Parallel Power Converter Startup Detection for Inrush Control
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Solution Overview
Problem
In parallel power converters with directly coupled outputs, premature steady-state operation can lead to excessive in-rush current, switch over-stress, and thermal dissipation, especially when power converters start up concurrently or in sequence without proper synchronization.
Innovation Solution
The introduction of node status detectors coupled to selected nodes within parallel-connected power converters to monitor voltage and/or current, working in parallel with output status detectors to ensure that both pump capacitors and output capacitors are adequately charged during the soft-start period before transitioning to full power steady-state operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power converters start up concurrently without synchronization, then startup speed is improved, but excessive in-rush current and switch over-stress occur
Solution Approach 1:
The patent implements a startup detection mechanism that monitors capacitor charging status before enabling full power operation. Node status detectors check whether pump capacitors and output capacitors are adequately charged, and only when startup is complete does the system transition to steady-state operation. This preliminary detection prevents premature full-power activation that would cause in-rush current when converters start concurrently.
2Speed
If power converters start up concurrently without synchronization, then startup speed is improved, but switch over-stress occurs
Solution Approach 1:
The patent employs feedback through node status detectors that continuously monitor the charging state of pump capacitors and output capacitors. This feedback mechanism provides real-time information about startup progress, allowing the control logic to determine when startup is complete and full power operation can begin. This feedback prevents switches from operating under stressful conditions during incomplete startup, thereby protecting switch durability.
3Device complexity
If output status detectors alone are used for startup detection, then device complexity is reduced, but inaccurate startup detection occurs
Solution Approach 1:
The patent segments the startup detection function into two independent detectors: an output status detector that monitors output capacitor charging and a node status detector that monitors pump capacitor charging. Each detector focuses on a specific aspect of the startup process, providing specialized monitoring. This segmentation improves detection accuracy by ensuring both critical capacitors are adequately charged, while keeping each individual detector relatively simple in structure.
Data Source
AI summary
Circuits/methods for controlling the startup of multiple parallel power converters that avoid inrush current or switch overstress in an added power converter or a power converter having fault conditions. Embodiments include node status detectors coupled to nodes within parallel-connected power converters to monitor voltage/current and configured in some embodiments to work in parallel with an output status detector measuring the startup output voltage of a power converter. With charge pump-based power converters, the node status detectors ensure that the power converter pump capacitors are charged while the output capacitor is charged as well. For such embodiments, a soft-start period of startup may be considered finished if both the shared output capacitors and the power converter pump capacitors are charged to target values. Embodiments may also be used for fault detection during steady-state operation.