Bridgeless PFC Rectifier for AC Ripple Reduction
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Solution Overview
Problem
Traditional voltage rectifiers face challenges such as high energy inefficiency due to high voltage requirements, dynamic power imbalances, and AC ripple voltage superimposed on DC bus voltage, making them difficult to construct and operate effectively.
Innovation Solution
A rectifier system comprising an AC/DC converter, a first DC/DC converter to compensate for AC ripple in the bus voltage, and a second DC/DC converter to generate a highly-regulated DC output voltage, with the compensating voltage canceling out AC ripple and allowing for efficient power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high voltage is used in boost type PFC topologies to achieve power factor correction, then power factor correction is realized, but energy efficiency deteriorates
Solution Approach 1:
The patent changes the voltage parameter from high voltage (380V or more) to lower voltage operation by using a bridgeless PFC topology with four switches, each handling a portion of the total power. This parameter change maintains power factor correction capability while reducing energy losses associated with high voltage switching and conduction.
Solution Approach 2:
The patent segments the power conversion function by dividing the PFC stage into four parallel switch paths, where each switch and its associated components handle a portion of the total input power. This segmentation allows each component to operate at lower voltage and current levels, improving overall energy efficiency while maintaining the required power factor correction performance.
2Adaptability or versatility
If traditional two-stage rectifier architecture is used, then power factor correction is achieved, but device complexity increases
Solution Approach 1:
The patent merges the PFC function and rectification function into a single integrated bridgeless PFC stage, eliminating the need for a separate rectifier stage. This consolidation reduces the number of components and simplifies the overall architecture while maintaining power factor correction capability. The four-switch bridgeless PFC converter directly produces the regulated DC output voltage without requiring a second conversion stage.
Solution Approach 2:
The bridgeless PFC stage performs multiple functions simultaneously: it achieves power factor correction, provides voltage doubling, and delivers regulated DC output. This multi-functionality eliminates the need for separate dedicated stages for each function, thereby reducing device complexity while maintaining all required performance characteristics.
3Stability of the object's composition
If large bulk capacitor is used to accommodate power imbalance, then power imbalance is compensated, but AC ripple voltage on bus increases
Solution Approach 1:
The patent changes the operating parameters of the PFC stage to achieve continuous power delivery without power imbalance. By using pulse-width modulation to control the duty cycle of each switch, the converter maintains continuous power transfer from AC input to DC output, eliminating the need for large bulk capacitors and the associated AC ripple voltage on the DC bus.
Solution Approach 2:
The patent ensures continuous power delivery through the PFC stage by using overlapping switching intervals and continuous inductor current operation. This continuity eliminates power gaps that would otherwise require large capacitors to bridge, thereby reducing AC ripple voltage on the DC bus while maintaining stable power balance.
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 proposed solution enhances energy efficiency by reducing AC ripple and operating with lower input bus voltage, potentially increasing hold-up time and reducing power consumption compared to existing rectifier topologies.
Implementation Method 1
an AC/DC converter, a first DC/DC converter, and a second DC/DC converter. The AC/DC converter may be configured to convert an AC source voltage to a DC bus voltage
Implementation Method 2
The first DC/DC converter may be configured to convert the bus voltage to a DC compensating voltage having an AC ripple to compensate for AC ripple of the bus voltage
Implementation Method 3
The second DC/DC converter may be configured to convert a DC compensated bus voltage to a DC output voltage, wherein the DC compensated bus voltage is equal to a difference between the bus voltage and the compensating voltage
Data Source
AI summary
In accordance with embodiments of the present disclosure, a voltage rectifier may include: an AC/DC converter, a first DC/DC converter, and a second DC/DC converter. The AC/DC converter may be configured to convert an AC source voltage to a DC bus voltage. The first DC/DC converter may be configured to convert the bus voltage to a DC compensating voltage having an AC ripple to compensate for AC ripple of the bus voltage. The second DC/DC converter may be configured to convert a DC compensated bus voltage to a DC output voltage, wherein the DC compensated bus voltage is equal to a difference between the bus voltage and the compensating voltage.