Other Parts Discussed in Thread: CONTROLSUITE, TIDM-1007
We are trying to design Boost PFC (1kW) 100Khz switching frequency using TMS320f28069 for VARIABLE Loading conditions(100W - 1kW) Output Voltage 380 Volts.
The documents that we have referred are SPRA902A and SPRUI55.
I also modeled the entire circuit in Matlab for all loops (Input Voltage squared inverse, Current Loop and Voltage Loop).
For Input Voltage and C-Inverse Calculation we have followed SPRA902A as it says!!
Only difference is that we are using a digital low pass filter to get Average of Input Voltage and we are scaling it to operate from 265Vrms to 85Vrms.
Here i have attached the Matlab script for controller design.
s = tf('s');
l = 260e-6;
c = 660e-6;
vout = 380;
vin = 230;
ro = 144.4; % Full Load
vmax = 265*1.4142;
vmin = 85*1.4142;
voutmax = 600.2;
Imax = 16.6;
%% Current Transfer Function
ctf = vout/(s*l);
opts = pidtuneOptions('PhaseMargin',60,'DesignFocus','balanced');
ccomp = pidtune((ctf/Imax),'PI',(2*3.1416*10000),opts);
ccompz = c2d(ccomp,1/50000,'tustin');
%% TI Voout to Control transfer function
vti = (vmin*Imax*ro)/((2+(s*c*ro))*vout); % Corrected from SPRA902A % removed the typo of 2
opts = pidtuneOptions('PhaseMargin',60,'DesignFocus','balanced');
vcomp = pidtune(vti/voutmax,'PI',(2*3.1416*10),opts);
vcompz = c2d(vcomp,1/10000,'tustin');
We are facing following issues:
1. When running at 85 Volts and Full Load (144.4 Ohms/ 1000W) the Inductor Current shape and value is proper but at Lighter Loads(1444Ohms / 100W) it gets distorted.
2. When Operating at 230 Volts for Both Full Load and Lighter Load the current shape is deformed but value appears to be approximately correct.
3. Also there is Issue with the value of Zf to be considered from SPRA902A. (For Constant Power Load or Impedance Load)???
Are we missing out something in Controller Design??
Are we missing something in Input Voltage Scaling??
Our previous conversation link is e2e.ti.com/.../8179788
