Abstract: A dual voltage automotive electrical system includes a generator for generating a first nominal voltage on a first voltage bus and a bi-directional DC/DC converter for converting the first nominal voltage to a second nominal voltage on a second voltage bus, the second nominal voltage being lower than said first nominal voltage. A battery is coupled to the first voltage bus and selectably coupled to the second voltage bus, and is capable of supplying power to loads on both the first voltage bus and the second voltage bus.

Abstract: A dual voltage automotive electrical system includes a generator for generating a first nominal voltage on a first voltage bus and a bi-directional DC/DC converter for converting the first nominal voltage to a second nominal voltage on a second voltage bus, the second nominal voltage being lower than said first nominal voltage. A battery is coupled to the first voltage bus and selectably coupled to the second voltage bus, and is capable of supplying power to loads on both the first voltage bus and the second voltage bus.

Abstract: A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary.