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SVM Implementation using abc to alpha beta transformation

Question asked by Amey Murkute on Jul 28, 2019
Latest reply on Aug 2, 2019 by David Tosenovjan

Hello all,

          As I have started to implement the SVM using etpu api provided by NXP which requires alpha beta inputs. I have calcultaed alpha & beta by the following manner.

alpha = a - b*cos60-c*cos60

Beta = b*cos30 - c*cos30

:where a,b & c are sine angle of of three phases 

fs_etpu_pwmmac_update_svm(PWM_master_channel, (Voltage.xalpha * 4194304), (Voltage.xbeta * 4194304));


when I input this alpha beta to etpu api, I get the sector in reverse order(the reference vector rotates in clockwise but it should rotate the anitclockwise as sector 1 to 6 lies in anticlockwise manner), I have also attached image of alpha & beta waveform which I have observed.                                                             

When I reverse the alpha beta as 

fs_etpu_pwmmac_update_svm(PWM_master_channel, (Voltage.xbeta * 4194304), (Voltage.xalpha * 4194304));

I get the correct sector wise waveform(from sector 1 to 6). So I dont know why this is happening. So please suggest a solution.