Improve Performance of Dual-output Configuration IPOS Structure

In renewable applications and DC grids, the bipolar or dual-output loads configuration is preferred due to flexibility, safety, and reliability. Hence, the conventional dual-output input-parallel output-series (IPOS) structure, which has high voltage gain, low switch voltage stress, low input current ripple, and natural output voltage balancing characteristics, is a good candidate. However, the topology still has some minor drawbacks, such as the PWM scheme needing to change when the duty ratio (D) is less than 0.5, leading to complexity in control, and the switch voltage and current waveforms varying through three levels, leading to potential EMI problems. This research introduces a modified IPOS structure, which can solve this problem, and all advantages remain. The switches (S-2 and D-2) current stresses reduce when D < 0.5, compared to those of the conventional converter. Furthermore, the capacitor voltage ripples are reduced. The modified converter is verified by simulation and experiments with a 1.6 kW prototype.