Integrated Bus Bar Voltage Rise Time Filter
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Solution Overview
Problem
High-frequency voltage fluctuations caused by rapid switching in semiconductor-powered electrical motors can damage insulation and lead to premature failure, necessitating additional filter components that are difficult to integrate into existing systems.
Innovation Solution
A bus bar with a compact filter design incorporating high relative permeability material layers to enhance inductance, capacitance, and damping resistance, providing a low pass electrical filter with a corner frequency greater than 50 kilohertz to manage voltage rise times effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional filter components are introduced to limit voltage rise time, then voltage rise time is controlled to be greater than 0.1 microseconds, but device complexity increases and installation becomes difficult
Solution Approach 1:
The patent combines multiple filter functions (inductance, capacitance, damping resistance) into a single integrated bus bar structure. The bus bar itself provides inductance, while wrapped conductive layers separated by insulating material provide capacitance and damping resistance, eliminating the need for separate filter components and simplifying installation.
Solution Approach 2:
The bus bar structure performs multiple functions simultaneously: it serves as the current conductor, the inductor, the capacitor, and the damper. This multi-functionality resolves the contradiction by providing voltage rise time control without adding separate filter components, thus maintaining simplicity while achieving reliability.
2Reliability
If traditional filter components are added between motor drive and motor, then voltage rise time is limited, but ease of operation deteriorates due to additional spacing requirements in cabinets
Solution Approach 1:
The filter functionality is merged into the bus bar itself, which is already a necessary component for current conduction. This integration means no additional space is required in the cabinet, as the filter is not a separate component but part of the existing bus bar structure.
Solution Approach 2:
The bus bar provides its own filtering capability through its inherent inductance and the integrated wrapped layers that provide capacitance and damping. This self-service approach eliminates the need for external filter components and simplifies installation by requiring no additional spacing or complex wiring.
3Reliability
If high-frequency filtering is provided separately from the bus bar, then voltage rise time is controlled, but volume of the system increases
Solution Approach 1:
The filtering components (inductor, capacitor, damper) are merged into the bus bar structure. The bus bar provides inductance, while wrapped conductive layers provide capacitance and damping resistance, all within the same physical space, thus eliminating the need for additional volume for separate filter components.
Solution Approach 2:
The filter components are nested within the bus bar structure. The wrapped conductive layers are positioned around the bus bar conductor, with insulating material between layers, creating a compact integrated structure that provides filtering functionality without increasing overall system volume.
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 solution effectively limits voltage rise times to greater than 0.1 microseconds, preventing insulation damage and bearing failure while maintaining a compact form factor suitable for high-current applications, simplifying installation and compatibility with various bus bar designs.
Implementation Method 1
A wrapping of alternate layers of a first and second layer of conductive material is provided in a spiral around the length of the low resistance conductor... where the first and second layer of conductive material are separated from each other by insulating material
Implementation Method 2
The first layer of conductive material is electrically attached to a first end of the low resistance conductor and the second layer of conductive material is electrically attached to a ground lead
Implementation Method 3
The result is a compact form factor bus bar that also provides high-frequency filtering
Data Source
AI summary
A bus bar or similar high current conductor may be sheathed in a high relative permeability material formed in layers to both increase the inductance of that conductor and to provide a capacitance and resistance useful for forming a low pass filter to reduce the rise time of the voltage signals on the bus bar such as can be damaging to motor insulation and the like.