Polyphase Machine Type Identification via Impedance Measurement
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Solution Overview
Problem
The challenge lies in automatically identifying the type of polyphase machine (motor or generator) connected to a converter without requiring manual input or knowledge of the machine type, as existing systems rely on operator knowledge and differentiation methods that are not always reliable, especially for servo motors which can resemble synchronous or asynchronous machines visually.
Innovation Solution
The converter is equipped with self-recognition functions that stimulate the machine with test signals to measure impedance over the stator angle, comparing these measurements with reference functions to determine the machine type, allowing for automatic adaptation of control and monitoring programs without operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual identification of machine type is used, then operator knowledge and control lists are required, but the process becomes complex and time-consuming
Solution Approach 1:
The converter performs self-identification of the connected machine type by automatically applying test signals and evaluating impedance characteristics, eliminating the need for manual operator input or knowledge of machine specifications
Solution Approach 2:
The manual mechanical process of checking type plates and consulting control lists is replaced by an electrical measurement system that automatically determines machine type through impedance testing
2Measurement precision
If manual identification using control lists is used, then type determination can be made, but the time required for putting into operation increases
Solution Approach 1:
The converter automatically performs impedance measurements and machine type determination during the initialization phase before normal operation begins, eliminating time delays during the operational phase
Solution Approach 2:
The system autonomously completes the identification process without requiring operator intervention or consultation of external documentation, significantly reducing the time required for machine commissioning
3Ease of operation
If automatic recognition functions are implemented, then operator intervention is reduced, but the converter requires additional test signal and measurement capabilities
Solution Approach 1:
The converter's existing control and measurement infrastructure is utilized for machine type identification, allowing the same system to perform both normal conversion operations and diagnostic testing functions
Solution Approach 2:
Test signals serve as intermediaries that enable the converter to probe and characterize the connected machine's electrical properties without requiring physical disassembly or direct operator manipulation of the machine
4Measurement precision
If impedance measurement over stator angle is performed, then accurate machine type determination is achieved, but the measurement process becomes more complex
Solution Approach 1:
The impedance measurement is divided into discrete angular positions around the stator, with test signals applied at specific intervals to build up the complete impedance characteristic curve through sequential measurements
Solution Approach 2:
The converter continuously monitors the impedance response at each angular position and uses this feedback information to determine machine type, allowing for adaptive adjustment of measurement parameters if needed
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
This approach enables safe and efficient operation by automatically recognizing the machine type, reducing setup time and eliminating the need for operator knowledge, ensuring accurate adaptation of control programs and monitoring functions to the connected polyphase machine.
Implementation Method 1
The impedance Z is determined as a function of the stator angle alpha by evaluating a sequence of test signals applied to the machine
Data Source
AI summary
The recognition of a polyphase machine (1) connected to a converter (10) is suggested in order to adapt the converter (10) to the connected machine (1) prior to an active productive operation. The following is arranged for. Connecting of the polyphase machine with its several electric phases to the converter (10). Supplying of at least a first and a second test signal from the converter (10) to at least one of the several electric phases of the connected machine. Measuring of at least two causal sequences of the test signals. Evaluating of the measuring result to obtain measuring values (r1, r2) and allocating of these measuring values to a comparison function (60, 50). Comparing of the comparison function with a reference function (60a, 60b, 50a, 50b) which represents one type of a polyphase machine.