Multi-Input Power Switching to Limit Inrush Current Surges
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Solution Overview
Problem
The existing dual-input power systems face output failure due to large instantaneous inrush currents when switching from an auxiliary input power source to a main input power source, especially when a standby power source is used, as it is sensitive to load changes and cannot supply power for an extended period.
Innovation Solution
A switching method that determines a strategy for each power supply unit to switch from the auxiliary input power source to the main input power source at different moments, reducing the inrush current by controlling the output current and voltage of capacitors, and ensuring the main input power source, including a standby power source, can supply power before the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple power supply units are switched from auxiliary input power source to main input power source simultaneously, then the system can quickly restore power supply, but large instantaneous inrush current will be generated causing output failure
Solution Approach 1:
The patent divides the simultaneous switching of multiple power supply units into sequential switching stages. Each power supply unit switches at a different time point, segmenting the total inrush current into smaller, time-separated current pulses. This prevents the accumulation of inrush currents that would occur with simultaneous switching, thereby avoiding output failure while still achieving relatively fast overall switching.
Solution Approach 2:
The patent implements periodic switching by introducing time intervals between the switching operations of different power supply units. The switching controller sequentially activates each power supply unit after a predetermined time delay, creating a periodic switching pattern that allows the standby power source to recover between load demands, thus preventing inrush current overload.
2Reliability
If standby power source is used as main input power source, then power supply reliability is improved, but the standby power source is sensitive to load changes and cannot supply power for extended period
Solution Approach 1:
The patent segments the total load among multiple power supply units that switch sequentially rather than simultaneously. This distribution of switching events over time reduces the instantaneous load demand on the standby power source, extending its operational capacity and holdup time while maintaining reliable power supply.
Solution Approach 2:
The patent applies partial action by having power supply units switch at different times rather than all at once. This partial sequencing of switching operations reduces the peak demand on the standby power source, allowing it to supply power for extended periods without being overwhelmed by simultaneous full-load transitions.
Data Source
AI summary
The embodiments of the present disclosure provide a switching method and a multi-input power system, where the method is used to control an input power source connected with N power supply units, and N is greater than 1, and the method includes: determining a switching strategy for each power supply unit, where the switching strategy is used to indicate a moment when input of a power supply unit is switched from an auxiliary input power source to a main input power source; switching, according to the switching strategy, the input of each power supply unit from the auxiliary input power source to the main input power source at the moment indicated by the switching strategy, where the main input power source includes a standby power source.