Input Capacitor Charging in Two-Wire Lighting Control Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lighting control systems face challenges in reliably communicating data over a single power line between a dimmer switch and an electronic dimming ballast without requiring additional wiring or complex commissioning processes, especially in retrofit installations where neutral wire connections are not available, leading to interference and reliability issues.
Innovation Solution
A load control system that uses a digital ballast controller to generate a control-hot voltage for transmitting digital messages to two-wire dimming ballasts, allowing for power and communication over existing wiring without a neutral connection, using a rectifier circuit, power converter, and input capacitor to manage phase-control voltage and charge capacitors, enabling independent control of lighting fixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard three-wire dimming ballast is used, then dimming control is achieved, but additional wiring and complex installation are required
Solution Approach 1:
The patent combines power delivery and communication functions into a single two-wire interface. The ballast receives both power and dimming control signals through the same two wires that connect to the lighting fixture, eliminating the need for separate control wiring and neutral connections required by traditional three-wire dimming ballasts.
Solution Approach 2:
The two-wire interface serves multiple functions simultaneously: it provides power to the ballast, transmits dimming control signals, and enables bidirectional communication between the controller and ballast. This multi-functional approach replaces the specialized three-wire configuration dedicated solely to power and analog dimming control.
2Device complexity
If power line communication is implemented over a single power line, then additional wiring is avoided, but interference and reliability issues occur
Solution Approach 1:
The patent introduces a controlled hot wire as an intermediary carrier that enables reliable communication without requiring a neutral connection. The controller generates controlled hot voltage signals that are transmitted through the hot wire to the ballast, where they are detected and processed. This intermediary approach avoids the interference problems associated with traditional power line communication while maintaining simplicity.
Solution Approach 2:
The communication system uses periodic voltage transitions on the controlled hot wire to encode digital signals. The controller applies periodic voltage changes during specific time intervals to represent binary data, enabling reliable transmission of control commands and status information through the power line without requiring complex modulation schemes that are susceptible to interference.
3Ease of manufacture
If retrofit installation without neutral connection is implemented, then installation cost is reduced, but control capability is limited
Solution Approach 1:
The ballast incorporates an internal rectifier circuit that converts the controlled hot voltage signals received on the two hot wires into usable DC control voltages. This self-service approach eliminates the need for external neutral connections or additional power conversion equipment, allowing the ballast to autonomously generate the required control voltages from the available hot wire signals.
Solution Approach 2:
The system controls lighting intensity by varying the width of voltage pulses applied to the controlled hot wire. By changing the duty cycle or duration of these periodic voltage signals, the ballast can adjust its output power to achieve different lighting levels. This parameter-based control method provides full dimming capability without requiring complex wiring or neutral connections.
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 reliable and cost-effective control of lighting intensity for multiple fixtures connected to a single controller via a single power line, reducing installation costs and avoiding the need for additional wiring, while maintaining system reliability and avoiding interference with other control devices.
Implementation Method 1
a rectifier circuit configured to receive a phase-control voltage and produce a rectified voltage
Implementation Method 2
A power converter may be configured to receive the rectified voltage at an input and generate a bus voltage
Implementation Method 3
An input capacitor may be coupled across the input of the power converter. The input capacitor may be adapted to charge when the magnitude of the phase control voltage is approximately zero volts
Data Source
AI summary
A load control device for controlling the amount of power delivered to an electrical load may include a rectifier circuit configured to receive a phase-control voltage and produce a rectified voltage. A power converter may be configured to receive the rectified voltage at an input and generate a bus voltage. An input capacitor may be coupled across the input of the power converter. The input capacitor may be adapted to charge when the magnitude of the phase control voltage is approximately zero volts. The power converter may be configured to operate in a boost mode, such that the magnitude of the bus voltage is greater than a peak magnitude of the input voltage. The power converter may be configured to operate in a buck mode to charge the input capacitor from the bus voltage when the magnitude of the phase-control voltage is approximately zero volts.