Advanced electric propulsion system concept for electric vehicles. Addendum 1. Voltage considerations
Seventeen electric vehicle propulsion systems were originally studied to select two designs that best met cost and performance goals. Both systems have now been examined to assess the effect of battery pack voltage on system performance and cost. A voltage range of 54 to 540 V was considered for a typical battery pack capacity of 24 kW-hr. The highest battery specific energy (W-hr/kg) and the lowest cost ($/kW-hr) were obtained at the minimum voltage level. The flywheel system traction motor is a dc, mechanically commutated machine with shunt field control, and due to the flywheel the traction motor and the battery are not subject to extreme peaks of power demand. Design changes in the battery pack voltage simply result in compensating changes in the motor configuration. The basic system uses a permanent-magnet motor with electronic commutation supplied by an ac power control unit. In this system the traction motor and power control unit must handle the peak power needed for acceleration. The traction motor can be designed to operate at specific battery voltages within a broad range, with little effect on motor efficiency, weight, or cost. The power control unit characteristics are effected by battery voltage, and the lowest voltages give the lowest efficiency, highest weight, and highest cost. In both systems, battery costs were the major factor in system voltage selection, and a battery pack with the minimum voltage of 54 V produced the lowest life-cycle cost. The minimum life-cycle cost for the basic system with lead-acid batteries was $0.057/km and for the flywheel system was $0.037/km.
- Research Organization:
- National Aeronautics and Space Administration, Washington, DC (USA); AiResearch Mfg. Co., Torrance, CA (USA)
- DOE Contract Number:
- AI01-77CS51044
- OSTI ID:
- 6347145
- Report Number(s):
- DOE/NASA/0081-2; NASA/CR-165243; ON: DE81030193
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
25 ENERGY STORAGE
ELECTRIC-POWERED VEHICLES
LEAD-ACID BATTERIES
LIFE-CYCLE COST
DESIGN
BATTERY CHARGERS
ELECTRIC MOTORS
FLYWHEELS
MAINTENANCE
OPERATING COST
OPERATION
PERFORMANCE
SAFETY
COST
ELECTRIC BATTERIES
ELECTROCHEMICAL CELLS
MECHANICAL ENERGY STORAGE EQUIPMENT
MOTORS
VEHICLES
330300* - Advanced Propulsion Systems- Electric-Powered Systems
250901 - Energy Storage- Batteries- Design & Development