Simulate BLDC Motor?

[Harimake]

I routinely repair BLDC controllers. Customers mail me their controllers for repair and often it's fairly easy to find and repair a problem.
But every once in a while I get a controller, which appears to work and I find it difficult to test it without the motor. Customers don't want to mail in the motor due to weight/size related costs.



So what I'm looking for is a way to implement a rough BLDC motor simulator. I'd have the controller on one side and my regular load tester on the other side. In between, there would be a circuit which takes in the three wires from the BLDC controller and the two wires from the load tester and acts like a typical BLDC motor effectively implementing the 3 phase motor timing sequence. The end result is that the controller thinks that it's running a real motor, the current flows through the controller testing the capacity and I can see the amount of current being used on my load tester.

Ideally, I'd like to find a cost effective off the shelf implementation. But I'm not against implementing my own circuit. I looked far and wide but I can't seem to find anything. But then again, BLDC is not my specialty.

[abdulbadii]

got to consult a SPICE forum simple of which is Spice section of Kicad
seems the comm. growing well

[Slh]

Are they always the same make and model of controller? You might be able to do something with some inductors in a star connection. If you always work on similar inverters then you could see what a good one does on it (it might detect that the 'motor' isn't spinning and trip out) and compare that to the broken ones.

If you can modify the software then it's even easier as you just give it a fixed.position and tell it to stay there.

Depending on the inverter power these inductors could be large and expensive. They probably have to be rated for the same current as the inverter and should definitely be a similar inductance or more

[Harimake]

Are they always the same make and model of controller? You might be able to do something with some inductors in a star connection. If you always work on similar inverters then you could see what a good one does on it (it might detect that the 'motor' isn't spinning and trip out) and compare that to the broken ones.

If you can modify the software then it's even easier as you just give it a fixed.position and tell it to stay there.

Depending on the inverter power these inductors could be large and expensive. They probably have to be rated for the same current as the inverter and should definitely be a similar inductance or more

You got me thinking in the right direction. Thank you.

The electronic load won't work here. I'd need to get an inductive or resistive load instead. Assuming the simplest case, having high current resistive load (light bulbs perhaps?), I should be able to still use it to simulate smaller motors as well.
The problem is that I still wouldn't be able to tell how much current is being used at high loads without a good current clamp... But I should be able to measure voltages at least.

[thm_w]

What about just having a handful of motors of various sizes?
Sensored or sensorless?

[fzabkar]

Some designs will alternatively drive each pair of phases while sensing the back EMF in the third phase to control the RPM. That's how sensorless hard drive spindle motors work. I don't know how you would simulate such a case.