Microcontroller Power Controller for Lamp Voltage Regulation
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Solution Overview
Problem
Conventional power controllers for lamps fail to maintain a constant RMS load voltage and limit load current effectively in response to variations in line voltage, leading to potential system overload and failure.
Innovation Solution
A microcontroller-based voltage conversion circuit that adjusts the phase conduction angle or pulse width modulation to maintain a constant RMS load voltage by sensing line voltage variations and limiting load current, using a switch and microcontroller to define the RMS load voltage and decrease it when line voltage drops below a normal operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phase-control clipping circuit is used to control power to load, then power control is achieved, but RMS load voltage cannot be maintained constant and load current cannot be limited when line voltage varies
Solution Approach 1:
The patent employs a microcontroller that continuously monitors line voltage and adjusts the phase conduction angle or PWM duty cycle accordingly. This closed-loop feedback mechanism enables the system to maintain constant RMS load voltage and limit load current when line voltage drops, preventing system overload and improving reliability under varying line voltage conditions.
2Reliability
If line voltage drops significantly, then voltage conversion circuit increases conduction angle or duty cycle to maintain RMS load voltage, but load current increases causing system overload
Solution Approach 1:
The microcontroller monitors both line voltage and load current, and adjusts the phase conduction angle or PWM duty cycle to maintain constant RMS load voltage within a safe operating range. When line voltage drops, the system increases conduction to maintain voltage but limits the maximum duty cycle to prevent excessive load current and system overload, ensuring both voltage stability and power safety.
3Ease of operation
If triac triggers early due to high line voltage, then power control is maintained, but RMS load voltage increases beyond desired level
Solution Approach 1:
The microcontroller continuously measures line voltage and dynamically adjusts the phase conduction angle or PWM duty cycle to compensate for line voltage variations. When line voltage is high, the system reduces the conduction angle or duty cycle to prevent early triac triggering and maintain precise RMS load voltage at the reference level, ensuring manufacturing precision in voltage control.
Data Source
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AI summary
A power controller converts a line voltage to an RMS load voltage for a lamp, and includes a switch and a microcontroller that operates the switch to define the RMS load voltage. The microcontroller senses a load voltage of the lamp, compares the sensed load voltage to a reference RMS voltage, and operates the switch in response to the comparison so that the RMS load voltage is substantially constant at the reference RMS voltage over an operating range of the line voltage and so that the RMS load voltage decreases with decreasing line voltage at line voltages less than the operating range. The operating range of the line voltage is defined to have a minimum that is a non-zero line voltage at which a load current is a predetermined maximum. The voltage conversion circuit may be a phase clipping circuit or a pulse width modulation circuit.