Integrated Starter Generator Research Articles

Quantification of External Heat Load on HEV Integrated IPMs Using the Air-Gap Shear Stress

State-of-the-art design methods for electric machines use published correlations of either power or torque with electromagnetic and current loading, available for different cooling approaches. However, the applicability of these correlations for electric machines used within hybrid electric vehicles, with their different degrees of integration into the overall system, is limited. Using an integrated starter generator and an electric rear axle drive as example case applications, we study the influences of the thermal environment within the hybrid electric vehicle application, i.e., heat sinks and sources external to the machine on the thermal design of the machines. We quantify these influences by scaling factors for the air-gap shear stress of the machine.

An Integrated Starter-Generator and Winding Configuration for Hybrid Vehicles

An Integrated Starter-Generator and Winding Configuration for Hybrid Vehicles

Distributed and self-adaptive vehicle speed estimation in the composite braking case for four-wheel drive hybrid electric car

ABSTRACTConsidering the controllability and observability of the braking torques of the hub motor, Integrated Starter Generator (ISG), and hydraulic brake for four-wheel drive (4WD) hybrid electric cars, a distributed and self-adaptive vehicle speed estimation algorithm for different braking situations has been proposed by fully utilising the Electronic Stability Program (ESP) sensor signals and multiple powersource signals. Firstly, the simulation platform of a 4WD hybrid electric car was established, which integrates an electronic-hydraulic composited braking system model and its control strategy, a nonlinear seven degrees-of-freedom vehicle dynamics model, and the Burckhardt tyre model. Secondly, combining the braking torque signals with the ESP signals, self-adaptive unscented Kalman sub-filter and main-filter adaptable to the observation noise were, respectively, designed. Thirdly, the fusion rules for the sub-filters and master filter were proposed herein, and the estimation results were compared with the simulated value of a real vehicle speed. Finally, based on the hardware in-the-loop platform and by picking up the regenerative motor torque signals and wheel cylinder pressure signals, the proposed speed estimation algorithm was tested under the case of moderate braking on the highly adhesive road, and the case of Antilock Braking System (ABS) action on the slippery road, as well as the case of ABS action on the icy road. Test results show that the presented vehicle speed estimation algorithm has not only a high precision but also a strong adaptability in the composite braking case.

Dynamic energy management for a novel hybrid electric system based on driving pattern recognition

This paper focuses on the dynamic energy management for Hybrid Electric Vehicles (HEV) based on driving pattern recognition. The hybrid electric system studied in this paper includes a one-way clutch, a multi-plate clutch and a planetary gear unit as the power coupling device in the architecture. The powertrain efficiency model is established by integrating the component level models for the engine, the battery and the Integrated Starter/Generator (ISG). The powertrain system efficiency has been analyzed at each operation mode, including electric driving mode, driving and charging mode, engine driving mode and hybrid driving mode. The mode switching schedule of HEV system has been designed based on static system efficiency. Adaptive control for hybrid electric vehicles under random driving cycles with battery life and fuel consumption as the main considerations has been optimized by particle swarm optimization algorithm (PSO). Furthermore, driving pattern recognition based on twenty typical reference cycles has been implemented using cluster analysis. Finally, the dynamic energy management strategy for the hybrid electric vehicle has been proposed based on driving pattern recognition. The simulation model of the HEV powertrain system has been established on Matlab/Simulink platform. Two energy management strategies under random driving condition have both been implemented in the study, one is knowledge-based and the other is based on driving pattern recognition. The model simulation results have validated the control strategy for the hybrid electric vehicle in this study in terms of drive pattern recognition and energy management optimization.

Controls development for motor-assisted engine starting in a full hybrid electric vehicle with an integrated starter generator

This paper focuses on the control strategy and the related experiments for motor-assisted engine starting in a full hybrid electric vehicle (FHEV) with an integrated starter generator (ISG). The characteristics of FHEV driving system have been analysed based on the dynamic model of hybrid powertrain system. The control strategy for motor-assisted engine starting during transition from the electric driving mode to the engine driving mode has been proposed. A simulation model of the hybrid powertrain system has been established based on Matlab/Simulink software platform. The results show that the proposed control strategy satisfies the engine starting requirement in terms of transient response and smoothness. Furthermore, both bench test system and prototype vehicle have been developed respectively based on D2P (From Development to Production) rapid prototype developing system. The effectiveness of the engine starting control strategy is validated by the comparison between simulation results and the test data.

