Power Line Carrier Load Control via DC Offset Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing load control systems for commercial buildings require costly dedicated wiring for control signals, making retrofitting and installation expensive, and existing wireless solutions face challenges in power quality reduction and cost-effectiveness.
Innovation Solution
The system uses Power Line Communicated Load Control (PCLC) to transmit control signals over existing AC power lines by modulating the supply voltage with a direct current offset, causing minimal harmonic distortion, allowing for remote load management without the need for new wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated control wiring is used for load control systems, then control signal transmission reliability is improved, but installation cost and complexity increase significantly
Solution Approach 1:
The power line is made to serve dual purposes: both power delivery and control signal transmission. By multiplexing the existing power wiring infrastructure, the system eliminates the need for separate dedicated control wiring while maintaining reliable communication through the power line carrier signals.
Solution Approach 2:
The patent combines power transmission and control signal transmission into a single wiring infrastructure. The power line carrier system merges the power delivery function with the control communication function, reducing overall system complexity and installation costs.
2Device complexity
If wireless control systems are used to avoid dedicated wiring, then installation cost is reduced, but power quality degradation occurs
Solution Approach 1:
The patent introduces power line carrier signals as an intermediary method that transmits control information through the existing power line infrastructure without requiring wireless communication. This intermediary approach maintains power quality by using the power line's inherent electrical signals rather than wireless transmission that causes interference and power degradation.
3Device complexity
If existing power lines are used for control signals, then installation cost is reduced, but signal interference and noise increase
Solution Approach 1:
The patent employs periodic modulation of the power line carrier signals to transmit control information. By using time-division multiplexing and periodic signal injection, the system separates control signals from power signals in the time domain, reducing interference and allowing reliable communication over the power line infrastructure.
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
PCLC reduces installation costs, maintains high power quality, and enables efficient load control in existing buildings by using existing AC wiring, allowing for load shave and load shed operations, and can be adapted for various lighting and HVAC applications.
Implementation Method 1
an injector circuit connected to a powered circuit conductor and configured to modulate a power signal with a direct current voltage asymmetrically resulting in a DC offset
Implementation Method 2
a decoder connected to the powered circuit conductor and a load, the decoder configured to demodulate the direct current voltage offset to control the load
Data Source
AI summary
A system for transmitting communication signals, the system comprising an injector circuit connected to a powered circuit conductor and configured to modulate a power signal with a direct current voltage offset, the direct current voltage offset being within a range that causes approximately 1 percent or less total harmonic distortion of the power signal; and a decoder connected to the powered circuit conductor and a load, the decoder configured to demodulate the direct current voltage offset to control the load. A method for transmitting communication signals, the method comprising modulating a power signal on a powered circuit conductor with a direct current voltage offset, the direct current voltage offset being within a range that causes approximately 1 percent or less total harmonic distortion of the power signal; and demodulating the direct current voltage offset to control a load.