Hybridization of an Urban Car(Series)

Battery Model

Tariq Kareemulla 30-05-2013

The Model

• Battery-circuit(Matlab-SIMULINK) :

The Model

• Dynamic Approach:

Battery Open-circuit voltage, Internal resistance & transient resistances/capacitances as a function of the SoC.

• Static Approach:

SoC is estimated by Coulomb Counting method (SOC is computed and corrected using a PI controller).

Proposed Methods

* Ref [1]

* Ref [6]

Dynamic Model

* Ref [1]

Equations:

Dynamic Model

Block Diagram of the Proposed Method

Data Necessary For Simulation

* Ref [1]

The MATLAB-Simulink model of the proposed technique was simulated , but the results were quite surprising compared to the reference*. Hence not shown in this presentation.

Simulation Results

* Ref [1]

Static Model

Where,SoCi = Initial SoC

Qnom = Nominal Capacity of the battery

I = Current flowing through the battery

N.B- The magnitude of current is taken as positive for discharging process and negative for charging process.

nomi Q

dt ISoCSoC

Equations:

Static Model

Block Diagram of the Proposed Method

* Ref [6]

• The error signal produced is given by,ε = Vbat, meas – Vbat, model

• The actual SoC estimated i.e. SoCe is given by,

SoCe = SoCcc + SoCcf

 The correction factor produced by the PI controller is given by, SoCcf = Gc(s). ε

Where, Gc(s) = Transfer Function of the PI Controller

Controller

The remaining runtime “Tr” is calculated as,

Tr = [SoCe – SoC(EoD)] * Qnom

_____________________________ Ibat

Where, Qnom = Nominal Capacity of the Battery

SoC(EoD) = SoC at End of Discharge (EoD)

Ibat = Battery Current

SoCe = Actual estimated SoC

Remaining Time estimation

The MATLAB-Simulink model of the proposed technique was simulated with the following parameters :• Qmax. (The capacity of the battery) =4.5Ah• The initial SoC(SoCi) =100%• OCV (Open-circuit voltage ) =3V

The model was simulated for a time-period of 75 seconds , for a discharge current and the SoC and terminal Voltage are estimated as shown in the following figures(Next slide)

Simulation Results

Simulation Results

SO

C (%

)Volt

age (V

)

Time (s)

Progress Report

• The basic principle behind the Hybrid powertrain and the parameters and equations governing their operation were thoroughly studied throughout the project.

• With the rising importance for battery, both in the automotive industry and the energy sector, it is of critical importance to develop more accurate algorithms for SoC estimation of the battery.

• Despite sincere efforts to understand all the characteristics of HEV batteries, simulation and analysis were mostly carried out for Discharge currents, during the course of the project work.

Conclusion

References[1] Ryan C. Kroeze and P. T. Krein, “Electrical Battery Model for Use in Dynamic Electric Vehicle Simulations”, in Power Electronics Specialists Conference, pp. 1336-1342, 15-19 June 2008.

[2] Vehicle Propulsion Systems- Lino Guzzella & Antonio Sciarretta

[3] Linden’s Handbook of Batteries - edited by Thomas B. Reddy

[4] Li-ion battery models for HEV simulator - M. Debert, G. Colin, M. Mensler, Y. Chamaillard, L. Guzzella

[5] Datasheet-A123 Systems (High Power AHR32113 Cylindrical Cell) http://www.a123systems.com/32113-lithium-iron-phosphate-high-power-batteries.htm

[6] SOC estimation of Rechargeable Batteries - Jeevan Reddy(M.Tech Power Electronics & Drives, VIT)

THANK YOU

Team Series– Abijoe

– Raaj– Rohan

– Shankar– Tariq

– Venkat