Sciebou
Newbie level 6
Hello,
I would like to simulate a buck converter in closed-loop with SABER. Here is the schematic:
Classically, there are two loops with PI controllers: external voltage loop, and internal current loop. The output of the current loop's PI controller is compared to a sawtooth signal in order to generate PWM signals for gate drive.
Vin = 270V
Vout_setpoint = 30V
Rload = 1.8V
fsw = 400k
time step = 0.5u
However, I obtained the following strange results:
Output voltage:
The two op amp are both saturated. (Vcc and Vee are increased to ±30V, which is very big, but if not Vout is very small).
The MOSFET's and diode's current are strange, the PWM signals as well:
Finally, the diode's cathode voltage is not as expected. Its maximum is normally Vin = 270V, but is limited here to 28V::-(
PI parameters are carefully calculated with these two transfert functions:
Do you have some diagnosis for my problem?
Many thanks for your help.
I would like to simulate a buck converter in closed-loop with SABER. Here is the schematic:
Classically, there are two loops with PI controllers: external voltage loop, and internal current loop. The output of the current loop's PI controller is compared to a sawtooth signal in order to generate PWM signals for gate drive.
Vin = 270V
Vout_setpoint = 30V
Rload = 1.8V
fsw = 400k
time step = 0.5u
However, I obtained the following strange results:
Output voltage:
The two op amp are both saturated. (Vcc and Vee are increased to ±30V, which is very big, but if not Vout is very small).
The MOSFET's and diode's current are strange, the PWM signals as well:
Finally, the diode's cathode voltage is not as expected. Its maximum is normally Vin = 270V, but is limited here to 28V::-(
PI parameters are carefully calculated with these two transfert functions:
Do you have some diagnosis for my problem?
Many thanks for your help.