Power Conversion Device Abnormal State Detection
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Solution Overview
Problem
Existing power conversion devices fail to accurately detect abnormal states in switching elements and current sensors, leading to disrupted normal operation and inability to continue operation when an abnormal state is identified.
Innovation Solution
A power conversion device with a first and second smoothing condenser, voltage conversion units, current sensors, voltage sensors, a control signal unit, and a failure decision unit that determines abnormal states based on detected values, allowing for the exclusion of abnormal switching elements and sensors to maintain normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage conversion units are controlled to stop abnormal units based on current sensor values, then abnormal states can be detected, but normal operation cannot be continued and operation is disrupted
Solution Approach 1:
The failure detection unit performs preliminary detection of abnormal states in voltage conversion units and current sensors before they cause system failure. By detecting abnormalities early and identifying specific faulty components, the system can prepare for continued operation with reduced functionality rather than forcing a complete shutdown, thus maintaining productivity while ensuring reliability
Solution Approach 2:
The control signal unit acts as an intermediary between the failure detection unit and the voltage conversion units. It processes detection results and generates appropriate control signals to isolate only the specific faulty components while allowing healthy units to continue operating, thereby resolving the contradiction between detecting abnormalities and maintaining continuous operation
2Reliability
If one or more voltage conversion units are made to stop when abnormal state is specified, then abnormal switching elements are eliminated, but it is not possible to continue normal operation
Solution Approach 1:
The system segments the voltage conversion functionality into independent units, each with its own switching elements and current sensors. When an abnormality is detected in a specific unit or component, only that segment is isolated and stopped, while other healthy segments continue to operate. This segmentation allows the system to maintain operation continuity by preserving functional independence of each unit
Solution Approach 2:
The system temporarily discards (stops) only the specific faulty voltage conversion unit or switching element identified by the failure detection unit, while recovering and maintaining operation of all other healthy units. This selective discarding and recovering approach ensures that normal operation can continue with reduced capacity rather than complete shutdown
3Device complexity
If current sensor abnormal state is not considered, then detection is simpler, but abnormal state part cannot be spotted accurately and current sensor failures are missed
Solution Approach 1:
The failure detection unit implements feedback mechanisms that monitor current sensor outputs and compare them against expected values calculated from voltage conversion unit operations. When discrepancies are detected, the system generates feedback signals to identify the faulty current sensor. This feedback approach enables accurate detection of sensor abnormalities without requiring overly complex detection systems, as it uses existing operational data for comparison
Data Source
AI summary
[Technical Problem] In a power conversion device for stepping up or stepping down the input voltage, when voltage converter become out of order, it is not possible to specify an IGBT element and a current sensor, which is in an extraordinary fault condition.[Solution to Problem] The power conversion device is configured to detect a voltage value of a smoothing condenser, connected in parallel to a load, where the load is to be connected to the power conversion device; detects, by a first current sensor, a current which flows through switching elements in a plurality of voltage converter; decides an abnormality of a switching element, by switching the switching element one by one; specifies the abnormality of the switching element; and specifies that the first current sensor is in an abnormal state, in a case where there is no abnormal state switching elements.