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This paper introduces a novel method for an electric power generation system (EPGS) employing a lead-unity-lag (LUL) permanent-magnet (PM) generator operation for a direct current (DC) power distribution bus. In addition, background information of the prior art for a leading power factor EPGS is discussed. The concept of the new approach is defined and a comparative analysis between the new and old state-of-the-art solutions are documented. The performance features and technical details of the system parameters with respect to power generation system requirements are presented and discussed. Analysis and testing results are included. Finally, the advantages of this system, a conclusion, and recommendations for future work are provided. Test results from a system having elements of this novel approach are included. With this method for an LUL EPGS, the capability of the high-performance electric power generation systems is improved substantially.

The power and thermal management system (PTMS) developed by Honeywell for aircraft is an integral approach combining the functions of the auxiliary power unit (APU), emergency power unit (EPU), environmental control system (ECS), and thermal management system (TMS). The next generation PTMS discussed in this paper incorporates the new more electric architecture (MEA) and energy efficient aircraft (EEA) initiatives. Advanced system architectures with increased functionality and further integration capabilities with other systems are included. Special emphasis is given to improvements resulting from interactions with the main engine, main electric power generation, and flight actuation. The major drivers for advancement are highlighted, as well as the potential use of new technologies for turbomachinery, heat exchangers, power electronics, and electric machines. More advanced control and protection algorithms are considered.

This paper presents a novel method and system for an electric power alternating-current (AC)-to-direct-current (DC) converter employing composite technology. The term composite entails utilization of more than one type of conversion operating in parallel. In addition, background information for the prior art, based on conventional autotransformer rectifier units (ATRUs), and active converters are discussed. The major requirements of AC-to-DC converters from both functional and protection perspectives are provided. The concept of the new approach is defined. Comparative analysis between the new and old methods is documented. The performance features and technical details of the system parameters with respect to AC-to-DC converter system requirements are presented and discussed. Analysis, simulation results, and test data are included. Finally, the advantages of this technology, which nearly doubles power density compared to the state-of-the-art, are summarized and a conclusion included.

Honeywell is currently working on several projects utilizing high-reactance permanent magnet machines (HRPMM) to develop advanced, high-performance power generation systems (HPPGS). These power generation systems (PGS), offer greatly increased safety and reduced operating costs compared to previous hardware. The approach utilizes an HRPMM that presents reduced short-circuit currents with simplified power topology and specifically developed control algorithms. These architectures offer inherent fail-safe features in that the maximum possible short-circuit current is not significantly higher than the normal operating current. Control approaches are discussed. Methodologies for system optimization to achieve top performance and robust operation are included. These power generators support implementation of on-shaft integration with the plant.

Launch vehicles that use electric actuators for thrust vector or flight control require a safe, reliable and lightweight source of electrical power. Honeywell, working with NASA Glenn Research Center and Lockheed Martin Space Systems, has developed and successfully tested a turbine-driven electric power generation system which meets these needs. This Turbine Power Unit (TPU) uses hydrogen and oxygen propellants which react catalytically to drive a shaft-speed turboalternator mounted on foil bearings. A high-reactance permanent-magnet machine (HRPMM) was selected for this application. The power conditioning and control electronics can be located within the TPU housing and the hydrogen fuel can be used to pressurize the bearings and electronics and to regeneratively cool the machine. A brassboard unit incorporating many of these features was successfully tested at output power levels from 0 to 138 kilowatts (kW).

In association with NASA Glenn Research Center and Lockheed Martin Space Systems, Honeywell has developed and successfully tested an electric power generation system that uses non-toxic hydrogen and oxygen propellants that are reacted catalytically. The resulting fuel-rich gases drive a turbogenerator. Speed control of this system is challenging due to highly variable electric load profile. Discrete two-position valves were used to control the propellant flow for improved reliability compared to proportional valves. This “bang-bang” speed control method exhibits variation in turbine acceleration and deceleration with load. The control thresholds for the turbine speed are adjusted based on load so as to compensate for increased speed overshoot and undershoot.

