This chapter contains sections titled: Introduction Development of the FFT Algorithm with Radix-2 Decimation-in-Frequency FFT Algorithm with Radix-2 Decimation-in-Time FFT Algorithm with Radix-2 Bit Reversal for Unscrambling Development of the FFT Algorithm with Radix-4 Inverse Fast Fourier Transform Programming Examples References

Fast Fourier Transform

More electric aircraft (MEA) architectures consist of several subsystems, which must all comply with the settled safety requirements of aerospace applications. Thus, achieving reliability and fault-tolerance represents the main cornerstone when classifying different solutions. Hybrid electric aircraft (HEA) extends the MEA concept by electrifying the propulsive power as well as the auxiliary power, and thereby pushing the limits of electrification. This paper gives an overview of the high-power electrical machine families and their associated power electronic converter (PEC) interfaces that are currently competing for aircraft power conversion systems. Various functionalities and starter-generator (S/G) solutions are also covered. In order to highlight the latest advancements, the efficiency of the world’s most powerful aerospace generator (Mark 1) developed within the E-Fan X HEA project is graphically represented and assessed against other rivaling solutions. Motivated by the strict requirements on efficiency, power density, trustworthiness, as well as starting functionalities, supplementary considerations on the system-level design are paramount. In order to highlight the MEA goals and take advantage of all potential benefits, all subsystems must be treated as a whole. It is then shown that the combination of PECs, aircraft grid and electrical machines can be better adapted to benefit the overall system. This survey outlines the influence of these concerns and offers a view of the future technology outlook, as well as covering the present challenges and opportunities.

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High-Power Machines and Starter-Generator Topologies for More Electric Aircraft: A Technology Outlook

PowerSynth is a multiobjective optimization tool for rapid design and verification of power semiconductor modules. By using reduced order models for the calculation of electrical parasitics of the layout and thermal coupling between devices, optimal trace layout and die placement can be simultaneously achieved orders of magnitude faster than conventional finite element analysis (FEA) techniques. An overview of the tool, its modeling methods, model validation, and module layout optimization are presented. The electrical and thermal models are validated against FEA simulations and physical measurements of built modules generated from the tool. The FEA comparisons are performed with FastHenry and ANSYS Icepak to evaluate electrical parasitics and thermal behavior, respectively. A sample hardware prototype based on a half-bridge circuit topology is chosen for testing. Excellent agreement between the FEA simulations, experimental measurements, and PowerSynth predictions are demonstrated. Additionally, when compared with conventional simulation runtime and workflow, PowerSynth takes considerably less computation and user time to produce several candidate layout solutions from which a designer may easily balance selected tradeoffs.

PowerSynth: A Power Module Layout Generation Tool

The 2050 carbon-neutral vision spawns a novel energy structure revolution, and the construction of the future energy structure is based on equipment innovation. Insulating material, as the core of electrical power equipment and electrified transportation asset, faces unprecedented challenges and opportunities. The goal of carbon neutral and the urgent need for innovation in electric power equipment and electrification assets are first discussed. The engineering challenges constrained by the insulation system in future electric power equipment/devices and electrified transportation assets are investigated. Insulating materials, including intelligent insulating material, high thermal conductivity insulating material, high energy storage density insulating material, extreme environment resistant insulating material, and environmental-friendly insulating material, are categorised with their scientific issues, opportunities and challenges under the goal of carbon neutrality being discussed. In the context of carbon neutrality, not only improves the understanding of the insulation problems from a macro level, that is, electrical power equipment and electrified transportation asset, but also offers opportunities, remaining issues and challenges from the insulating material level. It is hoped that this paper envisions the challenges regarding design and reliability of insulations in electrical equipment and electric vehicles in the context of policies towards carbon neutrality rules. The authors also hope that this paper can be helpful in future development and research of novel insulating materials, which promote the realisation of the carbon-neutral vision. 

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Insulating materials for realising carbon neutrality: Opportunities, remaining issues and challenges

Corner stitching is a technique for representing rectangular two-dimensional objects. It is especially well suited for interactive VLSI layout editing systems. The data structure has two important features: first, empty space is represented explicitly; and second, rectangular areas are stitched together at their corners like a patchwork quilt. This orga­ nization results in fast algorithms (linear or constant expected time) for searching, creation, deletion, stretching, and compaction. The algorithms are presented under a simplified model of VLSI circuits, and the storage requirements of the structure are discussed. Corner stitching has been implemented in a working layout editor. Initial measurements indicate that it requires about three times as much memory space as the simplest possible representation.

