Development of Wound Rotor Synchronous Motor for Belt-Driven e-Assist System

Abstract

The automotive industry is showing widespread interest in belt-driven electric motor-assisted (e-Assist) systems. A belt-driven assist system (BAS) starts and assists the combustion engine in place of the conventional generator. In this study, a water-cooled wound rotor synchronous motor (WRSM) for the e-Assist system was designed and analyzed. The performance of the WRSM was compared with that of an interior permanent magnet synchronous motor (IPMSM). The WRSM efficiency can be improved for the BAS by adjusting the field flux at high speeds. The field current map to obtain the maximum efficiency based on the speed and torque was developed. To control the field flux via field current control in the WRSM, a general H-bridge circuit was added to the WRSM inverter to get the rapid current response in the high-speed region; the characteristics were compared with the chopper circuit. A WRSM developed for the belt-driven e-Assist system and a prototype 115 V power electronic converter to drive the WRSM were tested with a 900 cc combustion engine. The test results showed that the WRSM-type e-Assist system had good characteristics and could successfully start and assist the 900 cc combustion engine.

Modeling and dynamic analysis of accessory drive systems with integrated starter generator for micro-hybrid vehicles

“…Second, the steady-state responses of the B-ISG system are investigated when the system is driven by crankshaft pulley. Compared with the traditional dynamic analysis of the belt drive system carried out at a certain engine speed 7 or speed by speed, 13 this study uses the excitation of the crankshaft with increasing speed, which is similar to the real testing conditions. Moreover, the arms of the two-pulley tensioner move toward the same direction as the crankshaft speed changes.…”

“…The matrix differential operators A , L , and W are obtained with the system parameters and the initial condition of the state vector X | t = 0 at the beginning of the calculation procedure. Compared to the numeral method used in Lee et al 7 and Ulsoy et al, 13 the matrix differential operator U is changed at each iteration. The matrix U is generated by the tensioner torques M t , k and M t , s and belt tension T i , which are related to the angular displacements of the pulleys and tensioner arms.…”

“…There are some critical issues for the application of the accessory drive system with ISG: (1) an ISG needs to generate a large torque at a speed of 1000 r/min within a short time period (usually less than 0.5 s) to rotate the engine crankshaft at more than 300 r/min to start the engine 6,7 ; (2) instantaneous torque generated by ISG leads to severe vibration and shock of the belt of the accessory drive system, and vibration and shock of belt cause excessive strain, leading to premature belt failure. Since noise, vibration, and harshness (NVH) are important factors which influence the subjective responses of drivers, 8,9 there are lots of complains about the annoying noise and vibration of the accessory drive system during the instantaneous torque.…”

“…In all published literature, the location of a tensioner is modeled using the Euclidean geometry method. [6][7][8][9][10][11][12][13][14][15] However, this method is not applicable to a wide range of tensioner motion. In an accessory drive system with ISG, the motion of twin-tensioners is larger than that of the motion of a single-arm tensioner due to instantaneous and rapid starting.…”

“…Compared to the traditional dynamic analysis of the belt drive system carried out at a certain engine speed 7 or speed by speed, 13 this study uses the excitation of the crankshaft with increasing speed, which is similar to the real testing conditions. Several conclusions can be made from the simulation and analysis of the B-ISG system at engine driving mode:…”