Belt-driven Starter Generator Research Articles

Steady-state and start-up transient responses of a belt-driven starter generator system for micro-hybrid electric vehicles

For micro-hybrid electric vehicles, the belt-driven starter generator system is a typical idle stop–start system that is used to substitute the traditional engine front-end accessory drive system. The aim of this work is to present a method to investigate steady-state and start-up transient responses of a typical belt-driven starter generator system with twin tensioner arms for micro-hybrid electric vehicles. A dynamic model of the belt-driven starter generator system is established for this scheme, where a smoothing dynamic friction model considering the velocity-weakening effect is presented to model the tensioner dry friction. Unlike some traditional dynamic models of the belt-driven starter generator system that the engine dynamics and dynamics of the belt-driven starter generator system are decoupled, an engine dynamic model, which is embedded in the dynamic model of the belt-driven starter generator system, is also established to calculate engine resistance torques at the engine starting process stage. Influences of the tensioner dry friction and stiffness on steady-state responses of the belt-driven starter generator system especially the stick–slip oscillations of the twin tensioner arms are examined. Angular oscillations and rotation speed variations of the belt-driven starter generator pulley and C/S pulley as well as the belt tension variations during the engine starting process are calculated. Influences of the tensioner dry friction and stiffness on transient dynamic performances of the belt-driven starter generator system during the engine starting process and its starting efficiency are investigated.

A High Current High Power Density Motor Drive for a 48-Volt Belt-Driven Starter Generator (BSG) System

A 48 V Belt-Driven Starter Generator (BSG) System is featured with high output current, high starting torque, and highly efficient thermal management. This paper firstly elaborates hardware design considerations of a high power density three-phase BSG inverter to address the challenges of even current distribution among paralleled MOSFETs, small drain-source voltage spike and good thermal dissipation. In order to satisfy the high-current requirement, a careful selection of MOSFET device with high-current rating and low on-resistance has been presented. In order to suppress circulating current among paralleled devices, individual gate resistors have been placed in the gate loop of each MOSFET. In order to provide good thermal dissipation, an Insulated Metal Substrate (IMS) board and single-layer layout technique have been implemented. Multiple low-profile electrolytic capacitors are used to increase the power density of the prototype. Moreover, the use of automotive gate driver IC TLE9180 and microcontroller TC1782 makes the prototype more readily accepted by industry. An improved Interior Permanent Magnet (IPM) motor control strategy and a pump-back system based on a virtual machine concept have been implemented to facilitate the validation of the prototype under rated condition without using a real motor. The control algorithm automatically adjusts the onset of field-weakening by using an additional inverter voltage loop and takes into account the nonlinearity of the stator flux linkage by using curve fitting technique, which makes the motor drive adaptive to machine parameter changes as well as DC bus voltage fluctuation. A three-phase BSG inverter prototype with a peak power of 12 kW has been built and tested. The prototype power density has reached 20.3 kW/L. Both PLECS simulations and hardware experiments show a continuous and stable operation with up to 200 A phase current and up to 600 Hz output frequency.

Multimode Optimization of Switched Reluctance Machines in Hybrid Electric Vehicles

The belt-driven starter/generator (BSG), as a cost-effective solution, has been widely employed in hybrid electric vehicles (HEVs) to improve the stability and reduce the fuel consumption of the vehicles. It can provide more than 10% reduction in CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . Electrical machine is the heart of the BSG system, which is functioned both as motor and generator. In order to optimize both aspects of motor and generator simultaneously, this paper presents a new multimode optimization method for the switched reluctance machines. First, the general multimode concept and optimization method are presented. The switched reluctance motor and the switched reluctance generator are the two operation modes. The optimization models are established based on motor and generator functions. Sensitivity analysis, surrogate models and genetic algorithms are employed to improve the efficiency of the multimode optimization. Then, a design example of a segmented-rotor switched reluctance machine (SSRM) is investigated. Seven design variables and four driving modes are considered in the multiobjective optimization model. The Kriging model is employed to approximate the finite element model (FEM) in the optimization. Finally, the optimization results are depicted, and an optimal solution is selected. The comparison between the initial and optimal designs shows that the proposed method can improve the foremost performance of the SSRM under all driving modes.

