Bridgeless PFC Converter Diode Segmentation for Noise and Loss
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Solution Overview
Problem
Bridgeless power factor correction converters face challenges in reducing common-mode noise and enhancing power density due to conduction losses and power bounce issues caused by rectifying diodes and high-frequency switching.
Innovation Solution
The implementation of a bridgeless power factor correction converter with a boost inductor, a switch circuit, and series rectifier circuits using rectifying diodes with fast and slow reverse recovery characteristics to minimize power bounce and common-mode noise, where the first series rectifier circuit has diodes with fast reverse recovery and the second series rectifier circuit has diodes with slow reverse recovery, allowing for efficient energy transfer and reduced electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rectifying diodes are used in bridgeless PFC converter, then power factor correction is achieved, but conduction losses increase and conversion efficiency degrades
Solution Approach 1:
The patent changes the reverse recovery time parameter of rectifying diodes by using two different types: fast reverse recovery diodes (with reverse recovery time trr ≤ 50ns) and slow reverse recovery diodes (with reverse recovery time trr ≥ 100ns). This parameter differentiation allows the converter to optimize conduction loss reduction while maintaining efficient energy transfer during different switching phases.
2Productivity
If high-frequency switching is used, then power density is enhanced, but common-mode noise increases
Solution Approach 1:
The patent segments the rectifier function into two separate circuits with different diode characteristics: the first series rectifier circuit uses fast reverse recovery diodes to handle high-frequency switching with reduced noise, while the second series rectifier circuit uses slow reverse recovery diodes to maintain low common-mode noise. This segmentation allows the converter to achieve high power density through high-frequency switching while suppressing common-mode noise through differentiated diode selection.
3Speed
If fast reverse recovery diodes are used, then switching speed is improved, but power bounce and common-mode noise increase
Solution Approach 1:
The patent applies local quality by assigning different diode characteristics to different circuit locations and functional requirements. Fast reverse recovery diodes are placed in the first series rectifier circuit where high switching speed is critical, while slow reverse recovery diodes are placed in the second series rectifier circuit where noise suppression is prioritized. This localized optimization resolves the contradiction between switching speed and power bounce.
4Object-affected harmful factors
If slow reverse recovery diodes are used, then common-mode noise is reduced, but switching efficiency and power density decrease
Solution Approach 1:
The patent segments the rectifier function into two parallel circuits, each optimized for different performance aspects. The second series rectifier circuit uses slow reverse recovery diodes to maintain low common-mode noise, while the first series rectifier circuit uses fast reverse recovery diodes to ensure high switching efficiency and power density. This segmentation allows both noise reduction and high power density to coexist.
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 configuration reduces conduction losses, minimizes power bounce, and effectively suppresses common-mode noise, enhancing the power density and efficiency of the converter by maintaining zero voltage across rectifying diodes during switching transitions and reducing high-frequency electromagnetic interference.
Implementation Method 1
A boost inductor L11 is connected to an output terminal of the bridge rectifier BR, and configured to store energy therein by receiving a current from the bridge rectifier BR and release the stored energy to an output capacitor C11 through a rectifying diode D11 according to the on/off operations of a switch Q11
Implementation Method 2
a bridge rectifier BR is connected to an input AC voltage Vin for converting the input AC voltage Vin into a full-wave rectified DC voltage
Data Source
AI summary
A bridgeless power factor correction converter that can reduce common-mode noise and enhance power density is made up of a boost inductor coupled to an input end, a bidirectional switch connected in series with the boost inductor, a first series rectifying circuit having a junction node connected between the boost inductor and the bi-directional switch, a second series rectifying circuit connected in parallel with the first series rectifying circuit and having a junction node coupled to the bi-directional switch, and an output capacitor connected in parallel with the second series rectifying circuit, in which the second series rectifying circuit is made up of slow-recovery diodes and the first series rectifying circuit is made up of fast-recovery diodes.