Transformer-Based Communication Circuit for EV Charging Signal Integrity
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Solution Overview
Problem
Existing communication systems between electric vehicles and electricity supply apparatuses face signal attenuation and noise resistance issues due to capacitors in the output and input circuits, which can degrade transmission speed and prevent the transmission and reception of control pilot signals when communication signals are superimposed on the control pilot line.
Innovation Solution
A communication system that employs transformers and lowpass filters with inductors and resistors to separate communication signals from control pilot signals, ensuring that communication signals are transmitted and received without attenuation, using a communication band of 1 MHz or higher, and maintaining the integrity of control pilot signals by reducing resonance and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If capacitors are provided in the output circuit and input circuit to remove noise, then noise resistance is improved, but communication signal is attenuated and transmission speed degrades
Solution Approach 1:
The patent segments the signal processing functions by separating the control pilot signal path from the communication signal path. The output circuit generates both signals but processes them differently, and the input circuit separately processes each signal type before combining their effects. This segmentation allows capacitors to filter noise from control pilot signals without attenuating communication signals, resolving the contradiction between noise resistance and transmission speed.
Solution Approach 2:
The patent introduces an intermediary approach by using the transformer to couple the communication signal to the control pilot line while maintaining electrical isolation. The transformer acts as a mediator that allows high-frequency communication signals to pass through while blocking low-frequency control pilot signals from interfering with the communication band, thus preventing signal attenuation while maintaining noise resistance.
2Object-affected harmful factors
If capacitors are provided in the output circuit and input circuit to remove noise, then noise resistance is improved, but degradation in noise resistance occurs
Solution Approach 1:
The patent segments the signal processing functions by separating the control pilot signal path from the communication signal path. The output circuit generates both signals but processes them differently, and the input circuit separately processes each signal type before combining their effects. This segmentation allows capacitors to filter noise from control pilot signals without attenuating communication signals, resolving the contradiction between noise resistance and transmission speed.
3Adaptability or versatility
If communication circuit is connected to the control pilot line to enable communication, then communication functionality is added, but transmission and reception of control pilot signal cannot be achieved
Solution Approach 1:
The patent segments the signal processing functions by separating the control pilot signal path from the communication signal path. The output circuit generates both signals but processes them differently, and the input circuit separately processes each signal type before combining their effects. This segmentation allows capacitors to filter noise from control pilot signals without attenuating communication signals, resolving the contradiction between noise resistance and transmission speed.
Solution Approach 2:
The patent introduces an intermediary approach by using the transformer to couple the communication signal to the control pilot line while maintaining electrical isolation. The transformer acts as a mediator that allows high-frequency communication signals to pass through while blocking low-frequency control pilot signals from interfering with the communication band, thus preventing signal attenuation while maintaining noise resistance.
4Adaptability or versatility
If communication signal is superimposed on the control pilot line, then communication between vehicle and electricity supply apparatus is enabled, but signal attenuation occurs
Solution Approach 1:
The patent introduces an intermediary approach by using the transformer to couple the communication signal to the control pilot line while maintaining electrical isolation. The transformer acts as a mediator that allows high-frequency communication signals to pass through while blocking low-frequency control pilot signals from interfering with the communication band, thus preventing signal attenuation while maintaining noise resistance.
Solution Approach 2:
The patent utilizes parameter changes by operating the communication signal at a frequency band (1 MHz or higher) that is significantly different from the control pilot signal frequency. This frequency separation parameter change allows the system to transmit both signals simultaneously over the same physical medium without mutual interference, eliminating signal attenuation while enabling communication capability.
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 suppresses signal attenuation and ensures reliable communication between vehicles and electricity supply apparatuses, maintaining the integrity of control pilot signals and preventing errors in signal transmission and reception, thereby enhancing noise resistance and transmission speed.
Implementation Method 1
a first communication unit provided in the electricity supply apparatus and transmitting and receiving a communication signal via a first transformer connected between the signal lines; a second communication unit provided in the vehicle and transmitting and receiving a communication signal via a second transformer connected between the signal lines
Implementation Method 2
a first lowpass filter interposed between the output circuit and the first transformer; and a second lowpass filter interposed between the input circuit and the second transformer
Implementation Method 3
each of the first and the second lowpass filters includes an inductor connected in series to the signal line
Data Source
Figure 1
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AI summary
Provided are a communication system and a communication device capable of suppressing attenuation of a communication signal superimposed upon a control pilot line. This output circuit (20) sends a control pilot signal which has been generated at a voltage generation source (21) to an input circuit (60). Between the control pilot line (4) and the ground line (3) of the output side of the output circuit (20), a communication unit (30) is connected via a transformer (31). Between the control pilot line (4) and the ground line (3) of the input side of the input circuit (60), a communication unit (70) is connected via a transformer (71). Between the output circuit (20) and the transformer (31), a lowpass filter (33) is interposed. Between the input circuit (60) and the transformer (71), a lowpass filter (73) is interposed.