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

48V systems enable not only mild hybrid functionalities such as recuperation or torque assist by a belt-driven starter generator (BSG), but also electrification of accessories and the engine boosting system. To maximize the powertrain efficiency, a proper layout of the electrified system and an optimized distribution of the electric power during transient operation is essential. In this study, a vehicle co-simulation of a conventional powertrain with a downsized turbocharged gasoline engine is extended by a 48V system with an electric compressor (eC) and a BSG. The control functions of the eC and BSG are based on a state-of-the-art vehicle application and calibrated for transient operating conditions. The engine model, which is built using a one-dimensional crank angle resolved approach in GT-POWER, has been validated with measurement data and is used to predict the interaction between the eC and the engine air path. The investigations using the simulation platform show that the 48V eC and the BSG can significantly improve the fuel effïciency if the electric energy consumption is initially neglected. However, when considering the electric energy consumption within the vehicle co-simulation, efficient operation is particularly depending on driver torque demand, the battery state-of-charge and charging effïciency. Hence, intelligent operating strategies are necessary to take advantage of the better torque response and improve fuel consumption at the same time.

Development of a digital control system for a belt-driven starter generator segmented switched reluctance motor for hybrid electric vehicles

A novel four-phase 16/10 belt-driven starter generator segmented switched reluctance motor has been proposed in a previous work to reduce torque ripple and increase the fault tolerance ability. Based on the previous research, the segmented switched reluctance motor digital control system is designed and presented. The digital control system including a power converter, detection circuits, and protection circuits is introduced in detail. For detection circuits, the half-detection method is employed to decrease the cost of the system. In addition, based on MicroAutoBox DS1401, a rapid control prototype platform is established. With this software system, it is easy to transfer control models and realize real-time control directly. Then, the speed closed closed-loop control for the segmented switched reluctance motor is applied to verify the proposed system. It contains current chopper control at a low speed and angle position control at a high speed. The simulation results are given, including the flux, current, torque, and efficiency range over the entire speed range of the segmented switched reluctance motor. Finally, the experimental results are presented to verify the simulation results and the effectiveness of the system. It can be found that the simulation and experimental results are consistent and acceptable, which means that the proposed digital system can operate naturally and accurately under speed closed loop control. Hence, the proposed digital system has high compatibility and practicability.

Electric Drives and Power Chargers: Recent Solutions to Improve Performance and Energy Efficiency for Hybrid and Fully Electric Vehicles

This article offers a survey of recent solutions involving electric drives and power chargers for fully electric vehicles (EVs) and hybrid EVs (HEVs). Based on our research and experimental activities regarding electric drives, we also show experimental data from prototypes. After reviewing the opportunities and challenges of vehicle electrification, the article analyzes electric machines and power converters for two main market trends: 1) low-voltage (48-V) HEVs, allowing for a smooth transition from internal combustion engine vehicles (ICEVs), and 2) full EVs, operating above 200 V. First, we discuss a 48-V integrated belt-driven starter generator (BSG), together with its tightly coupled power control electronics. Substituting a 12-V alternator, the BSG provides torque assistance to ICEVs for lowspeed, start-stop and regenerative-braking functionalities, and electric power generation for onboard loads. Instead, new topologies of electric machines are needed for full EVs.

