Soft Step Impedance Testing for Power Engineering Devices
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Solution Overview
Problem
The application of abrupt test signals to power engineering devices leads to high current peaks, causing metrological problems during impedance measurement, particularly in capacitive test objects, which limits the accuracy of initial measurement regions.
Innovation Solution
A method and device for electrical impedance testing using a monotonically increasing test signal, avoiding sudden voltage peaks by employing a 'soft step' approach, allowing for continuous measurement without initial peak issues, and enabling the determination of impedance properties, especially for low frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an abrupt test signal is applied to the power engineering device, then the measurement speed is improved, but high current peaks occur causing metrological problems
Solution Approach 1:
The test signal transitions from a static abrupt step function to a dynamic monotonically increasing function. The voltage rises continuously according to a controlled profile (linear, exponential, or logarithmic) rather than jumping instantaneously, adapting the signal application rate to avoid capacitive current peaks while maintaining measurement efficiency
Solution Approach 2:
The test signal parameters are changed from an abrupt step voltage to a monotonically increasing voltage with a controlled rate of change. By adjusting the rise time and profile shape of the test signal, the measurement process achieves both speed and precision without generating harmful current peaks
2Measurement precision
If a monotonically increasing test signal is used, then measurement precision is improved by avoiding current peaks, but measurement time increases
Solution Approach 1:
The test signal employs a dynamic monotonically increasing profile that can be adjusted in shape (linear, exponential, logarithmic) to optimize the balance between measurement precision and time. The continuous rise avoids abrupt transitions while maintaining a controlled pace that limits total measurement duration
Solution Approach 2:
The test signal application follows a structured temporal pattern with defined phases: initial monotonous rise, intermediate measurement phase, and final stabilization. This periodic structure allows precise measurements to be taken at optimal moments during the signal evolution, balancing accuracy requirements with time efficiency
Data Source
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Figure 3a~3b
AI summary
The method involves applying a voltage as a sinusoidal or step-like test signal to a power engineering device by a test signal generator, and measuring a current waveform (i-t) over the power engineering device. A response of the power engineering device to the test signal is detected by a measuring device. An electrical property e.g. impedance (Z-s), of the power engineering device is determined based on a ratio between a voltage waveform (u-t) and the current waveform, where the voltage waveform is generated by a voltage generator (2). An independent claim is also included for an apparatus for testing a power engineering device, comprising a test signal generator.