Part Number:TMS320F28379D
Hi, I have some questions about SFRA.
1. Is the source code of SFRA related functions such as SFRA_F_INJECT available?
2. Let's say we have 100 different frequencies injected from 1Hz to 100Hz, and we will get 100 groups of {FreqVect, OL_MagVect, OL_PhaseVect, Plant_MagVect,Plant_PhaseVect}
to draw the bode plot of the circuit. Is each group of
{FreqVect, OL_MagVect, OL_PhaseVect, Plant_MagVect, Plant_PhaseVect}
sent to the laptop through SCI as soon as they are available, or 100 groups are gathered and stored in MCU and then sent together to the laptop?
// assign a GUI "getable" parameter array address
arrayGetList[0] = (int32*)FreqVect; //Float 32
arrayGetList[1] = (int32*)OL_MagVect; //
arrayGetList[2] = (int32*)OL_PhaseVect; //
arrayGetList[3] = (int32*)Plant_MagVect; //
arrayGetList[4] = (int32*)Plant_PhaseVect; //
arrayGetList[5] = (int32*)&(SFRA1.Freq_Start); //Float 32
arrayGetList[6] = (int32*)&(SFRA1.amplitude); //Int32
arrayGetList[7] = (int32*)&(SFRA1.Freq_Step); //Float32
3. Let's say we are implementing SFRA in a buck converter. If we would like to use SFRA in open loop to get plant(H) Frequency Response:
we will inject different frequencies of duty cycle duty * sin(2pi*f*n*1/fs) (fs is SFRA_ISR_FREQ, and f is the injected signal frequency i.e. f=1Hz, 2Hz, 3Hz, 4Hz, 5Hz), and read back the output voltage Vout through ADC. What we get from the ADC are scattered points, we have to fit Vout to an equation like Vout=V*sin(2pi*f*t+theta) to get MagVect and PhaseVect, right? So we have to inject the signal for at least one period to get enough points to fit the equation, right? So how many period is injected in SFRA? And which function complete this fit and get MagVect and PhaseVect?
4. We have to power the circuit when we use SFRA in open loop to get plant(H) Frequency Response, right? But the circuit may work at an unstable condition, right? How can we avoid that?