Abstract: An electrical charging strategy and system for a high voltage electrical energy storage system able to supply electrical energy to a hybrid vehicle is disclosed. The system charges the electrical energy storage system so state-of-charge at the end of a trip is substantially unchanged. The strategy and system employs opportunity charging to achieve maximum energy efficiency of the hybrid system, thus minimizing fuel consumption and maximizing fuel economy. The charging system operation is controlled, based upon: the state-of-charge of the electrical energy storage system, and, the operating efficiency of the internal combustion engine. Battery life is likewise extended through use of this strategy.

Abstract: A charging system for a hybrid vehicle comprises an internal combustion engine, an electric motor generator coupled to the internal combustion engine and operable to be driven as a generator to produce a charging voltage and a battery coupled to the electric motor generator and configured to receive a charge voltage. The charging system further comprises an engine control computer coupled to the internal combustion engine, the electric motor generator and the battery. The engine control computer is configured to determine a threshold CSFC, calculate an instantaneous CSFC, and initiate active charging of the battery if the instantaneous CSFC is less than or equal to the threshold CSFC.

Abstract: A method for determining a voltage based or current based state of charge (SOC) and state of health (SOH) of a battery system is provided. The method includes: providing a model of the battery system including an equivalent circuit having both low frequency and high frequency elements; establishing a plurality of functional relationships comprising relationship of the equivalent circuit with SOC; reducing at least part of the plurality of functional relationships into a set of time segmented recursive functional relationships, wherein a state at a first time t can be modeled by a functional presentation of a state at a second time t??t that occurred before the first time t; and computing a set of data points based upon the set of time segmented recursive functional relationships using a matrix for operation in matrix algebra.

Abstract: A refresh control system that selectively initiates a refresh charge cycle includes an energy storage device and an electric machine that is operable to charge the energy storage device. A control module monitors a usage period of the energy storage device and determines a bias factor. The control module determines a modified usage period threshold based on a usage period threshold and the bias factor. The control module regulates the electric machine to initiate a refresh charge cycle of the energy storage device when the usage period exceeds the modified usage period threshold.

Abstract: A method of estimating a state of charge (SOC) and a state of health (SOH) of an electrochemical cell (EC) includes modeling the EC with a linear equation, measuring a terminal current of the EC, measuring a terminal voltage of the EC and measuring a temperature of the EC. The linear equation is processed through a time-varying state and parameter estimator based on the terminal current, the terminal voltage and the temperature to determine states and parameters of the EC.

Abstract: A method for determining a state of charge (SOC) of a super-capacitor (SC) system includes modeling the SC system with an equivalent circuit having first and second parameters. The method further includes estimating a value of the first and second parameters based on a measured voltage and determining the SOC based on the first and second parameters.