Power Factor Corrector Shutdown During Voltage Drop Recovery
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Solution Overview
Problem
Instantaneous voltage drops or power failures in commercial power sources can cause excessive current surges in switching devices of power factor correctors, leading to malfunctions, and existing technologies fail to effectively mitigate these issues.
Innovation Solution
A power converter system that includes a rectifier, a power factor corrector with reactors and switching devices, and a controller that turns off the switching device during instantaneous voltage drops or power failures, suspending the power factor correction operation until the commercial power source recovers, thereby cutting off the current path and limiting voltage surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power factor corrector immediately resumes operation after commercial power source recovery, then the power factor correction function is restored quickly, but the output voltage surges causing excessive current in switching devices
Solution Approach 1:
The controller detects commercial power source recovery and implements a preliminary delay before resuming power factor correction operation. This preliminary action prevents immediate resumption that would cause voltage surge, allowing the output voltage to stabilize first. The switching device is turned off upon detecting recovery and only turned on after confirming the output voltage has reached a predetermined level, thus avoiding excessive current while still restoring function relatively quickly.
2Reliability
If the switching device is kept on during voltage drop, then the power factor correction continues, but the excessive current flows causing device malfunction
Solution Approach 1:
The controller detects instantaneous voltage drop or power failure and implements preliminary protective action by turning off the switching device before excessive current can flow. This preliminary anti-action prevents the harmful effect of voltage surge on the switching device. The controller monitors the input voltage continuously and immediately stops the power factor correction operation when abnormality is detected, protecting the switching device while accepting temporary interruption of the correction function.
3Ease of manufacture
If the switching device size is reduced to lower cost, then the device becomes more economical, but it becomes more susceptible to damage from current surges
Solution Approach 1:
The controller implements beforehand cushioning by detecting commercial power source abnormalities and preemptively stopping the power factor correction operation. This cushioning measure protects the switching device from the harmful impact of voltage surge that would occur upon immediate resumption. By controlling the resumption timing based on output voltage levels, the system allows smaller, more cost-effective switching devices to operate reliably without being subjected to damaging current surges.
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 reduces malfunctions in switching devices, decreases their size and cost, and allows for reliable determination of voltage drops or power failures, ensuring continuous air conditioner operation and minimizing performance declines.
Implementation Method 1
the rectifier rectifies an AC commercial voltage output from a commercial power source
Implementation Method 2
The rectified voltage is boosted to a desired voltage and smoothed by the power factor corrector
Data Source
AI summary
Malfunctions of a switching device included in a power factor corrector are reduced when an instantaneous voltage drop or an instantaneous power failure occurs. If the instantaneous voltage drop or the instantaneous power failure occurs in an AC power source while the power factor corrector is performing a power factor correction operation by boosting an input voltage, an instantaneous power failure controller turns off the switching device included in the power factor corrector so that the power factor correction operation stops. When the commercial power source recovers, too, the power factor corrector suspends the power factor correction operation.