Controls development for motor-assisted engine starting in a full hybrid electric vehicle with an integrated starter generator

This paper focuses on the control strategy and the related experiments for motor-assisted engine starting in a full hybrid electric vehicle (FHEV) with an integrated starter generator (ISG). The characteristics of FHEV driving system have been analysed based on the dynamic model of hybrid powertrain system. The control strategy for motor-assisted engine starting during transition from the electric driving mode to the engine driving mode has been proposed. A simulation model of the hybrid powertrain system has been established based on Matlab/Simulink software platform. The results show that the proposed control strategy satisfies the engine starting requirement in terms of transient response and smoothness. Furthermore, both bench test system and prototype vehicle have been developed respectively based on D2P (From Development to Production) rapid prototype developing system. The effectiveness of the engine starting control strategy is validated by the comparison between simulation results and the test data.

世界最初のハイブリッド自動車

This paper presents review of the first hybrid electric vehicle in the world. The first hybrid electric vehicle was proposed in the USA in 1898, and several prototypes appeared in automobile shows in 1999. In the early 1900s, several types of hybrid system such as series, parallel, range extender or integrated starter generator were developed. In this paper, the technical survey results of articles, patents, and journals are presented.

Thermal modeling of an asymmetrical totally enclosed permanent magnet integrated starter generator

Some electromechanical systems involve totally enclosed electrical machines. In these cases, forced internal air cooling, for instance by the use of fans, is nearly impossible. However, in the same time, permanent magnet machines have to expel their internal rotor losses. In this context, an accurate estimate of heat exchange transfers and heat sources are important, for instance for the determination of the temperature distribution. This can be used for future designs of the same type of machine. This paper details the thermal modeling of a totally enclosed permanent magnet machine, such as an integrated starter generator (ISG). For this purpose, a lumped parameter network is built. Thermal conduction, convection and radiation heat transfer modes are considered. Losses are calculated using both analytical expressions and (coupled) electromagnetic finite element analysis (FEA). Simulation results are compared and validated with experimental data.

Advanced Electrical Machines and Machine-Based Systems for Electric and Hybrid Vehicles

The paper presents a number of advanced solutions on electric machines and machine-based systems for the powertrain of electric vehicles (EVs). Two types of systems are considered, namely the drive systems designated to the EV propulsion and the power split devices utilized in the popular series-parallel hybrid electric vehicle architecture. After reviewing the main requirements for the electric drive systems, the paper illustrates advanced electric machine topologies, including a stator permanent magnet (stator-PM) motor, a hybrid-excitation motor, a flux memory motor and a redundant motor structure. Then, it illustrates advanced electric drive systems, such as the magnetic-geared in-wheel drive and the integrated starter generator (ISG). Finally, three machine-based implementations of the power split devices are expounded, built up around the dual-rotor PM machine, the dual-stator PM brushless machine and the magnetic-geared dual-rotor machine. As a conclusion, the development trends in the field of electric machines and machine-based systems for EVs are summarized.

Evaluation of the Effect of Operating Parameters on Thermal Performance of an Integrated Starter Generator in Hybrid Electric Vehicles

The belt-driven-type integrated starter generator motor in a hybrid electric vehicle is vulnerable to thermal problems owing to its high output power and proximity to the engine. These problems may cause demagnetization and insulation breakdown, reducing the performance and durability of the motor. Hence, it is necessary to evaluate the thermal performance and enhance the cooling capacity of the belt-driven type Integrated Starter Generator. In this study, the internal temperature variations of the motor were investigated with respect to the operating parameters, particularly the rotation speed and environment temperature. At a maximum ambient temperature of 105 °C and rotation speed (motor design point) of 4500 rpm, the coil of the motor was heated to approximately 189 °C in generating mode. The harsh conditions of the starting mode were analyzed by assuming that the motor operates during the start-up time at a maximum ambient temperature of 105 °C and rotation speed (motor design point) of 800 rpm; the coil was heated to approximately 200 °C, which is close to the insulation temperature limit. The model for analyzing the thermal performance of the ISG was verified by comparing its results with those obtained through a generating-mode-based experiment

Torque coordinating robust control of shifting process for dry dual clutch transmission equipped in a hybrid car

