Parallel Switch Short Circuit Protection Using Sum Current Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing short circuit protection apparatus for power conversion systems with multiple switches connected in parallel is costly and large due to the need for multiple current detectors, which increases the complexity and size of the system.
Innovation Solution
A short circuit protection apparatus that uses fewer current detectors than the number of switches by detecting the sum of currents flowing through multiple switches, allowing for efficient determination of short circuit failures and reducing the overall size and cost through the use of Rogowski coils and integrators to generate detection signals for the short circuit determiner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current detector is provided for each switch connected in parallel to detect individual currents, then short circuit protection accuracy is improved, but the cost and size of the short circuit protection apparatus increase
Solution Approach 1:
The patent merges the current detection function for multiple switches into a single current detector that detects the total current flowing through all switches connected in parallel. By detecting the sum current and using logical analysis of detection signals from different switch combinations, the system achieves accurate short circuit protection without requiring individual current detectors for each switch, thereby reducing cost and apparatus size while maintaining protection accuracy
Solution Approach 2:
The patent introduces an intermediary computational and logical analysis mechanism that processes the total current detection signal to infer individual switch status. By analyzing the detection signals from different switch combinations and applying logical operations, the system can identify which specific switch has a short circuit failure without directly measuring each switch's current, thus resolving the contradiction between detection accuracy and system complexity
2Device complexity
If the number of current detectors is reduced to fewer than the number of switches, then cost and size are reduced, but the ability to accurately identify which specific switch has failed may be compromised
Solution Approach 1:
The patent implements a feedback mechanism where the single current detector provides detection signals for different switch combinations, and the short circuit determiner analyzes these feedback signals through logical operations to identify the specific failed switch. By continuously monitoring different combinations of switches and applying logical analysis to the detection signals, the system can accurately pinpoint which switch has failed even though fewer detectors are used than switches
Solution Approach 2:
The patent uses partial action by having the single current detector monitor different combinations of switches rather than all switches simultaneously. By sequentially or selectively detecting current in different switch combinations and analyzing the patterns of detection signals, the system can identify the failed switch without needing a detector for every single switch, thus reducing the number of detectors while maintaining identification accuracy
Data Source
AI summary
A short circuit protection apparatus for a power conversion apparatus supplying power to a load via a plurality of switches connected to each other in parallel includes Ma current detectors each configured to detect a sum of currents flowing through two or more switches among the plurality of switches so as to output a detection signal indicative of the sum that is detected, wherein Ma is 1 less than M, which is the number of the plurality of switches, and a short circuit determiner configured to determine, based on detection signals obtained from the respective Ma current detectors, occurrence of short circuit failure in the plurality of switches to output a cutoff instruction signal for stopping on-off drive of the plurality of switches.