A Simple, Passive 24-pulse AC-DC Converter with Inherent Load Balancing Using Harmonic Voltage Injection

A new converter topology for a 3-phase, multi-pulse rectifier circuit is described, which is especially suitable for aircraft applications. This converter draws almost sinusoidal currents from the AC system with very low harmonic content, typically less than 3% total harmonic distortion. The topology uses only passive components and has a lower component count than other rectifier circuits with similar performance. Two six-pulse rectifier bridges are connected in series, fed by a series connection of transformers, to form a 12-pulse system. An additional low power harmonic injection circuit enhances the performance of the circuit to obtain low harmonic current pollution levels that are comparable with those achieved from a 24-pulse rectifier