Filter Capacitor Degradation Detection via Voltage Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power conversion systems face challenges in detecting degraded filter capacitor components, which can lead to costly replacements, system downtime, and undetected failures due to the inability to visually identify degradation and the inefficiency of protective fuses.
Innovation Solution
A method and apparatus for detecting filter capacitor degradation by measuring filter circuit currents and voltages, computing expected and measured DC equivalent voltage values, and calculating a voltage change value to identify capacitor degradation conditions, allowing for early detection and prevention of system damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no detection system is used, then device complexity is reduced, but loss of time increases due to undetected failures and system downtime
Solution Approach 1:
The detection system utilizes existing measurement circuits within the power conversion system to obtain current and voltage data, eliminating the need for separate dedicated measurement hardware. The processor leverages already-acquired operational data to compute expected voltage values and detect degradation, reducing overall system complexity while enabling timely failure detection.
Solution Approach 2:
The system performs preliminary detection of capacitor degradation by continuously computing expected voltage values and comparing them with measured values before actual failure occurs. This preliminary detection enables early identification of degradation trends, allowing for scheduled maintenance before catastrophic failure and system downtime.
2Ease of operation
If visual inspection methods are used, then ease of operation is improved, but measurement precision deteriorates because degradation cannot be visually identified
Solution Approach 1:
The patent replaces manual visual inspection with an automated electronic measurement and computation system. The processor calculates expected DC equivalent voltage values based on measured currents and capacitor impedance, then compares these with actual measured voltages to precisely detect degradation conditions that are imperceptible through visual inspection.
Solution Approach 2:
The system introduces an intermediary computational process that translates electrical measurements (currents and voltages) into degradation indicators through voltage deviation analysis. This intermediary computation layer bridges the gap between raw electrical signals and meaningful degradation detection, enabling precise identification of capacitor conditions.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Methods and apparatus are presented for detecting degrading filter capacitors in motor drives or other power converters, in which an expected DC equivalent voltage and a measured DC equivalent voltage are computed according to sampled filter circuit currents and voltages, and compared to selectively identify filter capacitor degradation conditions in a power converter filter circuit.