Asymmetric Full-Bridge Rectifier for DC/DC Ringing Suppression
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Solution Overview
Problem
Voltage converters for direct current face issues with parasitic oscillations during discontinuous mode, leading to heating, interference, and potential damage, especially due to the energy content of resonant circuits formed by coil inductance and parasitic capacitances, which also affects the power factor and efficiency.
Innovation Solution
Incorporating an additional capacitor that breaks the symmetry of the full-bridge rectifier arrangement, allowing for a controllable resonance effect and improved efficiency, and using a mix of fast and slow rectifier components to manage oscillations and power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If discontinuous mode operation is used, then voltage stress on components is reduced, but parasitic oscillations cause heating and interference
Solution Approach 1:
The patent converts the harmful parasitic oscillations into a beneficial resonant effect by introducing a resonant capacitor that tunes the oscillation frequency. The oscillations that would normally cause heating and interference are instead utilized to improve power factor and enable controllable resonance, transforming a harmful phenomenon into a useful feature for enhancing converter performance.
Solution Approach 2:
The patent changes the electrical parameters of the circuit by introducing a resonant capacitor with specific capacitance value. This modifies the resonant frequency and impedance characteristics of the circuit, allowing the parasitic oscillations to be controlled and converted into beneficial resonant behavior that improves power factor and reduces harmful effects.
2Loss of energy
If full-bridge rectifier arrangement is used, then power transmission efficiency is improved, but symmetry causes parasitic oscillations
Solution Approach 1:
The patent introduces a resonant capacitor connected to only one of the bridge legs, creating an asymmetric circuit configuration. This asymmetry breaks the symmetry that causes parasitic oscillations while maintaining the power transmission efficiency of the full-bridge rectifier arrangement. The asymmetric placement allows controlled resonance in one leg without the harmful effects of symmetric oscillations.
3Object-generated harmful factors
If additional capacitor is added to break symmetry, then parasitic oscillations are reduced, but device complexity increases
Solution Approach 1:
The resonant capacitor serves multiple functions simultaneously: it breaks circuit symmetry to reduce parasitic oscillations, creates controllable resonance to improve power factor, and enables adjustable transformation ratio range. By making this single component multi-functional, the patent reduces overall device complexity compared to using multiple separate components to achieve each function individually.
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 solution reduces parasitic oscillations, enhances efficiency, and expands the transformation ratio range between input and output voltages, while minimizing electromagnetic interference and component stress.
Implementation Method 1
it is advantageous to use a capacitor connected in parallel with the respective MOSFET, which functionally supplements the MOSFET's inherent output capacitance
Implementation Method 2
a damped oscillation ('ringing') is excited in the resonant circuit, which results from the coil inductance in conjunction with the parasitic capacitances
Implementation Method 3
the resonant circuit, which results from the coil inductance in conjunction with the parasitic capacitances of the coil, transformer, diodes, transistors and the circuitry
Implementation Method 4
allowing for a controllable resonance effect and improved efficiency
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
The invention relates to a power converter circuit with a primary-side switch converter bridge and a secondary-side full-bridge rectifier, wherein a capacitor is asymmetrically connected to a branch of the full-bridge rectifier.