John C. Morgante

Design and Performance of Electrical Propulsion System of Extended Range Electric Vehicle (EREV) Chevrolet Volt

This paper presents the design and performance details of the Chevrolet Volt electric propulsion system. The propulsion system has two machines: One machine is operating mostly as a motor while the other machine is operating mostly as a generator. Both machines of the Volt electric drive system are permanent-magnet ac synchronous machine types with the magnets buried inside the rotor. The motor has distributed windings. However, as opposed to a conventional stranded winding, the Chevrolet Volt motor has bar-wound construction to improve the motor performance, particularly in the low to medium speed range. At higher speed, the skin and proximity effects in the stator bars lead to increased stator winding losses but are addressed in the design. The bar-wound construction also has excellent thermal performance, in both the steady-state and transient conditions, necessary for full electric vehicle (EV) driving. The generator uses concentrated windings. The concentrated winding construction has good slot fill and short end-turn length. These features resulted in good performance in the intended operational region and were an enabler for machine packaging inside the transmission. Both the machines exhibit excellent efficiency and exceptionally smooth and quiet operation. The machine design and construction details, as well as the measured thermal, electromagnetic, and acoustic noise performances, are presented in this paper.

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.

Design and performance of electrical propulsion system of extended range electric vehicle (EREV) Chevrolet Voltec

This paper presents the design and performance details of the Chevrolet Voltec electric propulsion system. The propulsion system has two machines, one machine is operating mostly as a motor while the other machine is operating mostly as a generator. Both machines of the Voltec electric drive system are permanent magnet AC synchronous machine types with the magnets buried inside the rotor. The motor has distributed windings. However, as opposed to a conventional stranded winding the Chevrolet Volt motor has bar-wound construction to improve the motor performance, especially in the low to medium speed range. At higher speed the skin and proximity effects in the stator bars lead to increased stator winding losses but are addressed in the design. The bar-wound construction also has excellent thermal performance, in both the steady-state and the transient conditions, necessary for full EV driving. The generator uses concentrated windings. The concentrated winding construction has good slot fill and short end-turn length. These features resulted in good performance in the intended operational region and were an enabler for machine packaging inside the transmission. Both the machines exhibit excellent efficiency and exceptionally smooth and quiet operation. Machine design and construction details as well as the measured thermal, electromagnetic and acoustic noise performances are presented in the paper.

Electric machine design and selection for General Motors e-Assist Light Electrification Technology

The integrated starter generator replaces conventional starter and alternator with one electrical machine handling both functions. Start/Stop functionality, vehicle launch assistance and higher speed transient power supplementing enhances 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 in automotive industry and an approach to design a cost effective electrical machine for belted starter-alternator application. Design optimization of the induction machine is described to achieve desired performance including; rotor bar count, solid conductor (bar winding) vs. stranded winding design, rotor bar shape optimization and finally performance maps for the electrical machine including both, predicted and measured results. Thermal study of the machine is also presented as well as the NVH consideration in the design selection.