Power Circuit PFC Bypass for Low Load Efficiency
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Solution Overview
Problem
In electronic apparatuses with step-down power factor correctors (PFCs), the PFCs continue to operate even in low power consumption modes, leading to inefficiencies as they work for voltage drops, reducing overall system efficiency.
Innovation Solution
The electronic apparatus includes a power circuit that stops the PFC operation and lowers the voltage using an AC-AC transformer, with a controller managing the transformer's frequency and duty ratio to maintain efficiency, and a bypass mechanism to skip the PFC during low power consumption, allowing the voltage to be adjusted based on power consumption levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the step-down PFC continues to operate in low power consumption modes, then the voltage can be maintained, but the system efficiency is reduced due to unnecessary PFC operation
Solution Approach 1:
The PFC circuit dynamically switches between operating modes based on load conditions. In normal operation mode, the PFC operates to correct power factor. In light load mode, the PFC is bypassed to improve efficiency. This dynamic adaptation resolves the contradiction by adjusting the system configuration according to actual power consumption needs.
Solution Approach 2:
The power circuit is segmented into two distinct paths: one through the PFC for normal operation and another bypass path for light load conditions. This segmentation allows the system to select the appropriate path based on load requirements, eliminating unnecessary PFC operation during low power consumption modes while maintaining voltage stability when needed.
2Loss of energy
If the PFC is turned off in light load section, then the system efficiency is improved, but the voltage bypass may cause operational instability
Solution Approach 1:
The controller continuously monitors power consumption levels and provides feedback to determine whether to operate the PFC or activate the bypass path. This feedback mechanism ensures smooth transitions between modes and maintains operational stability by selecting the appropriate configuration based on real-time load conditions, preventing instability during bypass operation.
3Adaptability or versatility
If the AC-AC transformer adjusts voltage over a large variable range, then different power consumption levels are supported, but the circuit efficiency is lowered
Solution Approach 1:
The AC-AC transformer dynamically adjusts its voltage gain based on detected power consumption levels. The controller modifies the transformer's operating parameters (such as duty ratio or frequency) to provide appropriate voltage levels for different load conditions. This dynamic adjustment maintains high circuit efficiency by optimizing the transformer operation for each specific power consumption level rather than operating over the entire variable range continuously.
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 approach prevents efficiency losses by ensuring the PFC does not operate in low power modes, maintaining stability and efficiency even with a step-down PFC, and allows for voltage adjustments to match power requirements, thereby improving overall system efficiency.
Implementation Method 1
a first voltage converter (100) configured to output a first voltage based on input power
Data Source
AI summary
An electronic apparatus includes: an operator; and a power circuit configured to supply power to the operator, wherein the power circuit includes a first voltage converter configured to output a first voltage based on input power, and a power factor corrector (PFC) configured to output a second voltage by performing power factor correction for the first voltage, and supplies power based on the first voltage or the second voltage to the operator, wherein the power circuit stops an operation of the PFC, lowers the first voltage to have a level corresponding to the second voltage, and supplies power based on the lowered first voltage to the operator, based on power consumption of the operator lower than or equal to a predetermined value.