FORWARD CONTROLLER DESIGN

[davidraj]

Voltage Regulation of Forward Converter in Voltage Mode Control

The converter was designed for the following conditions:

• Enom = 48 V
• Vo = 12V
• n1:n2:n3 = 6:3:3
• Emax = 60V
• Emin = 40V
• Manetizing inductance of transformer seen from primary = 50µH
• E L = 10µH
• C = 400µF
• rC = 0,001Ω (Also called Capacitor ESR)
• Pmax = 150W
• Pmin = 15W

The PWM ramp has amplitude of 3V The Reference voltage for the regulator is 2.5V
All the diodes have the reference RB238NS100 Fsw = 100 kHz 1 The transistor is a MOSFET reference IPB107N20N3. I have implemented the control loop and I could also see that my capacitor and resistor values are wrong but my problem is that the simulation is so slow and I do not understand by. Please help me.

 

[BradtheRad]

* Your schematic has inductors/ transformers neighboring diodes (or PN junctions). In simulations I've seen these combinations generate high-frequency oscillations. My hunch is that the inductor produces a current spike (turns On) starting current again in the diode just after it shut Off.

* At this early stage of development your schematic is overly complicated. Try deleting the right half. Substitute a dirt-simple PWM signal which controls the mosfet at left. Experiment by adjusting all parameters of your PWM: frequency, peak voltage trough voltage, duty cycle, etc. Later you can add the second half.

* Delete unnecessary wires or else you force the simulator to calculate Amperes through wires needlessly. Example, where a component joins other components going to ground, give each a ground icon: to L3 D1 C1 R2. Delete current source I1.