Square Wave Width Control for APFC Load Support
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Solution Overview
Problem
Existing square wave power supply devices face issues with low output voltage and voltage recovery time when switching to battery mode, particularly in the first cycle and during load increases, which affects their ability to support Active Power Factor Correction (APFC) loads effectively.
Innovation Solution
A control method and system that adjusts the square wave width of the output voltage waveform to a larger value initially and then gradually decreases it to a stable value, ensuring the voltage meets APFC requirements without increasing costs, by extending open time and increasing waveform width when necessary, and adjusting it to the maximum when the peak voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the square wave width is increased to provide sufficient output voltage for APFC loads, then the voltage support capability is improved, but the voltage stability deteriorates due to oscillations
Solution Approach 1:
The patent applies periodic action by implementing a multi-stage control strategy that cycles through different square wave width adjustment phases. The controller periodically monitors voltage levels and adjusts the square wave width in stages: initially providing sufficient width for voltage build-up, then gradually reducing to stable operating width, and intervening with width increases when voltage drops are detected. This periodic monitoring and adjustment resolves the contradiction between needing wide pulses for voltage support and narrow pulses for stability.
Solution Approach 2:
The patent implements dynamics by making the square wave width adjustable and time-dependent rather than fixed. The controller dynamically modifies the square wave width based on real-time voltage conditions, transitioning from a static width design to a dynamic one that adapts to load changes and voltage fluctuations. This dynamic adjustment allows the system to optimize between voltage support and stability according to instantaneous conditions.
2Reliability
If the square wave width is increased to improve output voltage, then the voltage effective value is improved, but the waveform complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the square wave width parameter to optimize output voltage effectiveness. Instead of using complex multi-component circuits, the solution focuses on controlling a single key parameter (square wave width) through multiple stages: initial wide pulses for voltage build-up, transitional width reduction, and stable operating width. This single-parameter control approach improves voltage effectiveness while avoiding the complexity of multiple circuit components or complex waveforms.
3Stability of the object's composition
If the square wave width is gradually decreased to stabilize voltage, then the voltage stability is improved, but the response time to load changes increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the output voltage and using this information to adjust the square wave width in real-time. The controller detects voltage drops and responds by increasing the square wave width, then monitors the recovery and gradually reduces the width back to stable levels. This feedback mechanism allows the system to maintain stability while responding quickly to load changes, as the width adjustment is driven by actual voltage conditions rather than predetermined timing.
Data Source
AI summary
The present invention relates to a control method for supporting active power factor correction (APFC) loads, comprising: providing square wave width of an output voltage waveform to be a comparatively large value to improve effective value of the output voltage, in order to meet the requirements for active power factor correction (APFC) loads; and gradually decreasing square wave width of the output voltage waveform from the comparatively large value to a comparatively small value to gradually decrease effective value of the output voltage to a desirable stable voltage effective value. The present invention further relates to a control system for supporting active power factor correction (APFC) loads, comprising: a voltage increasing unit for providing square wave width of an output voltage waveform to be a comparatively large value to improve effective value of the output voltage, in order to meet the requirements for active power factor correction (APFC) loads; and a voltage stabilizing unit for adjusting square wave width to a comparatively large value, and gradually decreasing square wave width of the output voltage waveform from the comparatively large value to a comparatively small value to gradually decrease effective value of the output voltage to a desirable stable voltage effective value.