Periodic Reporting for period 2 - MuSiCA (Multi-level SiC Module for Aircraft applications)
Reporting period: 2021-09-01 to 2022-11-30
Power electronics is essential to convert electrical energy efficiently and to power and control generators, motors and other electrical energy users on board. Efficient and reliable power electronics is an important enabling technology for the electrification of aircrafts. MuSiCA, sponsored by the Clean Sky program, aims to design and deliver an innovative multilevel power electronics module, an essential building block for the construction of high efficiency converters for on-board electric energy conversion systems.
Power electronic equipment must maximise efficiency, reducing losses, while minimising weight and volume.
The power electronics modules developed within MuSiCA use novel Silicon carbide (SiC) semiconductor devices which offer higher power density than the conventional silicon (Si) ones and thus offer the potential to reduce the volume and weight of power module packaging. By using SiC semiconductor devices, higher power density with smaller module package size have been achieved. However, the use of novel fast switching SiC devices comes with several challenges in manufacturing, thermal management, optimization of design and layout to guarantee reliability and reduce unwanted parasitic behaviour. All these issues have been carefully considered in MuSiCA to deliver a power module with high efficiency, good thermal and electrical performances while demonstrating mature manufacturing methodologies achieving a manufacturability readiness level MRL 6. The developed power modules use 1.2kV devices, supporting converter voltages up to 1080V enablig future more electric aircrafft platforms. The devices are rated at 300A, enabling converters with output power above 100kW with power density above 17kW/kg.
The main objectives of MuSiCA have been to package SiC devices and associated gate drive in a manufacturable and reliable power module package to enable SiC technology to meet its full potential and demonstrate its competitiveness against current solutions. Hardware demonstrators have been built and tested comprehensively, including tests on a Clean Sky 2 motor drive test bed. The main achievement of the project is the demonstration of the manufacturability and reliability of the proposed power modules technologies while guaranteeing low weight and volume with the ultimate aim of contributing to the reduction of CO2, NOx and noise emissions in aircraft transportation.
1. Identification of requirements and specifications in the intended application:
We have worked in collaboration with the Topic Manager to identify the topology and the electrical and mechanical specifications of the required power module and gate drive, as well as the electrical, mechanical interfaces and test procedures for validations.
2. Design of power module and gate drive:
Extensive analyses based on detailed computer simulations have been performed to optimise the design of the power module and the selections of suitable components and manufacturing steps. Simulations have analysed the electrical and thermal performance of the power module in several scenarios in the intended applications and have guided the design process. The gate drive circuitry was designd for optimal switching performances.
3. Selection of parts, components and manufacturing steps:
SiC dies and all other components and parts for the manufacturing of the power modules and gate drives have been identified and procured.
4. Hardware build.
The final build of the power modules and gate drives was concluded successfully including extensive tests of prototypes and subcomponents before final assembly. Several prototypes modules and associated gate drives have been manufactured and individually tested by measuring both the electrical characteristics and ther thermal performance.
5. Hardware tests
Extensive tests have been conducted on the power modules and their gate drive to assess their performance in a number of operating conditions, including static conduction and switching. Both electrical and thermal characteristics have been evaluated. A demonstrator consisting of a three-phase converter suitable for an aircraft starter-generator application has been designed, built and tested confirming the expected performances.
The static and dynamic characteristics of the converters have been measured with DC voltages up to 1000V and currents up to 300A. A demonstrator consisting of a three phase converter suitable for e.g. driving a starter-generator has been designed and tested both at USFD and by the TM. The performances measured validated the expectations from the design.
6. Assessment of manufacturability and reliability
Extensive stress tests have been performed to evaluate the reliability of the modules. A manufacturing assessment has been conducted to evaluate the scalability of the module for different applications and assess the manufacturability readiness level 6.
7. Three conference papers, two invited talk have been delivered as well as additional journal paper submitted to disseminate the results of the projec. Communications through online channels, as well as company and project's website have also been done. Plans for patenting the technologies are being evaluated. Several avanues for exploitation both in the aerospace, automotive and other industrial applications are being actively explored.
The optimized design has lower commutation parasitic inductance compared to similarly rated solution on the market made with discrete modules resulting in optimised switching performances reducing overvoltages and improving device reliability and efficiency. As aircraft power systems are moving toward higher and higher power levels, there is a need for higher operating voltages (above the current 270V/540V systems). This transition will require higher voltage devices and converters such as the 3-level power converter developed in MuSiCA. It been demonstrated that SiC power modules developed in MuSiCA will enable converters that have approximately half the losses of equivalent Si converters, resulting in converters that can move closer to the goal of >20kW/kg power density. Thiese advances will contribute to increase the power density of future aicraft power systems and the use of higher power levels drives well above several hundreds of kWs.
The outcome of the project will be an important key building block for any aircraft power system architecture of the future. The aerospace sector has a strong need for increased efficiency and power density to reduce losses and achieve the goals of reducing CO2 and NOx emissions from aircraft transportation.
In addition to the intended aircraft applications, the modules have a power and voltage rating suitable for a number of other emerging applications such as EV charger stations, solar photovoltaic grid integration, wind generators, railway tractions etc. that are now being actively pursued.