Power conversion device and switching element fault diagnosis method

The three-level TNPP circuit detects the voltage change of the DC power supply, and outputs the test pulse to diagnose the short circuit fault of the switching element, which solves the problem of not being able to determine the damage to the switching element after first operation or long-term storage, ensuring the safe operation of the equipment.

JP7626328B2Active Publication Date: 2025-02-07TMEIC CORP (100 00)
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Patent Information

Application Number
JP2023532935
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2021-07-07
Publication Date
2025-02-07
Estimated Expiration
2041-07-07

AI Technical Summary

Technical Problem

The prior art cannot determine whether the switching elements are damaged after the first operation or long-term storage of the power conversion equipment, which may lead to accidents or damage to the components.

Method used

A three-level TNPP circuit is used to detect the voltage between the positive and negative electrodes of DC and the neutral point, output the test pulse to the switching element, and judge the short circuit fault based on the voltage changes.

Benefits of technology

It can diagnose short circuit failures of switching components when the power conversion equipment is connected to DC power supply, avoiding accidents and component damage.

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Abstract

According to one aspect of the present invention, a power conversion device that comprises a 3-level TNPP circuit is characterized by having a voltage detection unit that detects the voltage between a direct-current positive electrode and a direct-current neutral point, the voltage between the direct-current neutral point and a direct-current negative electrode, and the voltage between the direct-current positive electrode and the direct-current negative electrode, a test pulse outputting unit that, when the voltages detected by the voltage detection unit have risen above a prescribed threshold value, outputs a test pulse to an inside switching element that is connected in the forward direction from the direct-current neutral point toward an alternating-current output terminal, and a determination unit that, when the voltage between the direct-current neutral point and the direct-current negative electrode as detected by the voltage detection unit drops when the test pulse outputting unit has outputted the test pulse to the inside switching element that is connected in the forward direction from the direct-current neutral point toward the alternating-current output terminal, determines that a short circuit failure has occurred at an outside switching element that is connected to the direct-current negative electrode.
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Citation Information

Patent Citations

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    JP2003033045A

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    JP2013176240A

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    JP2020072503A

  • Power conversion device, method for diagnosing short-circuit faults in switching elements, and method for diagnosing open-circuit faults in switching elements

    JP6699253B2