Design of dual-output alternators with switched-mode rectification

The push to introduce dual-voltage (42 V/14 V) 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 (SMRs). 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. 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.