Periodic Reporting for period 2 - AMPS (Aircraft Modular Power Converter Solutions)
Reporting period: 2019-06-01 to 2020-02-29
With the overall objective to reduce CO2 emissions for aviation and the reduction of the overall costs of building, operating, and maintaining aircraft, one of the key enablers towards this objective, is the adoption of higher levels of electrification on aircraft. This higher level of electrification, more commonly known as More Electric Aircraft (MEA), looks at replacing traditional non electrical systems with lighter and more efficient electrical alternatives.
As a consequence of this progression towards MEA, there is an increasing requirement for power conversion methods in the power distribution network, which provide high density, and higher levels of efficiency. By replacing a traditional passive system with active power conversion, weight and power density of each power conversion stage can be significantly reduced, thus leading to reduction in system weight and costs.
The introduction of standard modular power systems in generation and distribution applications, will yield a number of benefits for airframe manufacturers, around lower cost solutions, improved reliability, and lower weight. The reduction in weight will have a direct impact on fuel consumption providing direct financial benefits to the airliner as well as the resulting environmental benefits. The cost reductions from reduced maintenance and overall system costs, will assist in reducing the overall costs of air travel with the subsequent societal benefits.
The objectives of the AMPS project is to demonstrate the use of integrated hybrid power modules in the design of aircraft power converters. The project aims to show that by using a standardized power module for various converter topologies, how this will result in numerous benefits, including higher power density, lower cost, and higher reliability. The first part of the project entails the design and manufacture of a family of power modules which will form the building blocks for different power converter types which can be used in commercial aircraft power distribution applications.
The second part of the project is the demonstration of the use of one of these power module types, developed in the first part of the project. This module will be used as the principle building block for a matrix contactor converter. This demonstrator will show the benefits of the modular approach, including small size, higher efficiency and ease of integration into the power distribution system.
The AMPS project has led to the development of the first baseless power modules qualified to aerospace standards. The application of silicon carbide baseless modules in a HVDC contact switch matrix for aerospace power distributions, has demonstrated how higher efficiency, reduced size and reduced weight can be achieved versus traditional aerospace power conversion and distribution systems.
For module development, a number of activities were carried towards the goal of developing and qualifying standardized power modules which would be both lighter, smaller and more efficient. The first activity was a tradeoff to study the differences between the major technologies, SiC, IGBT, GaN and also the use of baseless over baseplate technology. For the choice of Semiconductor, Silicon carbide has been shown to be preferable v Silicon devices, as it can deliver better high voltage ratings, higher power performance due to lower on-state resistance, and better thermal behavior compared to silicon devices. A comparison of the use of GaN was also carried out, however, although theoretically better, the lack of commercially available good quality GaN, coupled with its poor thermal conductivity, ruled this technology out.
Through simulations, the choice of baseless over baseplate technology has shown that very good thermal performance can be achieved on a thick copper power substrate compared to a traditional power module solution with an Alsic baseplate. The baseless solution utilizing a good phase change material has also yielded very good results.
Following on from this, a family of power modules were developed using SiC and baseless technology. As the use of baseless technology was new to aerospace applications, a qualification program to aerospace standards was carried out. The results of this qualification has shown the baseless modules compliant to these standards.
For the contact switch matrix demonstrator, following requirements from the topic manager, a proposal was developed. This proposal incorporated the use of PCB busbar technology, and incorporated features such as 0 cross over detection. After some reviews, construction of the demonstrator utilizing the baseless bi-directional module was undertaken. A test bench was also constructed to validate the demonstrator. The validation was successfully carried out and a relevant environment.
The overall objectives of the AMPS project have been achieved. A family of baseless power modules qualified for aerospace application have been developed achieving high efficiency, reduced size and reduced weight. The baseless power modules benefits have been demonstrated in a HVDC contact switch matrix.
For dissemination, Microchip has engaged its marketing organization through workshops and training in order to be able to engage with potential tier 1 customers to promote the benefits of baseless modules. Microchip will participate in conferences to promote baseless modules as well as trade fairs such as PCIM. Microchip website will also be updated to include information on the new modules.
The impact of the AMPS project has closely followed those set out in the original project proposal. As the aerospace power electronics market moves towards the needs of ‘More Electric Aircraft’, this is currently being driven by several factors including the need for;
- Weight Savings through improved power density and integration.
- Reductions in aircraft cooling requirements resulting in a reduction of weight and platform Costs.
- Simplification and improved reliability through the removal of complex hydraulic systems
- Maintenance and unit cost savings through standardization of the various components in the power distribution chain
- Higher levels of integration with other systems, including flight control and landing gear.