300 likes | 434 Views
Modeling and Simulation of Nickel-Cadmium Batteries during Discharge. Giuliano S. Sperandio Cairo L. Nascimento Jr. Geraldo J. Adabo Prof. Master Program in Aeronautical Eng. (ITA-EMBRAER) Instituto Tecnológico de Aeronáutica (ITA) Brazil. Introduction.
E N D
Modeling and Simulation of Nickel-Cadmium Batteries during Discharge Giuliano S. Sperandio Cairo L. Nascimento Jr. Geraldo J. Adabo Prof. Master Program in Aeronautical Eng. (ITA-EMBRAER) Instituto Tecnológico de Aeronáutica (ITA) Brazil
Introduction • Electrical batteries are essential components of an aircraft. • Main uses: • to start the propulsion engines, • to provide power during electrical emergencies. • The knowledge of the battery dynamics is important for the aircraft designers. • Virtual Aircraft Project.
Introduction • Battery manufacturers provide DATA: voltage curves over time considering • constant room temperature T, • constant discharge current I, • battery initially fully charged. • Battery manufacturers DO NOT provide MODELS.
Objective • Produce a mathematical model to be used for simulation of the battery discharge during eletrical emergencies when: • the discharge current is not constant, • the battery is not fully charged. using the data provided by the battery manufacturer to adjust the model parameters.
Ni-Cd Battery Model • U(t) = f(DOD(t),I(t),T(t)) U(t) = battery voltage DOD(t) = Depth of Discharge I(t) = discharge current T(t) = temperature
Battery Data Extraction • At least 50 points were manually captured for each curve. • A polynomial function was fitted to each curve. problem: how to select the order of the polynomial? • In each case, a polynomial function was used to interpolate and extrapolate the curve to U=0.
Ni-Cd Paatero's Battery Model • adapted from a lead-acid battery model, • 17 parameters.
Model Modification Proposal • Paatero's model considers the battery capacity constant. • The battery capacity is influenced by the discharge current and the room temperature. • Idea: to model the battery capacity as a function of the room temperature T and the discharge current I.
Battery Model Modification Proposal • Model the battery capacity using:
SIMULINK Simulation Case: constant current load
Model Simulation Case: Constant power load
Model Simulation Case: Constant resistance load
Conclusions • Proposal of a procedure to generate a Ni-Cd battery discharge model. • The results show that the proposed battery model fits the data well over a large range of discharge currents and room temperatures. • Use of the model to simulate battery discharge with different load types.
Future Research • Comparison of the simulation results for emergency situations with experimental data. • Proposal and validation of a model for the charging phase of aircraft batteries. • Proposal and validation of a model for battery aging (capacity degradation).