Hi,
We're using the STEVAL-SPIN3201 dev board and trying to control it form the MCSDK GUI on windows. Currently whenever we run the motor closed loop (FOC) using the hall sensors a speed feedback fault is returned. We've also tried running the motor in open loop (sensor-less) and a startup failure fault is returned. For our application we require low rpm rotation (~10 rpm) with high torque. I've included photos of our current motor params and pictures of our motor.
Regarding the speed feedback error based on previous user posts it seems that this issue is due to incorrect 'Placement electrical angle'', 'Sensor displacement' or noise on the sensors.
https://community.st.com/s/question/0D50X00009XkhhZ/speed-feedback-fault
We believe the sensor displacement to be 120 degrees in our case. We're not entirely sure about the placement electrical angle. We used a Teensy as an oscilloscope and produced the following graphs. Based on the ST diagram provided on p.89 (https://www.st.com/content/ccc/resource/technical/document/user_manual/5e/5e/d2/cb/07/35/45/a6/CD00298474.pdf/files/CD00298474.pdf/jcr:content/translations/en.CD00298474.pdf) from these diagrams we know the yellow wired hall sensor is H1 which is the blue line plotted below.
However our motor didn't come with a datasheet so we dont know which phase corresponds to UVW. Based on this we measured the B-emf on each phase and we estimated the electrical displacement angle to be 0, 120, or 240 degrees depending on which phase is U. We tried running the motor with each of these placement electrical angles but still returned a speed feedback fault. The other motor params we used are included in a screenshot below.
Our hall sensors are active low (H1 is the blue signal), so when measuring the electrical angle between the 'rising edge' of the hall and the peak of the back emf we instead used the falling edge of the hall. Based on that we estimated the angle below to be about 120 degrees between the yellow and blue signals?? The graph with the hall + emf output below was found by spinning the wheel by hand and scaling the value from one of the 3 phase wires so as not to break our teensy, this was done using a voltage divider 10,000 ohm for R2 and 47,000 ohm for R1, bringing the max voltage down from 24v to <5v. If any of that sounds incredibly stupid please do not hesitate to let me know! Only one of the phase + hall graphs is included, the other 2 the emf is just shifted left or right relative to the hall edge.
As an added note how do you change the filter to reduce the noise on the hall sensors?
If you have any ideas about the best way to solve this issue any help would be greatly appreciated 🙂
