Temperature-Adaptive PFC Bus Voltage for Low-Temperature Start-Up
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Solution Overview
Problem
Existing high-power power supplies struggle to achieve both high efficiency and long lifespan, particularly at low temperatures where electrolytic capacitors degrade, leading to poor start-up performance.
Innovation Solution
A switching power supply with a PFC boost circuit, a bus capacitor, a detection unit, and a control unit that adjusts the voltage across the bus capacitor based on temperature information to mitigate the effects of electrolytic capacitor degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the voltage difference between input and output of PFC stage and Buck stage is reduced to improve efficiency, then efficiency is improved, but the ability to compensate for low-temperature capacitor degradation is reduced
Solution Approach 1:
The patent implements dynamic voltage adjustment by making the PFC output voltage adaptive to temperature changes. The control system dynamically modifies the voltage difference between PFC output and Buck input based on detected temperature, allowing the system to optimize efficiency at normal temperatures while compensating for capacitor degradation at low temperatures.
Solution Approach 2:
The patent changes the voltage parameter dynamically based on temperature conditions. By adjusting the PFC output voltage according to temperature feedback, the system modifies operating parameters to compensate for the temperature-dependent degradation of electrolytic capacitor performance, particularly at low temperatures.
2Loss of energy
If a non-isolated topology is used to improve efficiency and heat dissipation, then efficiency and heat dissipation are improved, but the insulation strength between input and output is reduced
Solution Approach 1:
The patent extracts the insulation function from the power conversion topology itself and implements it separately through optical isolation in the control system. This allows the use of non-isolated PFC and Buck topologies for high efficiency while maintaining safety through dedicated isolation mechanisms in the control circuitry.
3Loss of energy
If electrolytic capacitors are used in high-power LED power supplies, then the power supply can achieve high efficiency, but the product lifespan is reduced due to capacitor degradation at low temperatures
Solution Approach 1:
The patent applies preliminary anti-action by detecting temperature trends and proactively adjusting the PFC output voltage before significant capacitor degradation occurs. This preventive approach compensates for upcoming capacitor performance issues, particularly at low temperatures, thereby extending the effective lifespan of the power supply while maintaining high efficiency operation.
Data Source
AI summary
The present disclosure provides a switching power supply and a control method for a switching power supply, and relates to the technical field of power supply. The method includes: detecting a temperature of a bus capacitor and determining temperature information of the bus capacitor, where an input terminal of a PFC boost circuit is connected to a power source, and the bus capacitor is located at an output terminal of the PFC boost circuit; and adjusting a voltage across the bus capacitor in a preset manner according to the temperature information of the bus capacitor.