Power loss reduction of a AC-DC converter features 10-V and 10,000-A sintering power supply

This paper discusses a high-efficiency AC-DC converter developed for low-voltage and high-current conditions for sintering power applications. First, the circuit configuration and the control principle for the proposed low-voltage high-current AC-DC converter are described. The proposed system consists of four 2,500-A units of the AC-DC converter connected in parallel. The input current harmonics are suppressed by multiple transformers on the input side. Also, imbalance issues on the transformer parameters and the output wiring are discussed. The proposed system demonstrates that each individual circuit yields a balanced 10,000-A(10-kA) output. In addition, loss analysis shows that the power loss on the secondary rectifier is 49% dominated by semiconductor loss. Furthermore, it is shown that by implementing a MOSFET synchronous rectifier instead of a Schottky barrier diode, the loss will be reduced by 35%. Finally, the input current harmonics are reduced by using multiple transformers and the validity of this result is demonstrated.