Hello,
I have been working on an electric vehicle project at university and we are currently using a Semikron SKAI MD5001MD15-1450L which has a TMS320LF2406A DSP inside the system.
The 3ph PMSM rotor angle (and also speed n) is detected via a Resolver and the signal is converted to a digital value via a custom built board and input into the DSP.
Up to now simple motor code using 6-step implementation has been used. The next step is to implement Field oriented control and have referred to the SPRA588 document.
I understand all the Clark and Park transforms and their use to convert the phase currents into a vector (in a rotating frame) who's axis is flux and torque.
The reference motor speed (nref) will be determined by a potentiometer input which is connected to the accelerator.
What has had me stuck in understanding the system in the last few days is:
- how to get Isqref from n and nref. I believe this is though the PI (speed) controller which there is no clear definition in the document about the implementation of this and getting a reference current by comparing the speed and reference speed. I am confused how the PI speed controller converts the speed comparison to a current
- how to get from the currents Isd, Isq, Isdref (=0) and Isqref to Vsdref and Vsqref. Once again I believe this is though a PI current controller (which I have never designed before) and am confused of how the PI current controller converts the current comparisons to voltages.
Is there someone could point me towards, and is there any updated example code as in the SPRA588 document in C rather than in assembly language. I understand this DSP is outdated but is was part of what we have been provided by the university and had no say in the selection of the inverter as it is a project continuing from previous years students.
Thanks,
Stefano
