Power Factor Converter With Nonlinear Inductor Switching
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Solution Overview
Problem
Conventional power-factor converters face challenges in achieving low total harmonic distortion and high power-factor, especially in electronic devices that require large power, leading to inefficiencies and increased energy consumption.
Innovation Solution
A power-factor converter with a nonlinear conversion ratio is designed, incorporating a rectifier circuit, first and second inductors, and a switch circuit that operates in both parallel and series configurations to manage the inductor-charging and discharging phases, utilizing bidirectional switches to optimize the input current slope and reduce harmonic distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional power-factor converter designs are used, then the device structure is simple, but the power-factor is low and total harmonic distortion is high
Solution Approach 1:
The converter is divided into two separate inductors (first inductor and second inductor) instead of using a single inductor. This segmentation allows independent control of magnetic flux in each inductor through bidirectional switches, enabling the nonlinear conversion ratio function and improving power-factor without requiring complex additional components
Solution Approach 2:
The patent implements dynamic switching of inductor connections using bidirectional switches that can connect the first and second inductors in series or parallel based on the operating phase. This dynamic reconfiguration enables the nonlinear conversion ratio that improves power-factor while maintaining a relatively simple overall device structure
2Device complexity
If conventional power-factor converter designs are used, then the circuit is simple, but energy efficiency is poor and power consumption is high
Solution Approach 1:
The patent changes the conversion ratio parameter dynamically by switching between series and parallel inductor configurations. During the first half-cycle, inductors are connected in series to increase the conversion ratio and improve energy efficiency. During the second half-cycle, they are connected in parallel to maintain appropriate current levels. This parameter change approach improves energy efficiency without requiring a completely complex circuit architecture
3Ease of operation
If linear conversion ratio is used, then the control is simple, but total harmonic distortion remains high
Solution Approach 1:
The patent implements periodic switching of the bidirectional switches at twice the line frequency (once per half-cycle). This periodic action creates a nonlinear conversion ratio that generates negative sequence current components, which cancel out positive sequence harmonics and reduce total harmonic distortion. The control remains relatively simple as it only requires timing the switches to operate at specific points in the AC cycle
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 effectively raises the power-factor and reduces total harmonic distortion, improving energy efficiency and reducing power consumption by adjusting the inductor connections based on the AC power source's phases, resulting in a more efficient power conversion process.
Implementation Method 1
The first inductor has a first terminal coupled to a first terminal of an AC power source, and a second terminal coupled to a first input terminal of the rectifier circuit. The second inductor has a first terminal coupled to a second terminal of the AC power source and a second terminal coupled to a second input terminal of the rectifier circuit.
Implementation Method 2
The switch circuit includes a first bidirectional switch and a second bidirectional switch. The first bidirectional switch has a first terminal coupled to the first terminal of the first inductor and a second terminal coupled to the second terminal of the second inductor.
Data Source
AI summary
The present invention provides a power-factor converter with nonlinear conversion ratio, wherein the power-factor converter includes a first inductor, a second inductor, a rectifier circuit and a switch circuit. The switch circuit is arranged to be switched to form a circuit equivalent to a parallel connection of the first inductor and the second inductor during an inductor-charging-phase for charging the first inductor and the second inductor in parallel by an AC power source, and form a circuit equivalent to a series connection of the first inductor L1 and the second inductor L2 during an inductor-discharging-phase for discharging the first inductor and the second inductor to the rectifier circuit in series.