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CCS/TMS320F28069M: Graphing Phase Currents Noisy

Jainil Gandhi
Prodigy 40 points

Part Number: TMS320F28069M

Tool/software: Code Composer Studio

I'm working on TI lab 05d for FOC Instaspin on CCS v5. I'm trying to graph the 3 phase currents for running the BLDC Motor. When graphing them all I get is, what looks to be noise. In order to obtain the currents I grab them from the "gAdcData" data structure, seen in image below. I create 3 float variable, "CurrentA", "CurrentB", "CurrentC", to which I multiply the full scale current = 10 and then convert the IQ value into float.

When graphing the 3 values I expect to see 3 sinusoidal wave in different phase from one another but all I see is noise.

Can you let me know what I may be doing wrong? The lab manuals show clear sinusoidal graphs.

Thank you

  • 0
    TI__Guru** 117110 points

    Did you use an oscilloscope with a current probe to check the phase current?

    You might refer to the lab01b or lab01c to use the datalog with graph tool to get the current waveform. You can't display the real current waveform by using the graph tool directly without a large data buffer. The data communication speed is not enough to get the real waveform.