Hybrid Electric Vehicle Simulation Research Articles

Development of equivalent fuel consumption minimization strategy for hybrid electric vehicles

Power distribution between an internal combustion engine and electric motors is one of main features of hybrid electric vehicles that improves their fuel economy. An equivalent fuel consumption minimization strategy can instantaneously identify the optimal power distribution by converting the battery power into the equivalent fuel power and minimizing the overall fuel consumption. To guarantee the effectiveness of the strategy, it is essential to find the proper value of the conversion factor used to obtain the equivalent fuel power. However, finding the proper value is not a straightforward process because it is necessary to consider the overall power conversion efficiencies and battery charge sustaining strategy for the target driving cycle in advance. In this study, a model-based parameter optimization method is introduced to find the optimal conversion factor. A hybrid electric vehicle simulation model capable of estimating fuel consumption was developed, and the optimal conversion factor was discovered using a genetic algorithm that evaluates its population members using the simulation model. A series of simulations and vehicle tests was conducted to verify the effectiveness of the optimized strategy, and the results show a distinct improvement in fuel economy.

Simulation and control of hybrid electric vehicles

This research develops a typical model for a parallel hybrid electric vehicle. Model predictive controllers and simulations for this model have been built to verify the ability of the system to control the speeds and to handle the transitional period for the clutch engagement from the pure electrical driving to the hybrid driving. If the output constraints are the measured speeds and the unmeasured torques which are not strictly imposed and can be violated somewhat during the clutch engagements, a modified model predictive controller with soften output constraints has been developed. Simulations show that the new model predictive controller can control the speeds very well for rapid clutch engagements, which enhance the driving comfort and reduce the jerk on the parallel hybrid electric vehicles.

Hybrid electric vehicle power train using battery model simulation in Simulink and its use for power management studies

This paper discusses the need for modelling and simulation of hybrid electric vehicle (HEV). Different modelling methods are presented with powertrain component and system modelling examples. The MATLAB/Simulink modelling and simulation of the hybrid electric vehicle (HEV) are represented in this paper. This simulation tool is meant as a help in the design and evaluation of the hybrid electric vehicle. Components in the driveline can be varied and the effect on the hybrid electric vehicle efficiency can be investigated. Both simulation tools consist of a Simulink vehicle model, where the driveline components are represented as interconnected blocks that are communicating physical signals between each other in the level of seconds. The demonstration shows different operating modes of the HEV over one complete cycle: accelerating, cruising, recharging the battery while accelerating and regenerative braking.

Development and experimental validation of a low-frequency dynamic model for a Hybrid Electric Vehicle

This paper describes the development and experimental validation of a high-fidelity Hybrid Electric Vehicle (HEV) simulator that enables testing and calibration of energy management and driveline control strategies. The model is capable of predicting longitudinal vehicle responses that affect energy consumption and drivability in the low-to-mid frequency region (up to 10 Hz). The simulator focuses primarily on the drivetrain dynamics, while the dynamics of the actuators are represented by simplified models. The vehicle simulator is validated by a number of experiments that include electric only, engine only and hybrid operating conditions. The test vehicle has a through-the-road parallel hybrid architecture that utilises a dual electric machine configuration. Experimental results confirm that important driveline phenomena such as shunt, shuffle, torque holes and other transient disturbances related to operating mode changes are accurately predicted.

Development of a software platform for a plug-in hybrid electric vehicle simulator

Abstract Electricity use for transportation has had limited applications because of battery storage range issues, although many recent successful demonstrations of electric vehicles have been achieved. Renewable biofuels such as biodiesel and bioethanol also contribute only a small percentage of the overall energy mix for mobility. Recent advances in hybrid technologies have significantly increased vehicle efficiencies. More importantly, hybridization now allows a significant reduction in battery capacity requirements compared to pure electric vehicles, allowing electricity to be used in the overall energy mix in the transportation sector. This paper presents an effort made to develop a Plug-in Hybrid Electric Vehicle (PHEV) platform that can act as a comprehensive alternative energy vehicle simulator. Its goal is to help in solving the pressing needs of the transportation sector, both in terms of contributing data to aid policy decisions for reducing fossil fuel use, and to support research in this important area. The Simulator will allow analysing different vehicle configurations, and control strategies with regards to renewable and non-renewable fuel and electricity sources. The simulation platform models the fundamental aspects of PHEV components, that is, process control, heat transfer, chemical reactions, thermodynamics and fluid properties. The outcomes of the Simulator are: (i) determining the optimal combination of fuels and grid electricity use, (ii) performing greenhouse gas calculations based on emerging protocols being developed, and (iii) optimizing the efficient and proper use of renewable energy sources in a carbon constrained world.

