Modelling of Hybrid Electric Vehicle Components in Modelica And Comparison with Simulink THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Avinash Divecha Graduate Program in Mechanical Engineering The Ohio State University 2016 Thesis Committee: Dr. Giorgio Rizzoni, Advisor Dr. Marcello Canova Copyright by Avinash Divecha 2016 ABSTRACT Automobiles affect growth of humanity. Vehicles affect everything from economy to our environment. One of the advancements to ensure the energy consumed by vehicles is sustainable are Hybrid-electric vehicles. Hybrid-electric vehicles cover various domains under its umbrella. They are a combination of different systems including Electrical, Mechanical, Chemical, and Thermal. One of the tools used to model the dynamics of Hybrid-electric vehicles is MATLAB/Simulink which is a general purpose modelling tool. The language of Modelica and its simulation environments allows multi-domain modeling while modeling from the physical perspective. The focus of this thesis was to model components of Hybrid–electric vehicles in a Modelica based simulation environment, in the process learning the advantages and disadvantages of using the Modelica language and the tools which act as the front ends for the language. A model was created to simulate the electrical dynamics of a battery cell and pack. A model of an electric drive was taken from a commercial library and its dynamics were observed by integrating the model of the battery pack along with the electric drive. The models created using Dymola simulated in Dymola and were exported to Simulink to compare results and simulation times. The differences in creating a model in Simulink and a Modelica Simulation environment were examined and noted along with the benefits and shortcomings of the different modeling methodologies. ii DEDICATION To My parents Shailesh and Vibha, Who have molded me into the person I am today and provided for everything I have needed. My brother Yash, Who has always been there for me. All my teachers, Who have taken great efforts to aid my development. And my friends, Who have made this world an enjoyable place to be in. Without you all, none of this would be possible. iii ACKNOWLEDGEMENTS I am grateful to my advisor, Dr. Giorgio Rizzoni who has not only guided me on academic topics and how to conduct research, but also on how live a balanced life, and how to play golf. I would like to express my gratitude to the researchers at The Center for Automotive Research, especially Dr. Qadeer Ahmed, who has helped shaped the outcome of this project, and Dr. Stephanie Stockar, who was not a part of this project but has had an immense influence on me and my research. I would like to thank all the students who have helped me with my difficulties and helped further my knowledge, especially Bharatkumar Hegde, who has always made himself available for discussions which have provided me with insight. I would also like to thank Cummins for funding this research and the entire team there whose questions and feedback were essential to the direction of this project. iv VITA May 2013 ..........................................................B.E. Mechanical Engineering, K. J. Somaiya College of Engineering, University of Mumbai August 2013 to June 2014 ................................Graduate Engineer Trainee, Godrej and Boyce Mfg. Pvt. Ltd., Mumbai, India Jan 2015 to April 2015 .....................................Undergraduate Teaching Assistant, Department of Mechanical Engineering, The Ohio State University March 2015 to May 2015 .................................Student Research Associate, Department of Mechanical Engineering, The Ohio State University May 2015 to Present ........................................Graduate Research Associate, Department of Mechanical Engineering, The Ohio State University FIELDS OF STUDY Major Field: Mechanical Engineering v TABLE OF CONTENTS ABSTRACT ........................................................................................................................ ii DEDICATION ................................................................................................................... iii ACKNOWLEDGEMENTS ............................................................................................... iv VITA ................................................................................................................................... v TABLE OF CONTENTS ................................................................................................... vi LIST OF FIGURES ......................................................................................................... viii CHAPTER 1: INTRODUCTION .................................................................................. 1 1.1 Motivation............................................................................................................... 1 1.2 Simulation Environments ....................................................................................... 4 CHAPTER 2: LITERATURE REVIEW ....................................................................... 7 2.1 HEV Component Modelling Review...................................................................... 7 2.2 Battery Modeling and Comparison of Methods ................................................... 12 CHAPTER 3: THE MODELICA LANGUAGE ......................................................... 13 3.1 Introduction to Modelica ...................................................................................... 13 3.2 Acausality in Modelica ......................................................................................... 18 3.3 Tools running Modelica ........................................................................................ 20 3.4 Comparison of Modelica Simulation Environments ............................................ 28 3.5 Dymola ................................................................................................................. 30 CHAPTER 4: BATTERY MODELING IN MODELICA .......................................... 32 4.1 Overview of Battery Modelling ............................................................................ 32 4.2 0th order Battery Model ......................................................................................... 33 4.3 1st Order Battery Model ........................................................................................ 45 4.4 1st Order Battery Pack Model ............................................................................... 49 4.5 Exporting Battery Models to Simulink ................................................................. 57 CHAPTER 5: ELECTRIC DRIVES MODELING IN MODELICA .......................... 64 vi 5.1 Overview of Electric Drives ................................................................................. 64 5.2 Electric Machine Model ....................................................................................... 67 5.3 Inverter Model ...................................................................................................... 68 5.4 Simulating the Electric Drive ............................................................................... 69 CHAPTER 6: COMPARISON OF MODELICA AND SIMULINK MODELS ........ 75 6.1 Overview of comparison between Modelica and Simulink .................................. 75 6.2 Modeling Approach .............................................................................................. 76 6.3 Data Collection and Plotting ................................................................................. 79 6.4 Acausal Modeling ................................................................................................. 80 CHAPTER 7: CONCLUSION ..................................................................................... 84 REFERENCES ................................................................................................................. 86 vii LIST OF FIGURES Figure 1- Fuel Economy Prediction of Hybrid Vehicles [3] ............................................... 2 Figure 2 – Equations and Schematic of Equivalent Circuit Model .................................... 8 Figure 3 – Simulink Model for Battery Cell Level Calculations ........................................ 8 Figure 4 – Simulink Model for Lumped Battery Pack ....................................................... 9 Figure 5 – Overview of Simulink Model for Interconnected Battery Pack ...................... 10 Figure 6 – Diagram for Inverter ........................................................................................ 11 Figure 7 – Integrator and Derivative blocks with code in Modelica ................................ 19 Figure 8- Equivalent Circuit Model for ECM Battery Modeling ..................................... 33 Figure 9- Model of Capacity Calculator ........................................................................... 34 Figure 10- Model of SOC Calculator................................................................................ 34 Figure 11- Model of Open Circuit Voltage (E0) Calculator ............................................. 35 Figure 12- Model of Resistance R0 Calculator ................................................................. 36 Figure 13- Model of 0th Order Parameter Calculator ........................................................ 37 Figure 14- 0th Order Battery Model .................................................................................