Belt-Driven Integrated Starter and Generator Using Planetary Gears for Micro Hybrid Electric Vehicles

Abstract

This paper presents a 12 V mechanical torque converting belt-driven integrated starter and generator (BSG) system without a DC-DC converter. A micro hybrid electric vehicle (micro HEV) typically uses a 12 V battery with a 12/48 V bidirectional DC-DC converter to satisfy its high starting torque and wide operating speed for generating the required power. In contrast, the proposed BSG consists of a wound field synchronous machine (WFSM), planetary gears, and a belt-type pulley, which does not require an additional bidirectional DC-DC converter. Owing to the mechanical torque converter, the proposed BSG system produces a high starting torque in starter-mode with a 12:1 gear ratio, and it operates in generator-mode with a 1:2 gear ratio to satisfy the required target specifications. To verify that the proposed BSG system meets the required target design specifications, simulations using MATLAB/Simulink 2018b and ANSYS electromagnetic 19.0 were performed. Additionally, the experimental results verify that this proposed BSG meets the required starter and generator modes specifications. Based on an analysis of the cost and vehicle environment conditions, the proposed BSG provides an efficient solution to the high cost issue incurred by a micro-HEV that requires a DC-DC converter system.

Internal Combustion Engine Starting and Torque Boosting Control System Design with Vibration Active Damping Features for a P0 Mild Hybrid Vehicle Configuration

“…However, the very same coupling of ICE and a motor/generator electrical machine within the hybrid electric vehicle requires a different mechanical transmission system configuration compared to the one found in a conventional (ICE-based) road vehicle [18]. To this end, mild hybrid electric vehicles offer certain advantages in terms of straightforward coupling of the front end accessory drive (FEAD) using a high-power/low-voltage (typically 48-V DC) electrical machine via a belt drive, the so-called belt starter generator (BSG) equipped with its own electronic power converter unit [19], thus serving both as the engine starter/torque booster and a generator unit [20], with some applications also including a planetary gear system to facilitate a wide range of BSG drive operations [21]. Utilization of BSG may even simplify the power train design; the more traditional torque boosting solution in the form of a turbo-charger unit [22] may be omitted from the automotive engine because BSG is capable of near instantaneous torque assistance [23].…”

“…Therefore, this paper investigates the possibility of designing a vibration active damping control system suitable for mild hybrid vehicles equipped with the low-voltage directcurrent (DC) bus [14] supplying the suitable integrated starter-alternator-booster (also known as the belt starter generator or BSG [21]) within the so-called P0 mild hybrid power train architecture. The active damping control system design is based on the suitable dynamic model of the FEAD, used for ICE starting and torque boosting, and the practical optima design methodology based on the so-called damping optimum criterion [34].…”