CAN Bus Power and Data Transmission via Frequency-Domain Filtering
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Solution Overview
Problem
Existing communication and power transmission methods for CAN bus systems require separate lines, leading to material and space inefficiencies, high installation costs, and fire risks, while powerline communication and PoE solutions are not compatible without complex modifications that disrupt data arbitration.
Innovation Solution
An apparatus and method using low-pass and high-pass filters to transmit communication signals and electric power as high-frequency signals over a shared bus line, allowing for simple, reliable, and inexpensive power supply and data transmission, compatible with existing CAN bus systems without altering arbitration methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate lines are used for communication and power supply, then transmission reliability is improved, but material consumption and installation complexity increase
Solution Approach 1:
The patent combines communication signal transmission and power supply functions into a single bus line. The communication signal and high-frequency power signal share the same physical medium, eliminating the need for separate cables while maintaining functional reliability through frequency-domain separation.
Solution Approach 2:
The bus line is designed to serve multiple functions simultaneously: it acts as both a communication channel for data transmission and a power delivery medium for electrical loads. This multi-functional approach reduces material consumption while preserving transmission reliability.
2Reliability
If separate lines are used for communication and power supply, then signal interference is reduced, but installation cost and space requirements increase
Solution Approach 1:
The patent segments the signal spectrum into different frequency ranges: low-frequency communication signals occupy the baseband spectrum while high-frequency power signals occupy a separate high-frequency band. This spectral segmentation allows both signals to coexist on the same line without interference, reducing installation complexity.
Solution Approach 2:
The patent introduces filtering components as intermediaries that separate and manage the different signal types on the shared bus line. These filters act as mediators that allow simultaneous transmission of communication and power signals while preventing mutual interference.
3Quantity of substance
If powerline communication is used to share lines for communication and power, then material efficiency is improved, but data transmission efficiency deteriorates at high data rates
Solution Approach 1:
The patent transitions from time-domain multiplexing to frequency-domain multiplexing, utilizing the frequency dimension to separate communication and power signals. This allows simultaneous transmission without the bandwidth conflicts that plague traditional powerline communication systems, maintaining high data transmission efficiency while achieving material efficiency.
4Use of energy by moving object
If DC voltage component is separated using transformers and splitters, then power input efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/physical separation approach (transformers and splitters) with an electromagnetic field-based approach using frequency-selective filtering. Instead of physically separating DC and HF components through bulky transformers, the system uses electronic filters to separate signals in the frequency domain, reducing device complexity while maintaining power input efficiency.
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
Enables efficient and cost-effective transmission of both communication signals and electric power over a single line in CAN bus systems, reducing material needs and installation costs while ensuring reliable and collision-free access to the bus line.
Implementation Method 1
a low-pass filter for filtering the communication signal such that signal frequencies below the cutoff frequency of the low-pass filter are input into the bus line
Implementation Method 2
a high-pass filter for filtering the bus signal such that signal frequencies above the cutoff frequency of the high-pass filter are output from the bus line
Data Source
AI summary
A method of transmitting a communication signal and electric power between two user stations of a bus system includes coupling the communication signal into a bus line via a low-pass filter that filters the communication signal, such that signal frequencies below a cut-off frequency of the low-pass filter are coupled into the bus line of the bus system. The method also includes coupling, using a power coupling device, electric power in the form of a high-frequency signal into the bus line, transmitting the communication signal and the electric power as a bus signal to an electrical load using the bus line, and decoupling the communication signal from the bus line via a low-pass filter that filters the bus signal, such that signal frequencies below the cut-off frequency of the low-pass filter are decoupled from the bus line of the bus system.