Analysis of torque ripple and fault-tolerant capability for a 16/10 segmented switched reluctance motor in HEV applications

PurposeThe torque ripple and fault-tolerant capability are the two main problems for the switched reluctance motors (SRMs) in applications. The purpose of this paper, therefore, is to propose a novel 16/10 segmented SRM (SSRM) to reduce the torque ripple and improve the fault-tolerant capability in this work.Design/methodology/approachThe stator of the proposed SSRM is composed of exciting and auxiliary stator poles, while the rotor consists of a series of discrete segments. The fault-tolerant and torque ripple characteristics of the proposed SSRM are studied by the finite element analysis (FEA) method. Meanwhile, the characteristics of the SSRM are compared with those of a conventional SRM with 8/6 stator/rotor poles. Finally, FEA and experimental results are provided to validate the static and dynamic characteristics of the proposed SSRM.FindingsIt is found that the proposed novel 16/10 SSRM for the application in the belt-driven starter generator (BSG) possesses these functions: less mutual inductance and high fault-tolerant capability. It is also found that the proposed SSRM provides lower torque ripple and higher output torque. Finally, the experimental results validate that the proposed SSRM runs with lower torque ripple, better output torque and fault-tolerant characteristics, making it an ideal candidate for the BSG and similar systems.Originality/valueThis paper presents the analysis of torque ripple and fault-tolerant capability for a 16/10 segmented switched reluctance motor in hybrid electric vehicles. Using FEA simulation and building a test bench to verify the proposed SSRM’s superiority in both torque ripple and fault-tolerant capability.

Active torsional vibration reduction: potential analysis and controller development for a belt-driven 48 V system

Modern internal combustion engines (ICE) reach higher peak pressure thanks to the improved thermodynamic processes and charging technologies. Passive vibration damping approaches face challenges motivating the application of active methods. Active torsional vibration reduction achieves reduced torsional oscillations using the compensation torque generated by an electric traction machine (ETM). 48 V-based hybridization is gaining increased attention as an intermediate step towards higher levels of powertrain electrification. This trend opens new challenges for active vibration reduction with non-inline integration of the ETM using belt drive systems. We analyze the available potential for active torsional vibration attenuation in such belt drive systems in combination with a 48 V belt-driven starter generator (BSG). The study shows that a dual-mass flywheel (DMF) with a centrifugal pendulum absorber can be replaced by a simplified DMF with active vibration reduction using the 48 V BSG system. The effectiveness of active vibration reduction depends on the control functionality. In this contribution, we present an adaptive controller which does not require sensors for reference signal measurement. Besides simulative analysis, the performance of the proposed controller is demonstrated on the experimental test setup with a 2-cylinder ICE and an ETM in an inline configuration.

Design of the centrifugal fan of a belt-driven starter generator with reduced flow noise

Large eddy simulations based on the explicit algebraic subgrid-scale stress model were carried out to predict the flow-induced noise generated on the centrifugal fan of a belt-driven starter generator using Lighthill's analogy and the method of Ffowcs Williams and Hawkings. The surrounding air was approximated by an ideal gas at fixed room temperature (Tin = 300 K), and the rotating velocity of the fan was considered to be 6000 rpm. The blade array angles were designed using the modulation method, and a large blade curvature was adopted. We identified several centrifugal fan design parameters that could minimize the flow-induced noise while also minimizing fan efficiency losses. Three design parameters: the top serrated edge (θt), the step leading edge (0.52 Hb) and the tail edge (db and rb), played a critical role in preventing vortex generation and collision, significantly weakening the surface pressure fluctuations on the blade. The maximum sound pressure level at 800 Hz at a specific location was reduced by 5.5 dB (at the top serrated edge) and 6.8 dB (at the step leading edge) relative to the baseline case. The sound power, calculated over a hemisphere surface of 950 mm, was reduced by 77.3% (at the top serrated edge) and 61.0% (at the step leading edge) relative to the baseline whereas the mass flow rates were reduced by 5.2% and 10.6%, respectively. Experiments were performed using the optimally designed fan in a semi-anechoic chamber. The predicted sound pressure level and frequency were in good agreement with the experimentally measured values.

차량 BSG 모터의 홴 소음 저감

In this study, we studied fan noise reduction of a vehicle BSG (belt driven starter & generator) motor. The noise levels and frequency spectra of the BSG motor were measured experimentally. Based on these results, the blade passing frequency (BPF) generated by the fan was proven to be the main noise source of the BSG motor. In order to reduce the fan noise, design parameters of the fan were selected and noise analysis was performed through simulation. Using the design of experiments, the influence of the design parameters on the noise was analyzed and the fan design to reduce the fan noise was performed. Finally, the improved fan was manufactured and the noise test was performed. The noise level of the BSG motor with the improved fan was evaluated by comparison with the noise level of the existing BSG motor.

