My aim is to demonstrate me and my colleagues simulated controller algorithms for a PMSM motor, using field oriented- and direct torque control. The hardware used consists of an existing PMSM with 8 pole pairs, and using the development board ( MTRCKTSBN5643L Product Summary Page ) for MCU and drive stage.
I've been able to get the motor running open loop, and am now trying to get the implementation successfull doing steps by steps.
Now, in order for both the algorithms to work, the current needs to be measured accurately and in the right instant. The evaluation board has three commonly used shunt resistors for phase current measurments, and should be sampled in the middle of the pulse width of the bottom transistor pairs, according to this guide: http://www.freescale.com/files/32bit/doc/brochure/BB3PHCRMSRART.pdf .
Again, since the ADC conversion needs to take place exactly at half the pulse width of the bottom transistor pairs, the ADC conversion and the PWM generation needs to be synchronized, as explained in the brochure. I'm not familiar with existing techniques to do this, but if I'm not wrong, this is where the Cross Triggering Unit needs to be configured properly, so that the ADC conversion is triggered by the CTU.
I've read and understand the theory behind the operation, but can't find the right configuration of the CTU module in the Simulink environment. I've of course tried to follow the MCD Toolbox manual, but can't really follow the explination written there. Is someone here familiar with CTU configuring in the Simulink Environment? I would very much appreciate some help and if possible printscreens for the configuration.