Improving Circuit and Transformer Complexity for 24-Pulse AC-DC Converter Topology

This paper proposes a novel three-phase 24-pulse diode converter topology derived from cascading two 12-pulse rectifiers. Unlike existing designs that use multi-tap Interphase Reactors (IPR) or transformers, our configuration eliminates the need for interface transformers or reactors, significantly reducing cost and complexity. The topology provides galvanic isolation between input and output, making it suitable for high-power applications like high voltage direct current (HVDC) transmission. Theoretical analysis shows the design achieves low input current harmonic distortion by canceling harmonics up to the 21st order. Experimental results from a reduced-scale 500W prototype validate the topology, demonstrating an output voltage of 547.6V, input current total harmonic distortion (THD) of 4.4%, and efficiency of 87.4% at full load. This simple yet effective design offers a competitive balance of performance and practicality for multi-pulse AC-DC conversion.