Resonant-Tapped Inductor Converter Control Adaptation
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Solution Overview
Problem
Resonant and semi-resonant DC-DC converters with synchronous rectification (SR) switches face non-linear behavior due to changing load and input conditions, leading to instability and efficiency issues.
Innovation Solution
Implementing control adaptation techniques using linear controllers, PID controllers with feed-forward adjustments, and adaptive voltage positioning (AVP) filters, along with band stop filters, to dynamically adjust switching frequencies and output scaling based on load current, thereby mitigating non-linear behavior and maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If variable switching frequency is used to meet power requirements, then output voltage regulation is improved, but non-linear behavior increases
Solution Approach 1:
The patent implements dynamic control adaptation that adjusts controller parameters based on operating conditions. The system transitions from static control to dynamic control where the controller output is scaled according to load current, thereby maintaining stability while achieving precise output voltage regulation across varying loads.
Solution Approach 2:
The patent changes control parameters dynamically by scaling the controller output based on load current thresholds. When load current exceeds the first threshold, the controller output is scaled down to counteract increased DC gain, thus maintaining system stability while achieving precise voltage regulation.
2Loss of energy
If synchronous rectification switch is used to improve efficiency, then power loss is reduced, but non-linear behavior increases
Solution Approach 1:
The patent implements feedback control by monitoring load current and using it to scale the controller output. The feedback mechanism detects when load current exceeds thresholds and automatically adjusts the controller gain, thereby maintaining stability while preserving the efficiency benefits of synchronous rectification.
Solution Approach 2:
The patent introduces an intermediary scaling factor between the controller and the synchronous rectification switch. This intermediary element (the scaling operation) mediates between the efficiency requirements of SR and the stability requirements, preventing non-linear behavior while maintaining low power loss.
3Stability of the object's composition
If controller output is scaled down to counteract DC gain increase, then stability is improved, but control authority is reduced
Solution Approach 1:
The patent uses dynamic parameter adjustment where the controller scaling factor changes based on load conditions. At light loads, full control authority is maintained, while at heavy loads (above first threshold), the scaling factor reduces control authority slightly to prevent instability, thus optimizing performance across the entire operating range.
Solution Approach 2:
The patent applies partial scaling only when necessary (when load current exceeds the first threshold). The scaling factor is designed to provide just enough reduction in controller output to counteract the DC gain increase, rather than applying full scaling at all times, thus maintaining adequate control authority while ensuring stability.
Data Source
AI summary
A semi-resonant voltage converter has a synchronous rectification (SR) switch through which a half-cycle sinusoidal-like current is conducted when turned on. An embodiment of a method of controlling operation of the semi-resonant voltage converter includes switching the SR switch and other switches of the semi-resonant voltage converter via a linear controller so as to supply output power to a load, the semi-resonant voltage converter having a DC gain that increases when load current increases, and scaling downward an output of the linear controller used to control the switching of the SR switch responsive to the load current exceeding a first threshold, so as to at least partly counteract an increase in the DC gain of the semi-resonant voltage converter. Other control adaptation methods are also described.