3 phase motor control through stamp

Chaz

Okay so both me and remmi870 are trying to get a 3 phase motor controlled through a stamp although i am not sure we are thinking the same way. It was mentioned but how could i make a pwm just from the stamp 2px that a speed controller could interpret and get full power as well as no power to my motor. I do not need fine motor control, full on or completely off will do. If it helps i have a castle creations speed controller. Any help would be appreciated as well as any links to common themes to this. I understantd that i will need to have both digital and analog commands but have not found a diagram detailing what the wire set up is one the input to the speed controller.

T Chap

You haven't mentioned what you are trying to drive the motor with, but here are some suggestions.

There are 3 phase drivers that you can drive from any processor with pins for Direction, Enable(Run/Stop), Brake(if needed), PWM for speed or Voltage for speed.

Since you only want full on or off, you can drive a motor with Direction, and On/Off only.

If you don't have a motor driver, I can point you in some directions for either 3 phase driver IC's or complete 3phase driver boards ready to go.

Chaz

Yeah well i guess i need one of those. I'll google it but some links would be great too.

Thanks

T Chap

If you just want a PCB that you can apply power and command lines, there are numerous companies that make drivers, but here is a driver I have used that works great for under $100.

anaheimautomation.com/brushless-dc-driver-mdc050-050051.aspx

This board uses a Motorola IC MC33035 3 phase motor driver, but instead of driving the fets they used the outputs to drive an Intersil HIP4086 N-Channel MOSFET driver IC, which driver 6 mosfets.

You can search for the parts on Digi, or google to see how they work. One thing about the board above is you can set the speed with a trim pot, then just turn the motor on or off as needed.

I have created a schematic for this combo as well in Eagle if you are a DIYer, it is all SMT, but should be simple to build with a solder pencil if needed.

Chaz

I have small problem with that driver. My motor is bigger here are the specs



# Power: 2200W
# KV: 230
# ESC Rating: 80A

and that comes out of my 11.1v lithium poly battery

So sorry i should have said that before


One thing i do not understand is normally with my speed controller and motor they would be controlled by a radio receiver because they are for a model airplane. In my set up i am replacing the reciever with the stamp 2px so it is autonomous with various other sensors providing input. So why cant the stamp just send out the small pwm signal for the speed controller then the speed controller can handle the high amps. From my understanding the pwm signal is rather small and simply is amplified, for lack of better word, into what drives the correct watts to the motor. Maybe my entire philosophy is wrong. I have been struggling to find good explanations into how this works so if you can provide one please do.

remmi870

i guess we are trying to do different things, anyone can find a 3 phase motor starter or driver that one could use a bs2 to control using digial or analog inputs but im trying to find a chip that would be a go between to control IGBT or isolated gate bipolar transistors to control a rectified DC current back to a variable frequency, essentialy im creating a variable frequency drive from scratch, if i use a bs2 i can program it to do whatever i want to ramp up a motor or even adjust the speed of a motor on the fly.

Jesse Hasty

You can accomplish this with the stamp, but you need the power control device.· Essentially you need a 3 phase full wave rectifier and 6 output transistors.· There are such transistors, called GTT or giant transistor technology.· The pulse width output of the stamp will accomplish your goal.·

Chaz

Can you be a little more specific...
Why the rectifier?
Why the GTT?

This might be a stupid question but why cant i just make a simple pwm signal on my stamp and plug it into the speed controller? All i want is a neutral position, a full on position, and a full off position. That is it

Maybe i am missing something here

remmi870

you should be able to control the speed controler via pwm or you would need to see what the input protocol is, some use descreet digital inputs, some use analog voltage with inputs controling speed and on and off, break, ramp. the problem with using a stamp to execute the pwm through a loop is if you have conditional statements or a considerable amount of code, after the pwm execution ther will be a delay, maby in the range of 1-3 ms, considering the pwm is in 2/1000000 of a second and the pause after way be too slow to keep up the speed of your motor.

Post Edited (remmi870) : 11/21/2008 9:55:51 AM GMT