For a hybrid car equipped with dual clutch transmission (DCT), the coordination control problems of clutches and power sources are investigated while taking full advantage of the integrated starter generator motor's fast response speed and high accuracy (speed and torque). First, a dynamic model of the shifting process is established, the vehicle acceleration is quantified according to the intentions of the driver, and the torque transmitted by clutches is calculated based on the designed disengaging principle during the torque phase. Next, a robust H∞ controller is designed to ensure speed synchronisation despite the existence of model uncertainties, measurement noise, and engine torque lag. The engine torque lag and measurement noise are used as external disturbances to initially modify the output torque of the power source. Additionally, during the torque switch phase, the torque of the power sources is smoothly transitioned to the driver's demanded torque. Finally, the torque of the power sources is further distributed based on the optimisation of system efficiency, and the throttle opening of the engine is constrained to avoid sharp torque variations. The simulation results verify that the proposed control strategies effectively address the problem of coordinating control of clutches and power sources, establishing a foundation for the application of DCT in hybrid cars.

Research on the Modeling and Simulation of Power System for the Single-Axle Parallel HEV

To research the hybrid powertrain vehicle, a forward-facing model is built in this paper. Based on the modeling method of experimental data, the model of throttle percentage and the torque of the engine is built, and the relation model of fuel consumption and emissions is given. Considering the Integrated Starter Generator (ISG) and its controller, the relation model of voltage, temperature, torque and current is established. According to the vector superposition principle of the engine and ISG torque, the model of dynamic coupling is also built. Considering the various external force along the driving direction of the vehicle, the running equation is given. Aim to a single-shaft parallel hybrid vehicle, the simulation of whole vehicle and the semi-physical simulation of ISG drive system are presented in this paper. Results show that the simulations are rational, and the fuel economy of the vehicle is enhanced efficiently.

Induction Machine Design and Analysis for General Motors e-Assist Electrification Technology

The integrated starter generator replaces the conventional starter and alternator with one electrical machine handling both functions. Start/Stop functionality, vehicle launch assistance, and higher speed transient power supplementing enhance the vehicle performance at the lower fuel consumption rate. This functionality requires the electrical machine to provide high starting and launch assistant torque in motoring mode and relatively high power capability over the wide speed range for battery charging. The overall cost of the system is the underlining concern and crucial part of the design optimization. This paper focuses on advantages of induction machines (IMs) in automotive industry and an approach to design a cost-effective electrical machine for belted starter–alternator applications. Design optimization of the IM is described to achieve desired performance, including rotor bar count, solid conductor (bar winding) versus stranded winding design, rotor bar shape optimization, and finally performance maps for the electrical machine, including both predicted and measured results. A thermal study of the machine is also presented, as well as the noise, vibration, and harshness (NVH) consideration in the design selection.

Optimal torque control of an integrated starter–generator using genetic algorithms

A mild hybrid electric vehicle is a type of hybrid electric vehicle with a simplified hybrid drivetrain mechanism. These mild hybrid electric vehicles use an integrated starter–generator to assist the internal-combustion engine simply rather than to drive the vehicle independently of the internal-combustion engine. In a previous study, a lookup- table-based control scheme was proposed for optimal control of the integrated starter–generator and the internal-combustion engine on a mild hybrid vehicle. In order to investigate further the optimality of the integrated starter–generator control lookup table, a widely used global optimization technique called a genetic algorithm is utilized in this study. The constructed optimal lookup tables are implemented in MATLAB/Simulink together with a mild hybrid vehicle model, which is based on an US Environmental Protection Agency light-duty vehicle model. The simulation results show that the genetic algorithm can construct an optimal lookup table with better performance characteristics than the weighted cost function method.

Torque Split Strategy for Parallel Hybrid Electric Vehicles with an Integrated Starter Generator

This paper presents a torque split strategy for parallel hybrid electric vehicles with an integrated starter generator (ISG-PHEV) by using fuzzy logic control. By combining the efficiency map and the optimum torque curve of the internal combustion engine (ICE) with the state of charge (SOC) of the batteries, the torque split strategy is designed, which manages the ICE within its peak efficiency region. Taking the quantified ICE torque, the quantified SOC of the batteries, and the quantified ICE speed as inputs, and regarding the output torque demanded on the ICE as an output, a fuzzy logic controller (FLC) with relevant fuzzy rules has been developed to determine the optimal torque distribution among the ICE, the ISG, and the electric motor/generator (EMG) effectively. The simulation results reveal that, compared with the conventional torque control strategy which uses rule-based controller (RBC) in different driving cycles, the proposed FLC improves the fuel economy of the ISG-PHEV, increases the efficiency of the ICE, and maintains batteries SOC within its operation range more availably.

