SVM Implementation using abc to alpha beta transformation

[amey_murkute]

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. 

[davidtosenovjan]

Hi, I was searching over old ticket database, it seems AN2969 Figure 2 is incorrect. Unfortunately there is currently no available eTPU expert who could help with that.

I am attaching excel sheet I understand it is correct. Inside that spreadsheet is also a plot of the angle vs sector and our eTPU experts stated it is correct.

Not sure if this helps, at least trying