Patent ID: 6469476
Filing Date: 2002-10-22
Classification: H02J,H02M,H02P

Abstract:
A motor vehicle electrical system, including a storage battery connected to supply power to electrical loads and an alternator driven by a vehicle engine for generating electrical power during operation of the engine, and further comprising:a DC-to-DC resonant converter coupled between the alternator and the storage battery, and operable to supply generated electrical power to the storage battery in a selected one of a plurality of modes providing different voltage transfer ratios between the alternator and storage battery, including a forward boost mode in which the converter supplies power to the storage battery at an output voltage which is higher than that generated by the alternator and a forward unity mode in which the voltage generated by the alternator is transferred to the storage battery at a unity transfer ratio; and control means for obtaining a speed of the engine or alternator, determining which of a plurality of predefined speed ranges said speed is within, selecting the forward boost mode when said speed is in a first speed range including an idle speed of the engine, and selecting the forward unity mode when said speed is in a second speed range above said first speed range.