An Integrated Permanent-Magnet-Synchronous Generator-Rectifier Architecture for Limited-Speed-Range Applications

Conventional high-power ac - dc conversion architectures rely heavily on active rectifiers, which consist of fully controlled power-electronic switches. These make the system bulky, lossy, and less reliable. This article presents an alternative approach - integrating a multiport permanent-magnet synchronous generator (PMSG) with series-stacked power converters. An active rectifier processes only a fraction of the total converted power while regulating the dc bus. The remaining power is processed by diode bridges, which allows a substantial increase in overall efficiency, power density, and reliability. Theoretical analysis shows that for wind-power generation applications, the active rectifier processes a maximum of 39% of the rated power while the generator operates in a speed range similar to the conventional doubly fed induction machine. The conversion loss is reduced by 47%. Results from a laboratory-scale experimental setup corroborate the proposed architecture. This approach potentially increases integration of medium-voltage dc distribution to the megawatt-class mechanical-to-electrical energy conversion systems to achieve higher efficiency, higher power density, and lower cost compared to the conventional solutions based on a single-port PMSG with a full-power-rated converter.