Bridgeless PFC Circuit Shared Snubber Area Reduction
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Solution Overview
Problem
Existing bridgeless power factor correction circuits require significant mounting area for separate snubber circuits connected in parallel to each switch, which is undesirable and inefficient.
Innovation Solution
A bridgeless power factor correction circuit configuration where a single snubber circuit is shared between two legs, with a control circuit managing the switches to maintain a constantly on state for one switch during positive AC polarity and perform switching operations during negative AC polarity, effectively reducing the overall mounting area by half.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate snubber circuits are connected in parallel to each main switch, then each switch is protected from voltage spikes and noise, but the overall mounting area of the snubber circuits increases
Solution Approach 1:
The patent merges two separate snubber circuits into a single shared snubber circuit that is connected between the first connection point (between first rectifier and first switch) and the second connection point (between second rectifier and second switch). This single snubber circuit serves both switches simultaneously, reducing the total mounting area while maintaining protection functionality for both switches during their respective switching operations
Solution Approach 2:
The shared snubber circuit performs multiple functions: it protects the first switch when the first switch is operating, protects the second switch when the second switch is operating, and does so using a single circuit configuration. The control circuit enables this multi-functionality by coordinating the switching of both switches, allowing one snubber circuit to serve dual purposes
Data Source
AI summary
A bridgeless power factor correction circuit includes: a first leg composed of a series circuit with a first rectifier and a first switch; a second leg that is composed of a series circuit with a second rectifier and a second switch and is connected in parallel to the first leg; a smoothing capacitor connected in parallel to the first leg; a snubber circuit that is connected between a first connection point, which is located between the first rectifier and the first switch and is connected via a first inductor to one end of an AC power supply, and a second connection point, which is located between the second rectifier and the second switch and is connected via a second inductor to another end of the AC power supply; and a control circuit that executes on/off control of the first switch and the second switch.