Powerline Receiver Impedance Compensation for Signal Reinjection Control
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Solution Overview
Problem
High-voltage power line impedance variations due to environmental conditions cause parasitic signal reinjection in line carrier data transmission systems, disrupting signal reception and synchronization, especially in systems using superimposed transmission modes like QAM, where the impedance mismatch between the line and equipment is not accounted for.
Innovation Solution
An adjustment device and method that transmit a reference signal, measure the power of the reinjected signal, and adjust the compensation impedance to minimize signal reinjection, using a variable compensation impedance module and control module to periodically adapt to impedance changes, ensuring optimal signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual impedance compensation is configured during equipment commissioning, then the initial feedback from local transmitter to receiver is minimized, but variations in line impedance over time are not accounted for, causing feedback to disrupt data reception
Solution Approach 1:
The patent implements dynamic impedance compensation by periodically injecting a test signal, measuring the reinjected signal power, and adjusting the compensation impedance values (Rc and Xc) based on current line conditions. This transforms the static manual compensation into a dynamic adaptive system that responds to impedance variations caused by environmental changes, loading conditions, and temperature fluctuations.
Solution Approach 2:
The system employs feedback mechanisms where the power of the reinjected signal is measured and used to adjust the compensation impedance. The control unit modifies the compensation values based on the measured feedback signal power, creating a closed-loop control system that continuously optimizes the impedance matching to minimize feedback disruption.
2Power
If the transmitted signal power is increased to improve transmission distance, then the received signal power increases, but the feedback signal power also increases, potentially masking the received signal completely
Solution Approach 1:
The patent converts the harmful feedback signal into a useful measurement tool. By measuring the power of the reinjected feedback signal, the system gains information about the line impedance conditions and uses this information to adjust the compensation impedance, thereby transforming the harmful interference into a diagnostic and control mechanism.
Solution Approach 2:
The system changes the compensation impedance parameters (resistive component Rc and reactive component Xc) dynamically based on the measured feedback signal power. This parameter adjustment optimizes the impedance matching between the transmitter and line, minimizing the feedback effect while allowing the transmitted power to remain high for extended transmission distance.
3Ease of operation
If a hybrid transformer is used for 2-wire/4-wire conversion, then the basic signal transmission is enabled, but complex impedance compensation is required and only fixed manual settings are available
Solution Approach 1:
The system performs self-adjustment of the impedance compensation through automated measurement and control. The control unit automatically measures the reinjected signal power and adjusts the compensation impedance values without requiring manual intervention, making the complex compensation process transparent and self-managing.
Solution Approach 2:
The impedance compensation adjustment is performed periodically by injecting test signals at regular intervals and updating the compensation values based on the measurements. This periodic action ensures that the compensation remains optimized despite gradual changes in line conditions, while maintaining simplicity in the overall system operation.
Data Source
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AI summary
Device for adjusting the reinjection of a transmission signal into a reception chain of equipment (1) for data transmission by line carrier currents, characterized in that it comprises: - a measuring means (18 , 19) of the power of a signal reinjected into the reception chain, when the transmission signal is emitted, - a means of comparing (18, 19) the measured power with a predetermined power value, - a means adjusting (18, 19) the value of a compensation impedance (Zc), if the measured power is outside a predetermined interval around the predetermined power value.