Voltage Feed-Forward Circuit for Power Factor Correction
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Solution Overview
Problem
Existing power factor correction (PFC) circuits face instability due to increasing open-loop gain with input voltage, leading to distortion and reduced correction effectiveness, and prior voltage feed-forward solutions require external components that compromise performance and stability.
Innovation Solution
A voltage feed-forward circuit using on-chip capacitors and a logic control unit to maintain and output peak voltage, allowing charge sharing and redistribution between capacitors, eliminating the need for external components and improving stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the open-loop gain is increased to improve power factor correction performance, then the correction effectiveness improves, but the circuit stability deteriorates due to unity-gain bandwidth increase
Solution Approach 1:
The patent applies dynamics by making the multiplier gain adjustable and controllable. The gain of the multiplier is dynamically adjusted based on operating conditions to maintain optimal power factor correction performance while preventing circuit instability. This is achieved through control circuits that modify the multiplier's transfer characteristic in real-time.
Solution Approach 2:
The patent changes the parameter of multiplier gain from a fixed value to a variable parameter that can be adjusted according to operating conditions. By modifying the gain parameter dynamically, the system achieves both high correction effectiveness and stable operation, resolving the contradiction between performance and stability.
2Stability of the object's composition
If external capacitors are used in voltage feed-forward circuit to improve peak voltage holding, then the voltage stability improves, but the device complexity increases due to additional external components
Solution Approach 1:
The patent merges the voltage feed-forward function with the existing on-chip capacitors that are already present in the power factor correction circuit. Instead of adding external capacitors, the design utilizes and integrates with the existing capacitive elements on the chip, thereby achieving peak voltage holding stability without increasing device complexity or requiring additional external components.
Solution Approach 2:
The on-chip capacitors serve multiple functions: they are used for both the voltage feed-forward operation (holding peak voltage) and other circuit functions. This multi-functionality eliminates the need for dedicated external capacitors, reducing overall component count while maintaining stability.
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 solution maintains stable output voltage, reduces distortion, and enhances power factor correction efficiency by adjusting capacitance ratios and using leakage current compensation, while eliminating the need for external components, thus improving system cost-effectiveness and stability.
Implementation Method 1
a first capacitor C1, a first end of which is grounded; a second capacitor C2, a first end of which is grounded, and a second end of which is connected to a second end of the third switch element S3 and used to output the peak voltage maintained by the second end of the second capacitor C2
Data Source
AI summary
A voltage feed-forward circuit, a multiplier using the voltage feed-forward circuit, and a power factor correction circuit using the multiplier. The voltage feed-forward circuit is used to maintain and output a peak voltage (Vff) of an input voltage (Vin), and includes first switch element (S1), a logic control unit (U1), a second switch element (S2), a first capacitor (C1), a third switch element (S3) and a second capacitor (C2). The first control signal (Φ1) and the second control signal (Φ2) begin to be provided at the same time, and the first control signal (Φ1) stops being provided when a voltage of the second end of the first capacitor (C1) is greater than the peak voltage (Vff) of the input voltage (Vin).