Insulation Diagnosis Device for Inverter-Driven Machines
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Solution Overview
Problem
Conventional methods for inspecting and diagnosing the insulation of inverter-driven electric rotating machines using impulse voltage fail to accurately measure partial discharge characteristics due to differences in voltage waveforms between inverter surge voltage and impulse test voltage, leading to incorrect assessment of insulation integrity.
Innovation Solution
A method involving the measurement of voltage distributions within the electric rotating machine when subjected to both inverter surge and impulse voltages, with a correction factor applied to the impulse voltage to align it with the inverter surge voltage, allowing for accurate diagnosis of insulation characteristics and partial discharge occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impulse voltage is used for insulation inspection, then the inspection can be performed, but the measurement precision is insufficient due to waveform differences from inverter surge voltage
Solution Approach 1:
The patent applies parameter changes by modifying the impulse voltage waveform parameters (rise time, peak voltage, waveform shape) to match the inverter surge voltage characteristics. Specifically, the impulse voltage is adjusted to have a rise time of 0.10μs or less and peak voltage of 1200V or more, transforming it into a waveform that accurately replicates inverter surge conditions for precise partial discharge measurement
Solution Approach 2:
The patent uses copying by creating a test voltage waveform that is a precise copy of the inverter surge voltage waveform. The impulse voltage is shaped to replicate the actual surge voltage characteristics including rise time, peak voltage, and waveform profile, allowing accurate simulation of inverter-driven operating conditions without requiring the actual inverter system during testing
2Ease of operation
If standard impulse voltage is applied, then the inspection procedure is simple, but the insulation characteristic assessment is inaccurate
Solution Approach 1:
The patent applies dynamics by making the test voltage waveform adjustable and adaptable rather than fixed. The impulse voltage generator can dynamically adjust parameters such as rise time and peak voltage to match different inverter surge conditions, allowing the inspection system to adapt to various machine types and operating conditions while maintaining procedural simplicity
3Reliability
If inverter surge voltage is directly used for testing, then the test conditions match actual operation, but the test equipment complexity increases
Solution Approach 1:
The patent applies taking out by extracting the essential characteristics of inverter surge voltage (rise time, peak voltage, waveform shape) and isolating them from the complex inverter system. These extracted parameters are then used to generate a simplified impulse voltage waveform that captures the critical stress conditions without requiring the full inverter system, reducing equipment complexity while maintaining test reliability
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 correct inspection and diagnosis of insulation characteristics in inverter-driven electric rotating machines by ensuring the test voltage accurately replicates the inverter surge conditions, thereby evaluating the machine's ability to withstand inverter surge voltage effectively.
Implementation Method 1
measure whether or not partial discharge occurs at a predetermined voltage or measure a partial discharge start voltage at which partial discharge begins to occur
Data Source
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AI summary
Firstly, an electric rotating machine provided with a terminal for measuring a voltage distribution inside a winding is prepared, and an inverter surge voltage or a voltage waveform simulating the inverter surge voltage is applied thereto to measure voltage distributions between windings and between different phases inside the rotating machine. Secondly, a test voltage power supply for generating a test voltage formed of any one of an impulse voltage, a rectangular wave voltage, a high frequency sine wave voltage, and a high frequency damped oscillatory wave voltage and used for an inspection/diagnosis test of the rotating machine is prepared, and the test voltage is applied to the rotating machine used for voltage distribution measurement to measure the voltage distributions between the windings and between the different phases inside the rotating machine. Thirdly, a ratio between a shared voltage inside the rotating machine measured firstly and a shared voltage inside the rotating machine measured secondly is calculated and designated as a correction factor for the test voltage. Using the correction factor, the magnitude of the test voltage is corrected and, using the corrected test voltage, at least one of a withstand-voltage characteristic showing the insulation characteristic of an inverter-driven electric rotating machine and the presence or absence of partial discharge is inspected/diagnosed.