Valley-Fill PFC Power Module With AC-Dependent Switching
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Solution Overview
Problem
Power conversion efficiency in electronic devices is reduced due to the operation of power factor correction (PFC) circuits, even when harmonic requirements are low, leading to unnecessary energy consumption and inefficiency.
Innovation Solution
A power module with a valley-fill PFC circuit and a controllable switch, controlled by a circuit that adjusts power factor correction based on the type of alternating current input, turning off PFC when low-voltage AC is detected to prevent power factor correction and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the power factor correction circuit operates continuously, then the power factor is improved, but the power conversion efficiency is reduced due to unnecessary energy consumption
Solution Approach 1:
The PFC circuit transitions from a static always-on state to a dynamic state where it can be switched on or off based on operating conditions. The control circuit dynamically adjusts the circuit operation mode (PFC mode or non-PFC mode) according to the detected AC voltage characteristics, optimizing both power factor correction and energy efficiency.
Solution Approach 2:
The system changes its operational parameters based on the type of AC input. When high-voltage AC is detected, the PFC circuit is activated to correct power factor. When low-voltage AC is detected, the PFC circuit is deactivated to avoid energy loss. This parameter change approach allows the system to adapt to different electrical environments.
2Loss of energy
If the power factor correction circuit is disabled to improve efficiency, then power conversion efficiency is improved, but the power factor deteriorates
Solution Approach 1:
The control circuit continuously monitors the AC voltage characteristics and provides feedback to determine the appropriate operating mode. Based on this feedback, the system automatically switches between PFC and non-PFC modes, ensuring optimal performance for the current electrical environment without manual intervention.
Solution Approach 2:
The system employs dynamic control to adjust the PFC circuit operation based on real-time detection of AC voltage parameters. This dynamic approach allows the system to maintain good power factor when needed while achieving high efficiency when the electrical environment does not require PFC.
3Loss of energy
If the controllable switch is always on, then power conversion efficiency is improved, but the ability to meet harmonic requirements deteriorates
Solution Approach 1:
The system changes its operational state based on detected AC voltage parameters. When high-voltage AC is detected, the switch is turned off to activate PFC for harmonic compliance. When low-voltage AC is detected, the switch is turned on to achieve high efficiency. This parameter-based control resolves the contradiction between efficiency and compliance.
Solution Approach 2:
The controllable switch transitions from a static always-on or always-off state to a dynamic state where it can switch between modes based on electrical conditions. This dynamic control enables the system to meet harmonic requirements when necessary while maintaining high efficiency when the electrical environment permits.
4Reliability
If the power factor correction circuit is always active, then harmonic requirements are met, but power conversion efficiency is reduced
Solution Approach 1:
The PFC circuit is designed to dynamically adjust its operation based on the electrical environment. The control circuit detects AC voltage characteristics and switches the PFC circuit on or off accordingly, allowing the system to meet harmonic requirements when necessary while avoiding unnecessary energy consumption when PFC is not needed.
Solution Approach 2:
The system changes its operational mode based on detected voltage parameters. When high-voltage AC is detected, PFC is activated to ensure harmonic compliance. When low-voltage AC is detected, PFC is deactivated to maximize efficiency. This parameter-driven approach resolves the contradiction between reliability and energy efficiency.
Data Source
AI summary
A power module, a control circuit, and an electronic device. The power module is configured to receive an alternating current input by an alternating-current power supply. The power module includes a rectifier circuit, a valley-fill PFC circuit, a controllable switch, and a control circuit. The controllable switch is connected between one capacitor of the valley-fill PFC circuit and a reference ground, and is connected in parallel to in series to a diode. The control circuit controls, depending on a type of the alternating current, the controllable switch to be turned on or off. In the embodiments, when the power module receives a low-voltage alternating current, the valley-fill PFC circuit stops running, to improve power conversion efficiency of the power module.