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

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.