Analysis of digital controllers for equilibrated current distribution in an interleaved inverter

The control of the current distribution in a two leg interleaved inverter is analyzed in this paper. Feedback is used in order to control the current distribution on the inverter legs, avoiding the use of bulky and costly passive solutions. Low THD in the output voltage is ensured by a PI compensator and a repetitive controller. The design of the current compensators was accomplished by approximating the system to two SISO systems. It is shown that this method is feasible if the output voltage is decoupled by using output voltage decoupling. Good experimental results were achieved in a two leg 4kVA inverter operating at 7680Hz. They showed that the benefits of interleaving are not highly affected by using distinct modulator signals provided that the differences between the legs parameters are small.