Inverter Neutral Point Capacitor Disconnection Detection Control
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Solution Overview
Problem
Existing power conversion devices struggle to accurately determine electrical disconnection abnormalities, which can lead to overvoltage conditions and potential failures in inverters and neutral point capacitors.
Innovation Solution
A power conversion device with a neutral point capacitor and a parameter detection unit that monitors the electrical parameter of the connection path, enabling the control unit to perform switching control and determine disconnection abnormalities through voltage change rate monitoring, triggering a fail-safe process to prevent overvoltage and capacitor failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switching control of the inverter is performed to supply current to the connection path, then power conversion efficiency is improved, but electrical disconnection abnormalities may occur causing overvoltage conditions and potential failures
Solution Approach 1:
The patent performs preliminary detection of electrical parameters (voltage, current) before switching control is executed. The control unit monitors the connection path status in advance and determines potential disconnection abnormalities before they cause overvoltage conditions, allowing preventive action to be taken while maintaining efficient power conversion operation
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors electrical parameters of the connection path during switching control operation. Based on detected parameter changes indicating disconnection abnormalities, the control unit adjusts switching control to prevent overvoltage conditions, thus maintaining both efficiency and reliability through real-time feedback adjustment
2Measurement precision
If parameter detection is implemented to monitor the connection path, then detection accuracy of disconnection abnormalities is improved, but device complexity increases
Solution Approach 1:
The patent uses the existing electrical parameters (voltage and current) that are already present in the power conversion system to detect disconnection abnormalities. The control unit utilizes these inherent system parameters without requiring external detection equipment, achieving accurate detection while avoiding additional device complexity through self-service monitoring
Solution Approach 2:
The control unit performs multiple functions: it manages switching control for power conversion efficiency while simultaneously detecting electrical parameters and determining disconnection abnormalities. This multi-functionality eliminates the need for separate dedicated detection devices, improving measurement precision without increasing overall device complexity
Data Source
AI summary
A power conversion device includes a high-potential side path that electrically connects a positive electrode terminal of a first electrical storage unit and a high-potential side terminal of an upper arm switch of an inverter, a low-potential side path that electrically connects a negative electrode terminal of a second electrical storage unit and a low-potential side terminal of a lower arm switch, a connection path, a neutral point capacitor, a parameter detection unit that detects an electrical parameter of the neutral point capacitor or the connection path, and a control unit. When performing switching control of the inverter to supply current to the connection path, the control unit determines whether an electrical disconnection abnormality has occurred on the connection path, based on a detection value of the parameter detection unit.