Research on Powertrain System of Series HEB Control Strategy Simulation

Based on the development status of hybrid electric vehicle(HEV) at home and abroad, combining the features of urban traffic and urban bus operation, the control strategy of hybrid buses powertrain is analyzed and researched. The whole performance of series hybrid electric bus(HEB) control scheme is simulated and analyzed using HEV simulation software ADVISOR. The result shows that the control strategy plays a positive role to improve automobile fuel economy.

Cooperative regenerative braking control algorithm for an automatic-transmission-based hybrid electric vehicle during a downshift

A cooperative regenerative braking control algorithm is proposed for a six-speed automatic-transmission-based parallel hybrid electric vehicle (HEV) during a downshift that satisfies the requirements for braking force and driving comfort. First, a downshift strategy during braking is suggested by considering the re-acceleration performance. To maintain driving comfort, a cooperative regenerative braking control algorithm is developed that considers the response characteristics of the electrohydraulic brake. Using the electrohydraulic brake’s hardware and an HEV simulator, a hardware-in-the-loop simulation (HILS) is performed. From the HILS results, it is found that the proposed cooperative regenerative braking control algorithm satisfies the demanded braking force and driving comfort during the downshift with regenerative braking.

Energy and Battery Management of a Plug-In Series Hybrid Electric Vehicle Using Fuzzy Logic

Fuzzy logic is used to define a new quantity called the battery working state (BWS), which is based on both battery terminal voltage and state of charge (SOC), to overcome the problem of battery over-discharge and associated damage resulting from inaccurate estimates of the SOC. The BWS is used by a fuzzy logic energy-management system of a plug-in series hybrid electric vehicle (HEV) to make a decision on the power split between the battery and the engine, based on the BWS and vehicle power demand, while controlling the engine to work in its fuel economic region. The fuzzy logic management system was tested in real time using an HEV simulation test bench with a real battery in the loop. Simulation results are presented to demonstrate the performance of the proposed fuzzy logic energy-management system under different driving conditions and battery SOCs. The results indicate that the fuzzy logic energy-management system using the BWS was effective in ensuring that the engine operates in the vicinity of its maximum fuel efficiency region while preventing the battery from over-discharging.

Torque control of engine clutch to improve the driving quality of hybrid electric vehicles

As a powertrain for hybrid electric vehicles (HEVs), the automatic transmission (AT) is not only convenient for the driver but also reduces hybridization costs because the existing production line is used to produce the AT. However, it has low fuel economy due to the torque converter. To overcome this disadvantage, this paper studies HEVs equipped an AT without a torque converter. In this case, additional torque control is needed to prevent the driving quality from deteriorating. This paper suggests three different torque control methods and develops a simulator for an HEV that can simulate the dynamic behaviors of the HEV when the engine clutch is engaged. The HEV drive train is modeled with AMESim, and a controller model is developed with MATLAB/Simulink. A co-simulation environment is established. By using the developed HEV simulator, simulations are conducted to analyze the dynamic behaviors of the HEV according to the control methods.

Coordinated Torque Control for Mode-Switch between Motor and Engine Driving in Heavy Hybrid Electric Vehicle

Aiming the vehicle ride performance, the process of driving mode-switch for a heavy hybrid power system and parameter changes among the engine, motor, clutch and transmission during the Mode-Switch process between Motor and Engine Driving were analyzed. The coordinated torque control strategy was established for Mode-Switch between motor and engine driving. The heavy hybrid electric vehicle simulation model was developed based on the strategy. The performance for the mode-switch process between motor and engine driving was simulated and analyzed. The results show that introducing the coordinated control strategy reduces the torque fluctuation during the driving-mode-switch process and improves the vehicle drivability.