Thermal Performance of Motor and Inverter in an Integrated Starter Generator System for a Hybrid Electric Vehicle

If the integrated starter generator (ISG) motor and inverter operate under continuously high loading conditions, the system’s performance and durability will decrease and the heat dissipation requirements will increase. Therefore, in this study, we developed two cooling designs for the ISG motor and inverter, and then carried out both a model analysis and an experiment on the fluid flow and thermal characteristics of the system under various operating conditions. As the outdoor temperature increased from 25 °C to 95 °C, the coil temperature of the air-cooled motor increased by about 82 °C. Under the harsh-air condition of 95 °C, the coil of the air-cooled motor increased to a maximum temperature of about 158.5 °C. We also determined that the temperature of the metal-oxide-semiconductor field-effect transistor (MOSFET) chip in the liquid-cooled inverter increased to a maximum temperature of about 96.8 °C under a coolant flow rate of 4 L/min and a coolant temperature of 65 °C. The observed thermal performance of the ISG motor and inverter using the proposed cooling structures was found to be sufficient for heat loads under various real driving conditions for a hybrid electric vehicle (HEV).

ISG 구동용 인버터의 열유동 해석에 관한 연구

Recently, many vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. ISG (integrated starter & generator) is one of main electric parts and can improve fuel efficiency by using idle stop & go function and regenerative braking system. However, if ISG driving inverter works under the continuously high load condition, it will make the performance and durability of the inverter decreased with rising temperature. In this study, we carried out the analysis on the fluid flow and thermal characteristics of the inverter. As a result, we found the MOSFET of the air cooled inverter was increased up to <TEX>$116^{\circ}C$</TEX> over the limit temperature. On the other hand, the liquid cooled type inverter's MOSFET was decreased by about <TEX>$17^{\circ}C$</TEX> compared to that of the air cooled inverter. Therefore, we verified the feasibility of the liquid cooled type using the present cooling structure.

Adaptive Backstepping Control for PMSM Integrated Starter Generator

In this paper a speed tracking controller is designed for Permanent Magnet Synchronous Motor (PMSM) integrated starter generator (ISG) operation in the starter based on adaptive backstepping technique. The PMSM drive system is often faced with some parameter variations and unknown disturbances. The designed controller can make the internal combustion engine (ICE) reach ignition speed quickly and meet the torque small pulsating and speed goes smoothly requirements. Then establish the controller model and simulate the ISG operation in the starter. Some simulation results verify the feasibility and illustrate the performance of the controller under the various conditions.

Motor Control of a Parallel Hybrid Electric Vehicle during Mode Change without an Integrated Starter Generator

In this paper, a motor control algorithm for performing a mode change without an integrated starter generator (ISG) is suggested for the automatic transmission-based hybrid electric vehicle (HEV). Dynamic models of the HEV powertrains such as engine, motor, and mode clutch are derived for the transient state during the mode change, and the HEV performance simulator is developed. Using the HEV performance bench tester, the characteristics of the mode clutch torque are measured and the motor torque required for the mode clutch synchronization is determined. Based on the dynamic models and the mode clutch torque, a motor torque control algorithm is presented for mode changes, and motor control without the ISG is investigated and compared with the existing ISG control.

하이브리드 차량용 ISG(Integrated Starter Generator)의 방열 설계를 위한 해석적 연구

Hybrid electric vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. Electrification of automobiles is indispensable for entering into global market because of enhanced environment restriction. ISG (Integrated Starter & Generator) system is one of main electric parts and can improve fuel efficiency more than other components by using Idle Stop & Go function and regenerative braking system. However, if ISG motor and inverter work under the continuously high load condition, it will make them the decrease of performance and durability. So the ISG motor and inverter need to properly design the cooling system of them. In this study, we suggested the enhancement points by modifying the thermal design of ISG motor and then confirmed the improvement of the cooling performance.