We are trying to run Hall-based FOC PM Motor control at 20kHz rate on TM4C123AE6PM (80MHz). Has anybody achieved this rate? My program modified from SMO FOC Sensorless Example cannot even run at 10kHz. (Runs at about 8kHz rate). Is there any way to expedite the processing throughput so that we can run close to 20kHz rate? Is execution from RAM a way to shorten the cycle time? Is there any other tricks?
Dal Ohm, Drivetech.
Dr. Ohm,
Did you ever make progress on this topic? I happened to see this during a search and watned to respond. From the DK-LM4F-DRV8312 kit we were using 55% of the CPU for 10 KHz SMO FOC. The SMO is about 10% of that, so subtracting that out and adding back in a hall counter / angle generator you're somewhere near 50%. That makes it impractical to run the entire control system at 20 KHz then (nothing left for background tasks) but that usually isn't required. As you are aware if you want to run the PWM at 20 KHz and derate the angle generation and current controller to 10-15 KHz that will be practical.
Hope you are having success.
Image from C:\StellarisWare\AppNotes\sw01294\motorware_1_00_01_00\sw\solutions\foc_smo\boards\drv8312kit_revD\stellaris\lm4f211\projects\ccs5\project01\docs\foc_smo_lm4f211.pdf
