Bridgeless AC-to-DC Converter Topology for Loss Reduction
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Solution Overview
Problem
Traditional AC-to-DC converters face issues with high conduction losses due to bridge rectifier diodes, inrush currents, high output voltages requiring expensive capacitors, and increased component count leading to high costs.
Innovation Solution
A bridgeless step-up and step-down AC-to-DC converter design that uses two circuits with switches, inductors, and diodes to manage energy storage and release across an output capacitor, eliminating the need for bridge rectifiers and allowing for flexible output voltage management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If bridge rectifier diodes are used in traditional boost PFC, then the circuit structure is simple, but the conduction loss is high
Solution Approach 1:
The patent removes the bridge rectifier diodes from the traditional boost PFC circuit structure. By extracting this component, the conduction loss is significantly reduced while the remaining circuit structure (switch, inductor, diodes, and control circuitry) maintains the necessary power factor correction functionality without requiring a full bridge rectifier configuration.
2Adaptability or versatility
If 400-volt or 450-volt electrolytic capacitors are used to achieve higher output voltage, then the output voltage requirement is met, but the capacitor cost increases
Solution Approach 1:
The patent implements a dynamic voltage regulation system that can adjust the output voltage level based on requirements. By using controllable switches and a buck-boost topology, the circuit can dynamically operate in step-up or step-down mode, allowing the use of lower-voltage capacitors (e.g., 400V instead of 450V) while still meeting various output voltage requirements through active control rather than passive component selection.
3Object-affected harmful factors
If a large capacity electrolytic capacitor is used to suppress inrush current, then the inrush current is reduced, but the circuit complexity and cost increase
Solution Approach 1:
The patent employs a pre-charge circuit that activates before the main power switch closes. This pre-charge path gradually charges the output capacitor through a controlled route, limiting the inrush current before the main switching operation begins. By performing this charging action preliminarily and controllably, the harmful inrush current is suppressed without requiring oversized capacitors or additional complex protection circuits.
4Loss of energy
If bridgeless PFC converters are used to reduce diode loss, then the conduction loss is reduced, but the inrush current and high output voltage problems remain
Solution Approach 1:
The patent creates a universal converter topology that combines both step-up and step-down capabilities in a single circuit configuration. This multi-functional design allows the same circuit to operate in different modes (boost or buck) depending on the required output voltage, thereby achieving reduced diode conduction loss while simultaneously addressing inrush current and output voltage flexibility requirements through a single integrated solution rather than separate dedicated 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
This design enhances conversion efficiency, reduces the need for high-voltage capacitors, eliminates inrush current issues, and simplifies the circuit to lower overall costs while maintaining operational flexibility across different conduction modes.
Implementation Method 1
When the AC input power source is in a positive half cycle and the first control signal is used to turn on the first switch, the first inductor stores energy; when the AC input power source is in the positive half cycle and the first control signal is used to turn off the first switch, the first inductor releases energy
Implementation Method 2
The first diode has a cathode end and an anode end; the cathode end of the first diode is coupled to the second end of the first switch and the first end of the first inductor, and the anode end of the first diode is coupled to the positive end or the negative end of the DC output power source
Data Source
AI summary
A bridgeless step-up and step-down AC-to-DC converter is used to convert an AC input power source into a DC output power source. The converter includes a first circuit, a second circuit, a third circuit, a third diode, and a fourth diode. The first circuit has a first end, a second send, and a third end; the first end is coupled to the AC input power source, the second end is coupled to a ground end, and the third end is coupled to the DC output power source. The second circuit has a first end, a second end, and a third end; the first end is coupled to the AC input power source, the second end is coupled to the ground end, and the third end is coupled to the DC output power source.