Power Conversion Control for Ripple-Current Abnormality Detection
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Solution Overview
Problem
Existing systems lack an accurate method to determine abnormalities in temperature rise control, which can lead to overcurrents and decreased reliability of inverters and batteries.
Innovation Solution
A power conversion device with a controller that performs temperature rise control by causing a ripple current through power storages, using a current sensor to detect current flow, and determining abnormalities based on detection values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If temperature rise control is performed by switching inverters to cause ripple current through batteries, then battery temperature increases, but abnormality detection accuracy deteriorates
Solution Approach 1:
The patent introduces a current sensor as an intermediary device to detect connection path current during temperature rise control. This mediator enables accurate abnormality detection by providing current flow information that indicates whether the ripple current is properly flowing through the batteries, thus resolving the contradiction between temperature increase and detection accuracy.
Solution Approach 2:
The system implements feedback by continuously monitoring the connection path current during temperature rise control and comparing it against expected values. When the detected current deviates from the expected ripple current pattern, the system identifies an abnormality and can terminate the temperature rise control, ensuring safe operation while maintaining detection accuracy.
2Device complexity
If temperature rise control is performed without accurate abnormality detection, then system complexity is reduced, but reliability deteriorates due to potential overcurrents
Solution Approach 1:
The current sensor serves as a simple intermediary that provides critical reliability information without adding complex control logic. By monitoring connection path current, the system gains reliable abnormality detection capability with minimal additional complexity, preventing overcurrents while maintaining system simplicity.
Solution Approach 2:
The temperature rise control system performs self-diagnosis by monitoring its own operating parameters (connection path current) during operation. This self-service approach enables the system to detect abnormalities and protect itself from overcurrent conditions without requiring external monitoring systems, thereby improving reliability with minimal added complexity.
Data Source
AI summary
A power conversion device includes: a high-potential-side path electrically connecting a first power storage and an upper arm switch; a low-potential-side path electrically connecting a second power storage and a lower arm switch; a power-storage-to-power-storage switch; a bypass switch; a connection path; a neutral point capacitor; a current sensor detecting a current flowing through the connection path or a current flowing through an armature winding; and a controller. The controller performs a temperature rise control in which to cause a ripple current to flow through the first and second power storages, at least one of the upper and lower arm switches is switched in a state where the bypass switch is on and the power-storage-to-power-storage switch is off, and determines whether an abnormality in the temperature rise control occurs based on a detection value of the current sensor during the temperature rise control.