This paper discusses the problem of designing electric machines (EM) for advanced electric generators (AEG) used in aerospace more electric architecture (MEA) that would be applicable to aircraft, spacecraft, and military ground vehicles. The AEG's are analyzed using aspects of Six Sigma theory that relate to critical-to-quality (CTQ) subjects. Using this approach, weight, volume, reliability, efficiency, and cost (CTQs) are addressed to develop a balance among them, resulting in an optimized power generation system. The influence of the machine power conditioners and system considerations are also discussed. As a part of the machine evaluation process, speeds, bearings, complexities, rotor mechanical and thermal limitations, torque pulsations, currents, and power densities are also considered. A methodology for electric machine selection is demonstrated. Examples of high-speed, high-performance machine applications are shown.

This paper introduces several new concepts for improving the peak electrical power capability of an aircraft. This capability is becoming very important for the development of future electric power systems and is reflected in the Honeywell more electric architecture (MEA) design concept and energy optimized aircraft (EOA) initiative. There are many system benefits of using electrically driven actuators on aircraft rather than those that are hydraulically driven. These benefits include enhanced reliability, lower weight, lower volume, and lower cost. However, the introduction of electromechanical actuation (EMA) and electro-hydrostatic actuation (EHA) into aircraft systems has increased the needs for peak electrical power demand.

This paper presents new concepts for improving management of the electrical load power regeneration of an aircraft. A novel electrical system that allows for load regeneration back to the distribution bus is described. This approach offers the benefits of reduced weight, volume, and cost, as well as improved reliability. Also described is an electrical machine control mechanism that creates motor power to run the prime mover (i.e., the main engine to dissipate the regenerated power). Instead of main engine generation, this approach can be applied to an auxiliary power unit (APU) or power and thermal management system (PTMS). Background information regarding the regeneration concept is presented. The concept definition and the various modes of operation of the improved system are analyzed and described in detail. Results from the dynamic simulation of the system model are included.

The aircraft power and thermal management system (PTMS) developed by Honeywell combines the functions of an auxiliary power unit (APU), emergency power unit (EPU), environmental control system (ECS), and thermal management system (TMS) in one integrated system. For the F-35 aircraft this approach resulted in a substantial reduction in overall aircraft size and weight as compared to configurations using separate “federated” secondary power systems. Future aircraft incorporating the new more electric architecture (MEA) and energy efficient aircraft (EEA) initiatives are likely to benefit from this integrated approach as well, but they are also likely to require increased electric power generation capability, greater cooling capacity and higher operating efficiency.

Honeywell is working with Lockheed Martin and NASA to develop a lightweight, turbine-driven electric power generation system that offers greatly increased safety and reduced operating costs as compared to existing systems. The approach is to utilize a “bang-bang” speed control system with fuel-rich, catalytically-reacted hydrogen and oxygen propellants to drive a turbine and shaft-speed, high-reactance permanent-magnet generator. The rotating assembly is supported by gas-cooled “foil” bearings. The flight system is envisioned to be regeneratively cooled and have power conditioning and control electronics integrated within the pressurized turbogenerator housing. System definition and component development have been completed. “Brassboard” system testing is currently underway.

This paper discusses the problem of obtaining electric machines (EM) for advanced electric drives (AED) used in more electric architecture (MEA) applicable to aircraft, spacecraft, and military ground vehicles. The AED are analyzed by those aspects of Six Sigma theory that relate to critical-to-quality (CTQ) subjects. Using this approach, weight, volume, reliability, efficiency, and cost CTQ are addressed to develop a balance among them, resulting in an optimized system. The influence of machine controllers and system considerations is discussed. As a part of the machine evaluation process, speeds, bearings, complexities, rotor mechanical and thermal limitations, torque pulsations, currents, and power densities are considered. A methodology for electric machine selection is demonstrated. An example of high-speed, high-performance machine application is shown. A system approach is used for overall electric machine selection and optimization.

This paper addresses the implementation of electric taxiing without the use of main engines by using electric propulsion of the landing gears. Substantial progress in this area has been achieved by Honeywell Aerospace and Safran in a joint initiative for developing an electric green taxiing system (eTaxi). Considerable analysis, design, fabrication, and testing have already been completed, which culminated in a demonstration at the Paris Air Show (PAS) in 2013. The eTaxi system has been installed on an A320 airplane that uses the auxiliary power unit (APU) to generate electric power to provide propulsion to two wheels of the main landing gear. The main advantages of such a system are reduction of fuel consumption and audio noise, reduction of CO2 , carbon and nitrous emissions, reduced engine foreign object damage (FOD) exposure and fast-turn time savings by elimination of the ground tractor for pushback operation.