Parallel Current Measurement for Converter Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring current in converters lack precision, particularly in high-precision applications like controlling electric motors, due to limitations in existing current measurement technologies such as sensor drift and limited operating states for calibration.
Innovation Solution
The method involves using at least two current measuring devices in parallel to average measurements, allowing for continuous calibration and switching between different measuring ranges, which enhances precision and accounts for offset and gain deviations over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two current measuring devices are used in parallel to average measurements, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The current measurement function is segmented into two separate measuring devices instead of using a single device. Each device independently measures the current, and their results are averaged to achieve higher precision. This segmentation allows the system to overcome the limitations of individual sensors while maintaining manageable complexity through modular architecture.
Solution Approach 2:
The measurement results from two separate current measuring devices are merged through averaging to produce a single, more accurate measurement value. This combining of multiple measurement sources compensates for individual sensor errors and drift, achieving higher precision without requiring a single complex high-precision sensor.
2Measurement precision
If continuous calibration is implemented during measurement operation, then measurement precision is maintained over time, but loss of time occurs during calibration switching
Solution Approach 1:
The system performs calibration actions in advance and alternates between calibration and measurement modes. By preparing calibration data beforehand and using multiple measuring devices, the system can switch between calibration and operation without significant interruption to the overall measurement process, maintaining precision while minimizing time loss.
Solution Approach 2:
The calibration process is implemented periodically rather than continuously, with the system alternating between measurement and calibration phases. This periodic approach maintains measurement precision over time while minimizing the time spent in calibration mode, as the system can quickly switch between the two states using the redundant measuring devices.
3Adaptability or versatility
If multiple measuring ranges are switched to adapt to varying currents, then adaptability is improved, but device complexity increases
Solution Approach 1:
The measuring devices are designed with dynamic range switching capability, allowing them to adapt to varying current magnitudes by switching between multiple predefined measuring ranges. This dynamic adjustment enables the system to maintain high precision across different operating conditions without requiring multiple dedicated devices for each range, thus balancing adaptability with manageable complexity.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a method and a device for measuring current at a converter, wherein the respective phase current (ij) is determined at the output of the converter (U) by current measuring devices (4, 5; 4', 5') in order to supply it to a control device associated with the converter (U). The respective phase current (ij) to be determined at an output of the converter (U) is measured independently at two current measuring devices (4, 5; 4', 5'), and the measurement results of both current measuring devices (4, 5; 4', 5') are used to determine the respective phase current.