DC Line Data Transmission Impedance Adaptation
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Solution Overview
Problem
Power line communication in photovoltaic systems with branched DC circuits faces challenges due to varying impedances, leading to unpredictable signal strength and interference, making reliable data transmission difficult.
Innovation Solution
A method and system that use a high-frequency test signal to determine the impedance of the DC circuit, allowing for the adjustment of the signal amplitude for optimal data transmission, ensuring robust communication across varying impedance conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-frequency signals are coupled onto DC lines for power line communication in branched PV systems, then data transmission is enabled, but signal strength becomes unpredictable and interference increases due to varying impedances
Solution Approach 1:
The system performs preliminary impedance measurement by sending a test signal before actual data transmission. This preliminary action characterizes the transmission path properties, allowing the system to adapt subsequent communication parameters to the measured impedance conditions, thereby ensuring reliable data transmission despite varying impedances in branched PV systems
Solution Approach 2:
The system changes communication parameters (signal amplitude, frequency, modulation scheme) based on the measured impedance characteristics. By adapting these parameters to the actual transmission conditions, the system overcomes the unpredictability of signal strength in branched circuits while maintaining reliable data transmission
2Strength
If signal amplitude is increased to overcome impedance variations, then signal strength improves, but interference and distortion increase
Solution Approach 1:
Instead of uniformly increasing signal amplitude, the system adjusts the signal amplitude based on the measured impedance characteristics. This selective parameter adaptation ensures sufficient signal strength for reliable communication while avoiding excessive amplitude that would cause interference and distortion
Solution Approach 2:
The system uses feedback from the measured test signal response to determine appropriate signal amplitude. By continuously monitoring the transmission path characteristics and adjusting signal parameters accordingly, the system maintains optimal signal strength without generating harmful interference
3Reliability
If impedance measurement and signal adaptation are implemented, then data transmission reliability improves, but system complexity increases
Solution Approach 1:
The communication units are designed to perform multiple functions: they can both measure impedance by sending test signals and transmit data. This multi-functionality reduces the need for separate dedicated measurement equipment, thereby limiting the increase in system complexity while still achieving reliable adaptive communication
Solution Approach 2:
The system merges the impedance measurement function with the data transmission function by using the same communication units and infrastructure. The test signal and data signals share the same transmission path and coupling mechanisms, consolidating the system architecture and reducing overall complexity
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
This approach enables reliable and efficient data transmission between communication units in photovoltaic systems with branched DC circuits by adapting signal amplitude based on real-time impedance measurements, improving signal strength and reducing interference.
Implementation Method 1
each of which has a coupling means for coupling high-frequency signals onto the direct current lines
Implementation Method 2
a decoupling means for decoupling HF signals from the direct current lines
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method for transmitting data via direct current lines (3, 4) for energy transmission from a first to a second communication unit (10a, 10b, 10c), having the following steps: generating a high frequency test signal having a specified voltage amplitude (uTXa, UTXC) by the first or second communication unit (10a, 10b, 10c) and coupling the high frequency test signal to the direct current lines (3, 4); determining a size of a current (ia, ib, ic) produced by the high frequency test signal on the direct current lines (3, 4) by the first communication unit (10a, 10b, 10c); determining a voltage amplitude for a high frequency signal depending on the size of the current (ia, ib, ic) produced by the test signal and coupling a high frequency signal having the previously determined voltage amplitude on the direct current lines (3, 4) by the first communication unit (10a, 10b, 10c) for transmitting data to the second communication unit (10a, 10b, 10c). The invention further relates to a system for transmitting data via direct current lines (3, 4) for energy transmission and to a photovoltaic plant having such a system.