Two-Wire Power Supply for Fan and Light Control
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Solution Overview
Problem
Existing systems fail to provide independent control of a fan motor and a lighting source located in the same enclosure from a remote location using existing building wiring, which typically only includes a single pair of wires without a neutral connection, limiting control options and requiring separate wires for independent control.
Innovation Solution
A power supply system that includes a controllably conductive device, a triggering circuit, and a charging circuit, which charges an energy storage device when the conductive device is non-conductive, allowing for minimal power derivation from the AC voltage source to power a microcontroller and other low-voltage circuitry while maintaining substantial AC voltage availability to the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dual light and fan speed control is used to provide independent control of loads, then independent control capability is improved, but device complexity and wiring requirements increase
Solution Approach 1:
The patent combines the power supply function and control function into a single integrated control device that can be installed in the existing electrical wallbox. This merging eliminates the need for separate power supply units and reduces wiring complexity while maintaining independent control capability for both lighting and fan loads.
Solution Approach 2:
The control device is designed to perform multiple functions: it provides independent control of lighting loads and fan motors, includes a microcontroller for intelligent control, and integrates a power supply system. This multi-functionality allows a single device to replace multiple separate components, reducing overall system complexity.
2Power
If power is derived from AC voltage to power control circuitry, then control device operation is enabled, but voltage available to load decreases
Solution Approach 1:
The power supply uses a capacitor that charges during the period when the triac is non-conductive and then discharges to power the microcontroller during operation. This periodic charging action allows the control circuitry to be powered without creating a continuous voltage drop across the load, as power is transferred in discrete pulses rather than continuously.
Solution Approach 2:
The capacitor is charged in advance during the off-period of the triac before power is needed by the microcontroller. This preliminary charging action ensures that when the control circuitry needs power, the voltage has already been stored in the capacitor, avoiding any voltage drop across the load at the moment power is drawn.
3Ease of manufacture
If a two-wire control device is used to match existing building wiring, then ease of installation is improved, but power availability for control circuitry is limited
Solution Approach 1:
The power supply parameters are specifically designed to operate from the limited power available in a two-wire system. The capacitor value and charging circuit parameters are optimized to extract maximum power during the brief charging period, enabling the microcontroller to function with the constrained power supply while maintaining compatibility with standard two-wire installations.
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 independent control of fan motors and lighting sources using a two-wire control device, minimizing voltage drop and allowing control from a remote location without the need for additional neutral connections, ensuring reliable operation with reduced noise and flicker.
Implementation Method 1
an energy storage capacitor coupled to a charging circuit
Implementation Method 2
a triac coupled in series electrical connection between the energy storage capacitor and the electrical load
Data Source
AI summary
A power supply adapted to be coupled in series electrical connection between an AC voltage source and an electrical load for generating a DC voltage, the power supply comprising an energy storage capacitor, the DC voltage produced across the capacitor; a charging circuit adapted to be coupled in series electrical connection between the source and the load and to conduct a load current from the source to the load, the charging circuit coupled to the energy storage capacitor for charging the energy storage capacitor; a controllably conductive device coupled in parallel electrical connection with the charging circuit and having a control input for rendering the controllably conductive device conductive, the controllably conductive device adapted to carry the load current from the source to the load when the controllably conductive device is conductive; and a triggering circuit coupled to the control input of the controllably conductive device for causing the controllably conductive device to become conductive when the energy storage capacitor has charged to a desired maximum value; wherein the charging circuit is adapted to conduct the load current from the source to the load when the controllably conductive device is non-conductive, the charging circuit imposing a low voltage drop relative to the peak value of an AC voltage of the AC voltage source, such that substantially all of the AC voltage is available to the load during the time when the controllably conductive device is non-conductive.