Power-Dense Inverter Commutation Cell for Low-Inductance Switching
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Solution Overview
Problem
Aircraft power and propulsion systems face limitations in efficiency and power-to-weight ratio due to high parasitic inductance in existing power electronics converters, which restricts the performance and mission range of electric aircraft.
Innovation Solution
A power electronics converter design with a commutation cell featuring a power circuit and gate driver circuit, utilizing MOSFETs with reduced parasitic inductance, embedded in a multi-layer planar carrier substrate, and optimized electrical connections to minimize inductance and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If power module-based converters are used with conventional electrical connections, then device complexity is reduced and ease of manufacture is improved, but parasitic inductance increases leading to reduced efficiency and power density
Solution Approach 1:
The patent merges the power semiconductor devices, DC-link capacitors, and electrical connections into an integrated power module assembly. The carrier substrate integrates multiple electrical connections (first and second electrical connections) that directly connect the power semiconductor devices to the capacitors, eliminating separate mounting and reducing parasitic inductance. This merging achieves efficiencies up to 99% while maintaining manufacturability through modular assembly.
Solution Approach 2:
The patent utilizes a three-dimensional integrated layout on the carrier substrate, arranging power semiconductor devices and DC-link capacitors in a spatial configuration that minimizes connection length. The electrical connections are routed through multiple layers and dimensions of the carrier substrate, creating compact current paths that reduce parasitic inductance while maintaining a compact overall structure suitable for aerospace applications.
2Power
If parasitic inductance is reduced through optimized electrical connections, then efficiency and power density improve, but manufacturing complexity and cost increase
Solution Approach 1:
The patent segments the converter into modular power module assemblies that can be manufactured independently and then integrated into the overall converter system. Each power module contains segmented functional units (power semiconductor devices, capacitors, and integrated connections) that can be manufactured using standardized processes. This segmentation enables optimized electrical connections within each module while maintaining ease of manufacture through modular assembly and potential mass production of identical modules.
3Productivity
If switching frequency is increased to improve power density, then output power increases, but transistor switching losses and voltage overshoot increase due to parasitic inductance
Solution Approach 1:
The patent implements preliminary action by pre-integrating the DC-link capacitors directly onto the same carrier substrate as the power semiconductor devices during module manufacturing. This preliminary integration ensures that the electrical connections are established with minimal length and optimized geometry before the module is installed in the converter. The capacitors are positioned and connected in advance, creating low-inductance current paths that enable high switching frequencies without excessive switching losses or voltage overshoot.
Data Source
AI summary
An electrical power system includes an electrical machine having one or more windings and an AC-DC power electronics converter including a commutation cell having a power circuit and a gate driver circuit. The power circuit includes a plurality of power semiconductor switching elements and a capacitor. The gate driver circuit is electrically connected to and configured to provide switching signals to a gate terminal of each power semiconductor switching element. A peak rated power output of the electrical machine and the AC-DC power electronics converter is greater than 25 kW, a maximum efficiency of the AC-DC power electronics converter is greater than 97%, and a value of parameter β is greater than or equal to 0.3 PV/s2, where β is a product of a maximum switching frequency of the switching signals and a maximum rate of change of a source-drain voltage of the plurality of power semiconductor switching elements.