Buck boost converter not working

[Phrancees69]

Hi engineers, I need help with my buck boost converter. I designed a high gain buck boost converter and it works perfectly on simulation (Proteus/Ltspice). However when I build the prototype on pcb and breadboard it doesn't work. My circuit has two switches; high and low side. I have tried ir2110 and hcpl3150 optocoupler switch drivers and the the drivers work just fine as they supply the required gate pwm pulses. but the main converter is not working. I also notice that whenever I turn on the power supply, the value drops drastically and there is no output from my converter. My circuit schematic is posted, kindly check to discover errors. Thank you

 

[Phrancees69]

Hello, I recently discovered that current through my diode is as high as 7A in the simulation. But in my prototype I am using 1N5822 diode which has an average forward current of 3A. Hence, this could be the reason why I don't have an output since current is not passing through the diode. Kindly suggest any other diode type that can handle as much as 8A current. Also, before now i didn't supply any current from my DC power supply to my input, that's why the value diminishes when I energise the circuit. Thank you for your support thus far

 

[Easy peasy]

parallel up your diodes - but remember the PIV on the diode is only ... 40V, go over this and bang ....

--- Updated Oct 5, 2022 ---

p.s. a 3A diode will in fact pass 7A no worries, just with a slightly higher forward drop, and hence a warmer temp rise - also the sw losses will be higher ....