Dual Range Forward Topology for High Efficiency at Universal Mains

This paper introduces a Dual Range Forward converter which overcomes low efficiency of the conventional Forward converter for universal mains voltages, i.e. 220-230 V AC and 115 V AC. The topology comprises of reconfigurable primary power loops enabled by additional state switches. This combination allows the converter to run in parallel or series modes, optimizing the performance at high line, 230 V AC, and low line, 115 V AC mains and enhancing the performance over the 90-265 V AC universal mains. It reduces the voltage rating of devices, supports two optimized working points and improves the utilization of the devices. A 100 kHz, 75 W, 115 V AC or 230 V AC to 12 V DC converter has been designed and tested. The experimental results have been compared against a conventional Forward converter for the same rating. The results show a similar performance at low voltage and considerable improvement at high voltage of 5.5% to 23.5% efficiency increase.