Development of Fuel Cell Hybrid Electric Vehicle Simulator and HCU

Based on the Matlab/Simulink module modeling for Fuel Cell Hybrid Electric Vehicle was carried out, which is comprised of the fuel cell stack model, a DC/DC converter model, a battery model, a motor model, avehiclemodel and a driver model, and Hybrid Control Unit(HCU) was developed. The HCU control strategy also incorporates regenerative braking and recharge for battery capacity recovery. Vehicle speed effect is evaluated in New Europe Driving Cycle. The simulation result that the control strategy implemented by HCU is achievable, and which proves that the mode of Start, Accele_FCBat, Cruise, RE_Brake, Power_FC and Pause operate sequently as well as reliably.

Brushless PM machine drive in electric and hybrid electric vehicles based on the space vector current control

This paper presents a space vector current controller for a brushless permanent magnet motor in electric and hybrid electric vehicles. The proposed current controller selects space vectors based on the sector selection under a three-level hysteresis comparator to decrease the current ripple. The proposed approach can improve the performance of a brushless PM drive such as the average switching frequency and the total harmonic distortion (THD) compared with the conventional hysteresis current control. The experiment is performed first to verify the proposed control. Then, the method is implemented in a hybrid electric vehicle simulation model with standard driving cycles based on the control strategy to evaluate the drive performance in the vehicle system. The experimental and simulation results indicate that the presented control can improve the performance of the brushless PM machine drive.

Causal Fuel Cell System Model Suitable for Transportation Simulation Applications

This paper presents a model of a whole polymer electrolyte fuel cell system including the stack, an air compressor, a cooling system, and a power converter. This model allows its integration in a complete hybrid electric vehicle simulation. The level of detail of the model is chosen to enable control rules design, ancillaries sizing, and study of the interaction between the components of the vehicle. This model is formalized with energetic macroscopic representation, thus organized in a unified multidomain graphical description. Experimental results are compared to simulations for validation of the model accuracy.

Parameter Prediction and Modelling Methods for Traction Motor of Hybrid Electric Vehicle

This paper introduces the parameter prediction and modelling methods for the traction motor of hybrid electric vehicle (HEV). In the general HEV simulation, the traction motor is mainly defined by efficiency map and torque/speed curve. Therefore, this paper will focus on the prediction of these parameters, which involves the numerical analysis on the motor inductances calculation, iron-loss resistance calculation, and characteristic estimation algorithm and so on. The modelling method is split into tow major parts: configuration of model and composing graphic user interface (GUI). An experiment result will be used to compare with the calculated efficiency map to verify the validity of these methods. In addition, the model construction will be explained by flowcharts. Considering popularity, the MATLAB/Simulink will be used to construct the simulation program. And a GUI will be designed and used to show the simulation results. With the other models of vehicle components, the simulation will be processed in a parallel-type HEV model in an urban road condition (FTP72), and the simulation results will be shown in the end of this paper.

Modeling and Simulation of Hybrid Electric Vehicle Integrated Energy Model

With the improvement of electric vehicle technology and higher requirement for integrated performance,auxiliary power units(APUs,such as air conditioning system,electric power steering system,braking system and cooling system,etc.) will play more and more important functions.The analysis of APUs' energy flow change during vehicle running can consummate the energy flow management of full vehicle.The work characteristics of APUs is analyzed,APUs models are built by using ADVISOR software based on energy consumption map.The threetypes of APUs models adapt to the traditional bus,serial HEV and parallel HEV bus,which improve the vehicle model accuracy.Then the APUs' economic effect on the full vehicle is simulated,the results indicate that APUs occupy quite a few proportion of the energy consumption in the vehicle.In the USA city cycle,ECE cycle and Wuhan city bus cycle,the energy consumption of APUs occupies 6.1%～10% of the whole consumption.

