PFC with Stacked Half-Bridges for High Voltage Lighting
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Solution Overview
Problem
Existing power factor correction (PFC) circuits struggle to effectively operate at high frequencies and high voltages, leading to inefficiencies and increased component size and cost in lighting devices.
Innovation Solution
A PFC topology using a switched converter with a control circuitry and half bridge converters, where each half bridge converter is connected to a resonant circuit, allowing for high frequency switching without power factor detection, and galvanic isolation through transformers, enabling smaller component dimensions and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a PFC circuit operates at high frequency and high voltage, then the lighting device can achieve higher efficiency and smaller size, but the circuit complexity and difficulty of control increase significantly
Solution Approach 1:
The PFC circuit is divided into multiple half-bridge converter stages connected in series, where each stage operates at a lower voltage level. This segmentation allows the overall circuit to handle high input voltage while each individual switching element operates at manageable voltage levels, enabling high-frequency operation without excessive complexity
Solution Approach 2:
Capacitors are introduced as intermediary energy storage elements between the half-bridge stages to decouple the voltage levels and simplify control. These capacitors act as mediators that store and transfer energy between stages, reducing the control complexity while maintaining high-frequency operation
2Power
If a PFC circuit operates at high voltage, then the power handling capability increases, but the component size and manufacturing cost increase
Solution Approach 1:
The high voltage is divided across multiple series-connected half-bridge stages, allowing the use of lower-voltage-rated (and thus smaller, cheaper) switching components in each stage while maintaining the overall high voltage handling capability of the circuit
Solution Approach 2:
The circuit topology is changed from a single high-voltage switch to multiple lower-voltage switches arranged in series half-bridge configurations. This parameter change in voltage distribution allows the use of more economical components while achieving the same power handling capability
3Device complexity
If a PFC circuit uses traditional topology, then the design is simpler, but it cannot effectively operate at high frequencies and high voltages simultaneously
Solution Approach 1:
The patent employs resonant circuits with adjustable frequency to enable dynamic adaptation to different operating conditions. The resonant frequency can be tuned to match the switching frequency, allowing efficient high-frequency operation while maintaining a relatively simple overall circuit structure
Solution Approach 2:
The circuit uses resonant frequency as a key parameter that can be adjusted to optimize performance at high frequencies. By changing the resonant frequency parameter to match the high-frequency switching operation, the circuit achieves efficient performance without requiring complex control mechanisms
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
This solution enables efficient PFC functionality at high frequencies and voltages, reducing component size and manufacturing costs while simplifying control, and providing galvanic isolation, thus improving the overall performance and efficiency of lighting devices.
Implementation Method 1
each half bridge converter is connected to a resonant circuit, allowing for high frequency switching without power factor detection
Implementation Method 2
galvanic isolation through transformers
Data Source
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AI summary
The invention relates to an operating device (1) for lighting means (8), having a circuit (101) for dividing a rectified alternating voltage to direct voltages of lower levels, wherein the circuit (101) comprises a PFC block comprising a plurality of half bridge converters (102, 103, 104) that are arranged such that the sum of the input voltage drops across the half bridge converters (102, 103, 104) corresponds to the value of the rectified alternating voltage, wherein the circuit (101) is the first active stage in a power supply for the lighting means (8).