Boost PFC Converter Control for Ripple-Induced Intermittent Operation
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Solution Overview
Problem
The power factor correction section in power converters may experience intermittent operation due to increased ripple voltage in the smoothing capacitor, leading to insufficient power factor correction and high transient currents, which is not effectively addressed by increasing capacitance or reactor size, as this would increase device size and cost.
Innovation Solution
A power converter with a boost power factor correction section that includes a control system to adjust the booster circuit's boost amount, ensuring the output voltage of the smoothing capacitor remains above the input voltage, and detects ripple amplitude to determine necessary corrections, thereby preventing intermittent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitance of the smoothing capacitor and elements in the power factor correction section is increased to prevent intermittent operation, then the reliability is improved, but the device size and cost increase
Solution Approach 1:
The invention dynamically adjusts the boost amount of the booster circuit based on detected ripple amplitude. When ripple exceeds a threshold, the boost amount is increased to prevent intermittent operation. This dynamic adjustment allows the system to maintain reliability only when necessary, avoiding the need for permanently oversized capacitors and reactors.
Solution Approach 2:
The invention changes the operating parameter (boost amount) of the power factor correction section based on detected conditions. By varying the boost amount in response to ripple amplitude, the system adapts to changing conditions without requiring fixed oversized components, thus resolving the contradiction between reliability and device size.
2Reliability
If the capacitance of the smoothing capacitor and elements in the power factor correction section is increased to prevent intermittent operation, then the reliability is improved, but the manufacturing cost increases
Solution Approach 1:
The system uses dynamic control of the boost amount based on ripple detection, allowing standard-sized components to operate reliably under varying conditions. This eliminates the need for expensive oversized components while maintaining operational stability.
Solution Approach 2:
The invention implements a feedback mechanism where ripple amplitude is detected and used to adjust the boost amount. This closed-loop control ensures reliable operation without requiring marginally oversized components, reducing manufacturing costs while maintaining reliability.
3Volume of stationary object
If the power factor correction section operates intermittently due to high ripple voltage, then the device size can be reduced, but the power factor correction becomes insufficient and harmonic components increase
Solution Approach 1:
The invention replaces the mechanical approach of using oversized passive components with an electronic control approach. By using active control of the boost amount based on ripple detection, the system maintains power factor correction performance without relying on marginally oversized components.
Solution Approach 2:
The system changes the boost parameter dynamically to prevent intermittent operation. When ripple amplitude exceeds the threshold, the boost amount is increased to maintain continuous operation, preventing harmonic generation and insufficient power factor correction while keeping device size reasonable.
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 solution stabilizes power factor correction, reduces harmonic components in the supply current, and minimizes unnecessary boost, thereby cutting down losses and maintaining efficient operation without increasing device size or cost.
Implementation Method 1
a rectifier section (22) configured to rectify an incoming alternating current that has come from an AC power supply (91)
Implementation Method 2
a smoothing capacitor (26) configured to smooth an output of the booster circuit (25a)
Implementation Method 3
a power factor correction section (25) including a booster circuit (25a) configured to have a variable amount of boost and to boost an input voltage (V1) supplied from the rectifier section (22)
Data Source
AI summary
Disclosed herein is a technique for substantially preventing, in a power converter including a boost power factor correction section, the power factor correction section from starting an intermittent operation even if the ripple voltage of its smoothing capacitor has increased. The converter includes: a power factor correction section including a booster circuit boosting an input voltage supplied from a rectifier section and a smoothing capacitor smoothing an output of the booster circuit; and a control section correcting a power factor by controlling the booster circuit. The control section makes correction to the amount of boost of the booster circuit such that an output voltage of the smoothing capacitor does not become lower than the input voltage.