Auxiliary Voltage LED Driver for Power Factor Correction
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Solution Overview
Problem
Conventional LED lighting systems face challenges in efficiently managing power factor correction and rapid changes in power demand, leading to increased costs and inefficiencies due to the need for expensive integrated circuits and large capacitors.
Innovation Solution
A digital signal processor-based LED lighting system with a power factor correction (PFC) and LED drive controller that operates from a lower auxiliary voltage, using a common reference node to control conductivity of high voltage switches, and employing feedforward control to quickly respond to power demand changes, reducing the need for expensive components and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LED lighting systems use expensive integrated circuits and large capacitors for power factor correction, then power factor correction and rapid response to power demand changes are achieved, but system cost and component complexity increase
Solution Approach 1:
The patent changes the operating voltage parameter of the controller from high voltage (link voltage) to low voltage (auxiliary voltage less than link voltage). This parameter change allows the use of simpler, lower-cost integrated circuits that can operate from the auxiliary voltage, reducing component complexity while maintaining power factor correction performance through the voltage transformation ratio relationship
Solution Approach 2:
The patent introduces an auxiliary voltage source as an intermediary between the high voltage link voltage and the controller. The auxiliary voltage is generated through a transformer coupling the primary and secondary sides, serving as a mediator that enables the controller to operate at lower voltage while still controlling high voltage switches, thereby reducing component complexity
2Reliability
If conventional LED lighting systems use large capacitors for power factor correction, then power factor correction is achieved, but system cost increases
Solution Approach 1:
The patent changes the voltage parameter from high voltage to low voltage operation for the controller, which directly reduces the capacitor size requirement. The auxiliary voltage is maintained at a level less than the link voltage, enabling the use of smaller, less expensive capacitors while achieving the same power factor correction through the transformed voltage relationship
3Reliability
If conventional LED lighting systems use high voltage controllers, then power factor correction and LED drive control are achieved, but response speed to power demand changes decreases
Solution Approach 1:
The patent changes the operating voltage parameter from high voltage to low voltage for the controller. This parameter change enables faster response to power demand changes because low voltage controllers can process and respond to changes more quickly than high voltage controllers, while the transformer coupling maintains the necessary power factor correction and LED drive control functionality
Data Source
AI summary
A light emitting diode (LED) lighting system includes a PFC and output voltage controller and a LED lighting power system. The controller advantageously operates from an auxiliary voltage less than a link voltage generated by the LED lighting power system. The common reference voltage allows all the components of lighting system to work together. A power factor correction switch and an LED drive current switch are coupled to the common reference node and have control node-to-common node, absolute voltage that allows the controller to control the conductivity of the switches. The LED lighting system can utilize feed forward control to concurrently modify power demand by the LED lighting power system and power demand of one or more LEDs. The LED lighting system can utilize a common current sense device to provide a common feedback signal to the controller representing current in at least two of the LEDs.