Switched Capacitor Array for LED Power Factor Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply systems for DC devices connected to AC power lines often use filters, bridges, and switched-mode power supplies with inductive transformers, which can reduce efficiency and power factor, particularly when used with dimmable LED lighting fixtures that mimic incandescent characteristics and require power factor correction.
Innovation Solution
A switched capacitor array and a switched LED array system that dynamically adjusts the number of capacitors and LEDs based on input voltage levels, using a control system to charge and discharge capacitors in series and parallel configurations to maintain constant voltage and power factor correction, eliminating the need for filters and bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inductive transformers or inductors are used in switched-mode power supplies, then power can be supplied from AC to DC, but efficiency and power factor are adversely affected
Solution Approach 1:
The patent removes inductive components (transformers and inductors) from the power supply circuitry and replaces them with a capacitor-based switched-mode power supply. This extraction of harmful inductive elements directly addresses the efficiency and power factor problems while maintaining the AC-to-DC conversion functionality.
Solution Approach 2:
The invention changes the fundamental operating parameters of the power supply by using capacitive switching instead of inductive switching. The capacitor array is controlled to charge during voltage peaks and discharge during voltage troughs, fundamentally altering the power conversion mechanism to eliminate inductive losses.
2Loss of energy
If filters and bridges are used in power supply systems, then AC power can be converted to DC, but efficiency is reduced
Solution Approach 1:
The patent extracts and eliminates traditional filter and bridge components from the power supply circuit. Instead of using conventional rectification and filtering stages, the invention employs a capacitor array that directly synthesizes the DC output by switching capacitors in series and parallel configurations.
Solution Approach 2:
The invention replaces the mechanical/electromagnetic filtering and rectification mechanisms with an electronic capacitor-switching system. The microcontroller-controlled switches replace traditional diode bridges and LC filters, creating a more efficient solid-state power conversion system.
3Ease of operation
If LED lighting fixtures are made dimmable with TRIAC dimmers, then lighting control is improved, but power factor correction becomes necessary
Solution Approach 1:
The capacitor-based power supply serves multiple functions simultaneously: it provides AC-to-DC conversion, inherent power factor correction, and compatibility with TRIAC dimming controls. The capacitor array's switching characteristics naturally improve power factor while maintaining dimming functionality, eliminating the need for separate correction circuits.
Solution Approach 2:
The invention changes the electrical characteristics of the LED driver to be inherently compatible with TRIAC dimmers. By using capacitive switching with controlled timing, the system presents a more sinusoidal current draw that works harmoniously with TRIAC-based dimming circuits, improving both power factor and dimming performance.
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
The system provides efficient, stable DC power to LED lighting fixtures, maintaining constant voltage and power factor correction across varying AC input conditions, enhancing efficiency and compatibility with TRIAC dimmers.
Implementation Method 1
The switched capacitor array has a plurality of capacitors arranged in a plurality of branches having different numbers of capacitors, and a plurality of switches connected to selectively couple the capacitors across the input or the output
Data Source
AI summary
A switched capacitor array having a plurality of capacitors arranged in a plurality of branches having different numbers of capacitors, and a plurality of switches connected to selectively couple the capacitors across the input or the output may be used for powering a variety of loads. A switched LED array may be dynamically configured based on a voltage supplied thereto, which may be supplied by a switched capacitor array. A lighting apparatus may be provided with first and second blocks, each block comprising a switched capacitor array, a switched LED array, and a control system.