Modeling & Simulation, Testing & Validation (MSTV)


by Matthew Young; Angela Card; Stephen Phillips; G. Marshall Molen; Jim Gafford; Mike Mazzola


As more electrical-based systems are developed for battlefield use, the mobile and stationary power requirements of military vehicles continue to increase. Current power requirements of the light and medium duty class military vehicles’ 28 VDC system are exceeding what is achievable from a single alternator system that is belt-driven. In-service, belted alternator systems, such as the C803 Niehoff alternator (28 VDC, 520 A), are capable of providing up to 14.5 kW of electrical power at the maximum speed of the alternator. However, during stationary applications, these systems are only capable of producing 7.7 kW at an engine idle speed of 700 RPM. For these systems to be able to comply with the 10 kW plus power requirement, additional vehicle control is needed to elevate engine speed to an appropriate level to ensure the required power output may be achieved. For power levels above 15 kW, single-machine, belt-driven solutions become impracticable. This paper evaluates various power generation architectures that could meet the stationary requirements without the need for engine speed control on otherwise conventional (non-hybrid-electric) vehicles. Three architectures are considered in this study; all three include the original-equipment belt-driven alternator, making legacy or vehicles currently in production the most relevant platforms. The cases studied are as follows: dual alternators that are belt-driven, a combination of a belt-driven alternator and a transmission power-take-off (PTO) driven alternator, and a combination of a belt-driven alternator and a PTO-driven Permanent Magnet Brushless DC (PMDC) machine. The simulations account for power transfer efficiency for each of the proposed architectures and derive the total power required from the power sources to meet the desired load profile. The proposed architectures are compared based on the total energy required by the engine for running the 28 VDC power systems.