Corner Stitching: A Data-Structuring Technique for VLSI Layout Tools

The emergence of wide bandgap power semiconductor devices has opened the possibilities of improved electrical performance and power density. Advanced research into wide bandgap power electronics also includes advances in integrated circuit design, semiconductor device modeling, 3D electronic packaging, and computer-aided design of wide bandgap based electronics. These emerging trends are described along with some early results indicating the additional improvements possible in power density. Operation at extreme temperatures also becomes more feasible.

/pdf/emerging-trends-in-silicon-carbide-power-electronics-design-25ctciyddc.pdf

Emerging trends in silicon carbide power electronics design

As a critical energy-conversion system component, power semiconductor modules and their layout optimization has been identified as a crucial step in achieving the maximum performance and density for wide bandgap technologies (i.e., GaN and SiC). New packaging technologies are also introduced to produce reliable and efficient multichip power module (MCPM) designs to push the current limits. The complexity of the MCPM layout is surpassing the capability of a manual, iterative design process to produce an optimum design with agile development requirements. An electronic design automation tool called PowerSynth has been introduced with on-going research toward enhanced capabilities to speed up the optimized MCPM layout design process. As a part of this continuing research, in PowerSynth v1.9, a constraint-aware layout engine has been developed, which enables integrating heterogeneous components, handling complex geometry, exploring a larger solution space, improved success rate, and providing options for multiobjective optimization algorithms. The layout engine is generic, scalable, and efficient in performing electro-thermal optimizations on both 2-D and 2.5-D power modules. To validate these enhanced design capabilities, a 2.5-D full-bridge power module layout is designed, optimized, fabricated, and tested with measurement results matching closely with model prediction. This result closes the loop in the power electronics design process with an experimentally validated module design automation flow.

PowerSynth Design Automation Flow for Hierarchical and Heterogeneous 2.5-D Multichip Power Modules

As spacing between traces in power modules is reduced to meet increasing power density requirements, partial discharge (PD) starts becoming a threat that can cause insulation breakdown, if not checked. For high voltage applications, PD awareness is particularly important, and this paper describes how various trace shapes play a critical role in the electrical reliability of modules with regard to electrical breakdown. Sharp corners of traces must be avoided, as is generally done for mechanical stability reasons, by filleting the corners. High voltage experiments were performed to confirm the detrimental electrical effects of sharp corners. The degree of improvement by completely avoiding sharp corners was quantified for various trace gaps. Simulations were performed to predict the improvement in terms of E-field concentration with respect to the radius of fillets. Preliminary fillets were implemented in a stand-alone in-house tool called PowerSynth, which is used for electrical and thermal optimization.

Toward Partial Discharge Reduction by Corner Correction in Power Module Layouts

In our tool, PowerSynth, fast calculation of electrical parasitics is of paramount concern when evaluating the layout of an MCPM during multi-objective optimization. To this end, this work extends the current capabilities of PowerSynth to quickly and more accurately extract lumped RLC parameters by utilizing a response surface model. An MCPM is represented as a series of layers forming a stack corresponding to their physical dimensions and material properties. FastHenry is employed to run frequency sweep simulations on this layer stack with both rectangular traces and 90-degree corners with varying sizes, spacing, and positioning. The results of these simulations are then used to build a response surface model accounting for frequency dependence and current crowding effects. This model is then used in the MCPM optimization engine to evaluate loop parasitics for a given layout. The results of this model are then compared with FastHenry simulations and measurements using an LCR meter and Time Domain Reflectometry (TDR) of a fabricated prototype.

Quang Le

Papers

PowerSynth: A Power Module Layout Generation Tool

Emerging trends in silicon carbide power electronics design

PowerSynth Design Automation Flow for Hierarchical and Heterogeneous 2.5-D Multichip Power Modules

Toward Partial Discharge Reduction by Corner Correction in Power Module Layouts

Response surface modeling for parasitic extraction for multi-objective optimization of multi-chip power modules (MCPMs)