A real-time estimator for model parameters and state of charge of lead acid batteries in photovoltaic applications

Description of Acid Battery Operating Parameters

“…According to the aforementioned dependencies Equations ( 19) and ( 20), the battery operator transmittance was determined for the signal presented in Figure 7a and described using Equation (16). It was assumed that the input signal is the leap in the polarization electromotive force with a value equal to the sum of component amplitudes in Equation ( 16), given as Equation ( 22):…”

“…A description of the battery discharge characteristics by means of a linear combination of two or more exponential functions indicates the possibility and need to also apply a larger number of RC circuits connected in series to the equivalent circuit of the battery. Determination of the parameters of the circuit components is made possible on the basis of the test results of the battery discharge characteristics, as specified in (16,17). It is known that the capacitor discharge characteristic is the exponential curve in the following form (18):…”

“…For the state of charge of batteries, and its dynamic determination, supervised chaos genetic algorithms have been used [15]. The use of the Kalman filter based on the RC model for estimation of model parameters and the state of charge of lead-acid batteries requires knowledge of the value of the process covariance and the measurement noise [16]. The prediction voltage and lifetime of a lead-acid battery may be determined using neural network methods [17].…”

Exponential Moving Average Extended Kalman Filter for Robust Battery State-of-Charge Estimation

“…Model (8) or (9) provides the evolution of state variables of the battery equivalent circuit. However, the output or the value that is typically measured is the terminal voltage of the battery which is given by eq.…”

“…As highlighted in the previous Section, measurement noise and unavailability of the initial SOC make it difficult to apply Coulomb counting method in practice. Extended Kalman filter (EKF) [6]- [9] is a popular choice in the literature to overcome these issues. EKF can easily be applied to the nonlinear system ( 14) and ( 15) and based on the estimated states, battery SOC and filtered version of the terminal voltage can be obtained.…”