Power Factor Corrector Time-Based Switching to Reduce Hunting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The on-off control of a power factor corrector in power converters can fail to recognize the current state immediately after switching, leading to hunting, which causes disturbances in the current waveform and abnormal noise due to continuous alternate turning on and off.
Innovation Solution
A controller is configured to maintain the state of the power factor corrector for a predetermined time period after switching, regardless of parameter values, and then switch based on threshold comparisons, ensuring accurate state recognition and reducing hunting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller turns the power factor corrector on or off based on parameter value thresholds, then the power factor correction operation is controlled, but hunting occurs causing continuous on-off switching and waveform disturbance
Solution Approach 1:
The controller performs preliminary action by setting a predetermined time period Tg that elapses from the moment of switching. During this time period, the controller prohibits switching of the power factor corrector, preventing hunting before it can occur. This preliminary time-based constraint ensures stable operation by blocking premature re-switching that would cause waveform disturbance and continuous on-off cycling.
2Speed
If the controller switches the power factor corrector immediately when parameter values cross thresholds, then responsive control is achieved, but the controller fails to recognize the current state accurately immediately after switching
Solution Approach 1:
The controller performs preliminary action by establishing a predetermined time period Tg that starts from the switching moment. During this period, the controller maintains the current switching state and prohibits any switching operations, allowing the system to stabilize and parameter values to become reliable for accurate state recognition before permitting further switching decisions.
3Measurement precision
If the power factor corrector switches frequently to maintain accurate power factor correction, then correction precision is improved, but abnormal noise from the reactor increases
Solution Approach 1:
The controller performs preliminary action by imposing a predetermined time period Tg constraint that prevents frequent switching. This time-based restriction blocks switching operations during the stabilization period, thereby preventing the generation of abnormal noise from the reactor while still maintaining adequate power factor correction through controlled switching at appropriate intervals.
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 approach effectively reduces hunting by stabilizing the power factor corrector state during the predetermined time period, leading to improved waveform stability and noise reduction.
Implementation Method 1
a rectifier (22) configured to rectify an input alternate current (AC) from an AC power source (91)
Implementation Method 2
a power factor corrector (25) configured to perform a power factor correction operation on an input voltage (V1) output from the rectifier (22)
Data Source
AI summary
Reduced is occurrence of hunting in which a power factor corrector continuously turns on and off alternately for a short period of time. A power factor correction controller turns on a power factor corrector if a parameter value for an input current into the power factor corrector is greater than or equal to a first threshold, and turns off the power factor corrector if the parameter value is smaller than or equal to a second threshold below the first threshold. Through a predetermined time period from a moment when the power factor corrector is switched either from on to off or from off to on, the power factor correction controller maintains a state of the switched power factor corrector, regardless of the parameter value.