DC/DC Power-Side Shutdown for Reverse Current Protection
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Solution Overview
Problem
Existing power converters face damage and safety risks due to large reverse currents generated by abnormal conditions such as reverse connection, reverse injection, or multi-point grounding at the power side, which can lead to serious consequences like fires.
Innovation Solution
A power-side shutdown protection method that actively disconnects the power side from the DC power supply by short-circuiting the positive and negative electrodes of the target DC/DC conversion circuit and controlling the connected switch to turn off, with additional measures to verify the switch's actual off-state before stopping the short circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switch is arranged at the power side to disconnect DC power supply in abnormal conditions, then reverse current damage is prevented, but the switch may fail to turn off completely under high reverse current, causing continued damage risk
Solution Approach 1:
The patent applies preliminary action by short-circuiting the positive and negative electrodes at the power side of the target DC/DC conversion circuit before attempting to turn off the switch. This pre-short circuit action provides an alternative current path that bypasses the switch, ensuring that even if the switch fails to turn off completely, the reverse current is still diverted away from the DC power supply through the short circuit path, thereby maintaining protection reliability.
Solution Approach 2:
The patent introduces a short circuit path as an intermediary element between the power side electrodes. This short circuit path acts as a mediator that handles the reverse current when the primary protection mechanism (switch turn-off) fails or is insufficient, providing an additional layer of protection without requiring the switch to perfectly interrupt the current.
2Power
If multiple DC power supplies are connected in parallel at the power side, then power capacity is increased, but reverse current generation is amplified under abnormal conditions
Solution Approach 1:
The patent applies segmentation by identifying and isolating the specific DC/DC conversion circuit (and its associated switch) that is causing the reverse current problem. Instead of disconnecting all parallel DC power supplies, the system targets only the problematic segment (target DC/DC conversion circuit), short-circuiting its power side electrodes and turning off its specific switch. This segmented approach maintains power capacity from healthy parallel supplies while eliminating reverse current from the faulty segment.
3Reliability
If the switch is turned off to stop reverse current, then DC power supply protection is achieved, but verification of actual turn-off state is needed to ensure protection effectiveness
Solution Approach 1:
The patent implements feedback by monitoring the current state after the switch is turned off and verifying whether the reverse current has been successfully interrupted. The system detects the actual turn-off state of the switch and uses this feedback information to determine whether additional protection measures (such as maintaining the short circuit) are needed, ensuring that protection effectiveness is confirmed before normal operation is restored.
Data Source
AI summary
A power-side shutdown protection method for a power conversion circuit, a power converter, a combiner box, and a power conversion system are provided. The power-side shutdown protection method includes: determining a DC/DC conversion circuit connected to a DC power supply with a reverse current as a target DC/DC conversion circuit, and short circuiting a positive electrode and a negative electrode at a power side of the target DC/DC conversion circuit; controlling a switch connected to the target DC/DC conversion circuit to be turned off; determining whether the switch controlled to be turned off is actually turned off; and stopping short circuiting the positive electrode and the negative electrode at the power side of the target DC/DC conversion circuit in a case that the switch is actually turned off.