Adaptive PFC Output Voltage Control for Resonant Converters
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Solution Overview
Problem
The output voltage of existing PFC circuits is fixed and cannot be adjusted according to input voltage, leading to poor power factor correction and conversion efficiency.
Innovation Solution
A conversion control circuit that adaptively adjusts the output voltage of a PFC circuit based on input and output voltages, using transconductance circuits to generate current signals that correlate with these voltages, ensuring the output voltage remains above minimum operating levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the output voltage of the PFC circuit is fixed, then the circuit structure is simple, but the power factor correction efficiency is poor and conversion efficiency is poor
Solution Approach 1:
The patent implements dynamic adjustment of the PFC circuit output voltage through a conversion control circuit that receives both the output voltage signal from the PFC circuit and the output voltage signal from the resonant power converter. The control circuit dynamically adjusts the PFC output voltage based on the actual output voltage requirements of the resonant power converter, transforming the fixed voltage system into a dynamic adaptive system that improves power factor correction efficiency while maintaining reasonable circuit complexity through integrated control.
Solution Approach 2:
The patent employs feedback control by having the conversion control circuit receive the output voltage signal from the resonant power converter and use it to adjust the PFC circuit output voltage. This closed-loop feedback mechanism ensures that the PFC output voltage automatically adapts to the actual requirements of the downstream converter, improving both power factor correction efficiency and conversion efficiency without requiring overly complex circuit architecture.
2Productivity
If the PFC circuit output voltage is fixed, then the control circuit is simple, but the conversion efficiency of the resonant power converter is poor
Solution Approach 1:
The conversion control circuit serves multiple functions: it receives the output voltage signal from the PFC circuit, receives the output voltage signal from the resonant power converter, adjusts the PFC output voltage accordingly, and ensures the adjusted voltage meets the minimum input voltage requirement of the resonant power converter. This multi-functional integrated control approach improves conversion efficiency while avoiding the need for separate complex control circuits for each function.
Solution Approach 2:
The conversion control circuit acts as an intermediary between the PFC circuit and the resonant power converter. It receives signals from both sides, processes the voltage adjustment requirements, and outputs the adjusted voltage to the resonant power converter. This intermediary role allows for optimized voltage matching that improves conversion efficiency while keeping the control architecture manageable through a single mediating control unit.
3Productivity
If the PFC circuit output voltage is adjusted adaptively, then the power factor correction efficiency is improved, but the control circuit complexity increases
Solution Approach 1:
The patent merges the PFC control function with the resonant power converter control function into a single conversion control circuit. This unified control structure receives both the PFC output voltage signal and the resonant converter output voltage signal, and performs adaptive voltage adjustment in one integrated control unit. This merging approach improves power factor correction efficiency while limiting control circuit complexity growth through functional integration rather than adding separate control systems.
Data Source
AI summary
A conversion control circuit controls a resonant power converter and a first output voltage generated by a power factor correction (PFC) circuit. The resonant power converter generates a second output voltage based on the first output voltage. The conversion control circuit includes: a first transconductance circuit for generating a first signal based on a proportional output voltage related to the second output voltage; a second transconductance circuit for generating a second signal based on an input-related signal, wherein the input-related signal is related to a peak value of an input voltage of the PFC circuit; and a current control circuit for generating a third signal based on the first signal and the second signal. The third signal is for rendering the first output voltage such that the first output voltage decreases as the second output voltage decreases and also decreases as the input voltage decreases.