plan to make an order for a couple in the next few days.
Re: DIY AC Servo Drive - ATMega based
I have the board. It works very well. Note that you will need an ICD. I bought the Jlink EDU to support the vendor, but if you are on a tight budget, I see counterfeits on Ebay for $12. I don't know how well they work, but the Jlink is outstanding, when compared to the AVR dragon that I'm use to.
Re: DIY AC Servo Drive - ATMega based
Mihai, do you think the algorithm would work on a stepper motor? I believe it would be necessary to commutate 200 times per revolution.
Re: DIY AC Servo Drive - ATMega based
Hello.
I think the algorithm can be changed to handle steppers. Commutation speed is not a problem, you must only change the commutation table to handle 4 outputs. But the ATMEGA644 has only 6 PWM channels. You will need another 2 to make it work the way it is done now. Or you can use 4 pwm channels and 4 other outputs that can be used to change the Hi / Lo commutation of a half bridge. You must use PWM and obtain somekind of microstepping because otherways you will not be able to sync the 200 steps of the stepper with the PPR of the encoder. Except if you will use a 200 PPR encoder...
Mihai
Re: DIY AC Servo Drive - ATMega based
Thanks for the explanation. Something I am wondering about is how much actual advantage is provided by the vector control algorithm, which is the ideal for maximizing performance and minimizing power consumption. It adjusts the coil currents to keep the resultant force pushing perfectly in the rotation direction. Have you looked at it before?
Re: DIY AC Servo Drive - ATMega based
Good work, I like how you wrote it in pascal . I had pascal for the Z80 TimexSinclair along time ago, then TurboPascal then Delphi.
Do they make Mikropascal for pic processors ?
Re: DIY AC Servo Drive - ATMega based
Quote:
Originally Posted by
H500
Thanks for the explanation. Something I am wondering about is how much actual advantage is provided by the vector control algorithm, which is the ideal for maximizing performance and minimizing power consumption. It adjusts the coil currents to keep the resultant force pushing perfectly in the rotation direction. Have you looked at it before?
I've just looked at vector control. Motor Control AlgorithmsAC Motor Control Algorithms | Renesas Electronics Europe
However form what I understand Vector controls requires calculation of Clark, Park and Park Inverse equations. This requires a very powerful MCU if you want to run at high speeds. Whit ATMega 644 I do not think it's possible. There are lot of sines and other math functions there...
Mihai
Re: DIY AC Servo Drive - ATMega based
Quote:
Originally Posted by
Larken
Good work, I like how you wrote it in pascal . I had pascal for the Z80 TimexSinclair along time ago, then TurboPascal then Delphi.
Do they make Mikropascal for pic processors ?
Yes MikroPascal is also available for PIC. I think their PIC version is also much mature and stable. I could not help and not look at Viper Servo motor products. I see no drive for AC and BLDC motors... Do you have something on your mind...??? :)
Mihai
Re: DIY AC Servo Drive - ATMega based
Quote:
Originally Posted by
mcm_xyz
I've just looked at vector control.
However form what I understand Vector controls requires calculation of Clark, Park and Park Inverse equations. This requires a very powerful MCU if you want to run at high speeds. Whit ATMega 644 I do not think it's possible. There are lot of sines and other math functions there...
Mihai
Sine and cosine can be done by table lookup. Because values repeat, a 90 entry sine table is all that is needed. According to ST, the calculations take 70% of the cpu time on a 25 Mhz stm32. It's likely pushing beyond the limits of the atmega.
Re: DIY AC Servo Drive - ATMega based
Quote:
Originally Posted by
mcm_xyz
Yes MikroPascal is also available for PIC. I think their PIC version is also much mature and stable. I could not help and not look at
Viper Servo motor products. I see no drive for AC and BLDC motors... Do you have something on your mind...??? :)
Mihai
Yes, i've got one in the works for the 60 volts motors. I use the PIC 30F3011 with microchip C for most of it. But there isn't much of a market since the chinese have swamped the market with cheap AC servo drives and motors. The leadshine ac drive is pretty basic though and the tuning software is really bad. Mine uses the hall inputs though for now,.
Larry
1 Attachment(s)
Re: DIY AC Servo Drive - ATMega based
Hello again!
Here is the latest firmware and Servo Tuning Software. A new parameter has been added, the anti windup Integral limit value. I feel it is a mistake to add a predefined constant for that, I think it's specific to motor.
Those being said I am stopping development for this servo drives now. I will mount them on a machine soon and come back with impressions and maybe some other fixes after that. For now the drives fit my needs just fine.
Mihai
Re: DIY AC Servo Drive - ATMega based
hi all
can i use these all on near about 200 vdc servo motor . 1 kw.
shabbir
Re: DIY AC Servo Drive - ATMega based
I think diy servo controllers in general, would be further developed by now if everybody would separately design the logic side and the power stage as two separate boards.
1 Attachment(s)
Re: DIY AC Servo Drive - ATMega based
Hello,
Just found this thread. Good work!!!
I would recommend to buy components (North America) in :
Electronic Components from the Best - Future Electronics
or
Avnet Electronics Marketing - Electronic Components Distributor Services, Datasheet PDF Download, Part Number Search 4.5 Million + Components - Avnet Express
Digikey and Mouser are expensive.
It doesn't make sense to buy controller board on the eBay and add it to hand-made PCB. Better to use one PCB board for all components.
To make a high quality PCB in few hours at home use :
http://www.mgchemicals.com/products/...ed-600-series/
Print PCB layout on LaserPrinter on trasparent film. Then expose 10min under UV (I use regular energy saving fluorescent bulbs) and develop in MG Chemical solutions. All information is available on /www.mgchemicals.com
Power section layout is bad. Look at the attached tutorial from Mariss Freimanis for details.
I will probably try to make this drive for myself to test my small motors. PCB has to be redone in very compact form using CMD components.
Ohhhh :( Need to recover my PCB design sills. Didn't touch Altium Designer and Eagle for more than 4 years.
Another option is design a board and place it with 4PCB or other manufactures. With >20 boards it can be a very reasonable cost which we can share.
Just my 5 cents.
Re: DIY AC Servo Drive - ATMega based
Looking at IRLU3110ZPbF as a power MOSFET. Parameters are very good, Total Gate Charge is only 42nC, it switches fast. Another option is old friends IRF540 or STP30NF20. The last one is a little bit better.
Re: DIY AC Servo Drive - ATMega based
Hello dear machinists!
I'm very happy that the interest in this project grows. I did not stop development. I still have some upgrades to make to the firmware. I will post soon the changes.
As for the PCB you will have to excuse me. I'm a software engineer, my electronic skills are at hobby level. I would be very happy to participate in a common fund for creating some PCBs at some professionals.
I will let you know about progresS soon.
Mihai
Re: DIY AC Servo Drive - ATMega based
I know you've seen my PCB layout.
I wanted to say that I'm having 5 made to test. Should be here any day.
I've got the components ready as well as an application on my little CNC Router (6040 China model)
Hope to report soon with a review and lots of photos.
If it works out, I'll be happy to work toward getting more ordered at cost.
Anxious to try the latest firmware upgrades.
James