Parallel Electrical Machine Load Deviation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting load differences between parallel electrical machines connected to a common converter require a high number of current measuring sensors, leading to increased costs and potential sources of error, while also providing limited precision in determining the individual operating states of machines.
Innovation Solution
A method where currents in two supply lines of one machine and one supply line of another machine are measured, with unmeasured currents estimated based on corresponding currents from the first machine, allowing for the detection of load deviations without the need for additional sensors, using current space vectors and voltage jumps to determine machine states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current sensors are installed in all supply lines of parallel electrical machines, then accurate current measurement for each machine is achieved, but the number of sensors increases proportionally to the number of drives
Solution Approach 1:
The patent uses the measured currents from the first electrical machine as a reference model to estimate the currents in the second machine. Instead of directly measuring all currents, it copies the measurement pattern (measuring 2 out of 3 lines) and uses the known relationship between machines to infer unmeasured values, thereby reducing sensor count while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces an intermediary estimation process that uses the measured currents from the first machine as a mediator to determine the currents in the second machine. The control unit acts as an intermediary that processes the measured values and calculates the unmeasured currents based on the parallel operation relationship, avoiding the need for direct measurement in all supply lines.
2Device complexity
If current sensors are reduced to save costs and complexity, then fewer sources of error and lower costs are achieved, but information about individual machine currents is lost
Solution Approach 1:
The patent copies the current measurement pattern from the first machine to the second machine context. By measuring currents in corresponding supply lines of the first machine and using that information to estimate the second machine's currents, it preserves current information completeness without requiring sensors in all supply lines of both machines.
Solution Approach 2:
The system uses the first electrical machine's measured currents to serve the information needs of the second machine. The measured values from machine one effectively provide the current information needed for machine two through the estimation process, making the system self-sufficient without additional sensors.
3Device complexity
If current sensors are installed in common supply lines, then the number of sensors is reduced, but only average information for all machines is available without precise individual machine state determination
Solution Approach 1:
The patent segments the measurement approach by measuring specific supply lines of the first machine (2 out of 3 lines) and using that segmented information to infer the state of the second machine. This segmentation allows individual machine state determination without requiring sensors in all supply lines of all machines.
Solution Approach 2:
The patent applies local quality by measuring currents in specific local positions (supply lines of the first machine) and using those localized measurements to determine the global state of both machines. The measurement focus is placed strategically on the first machine's supply lines to provide information about both machines' operating states.
Data Source
Figure 1~2
Figure 3~4
AI summary
Method for detecting load differences between at least one first electrical machine (1) and at least one second electrical machine (2) connected in parallel, which are supplied by a converter (3), wherein the machines are each connected to the converter (3) via three supply lines (5, 6) and the currents in two supply lines (5) of the at least one first machine (1) and in one of the supply lines (6) of the at least one second machine (2) are measured using current measuring sensors (7, 8) and the corresponding unmeasured currents of the at least one second machine (2) are estimated on the basis of the measured current values of the at least one first machine (1), and the estimated total current of the supply lines (6) of the at least one second machine (2) is recorded as a measure of the deviation of the currents of the at least one second machine (2) from the at least one first machine (1).