Design of dual-output alternators with switched-mode rectification

The push to introduce dual-voltage (42V/14V) automotive electrical systems necessitates power generation solutions capable of supplying power to multiple outputs. A number of approaches for implementing dual-voltage electrical systems have been proposed, but most suffer from severe cost or performance limitations. This paper explores the design of alternators incorporating dual-output switched-mode rectifiers. The proposed approach enables the full load-matched power capability of the alternator machine to be achieved, with power delivered to the two outputs in any desired combination. Switched mode rectifier (SMR) topologies for this application are introduced. Alternator/SMR design guidelines are established, and appropriate control laws are derived. Simulation and experimental results are presented that demonstrate the feasibility and high performance of the approach.