Q: Hi, i have dual motor board from TI and I follow motor identification labs. In the early start there is a lab which identifies Rs, Ls,... My motor is high speed, low inductance brushless used for amateur drones (the cheapest I got from ebay). The motor doesn't run through the lab - is it supposed to rotate at all? There is no explanation about that
A: Glad you are already using InstaSPIN. You need to use proj_lab02c with proper settings to ID these high speed motors. Please ask your support questions on our InstaSPIN e2e Forum: https://e2e.ti.com/support/microcontrollers/c2000/f/902#pi317047=1&pi317049=1
Q: Are you using adaptive algorithms inside the chip?
A: While FAST does adapt to real-time feedback, nothing we are doing is what I would call adaptive (neural network, fuzzy logic, etc.)
Q: It looks like you are modeling the motor dynamically and adjusting current and voltage using that model based upon the desired operation.
A: Like all observers we are modeling the motor to make our estimations. Like all FOC controllers we are adjusting the voltage on the inverter phases to produce necessary current for the load.
Q: Is Instaspin available for other processors like Sitara?
A: No, it is only available in C2000 MCUs, and currently only in three of our Piccolo families.
Q: How accurate is the positioning?
A: For position control of InstaSPIN-MOTION the limitation is tied to the resolution of the rotor sensor being used. For FAST, it will NOT do accurate position control. It can produce a rotor flux angle if the rotor is moving at some minimum frequency. Above some threshold (based on motor flux / Bemf) the FAST estimates are within 1 count of an encoder.
Q: Do InstaSPIN and FAST work with Concerto?
A: No, it is only available in C2000 MCUs, and currently only in three of our Piccolo families.
Q: What is the max. FOC loop frequency?
A: This depends on the % of the CPU you are comfortable using. The default configuration runs at 45 KHz PWM with 15 KHz current/FAST loops and 1 KHz speed/trajectory loops. This can be adjusted as required, up to about 30 KHz current/FAST. Most applications only require 8 to 16 KHz current/FAST loops.
Q: Is it possible to write into the internal memory e.g. if I start the LaunchPad it is going into the temperature messurement mode. Is it possible to load up my own program, starting when the Launchpad is connected?
A: Yes, you can set the program to build for flash memory, boot the device, and start running
Q: What is the difference between FAST SW and sliding observer position?
A: While they are attempting to do the same thing at a fundamental level (model the motor and estimate the rotor flux angle) they do so in different ways and FAST is quite superior offering much lower frequencies of tracking, stability during stall and zero speed, more robust dynamic tracking, and better results in high/over-modulation and into deep field weakening. Simply FAST is a better mousetrap.
Q: Are these controllers also usable for high voltage/high current applicatinos. We have motors that needs for 600-800v and 1000+ Amps, running 10-12' RPM
A: Yes, the MCU does not care what voltage and current range you are using. All signals are scaled to 0-3.3V at the ADC pin and you simply update the software #define with the proper voltage and current ranges per your circuitry
About the high voltage/amp, we also need to run the motors at high speeds, 10.000-12.000 RPM
FAST is routinely used on high speed motors > 2 KHz electrical frequency
Q: Is the FAST sensing robust against EM noises? From eg an DC near...
A: FAST is only as good as the voltage and current signals used as feedback.