Community Research and Development Information Service - CORDIS


CoPoCo Report Summary

Project ID: 640714
Funded under: FP7-JTI
Country: Germany

Periodic Report Summary 1 - COPOCO (Optimizing power density of aircraft inverter by optimized topology and PWM-pattern)

Project Context and Objectives:
The CleanSky project ’Optimising Power Density of Aircraft Inverter Combing Topology and PWM Pattern’, with the acronym ’CoPoCo’ is aimed to increase the power density of a DC/AC converter for aerospace application by 10 %. At the same time the conducted disturbances shall be kept at least at the same or preferably lower level. This project is motivated through the advancements in the field of More Electric Aircraft (MEA). The More Electric Aircraft promises a reduction of emissions and decrease of fuel consumption. Typically different combinations of energy, including electrical, hydraulic and pneumatic are used to drive the different systems. At least for the hydraulic and the pneumatic systems power has to be provide constantly to keep the pressure. A replacement of such systems through electrical ones could therefore safe energy. The increasing number of electric components leads to growing influence of their weight. With this projects aim of increased power density it is tried to minimise this impact. To reach this goal several approaches are made in this project and analysed on two typical applications for today’s aircraft. The first application is a 10 kW converter which could be used to drive flight controls situated in the wings. A second important application is maintaining the cabin pressure. For this example a converter with 50 kW is analysed.
To reach this goal different aspects of a converter are analysed. The first aspect is the reduction of conducted noise since the used filters make up to 20% of the converters weight. The use of other topologies or different control schemes for the converter can lead to noise reduction.
Since the converter generates losses the weight of the cooling has as well a significant influence of the converters weight. For example the low power core shall be could through natural convection a relatively big cooling plate has to be used. The use of SiC-MOSFETs has the possibility of loss reduction through a faster switching process.
All possible solutions for weight reduction will be analysed and compared to each other. The optimal solution will be described through Pareto optimisation.

Project Results:
In the first 11 months of this project a benchmark and a requirement specification for the power cores was established. These analyses was necessary to have a proper comparison of the new converters with state of the art.
Further a simulation model in in Matlab/Simulink was created. In this model converters with adequate load are implemented to analyze common mode currents flowing in the system. Here the impact of different modulation techniques and topologies can be analyzed regarding the conducted noise. As modulation techniques the classic Space Vector Pulse Width Modulation (SVPWM) was compared to reduced common mode voltage modulation techniques (Discontinuous PWM, Remote State PWM, Near State PWM, Active Zero PWM 1 and Active Zero PWM 2). Near State PWM and Remote State PWM show advantages compared to the classic Space Vector PWM and will be most likely used in the final hardware for 10kW power core. A 3-level topology was analyzed as well. Here the advantage of reduced dv/dt leads to significantly reduced common mode noise and shows the best behavior for 50kW power core. Therefore in the next step a 3-level converter for the 50kW power core will be build.
Parallel to the simulation research on SiC-MOSFETs was conducted. A first prototype of a 2-Level converter was built in an early stage of the project to provide measurements for the switching speed and switching losses of SiC devices. This converter show superior behavior regarding switching losses and switching frequency. The reduced common mode voltage modulation techniques can be applied as well and therefore a combined solution for the 10kW will be chosen. With this combination it is likely that a reduction of cooling plate and the filters can be achieved.

Potential Impact:
This project will show different approaches to reduce the weight of converters for aircrafts. This approaches will be demonstrated with two converters. The first converter will have a power rating of 10kW and will be able to control electric machines to drive flight controls. The second with a power rating of 50kW could drive the cabin pressure system. Even though both converters will provide full functionality they will be designed as TRL4 and cannot be used in aircrafts. They will show the possibilities for further innovations in aircraft industry.
The results of this project can give a guideline for expansion of the More Electric Aircraft concept. New optimized solutions can be used to create a more efficient aircraft to reduce the global pollution.
The knowledge of this project will be spread through publications and teaching in lectures at the Technische Universität Darmstadt.


Melanie Meermann-Zimmermann, (EU-Liaison Officer)
Tel.: +496151 16 57225
Record Number: 184221 / Last updated on: 2016-06-07
Information source: SESAM