Design and Measurement of Integrated Converters for Belt-Driven Starter-Generator in 48 V Micro/Mild Hybrid Vehicles

With reference to a 48 V belt-driven starter-generator used in micro/mild hybrid vehicles, this paper shows the design and measurement of an integrated H-bridge and of a compact dc/dc converter, both fabricated in low-cost high voltage-metal oxide semiconductor (HV-MOS) technology. The H-bridge is in charge of rotor excitation and, thanks to a direct copper bonding of the HV-MOS devices on a ceramic substrate, it ensures a full-integrated solution with low on -resistance values. The compact dc/dc converter interfaces the 48 V power domain with the lower voltage domain of sensing and control electronics, such as 5 and 1.65 V in this case study, without using cumbersome inductors and transformers. The latter are difficult to integrate into silicon technology. The converter has a multistage architecture where each stage implements a switched capacitor regulation. Multiple voltage outputs are supported with a configurable regulation factor sustaining an input voltage variation from 6 V (in case of cranking) up to 60 V. Specific design techniques have been implemented to reduce electromagnetic interference (EMI), typical of switching converters. Experimental measurements on fabricated prototype chipsets confirm the suitability of the presented designs for low-EMI 48 V applications.

An Off-line Maximum Torque Control Strategy of Wound Rotor Synchronous Machine with Nonlinear Parameters

Belt-driven Starter Generator (BSG) differs from other mild hybrid systems as the crankshaft of vehicle are not run off. Motor permits a low-cost method of adding mild hybrid capabilities such as start-stop, power assist, and mild levels of regenerative braking. Wound rotor synchronous motor (WRSM) could be adopted in BSG system for HEV e-Assisted application instead of the interior permanent magnet synchronous motor (IPMSM). In practice, adequate torque is indispensable for starter assist system, and energy conversion should be taken into account for the HEV or EV as well. Particularly, flux weakening control is possible to realize by adjusting both direct axis components of current and field current in WRSM. Accordingly, this paper present an off-line current acquisition algorithm that can reasonably combine the stator and field current to acquire the maximum torque, meanwhile the energy conversion is taken into consideration by losses. Besides, on account of inductance influence by non-uniform air gap around rotor, nonlinear inductances and armature flux linkage against current variation are proposed to guarantee the results closer to reality. A computer-aided method for proposed algorithm are present and results are given in form of the Lookup table (LUT). The experiment shows the validity of algorithm.

Experimental Characterization of a Belt-Driven Multi-Phase Induction Machine for 48 V Automotive Applications: Losses and Temperatures Assessments

This paper presents the simulation and experimental results of the tests conducted for losses and temperature assessments on a belt-driven starter generator designed for 48-V mini-hybrid powertrains. In particular, a double three-phase 10-kW induction machine has been selected as the suitable candidate for the application. This paper reports and discusses in detail the experimental calibration of the lumped-parameter steady-state thermal model, particularly concerning the heat transfer thermal parameters. The testing activity has been conducted on a water-cooled prototype. Therefore, the validated thermal model has been used to predict the thermal behavior of the prototype at different load conditions in accordance with the design specifications. In the final part of this paper, some considerations regarding the prototype packaging and the embedded power electronics thermal issues are also reported.

Multiphase starter generator for 48V mini-hybrid powertrain: design and testing

This paper focuses on the design and experimental test results of a belt-driven starter generator for 48-V mini-hybrid powertrains. The functionalities required of the system are engine startup, launch assistant torque, regenerative braking, battery charging, and early fuel cutoff. The cost-effective electrical machine must provide high starting torque and wide constant power speed range, both in motor and generator modes. The authors outline the motivations of the electrical machine topology selection in relation to the specifications and constraints. In particular, a double three-phase induction machine has been selected as a suitable candidate. The aim of this paper is to summarize the design challenges of such kind of electrical machines, mainly subordinated to electromechanical and thermal issues imposed by the considered hybridization solution. Details of the machine design are presented, including a study on multilayer bar stator windings and on rotor slot design. Finally, predicted and measured performances of the prototype are reported and discussed for validation purposes.

