Patent ID: 8922217
Filing Date: 2014-12-30
Classification: G01R

Abstract:
1. A method of determining a state-of-charge for a battery while connected to a plurality of loads, the method comprising the steps of: measuring a terminal voltage of the battery at a plurality of time steps; measuring a terminal current draw of the battery coinciding with the measured terminal voltage at the plurality of time steps; measuring a temperature of the battery coinciding with the measured terminal voltage at the plurality of time steps; generating a state vector of a battery system model as a function of battery parameters, the measured voltage, the measured current, and the measured temperature for each time step, the battery parameters including internal battery resistance and capacitance; generating an estimated state vector as a function of nominal battery system matrices and battery parameter uncertainties for each time step; generating a stator vector for an augmented system as a function of the state vector of the battery system model and the estimated state vector for each time step; generating a covariance for the state vector of the augmented system for each time step; determining an upper bound of the covariance by recursively minimizing the upper bound of the covariance for each time step; determining an open circuit voltage based on an updated state vector utilizing the minimized upper bound; determining the state of charge of the battery as a function of the open circuit voltage; and regulating the battery in response to the state of charge.