Winding Layout Considerations for an Integrated Generator-Rectifier System

An integrated generator-rectifier system is a promising architecture to harvest energy in offshore wind turbines. The system processes the majority of the incoming power using reliable, efficient, and inexpensive passive diodes operating at generator line frequency. Elimination of capacitors at the diode rectifiers output by appropriately phase-shifting the voltages of a multi-port generator further improves the reliability of the overall architecture. This paper creates a generalized framework to evaluate the interactions among the different generator ports, diode-bridge rectifiers, and the active rectifier that is used to control the power flow. The framework enables quantifying the effect of integration on the dc bus power ripple and power imbalance among different generator ports. An exemplary winding layout is proposed that ensures theoretically zero interaction between the passive ports though all the ports are mounted on a magnetic structure. A 10 MW integrated generator-rectifier design and simulation proves the accuracy of the framework using coupled circuit-and-finite-element simulation. Finally, a laboratory prototype shows the realization of the winding layout. The proposed inductance-matrix based framework can be used to evaluate other winding layouts to estimate the effect of magnetic coupling on the systems performance.