Control of Dual Mode Power Split Transmission for a Hybrid Electric Vehicle

Motor control algorithm for a dual power split system is proposed for hybrid electric vehicles (HEV). The dual mode power split system consists of an electric variator, MG1 and MG2, and three planetary gear sets. In order to develop the control algorithm for the best fuel economy, the dual mode PST is analyzed by network analysis. From the network analysis results, it is found that the dual mode PST efficiency decreases in the speed ratios where the power circulation occurs, and it is required that the ICE needs to be operated on the speed ratio region where the powertrain efficiency is relatively high. Using the dynamic models of the HEV powertrain, a motor control algorithm to obtain the high system efficiency is designed by inversion-based control. In order to evaluate performance of the control algorithm, HEV simulator is developed using Cruise and MATLAB Simulink. It is found from the simulation results that the motor control algorithm proposed in this study provides improved fuel economy since the motor control is able to provide the ICE operation on the speed ratio range, which gives relatively high powertrain system efficiency.

Impedance-based and circuit-parameter-based battery models for HEV power systems

The relationship between voltage and current inside a battery, or the impedance, plays an important role in the simulation and design of hybrid electric vehicle (HEV) power systems. This paper proposes a new approach employing the Bode plot for evaluation of equivalent circuit parameters for a lithium polymer battery (LiPB) for HEV application. The main concept of the proposed circuit-parameter-based model approach is the application of a transfer function used to process the frequency response of the battery for calculation of accurate circuit parameters. Additionally, the Bode plot is also applied to derive the impedance-based model directly from frequency response measurements for short time simulations and practical use in the HEV. Two methods for battery modeling are proposed and verified experimentally with the voltage-current profile of a conventional HEV using the battery measured in this paper. The results show that the proposed circuit-parameter-based technique provides a satisfactory battery equivalent circuit model.

Control strategy for a dual-mode electromechanical, infinitely variable transmission for hybrid electric vehicles

An operating strategy is proposed for a dual-mode electromechanical, infinitely variable transmission (EVT) hybrid electric vehicle (HEV). First, network analysis is performed to evaluate the dual-mode EVT efficiency with respect to the speed ratio. It is found from the network analysis that the EVT efficiency decreases when the power circulation occurs along the electric variator and the EVT should be operated in the speed ratio region that provides a relatively high system efficiency, which requires an operating strategy from the viewpoint of the overall powertrain efficiency rather than the internal combustion engine thermal efficiency. In order to develop the operating strategy of the dual-mode EVT, dynamic equations of the HEV powertrain including the EVT are obtained and the motor torque control algorithm is designed using inversion-based control. To evaluate the performance of the operating strategy, an HEV simulator is developed on the basis of the dynamic models of the HEV powertrain using Cruise and MATLAB/Simulink. The simulation results indicate that the operating strategy proposed in this study is able to operate the engine in the desired speed ratio range having a relatively high EVT efficiency, which provides improved fuel economy compared with conventional control. It is expected that the operating strategy based on the transmission efficiency can be used effectively in the design of the dual-mode EVT for HEV application.

Multi Physics Model of a Nickel Based Battery Suitable for Hybrid Electric Vehicle Simulation

Multi Physics Model of a Nickel Based Battery Suitable for Hybrid Electric Vehicle Simulation

Modelling and control of a medium-duty hybrid electric truck

The main contributions of this paper are the development of a forward-looking hybrid vehicle simulation tool, and its application to the design of a power management control algorithm. The hybrid electric vehicle simulation tool (HE-VESIM) was developed at the Automotive Research Center of the University of Michigan to study the potential fuel economy and emission benefits of the parallel hybrid propulsion system for a medium truck. The fundamental architecture of the feed-forward simulation tool and the dynamic equations of its sub-system modules are first described. A power management control algorithm is then designed and evaluated, which is based on mimicking the behaviour of a dynamic-programming optimisation scheme. Simulation results over an urban driving cycle demonstrate that the hybrid control algorithm is able to improve vehicle fuel economy significantly, compared with the original vehicle, powered only by a diesel engine.