Converter Capacitance Monitoring Using Time-Shift Optimization
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Solution Overview
Problem
Existing converter systems lack effective methods for continuous capacitance monitoring during operation, leading to unexpected failures due to inaccuracies from measurement offsets, disturbances, and electromagnetic interference, and existing methods for determining capacitance during operation are inaccurate due to temporal shifts in measurement signals.
Innovation Solution
A method that determines capacitance by minimizing an objective function involving voltage, current, and time, using optimization techniques to account for temporal shifts and measurement errors, and includes steps to smooth and normalize data, compare with other energy storages, and detect abnormal values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If capacitance is determined during operation using voltage and current measurement, then continuous monitoring is enabled, but measurement accuracy deteriorates due to offsets, disturbances and electromagnetic interference
Solution Approach 1:
The patent applies preliminary action by performing capacitance determination during periods when the converter is not operating or during specific switching states when measurement conditions are optimal. This allows accurate capacitance measurement to be performed in advance or at scheduled intervals without being affected by full operational disturbances, while still enabling continuous monitoring capability through repeated measurements.
Solution Approach 2:
The patent introduces an intermediary approach by using the relationship between voltage and current measurements through integration to indirectly determine capacitance, rather than direct capacitance measurement. This intermediary method allows capacitance to be derived from easily measurable voltage and current signals while avoiding direct measurement of the capacitor itself during operation.
2Device complexity
If capacitance determination uses only capacitance as minimization parameter, then computation is simpler, but measurement errors from temporal shifts increase
Solution Approach 1:
The patent applies dimensionality change by adding time as an additional minimization parameter alongside capacitance. This transforms the optimization problem from a single-parameter to a two-parameter problem, allowing temporal shifts in measurement signals to be compensated. The time parameter enables the system to account for synchronization errors and temporal misalignments between voltage and current measurements, significantly improving accuracy.
3Ease of manufacture
If conventional capacitance measurement methods are used, then implementation is simpler, but unexpected failures occur due to lack of continuous monitoring
Solution Approach 1:
The patent implements feedback by continuously determining capacitance values during converter operation and using these values to monitor the health and status of the energy storage components. The capacitance information feeds back into the control system, enabling real-time detection of degradation, anomalies, or failures, thereby improving system reliability while maintaining implementation feasibility through integration with existing measurement systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and continuous capacitance monitoring during converter operation, reducing errors and enabling timely maintenance actions, thereby improving system reliability and reducing unexpected failures.
Implementation Method 1
determining a capacitance of said energy storage by minimizing an objective function of said voltage, said current, said capacitance and a time over minimization parameters capacitance and time
Implementation Method 2
the measured voltage and/or current values are smoothed before determining the capacity
Data Source
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AI summary
The invention relates to a method for operating a converter (1,7), said converter (1,7) comprising at least one switching module (12), said switching module (12) comprising an energy storage (C) and semiconductor switches (S1,S2) to allow and block current flow through said energy storage (C), said method comprising the steps of measuring a voltage present across said energy storage (C), measuring current flowing through said energy storage (C). The method is characterized in determining a capacitance of said energy storage (C) by minimizing an objective function of said voltage, said current, said capacitance and a time over minimization parameters capacitance and time. The present invention also relates to a converter with a converter control (13) that is configured to operate the converter in accordance with the above-described method.