Grin simulator with QS273

[harrisonpatm]

I felt like using the Grin simulator with my current build specs, just for fun to see how it tracks with my actual performance. But I must not be entering values correctly. Can someone help me out with that?

I've entered what I think are correct values, but results its spitting out are giving me 50% max efficiency and a max power of about 1200w. Which is ridiculous because I'm actually pulling 2-10kw. So it's obviously my fault.

What I have is:
QS273 8000w
Roughly 1500 rpm unloaded at 115v, for a KV of about 0.73
Phase to Phase winding resistance about 1.5 ohms (when measured at the lugs)
28 pole pairs
I am unaware of the inductance, eddie current torque, or hysteresis torque, so I've left those at default values.

Battery I've set to 115v, 90ah, 0 ohms

Controller is set to 300 battery amps, 1000 phase amps

(I'd snap a screenshot but I can't figure that one out either...)

Sorry for being unable to figure this out!

 

[Portugaline]

I also would like to simulate a qs273 but I think the most powerful motor is a cromotor 4t similar if not equal to a qs205.

 

[harrisonpatm]

I messed around with motor settings at random. By setting phase inductance to 0.1 instead of 1.5, I got some outputs that look more similar to what I've experienced with my setup with the QS273, both on this current 115v battery, as well as my last 72v battery.

It's entirely possible that my multimeter is off. Alternatively, perhaps the simulator's phase inductance variable is intended to be measured directly at windings, or something like that.

In any case, I was seeing efficiencies of 80-85% where I expected them. Copy and pasting my settings from above, edited, in case anyone else wants to estimate with the QS273

QS273 8000w
Roughly 1500 rpm unloaded at 115v, for a KV of about 0.73
Phase to Phase winding resistance about 0.1 ohms (when measured at the lugs)
28 pole pairs
I am unaware of the inductance, eddie current torque, or hysteresis torque, so I've left those at default values.

Edit: rereading this post, I see that I've typed "inductance" when I meant phase resistance. Inductance I've left at default values. Resistance I have at 0.1 ohms

 

[j bjork]

Your numbers looks very wrong. I dont think you have 1,5 ohm phase to phase resistance, should be a few milliohms. 0,75kv is totally off too, might be in the 5-20kv range. 0,1 or 1,5 inductance, mH, uH or what?

 

[harrisonpatm]

Well I'm not actually sure what the numbers should be, as I stated

 

[j bjork]

If the motor spins 1500rpm when fed 115v the kv is probably about 13. But that is probably stated on qs web page. You probably have to measure resistance and inductance. One way to measure resistance is to connect two of the phase wires in series with a battery and another load, like a heating element or something. Then you measure the current and voltage drop over the motor. Then you can calculate the resistance.

 

[harrisonpatm]

If the motor spins 1500rpm when fed 115v the kv is probably about 13. But that is probably stated on qs web page. You probably have to measure resistance and inductance. One way to measure resistance is to connect two of the phase wires in series with a battery and another load, like a heating element or something. Then you measure the current and voltage drop over the motor. Then you can calculate the resistance.

Thanks, I might do that next time I have the motor of the bike. For now I just thought I'd play with the sim variables to see how close my controller is getting to ideal outputs.

 

[dominik h]

.... I'm actually pulling 2-10kw...

You can easily pull 2 times the rated power for a few minutes and 3 times for acceleration.

Can you make a screenshot from your results including the input screen, becaus I never used the Grin simulator, and I would like to play with the tool and get a feeling for how my efficiency is with 30kW from 300-1100U/min on a 10kW QS273.

 

[gabry]

those are the values measured from VESC tool of QS273 40H 3.5T, Single phase (Grin uses phase to phase, so like double that resistance).
With 19" rim, about 24" tire diameter and 160kg total riding weigth i get up to 100km/h without field weakening at 150A battery.

Phase wire are pretty thin and long, with shorter and bigger wires the motor resistance would probably be half that.