Concept and Preliminary Sizing of a Dual DC-Bus Homopolar Generator Using Diode Rectifiers

Abstract

Synchronous Homopolar Generators represent an attractive solution for the future of power generation in propulsive systems based on hybrid turbo-electric drivetrains. In fact they feature both a fully controllable excitation, similar to wound-field synchronous machines, and a very robust rotor like switched reluctance machines. The above features make this machine topology a promising alternative also to PM synchronous generators, even when DC power buses have to be supplied via diode rectifiers. The preliminary electromagnetic sizing of a 15 kW @ 15 krpm homopolar synchronous generator is proposed as a concept demonstrator, and then validated via 3-D Finite-Element analysis. The generation system is designed on purpose to supply two independent 600 V DC power buses for improved redundancy, by using 4 winding sections supplying 2 three-phase diode rectifiers connected in series per each bus to reduce the voltage ripple.