PFC Boost Power Supply Circuit for Holdup Time and Power Density
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Solution Overview
Problem
Conventional power supply circuits face challenges with large-sized inductors and capacitors that limit power density and conversion efficiency, while maintaining sufficient holdup time and high conversion efficiency.
Innovation Solution
A power supply circuit design incorporating a power factor correction circuit, a first storage capacitor, and a boost conversion circuit with smaller capacitors and inductors, utilizing a first and second storage capacitor to manage electrical energy transfer and suppress inrush currents, enhancing power density and reducing hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If large-sized inductor L_pf and capacitor C_bk are used in conventional power supply circuits, then sufficient holdup time of electrical energy is achieved, but power density is limited and hardware cost increases
Solution Approach 1:
The patent divides the single large capacitor C_bk into multiple smaller capacitors (first capacitor, second capacitor, third capacitor, fourth capacitor) with different capacitance values. This segmentation allows the system to achieve the same total capacitance for sufficient holdup time while reducing the physical size and increasing power density. The first and second capacitors are connected in parallel, and the third and fourth capacitors are connected in parallel, creating a distributed capacitance network that maintains energy storage capability with smaller individual components.
Solution Approach 2:
The patent introduces a time-dimensional approach by controlling the switching of capacitors at different stages. The capacitors are switched on and off at different times during the startup process, allowing the system to achieve the required holdup time through temporal distribution rather than relying on a single large capacitor. This temporal dimension allows smaller capacitors to collectively provide the same energy storage function.
2Duration of action of stationary object
If large-sized inductor L_pf and capacitor C_bk are used in conventional power supply circuits, then sufficient holdup time of electrical energy is achieved, but hardware cost increases
Solution Approach 1:
The patent segments the single large capacitor into multiple smaller capacitors with different capacitance values. This segmentation reduces hardware cost because smaller capacitors are generally less expensive individually, and using multiple smaller capacitors provides design flexibility for optimization. The first and second capacitors connected in parallel, along with the third and fourth capacitors in parallel, create a cost-effective distributed capacitance solution that achieves the required holdup time without requiring a single expensive large capacitor.
3Power
If conventional boost conversion circuit is used, then output voltage is generated, but conversion efficiency is limited due to diode voltage drop
Solution Approach 1:
The patent introduces a current transformer as an intermediary device in the boost conversion circuit. The current transformer couples the primary and secondary circuits, enabling galvanic isolation while transferring energy with higher efficiency. This intermediary device replaces the conventional diode-based rectification, eliminating the diode voltage drop losses and improving overall conversion efficiency. The current transformer acts as a mediator that transfers power between circuits with minimal energy loss.
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 design achieves reduced capacitor size, increased power density, and maintained holdup time with improved conversion efficiency by transferring energy between capacitors, thus optimizing the power supply circuit's performance.
Implementation Method 1
The first storage capacitor is used to store a first electrical energy related to the intermediate voltage
Implementation Method 2
The second storage capacitor is connected to the first post-stage diode and is used to store the second electrical energy related to the output voltage
Implementation Method 3
The first post-stage inductor has a first end connected to the first end of the first storage capacitor
Implementation Method 4
The first switch is connected to the first storage capacitor, and used to suppress an inrush current generated by the PFC circuit
Data Source
AI summary
A power supply circuit includes a power factor correction (PFC) circuit used to perform a power factor correction to generate an intermediate voltage. A first storage capacitor is connected to an output end of the PFC circuit and used to store a first electrical energy related to the intermediate voltage. A boost conversion circuit is connected to the PFC circuit and used to generate an output voltage according to the intermediate voltage. The boost conversion circuit at least includes a first switch used to suppress an inrush current generated by the PFC circuit. A second storage capacitor is used to store a second electrical energy related to the output voltage. The capacitance value of the second storage capacitor is less than the capacitance value of the first storage capacitor; the first electrical energy is completely or partially transferred as the second electrical energy.