Abstract: A vehicle operates an internal combustion engine according to an automatic start-stop function to reduce fuel consumption. A first DC bus is adapted to connect to a plurality of DC loads. A primary battery is coupled between the first DC bus and a ground. A first alternator is driven by the internal combustion engine to supply electrical power to the first DC bus. A second DC bus is connected to a positive terminal of an auxiliary battery. A negative terminal of the auxiliary battery is connected to the first DC bus. A second alternator is driven by the internal combustion engine to supply electrical power to the second bus at a voltage corresponding to a sum of voltages of the primary and auxiliary batteries. An inverter receives electrical power from the second DC bus to generate an AC output adapted to connect to accessory AC loads.

Abstract: A system and method for controlling the voltage output of an alternator is disclosed. The system includes an alternator having a rotor, which has a field winding, a stator having a plurality of phases, a rectifier bridge connected to the plurality of phases, at least one detection circuit connected to each of the plurality of phases, and a controller in communication with the at least one detection circuit and the rectifier bridge. The plurality of phases of the stator are magnetically coupled to the field winding. The rectifier bridge has a plurality of switches for rectifying the alternating current developed in the plurality of stator phases. The at least one detection circuit connected to each of the plurality of phases are used to sense a current reversal in each of the plurality of stator phases. The controller controls the operation of the plurality of switches when the reversal of the current has been sensed by the at least one detection circuit.

Abstract: A method and system for controlling an alternator in a power supply system for a vehicle utilizing a digital current control or compensation algorithm. The alternator has field windings and provides an output current as a function of field voltage across the field windings. The alternator is controlled by a microprocessor-based voltage regulator programmed with the algorithm in response to a reference control signal and a load demand signal based on the current demand of the electric load. Desired responses of the alternator to corresponding current demands are defined by a data matrix of system operating coefficients. A set of the coefficients is selected based on the load demand signal and the set is used with the algorithm to calculate a desired field voltage so that the output current is responsive to variations in system load demand.