Power Factor Correction Circuit with Phase-Dependent Control
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Solution Overview
Problem
Power factor correction circuits face challenges in maintaining a constant output voltage due to rapid control responses causing ripple reflection and slow responses leading to over-voltage issues, especially when load fluctuations or unexpected input voltage changes occur.
Innovation Solution
A power factor correction circuit incorporating an inductor, power switch, and controller that employs a proportional control method during the start-up period and a proportional-integral method during the stabilization period, with an error amplification signal generator to manage switching operations based on output voltage errors, minimizing over-voltage and ripple influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control response of the power factor correction circuit is too fast, then the output voltage can be quickly regulated, but a ripple of the input voltage is reflected to the output voltage making it difficult to maintain a good power factor
Solution Approach 1:
The patent applies dynamic control by switching between proportional control mode during start-up period and proportional-integral control mode during stabilization period. This dynamic adjustment of control strategy based on operating phase allows fast response when needed while minimizing ripple during steady-state operation, thus resolving the contradiction between control speed and output voltage quality.
2Device complexity
If the control response of the power factor correction circuit is slow, then the control structure is simpler, but an over-shoot of the output voltage cannot be promptly responded to causing over-voltage
Solution Approach 1:
The patent segments the control process into two distinct phases: start-up period and stabilization period. During start-up, proportional control provides simple and fast response to prevent over-voltage. During stabilization, proportional-integral control ensures precise voltage regulation. This segmentation allows the system to maintain simplicity when needed while ensuring reliability during critical phases.
3Stability of the object's composition
If the control response is slow, then the circuit can handle load fluctuations better, but the power factor correction circuit cannot react to unexpected increases of input voltage or load changes
Solution Approach 1:
The patent implements dynamic control strategy adjustment based on the operational phase. The controller switches between proportional control during start-up (providing fast adaptability to input voltage changes) and proportional-integral control during stabilization (providing excellent output voltage constancy). This dynamic adaptation resolves the contradiction between stability and adaptability to load fluctuations.
Data Source
AI summary
The present invention relates to a power factor correction circuit and a driving method thereof. The power factor correction circuit receives an input voltage and maintains an output voltage at a constant level by controlling switching operation of a power switch connected to an inductor that supplies the output voltage. In this case, the power factor correction circuit controls switching operation of the power switch by differentiating a control structure for an output voltage respectively according to a stabilization period during which the output voltage is constantly maintained and a start-up period during which the output voltage is increased before being stabilized. In addition, the power factor correction circuit controls the switching operation of the power switch according to the control structure of the start-up period during a predetermined correction delay period from a time that the stabilization period starts.