yelstor
Junior Member level 1
Hello
I'm going to design a 3000W DC / DC source, so I thought it would be best to parallelize 2 1500W sources, to facilitate the fabrication of the transformers (I plan to use 2 fullbridge). Consulting the literature, it is necessary to balance the currents of each stage. for this I have seen reference designs of texas instruments and infineon, which basically use 2 independent controllers for each stage, and synchronize them with a synchronization pin arranged in the integrated circuit. My question is that I have had the opportunity to see some 48Vdc / 110Vac inverters. These inverters when the power is high, parallel several pushpull stages, but only have one controller! How do these manufacturers ensure that the current is the same in each stage?
for example, in the schematic that I attached that corresponds to a 1500W inverter, two stages are parallelized, but their pwm signals are the same.
I have thought that perhaps when they implement the transformers, they are as equal as possible, but a difference of only 5% (magnetic cores have a tolerance of 10%) makes the current in a stage is greater than in the other. I do not know if there is something in the circuit that I attach that ensures the current balance, so please tell me where.
Thank you very much.
View attachment 1500W INVERTER full schematics and pcb (1).pdf
I'm going to design a 3000W DC / DC source, so I thought it would be best to parallelize 2 1500W sources, to facilitate the fabrication of the transformers (I plan to use 2 fullbridge). Consulting the literature, it is necessary to balance the currents of each stage. for this I have seen reference designs of texas instruments and infineon, which basically use 2 independent controllers for each stage, and synchronize them with a synchronization pin arranged in the integrated circuit. My question is that I have had the opportunity to see some 48Vdc / 110Vac inverters. These inverters when the power is high, parallel several pushpull stages, but only have one controller! How do these manufacturers ensure that the current is the same in each stage?
for example, in the schematic that I attached that corresponds to a 1500W inverter, two stages are parallelized, but their pwm signals are the same.
I have thought that perhaps when they implement the transformers, they are as equal as possible, but a difference of only 5% (magnetic cores have a tolerance of 10%) makes the current in a stage is greater than in the other. I do not know if there is something in the circuit that I attach that ensures the current balance, so please tell me where.
Thank you very much.
View attachment 1500W INVERTER full schematics and pcb (1).pdf