Patent ID: 7271570
Filing Date: 2007-09-18
Classification: H02J,H02P,Y02T

Abstract:
1. An automotive electrical system comprising: a DC bus; a voltage sensor configured to sense a voltage of the DC bus; a current sensor configured to sense a current of the DC bus; an alternator; an active rectifier coupling the alternator to the DC bus, the alternator comprising a plurality of FETs; and a microcontroller coupled to the voltage sensor, the current sensor, and the active rectifier, the microcontroller configured to control switching of the plurality of FETs without reference to a shaft position of the alternator by analyzing the voltage and current of the DC bus wherein under normal operating the microcontroller switches the plurality of FETs to minimize ripple current on the DC bus by executing instructions corresponding to the method comprising: sensing a first ripple current and first average current on the DC bus to which the output of the rectifier is connected; perturbing a phase of FET switching relative to an AC voltage generated by the alternator in a first direction; sensing a second ripple current and a second average current on the DC bus after perturbing the phase of FET switching; and comparing the first ripple current and first average current to the second ripple current and the second average current to determine whether the phase of FET switching should be again perturbed in the first direction or a second direction opposite the first direction.