High-Voltage Converter EMI Filter With Ground Leakage Sensing
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Solution Overview
Problem
There is a need for a lightweight, reliable, high-density, high-voltage, high-power electric power supply system that exhibits high thermal, vibration, and electromagnetic interference (EMI) performance characteristics, particularly for applications such as electric motors in aircraft.
Innovation Solution
A high-power, high-voltage converter/inverter system utilizing Silicon Carbide (SiC) MosFET power switches, integrated EMI filters with ferrite rings, and ground fault detection, along with a liquid cooling system and modular, scalable motor controllers, achieving power densities of 10 kw/kg or greater and efficiency up to 98%, while regulating power delivery to electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power supply systems are used, then reliability is improved, but weight increases and power density decreases
Solution Approach 1:
The patent applies parameter changes by transitioning from silicon-based power switches to silicon carbide (SiC) MosFETs, which fundamentally alters the electrical and thermal parameters of the system. This material substitution enables higher operating temperatures, higher switching frequencies, and lower on-resistance, achieving both weight reduction and maintained reliability through superior material properties
Solution Approach 2:
The patent employs composite materials by integrating SiC MosFETs with advanced packaging substrates and thermal management materials. The modular converter design combines multiple materials (SiC semiconductors, ceramic substrates, thermal interface materials, and cooling system components) to achieve high power density while maintaining structural integrity and reliability
2Power
If power density is increased to 10 kw/kg or greater, then weight efficiency is improved, but thermal management difficulty increases
Solution Approach 1:
The patent introduces liquid coolant as an intermediary thermal management medium that flows through channels in the housing, absorbing heat from the high-power SiC MosFETs and transferring it away from the converter. This intermediary cooling system enables high power density operation by efficiently mediating heat removal without requiring direct thermal contact between power components and external cooling systems
Solution Approach 2:
The patent applies hydraulic principles through the liquid cooling system, where pressurized coolant flows through defined channels to remove heat. The housing incorporates integrated coolant flow paths that utilize fluid dynamics to efficiently transport thermal energy from high-power density regions, enabling sustained high-power operation
3Object-affected harmful factors
If integrated EMI filter with ferrite rings is added, then EMI protection is improved, but device complexity increases
Solution Approach 1:
The patent merges the EMI filtering function with the existing power input structure by integrating ferrite rings directly onto the input conductors and housing elements. Rather than adding separate EMI filter components, the design combines electromagnetic interference suppression with the mechanical and electrical input structure, reducing overall system complexity while maintaining EMI protection
Solution Approach 2:
The patent converts the potentially harmful EMI generated by high-frequency SiC MosFET switching into a manageable parameter by using ferrite materials that absorb and dissipate electromagnetic interference. The high-frequency switching that could generate EMI is simultaneously the source of high efficiency, and the ferrite rings transform the harmful electromagnetic radiation into harmless heat through magnetic hysteresis losses
4Loss of energy
If Silicon Carbide MosFET power switches are used, then efficiency reaches 98% or greater, but manufacturing cost increases
Solution Approach 1:
The patent applies parameter changes by utilizing SiC MosFETs with fundamentally different electrical characteristics compared to conventional silicon devices. The higher breakdown voltage, lower on-resistance, and higher switching frequency capability of SiC devices enable 98% or greater efficiency by minimizing conduction and switching losses, accepting higher component cost in exchange for dramatically reduced energy losses
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides efficient, reliable power delivery with high power density and EMI protection, capable of converting between HVDC and HVAC, and regulating motor output, meeting aviation standards for weight, thermal stability, and EMI resistance.
Implementation Method 1
The GFD includes a sensing element, preferably a linear Hall-effect sensor, to detect leakage current escaping to ground
Implementation Method 2
The EMI filter in an aspect includes ferrite rings surrounding the rail conductors
Implementation Method 3
The housing in an embodiment includes a vent to equalize pressure between the interior and the exterior of the housing
Data Source
AI summary
An electric power supply is described that has direct-current (DC) to alternating-current (AC) circuitry adapted and configured to receive DC power input having a DC input voltage and convert the DC power input to multi-phase, alternating-current (AC) power output. The DC to AC circuitry includes an electromagnetic interference (EMI) noise filter to suppress EMI noise, wherein the EMI noise filter comprises two, electrically insulated, conductive rails configured and adapted to receive the DC power input, ferrite material at least partially surrounding the two conductive rails, and a current sensing element positioned in a gap in the ferrite material and configured to measure leakage current escaping to ground.