Switching Power Converter Control for Smooth Conduction Mode Transitions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Switching power converters experience increased total harmonic distortion due to abrupt changes in conduction modes, particularly in discontinuous-conduction mode (DCM), leading to parasitic oscillations in current draw from the AC mains.
Innovation Solution
A control module adjusts the duration of charge modes in switching power converters by modifying the on-time of the drive signal in response to changes in conduction modes, specifically through a transition controller that makes adjustments to the drive signal conveyed to the electrically-controlled switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conduction modes are changed to improve power converter performance, then adaptability is improved, but total harmonic distortion increases due to abrupt current changes
Solution Approach 1:
The transition controller preemptively adjusts the on-time of the drive signal before and during conduction mode transitions. By predicting the mode change and pre-modifying the on-time parameter, the controller smooths the current transition, preventing abrupt changes that cause harmonic distortion while maintaining the benefits of conduction mode adaptability
2Object-generated harmful factors
If on-time is modified during conduction mode transitions, then total harmonic distortion is reduced, but device complexity increases due to additional control circuitry
Solution Approach 1:
The transition controller combines multiple functions into a single control module: it monitors conduction mode status, determines when transitions occur, calculates appropriate on-time adjustments, and outputs the modified drive signal. This consolidation achieves harmonic distortion reduction without proportionally increasing overall system complexity
3Stability of the object's composition
If on-time adjustments are made during conduction mode changes, then current consistency is improved, but response time is affected by the adjustment process
Solution Approach 1:
The controller applies periodic on-time adjustments synchronized with the switching frequency and conduction mode transition rhythm. By timing the adjustments to occur at optimal points in the switching cycle, the controller maintains current consistency while minimizing the time penalty, as the adjustments are applied in a rhythmic, predictable manner rather than causing random delays
Data Source
AI summary
Switching power converters, and methods and control modules for operating same. At least one example is a method of operating a switching power converter, the method comprising: generating, by a regulator, a drive signal that is periodic, each period defining an on-time and an off-time; passing unchanged, by a transition controller, the drive signal to an electrically-controlled switch; and then responsive to a mode controller changing conduction modes of an inductor of the switching power converter, conveying with adjustments, by the transition controller, the drive signal to the electrically-controlled switch.