It is especially necessary to make the most efficient utilization of the available power source capacity because it is limited; it is very difficult and expensive to increase power source capacity. Besides the power source itself, an increase usually requires increased distribution capacity, increased cooling for the power source, and increased drive system capacity. Space and weight provisions for these may be impossible without a major airframe redesign.

Aircraft electric power systems need to support increases in connected loads that result from new and expanded aircraft mission requirements. Increases in power source capacity are not feasible without major aircraft redesign, thus mandating making better, more intelligent use of the available power so that a variety of aircraft missions can be supported without overloading the electrical power system. Therefore, an advanced electrical power distribution and load management system to utilize aircraft electric power source capacity more effectively is needed. The new technology should provide improvements to power distribution load control, fault recognition/isolation and protection and automation with features to: 1) monitor bus power quality and excess power source capacity; 2) monitor status of solid-state power controllers, smart relays, and other circuit protective devices; 3) maintain data bus communications within the electrical load management system and with other aircraft systems; 4) utilize smart load shedding to optimize aircraft performance and prevent power source overload during periods of high demand;

5) balance loading of power sources to improve power source reliability; 6) collect fault data that can reduce troubleshooting time by maintainers; and 7) provide crew alerts and status advisories. Smart load shedding means shedding low-priority loads first, shedding mission essential loads only when necessary to prevent an overload and shedding loads that are not needed to support the current mission to improve reliability of utilization equipment. The proposed system should tailor the aircraft electrical loading to the current mission and reconfigure itself automatically in response to environmental changes and component failures. It should provide for crew overrides to effect changes in priorities during the course of a mission.

 

The existing MV-22 Block C aircraft electrical power system has been selected as the configuration baseline for this effort. The system is comprised of 4 generators, 3 converters, a main battery, 6 main AC buses, 4 main DC buses, 5 circuit breaker panels, 173 DC loads, 21 single-phase AC loads and 50 three-phase AC loads. Specifications will be provided by the Government to the Phase I performers. The proposed systems should be capable of being integrated into the existing aircraft platform, be compatible with V-22 power quality [Ref 4], including compatibility with V- 22 variable frequency (360 to 457 Hz), and V-22 environmental standards [Refs 5, 6, 7]. Installation, wiring and connections should be in accordance with V-22 installation and wiring standards [Refs 1, 8]. Compatibility with V- 22 aircraft power should be verified using applicable test methods [Ref 9].

 

Although not required, it is recommended that coordination with the original equipment manufacturer be a part of the development process to ensure a smooth transition.

 

PHASE I: Define and prove, through the use of modeling, the feasibility of the proposed power distribution system utilizing specification to be provided by the government. Provide analysis of expected improvements, such as fault recognition/isolation, power bus monitoring and crew alert status, and reliability. Estimate weight and space reductions that can be achieved while supporting the baseline loading, and also the growth in the number of load circuits and connected load (kVA or amperes) that can be supported within the space envelope of the existing power distribution system. The Phase I effort will include prototype plans to be developed under Phase II.

 

PHASE II: Design, develop, demonstrate, and validate a laboratory breadboard (prototype) of the proposed power distribution and load management system. Conduct a comprehensive analysis of potential integration and interface issues.

 

PHASE III DUAL USE APPLICATIONS: Package the validated electrical power distribution load management technology in a flightworthy configuration and demonstrate on a V-22 aircraft. Transition to the V-22 fleet by incorporating into a Common Configuration Readiness and Modernization (CC-RAM) upgrade. CC-RAM is intended to reduce the number of MV-22B aircraft configurations in the Fleet, improve reliability and readiness. Load management technology can be adapted to commercial aircraft, although commercial aircraft will benefit less as they are less likely to perform multiple missions.

 

REFERENCES: