AC-DC Converter with Shared Transistor for Power Factor Correction
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Solution Overview
Problem
Conventional AC-DC power converters face challenges in achieving high power factor correction and maintaining a constant output current, especially under transient loads, and are not cost-effective for small or middle-sized power electronic equipment due to high power consumption and low power density.
Innovation Solution
An AC-DC power converter design that includes a rectifier bridge, energy storage elements, and a transistor sharing conductive paths to manage energy storage and release in different operation modes, allowing for power factor correction and a substantially constant output current, utilizing a single transistor and control circuit for energy transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AC-DC power converters are designed to achieve high power factor correction and constant output current, then power quality is improved, but power consumption increases and power density decreases
Solution Approach 1:
The patent combines the power factor correction function and constant output current regulation into a single integrated control system. The controller simultaneously manages the switching of energy storage elements to achieve both power factor correction and constant current output, eliminating the need for separate control circuits and reducing overall power consumption while maintaining high power density.
Solution Approach 2:
The energy storage elements (inductors and capacitors) are designed to serve multiple functions: they store energy during the rectification phase, release energy during the output phase, and simultaneously enable power factor correction. This multi-functionality reduces the total component count and minimizes parasitic losses, thereby improving power efficiency while achieving reliable power factor correction.
2Adaptability or versatility
If conventional AC-DC power converters use multiple transistors and separate control circuits for different operation modes, then operational flexibility is improved, but device complexity increases
Solution Approach 1:
A single transistor is designed to operate in multiple modes by controlling its switching timing and duty cycle. The same transistor performs energy storage, energy release, and power factor correction functions across different operation modes, eliminating the need for multiple transistors and associated control circuits, thus reducing device complexity while maintaining operational flexibility.
Solution Approach 2:
The control circuit dynamically adjusts the switching parameters of the single transistor based on real-time operating conditions. By varying the duty cycle and switching frequency, the system adapts to different load conditions and maintains optimal performance across all operation modes without requiring additional hardware components.
3Ease of operation
If conventional designs separate energy storage and release paths for different operation modes, then operational control is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the energy storage and release paths into a unified circuit topology. The same inductor and capacitor are used for both storing energy during rectification and releasing energy during output, with a single transistor controlling both functions. This integration simplifies the circuit structure, reduces the number of components, and lowers cost while maintaining ease of operational control through unified switching management.
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 design achieves efficient power factor correction and a stable output current with reduced ripples and low voltage-withstanding requirements, making it suitable for LED loads and cost-effective for various power applications.
Implementation Method 1
a first energy storage element configured to store energy from the sine half-wave DC input voltage via a first current through a first conductive path when in a first operation mode
Implementation Method 2
a second energy storage element configured to store energy from a second DC voltage via a second current through a second conductive path when in the first operation mode
Implementation Method 3
the first energy storage element being configured to release energy to a third energy storage element and a load through a third conductive path when in a second operation mode
Implementation Method 4
the second energy storage element being configured to release energy to the load through a fourth conductive path during the second operation mode
Data Source
AI summary
In one embodiment, an AC-DC power converter can include: (i) a rectifier bridge and filter to convert an external AC voltage to a DC input voltage; (ii) a first energy storage element to store energy from the DC input voltage via a first current through a first conductive path when in a first operation mode; (iii) a second energy storage element configured to store energy from a second DC voltage via a second current through a second conductive path when in the first operation mode; (iv) a transistor configured to share the first and second conductive paths; (v) the first energy storage element releasing energy to a third energy storage element and a load through a third conductive path when in a second operation mode; and (vi) the second energy storage element releasing energy to the load through a fourth conductive path during the second operation mode.