Review of the Book Advanced Electric Drive Vehicles [Book Review

This book provides a unique treatise for attacking and solving some of the most complex problems encountered in the emerging field of electric vehicles. The book begins with an introduction to the automotive industry demonstrating the need to engage electrification and telecommunications effectively. In chapter 2, a two-dimensional model that focus on vehicle performance, including acceleration, speed, and grade-ability, as well as braking performance is presented in all technical details, while in chapter 3 the basics of Internal Combustion Engines are furnished. Chapters 4 through 7 consists a section of the book that focus on the major components of electrified vehicles. Chapter 8 introduces Hybrid Energy Storage Systems (ESS) for the decoupled power and energy components of the Plug-in Electric Vehicles (PEVs). Chapter 9 presents the electrification technologies applied to nonpropulsion loads with low-voltage electrical systems. Chapter 10 explains electrification and beltdriven starter generator systems, followed by chapters 11 and 12 that introduce the fundamentals of hybrid power trains and hybrid energy vehicles.

Diesel hybrid powertrain for passenger and light commercial vehicles

Diesel hybrid powertrain for passenger and light commercial vehicles

Realization and Analysis of Good Fuel Economy and Kinetic Performance of a Low-cost Hybrid Electric Vehicle

By using high-power and high-efficiency propulsion systems,current hybrid electric vehicles(HEVs) in market can achieve excellent fuel economy and kinetic performance.However,it is the cost of current HEVs that hinders HEVs coming into widespread use.A novel hybrid electric propulsion system is designed to balance HEV cost and performance for developing markets.A battery/supercapacitor-based hybrid energy storage system(HESS) is used to improve energy conversion efficiency and reduce battery size and cost.An all-in-one-controller(AIOC) which integrates engine electronic control unit(ECU),motor ECU,and HESS management system is developed to save materials and energy,and reduce the influence of distribution parameters on circuit.As for the powertrain configuration,four schemes are presented:belt-driven starter generator(BSG) scheme,four-wheel drive HEV scheme,full HEV scheme,and ranger-extender electric vehicle(EV) scheme.Component selection and parameter matching for the propulsion system are performed,and an energy management strategy is developed based on powertrain configuration and selected components.Forward-facing simulation models are built,comprehending the control strategy based on the optimal engine torque for the low-cost hybrid electric propulsion system.Co-simulation of AVL CRUISE and Matlab/Simulink is presented and the best scheme is selected.The simulation results indicate that,for the best design,fuel consumption in urban driving condition is 4.11 L/(100 km) and 0-50 km/h accelerating time is 10.95 s.The proposed research can realize low-cost concept for HEV while achieving satisfactory fuel economy and kinetic performance,and help to improve commercialization of HEVs.

Concept for low-cost low-voltage hybridisation

An electrically powered supercharger, a belt-driven starter-generator and a turbine for the recuperation of exhaust energy: these technologies, at the centre of which is a switched reluctance motor, are used in a hybrid concept developed by the British company Controlled Power Technologies (CPT). In combination with an internal combustion engine that has a 50 % reduction in swept volume, the cost-benefit ratio is claimed to be significantly better than that of conventional full hybrid solutions.

A Belt-Driven Starter-Generator Concept for a 4-Cylinder Gasoline Engine

Reducing the fuel consumption and emissions of passenger car engines is one of the most important targets of future developments. The belt-driven 14V starter-generator concept allows the engine to stop when the vehicle is stationary, for example at traffic lights, then restarts the engine almost instantaneously. This article describes a starter-generator concept with a Gates belt drive system on a 1.6-litre 4-cylinder gasoline engine.