Dual-Input AC-DC Converter PWM Ripple Reduction
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Solution Overview
Problem
Existing AC-DC power converters face inefficiencies in reducing AC ripple, leading to energy loss and heat generation, which affects the stability and reliability of electronic devices.
Innovation Solution
An AC-DC power converter design incorporating a rectification circuit, a power factor correction boost converter, a switched mode power supply output stage, and a buck and/or boost converter with pulse width modulation to generate an output DC voltage with reduced or eliminated AC ripple, using a buck and/or boost converter with two input voltage terminals to manage voltage levels efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitor-based filters are used to smooth out voltage variations and reduce ripple, then the ripple on the converted DC voltage is reduced, but considerable efficiency loss occurs and energy is converted to heat
Solution Approach 1:
The patent changes the operating parameters of the power converter by introducing a dual-input buck/boost converter that operates in different modes (buck mode, boost mode, or bypass mode) depending on the voltage conditions. This dynamic parameter adjustment allows the system to maintain high efficiency while reducing ripple, avoiding the continuous energy loss associated with traditional capacitor-based filtering.
Solution Approach 2:
The patent introduces an intermediary component - the dual-input buck/boost converter - that acts as a mediator between the PFC boost converter output and the switched-mode power supply input. This intermediary actively manages the voltage and ripple characteristics, providing a more efficient solution than passive capacitor filtering while maintaining system stability.
2Reliability
If the capacitance value of the filter capacitor is increased to better filter out ripple, then the ripple reduction capability is improved, but the efficiency loss and heat generation increase
Solution Approach 1:
The system dynamically changes operating parameters by switching between buck mode, boost mode, and bypass mode based on voltage conditions. This active parameter management reduces the need for large capacitor values, thereby minimizing heat generation while maintaining effective ripple reduction capability.
Solution Approach 2:
The patent replaces the passive mechanical/electrical filtering system (large capacitor-based filters) with an active electronic control system (dual-input buck/boost converter with PWM control). This substitution eliminates the need for large physical capacitors, reducing both the ripple effectively and the heat generation associated with high-capacitance filtering.
3Loss of energy
If a dual-input buck/boost converter is used to generate output DC voltage with reduced AC ripple, then the AC ripple is reduced or eliminated and efficiency is improved, but the device complexity increases
Solution Approach 1:
The dual-input buck/boost converter is designed as a multi-functional component that can operate in multiple modes (buck, boost, and bypass) depending on the voltage conditions. This universal design consolidates what would otherwise require separate circuits for different operating conditions, reducing overall system complexity while maintaining low power losses and effective ripple reduction.
Solution Approach 2:
The system employs dynamic switching between different operating modes based on real-time voltage conditions. The controller dynamically adjusts the converter operation between buck mode, boost mode, and bypass mode, allowing the system to adapt to varying input conditions and maintain optimal efficiency without requiring complex fixed-architecture circuits.
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 reduces AC ripple while minimizing power losses, providing a stable DC output voltage with improved efficiency and reduced heat generation.
Implementation Method 1
a rectification circuit configured to convert an input AC voltage to a rectified AC voltage
Implementation Method 2
a power factor correction boost converter circuit configured to convert the rectified AC voltage to a first boosted DC voltage
Implementation Method 3
a switched mode power supply output stage comprising a transformer
Implementation Method 4
the buck and/or boost converter is configured to be operated using pulse width modulation to generate an output DC voltage with reduced or eliminated AC ripple
Data Source
AI summary
An AC-DC power converter includes: a rectification circuit configured to convert an input AC voltage to a rectified AC voltage; a power factor correction boost converter circuit configured to convert the rectified AC voltage to a first boosted DC voltage, wherein the first boosted DC voltage has AC ripple; a switched mode power supply output stage having a transformer; a buck and/or boost converter having two input voltage terminals, wherein a first voltage input terminal is connected to the first boosted DC voltage or to a secondary side of the transformer, and wherein a second input voltage terminal is connected to a second DC voltage, wherein the second DC voltage is higher than the voltage on the first voltage input terminal within a predefined voltage range, and wherein the buck and/or boost converter uses pulse width modulation to generate an output DC voltage with reduced AC ripple.