Multi-Phase Machine Leakage Inductance Estimation Using VSD Control
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Solution Overview
Problem
Existing methods for estimating leakage inductance of multi-phase electrical machines are either complex and require additional equipment or sinusoidal power supplies, or they are inaccurate and time-consuming, especially during the commissioning phase.
Innovation Solution
A method involving a first and second machine investigation scheme using vector space decomposition (VSD) control model to estimate leakage inductance by controlling one and then all 3-phase windings, processing measured currents to match primary and secondary characteristics, without the need for sinusoidal signal sources or winding rearrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sophisticated estimation methods are used, then measurement precision is improved, but device complexity increases and additional equipment is required
Solution Approach 1:
The patent extracts only the essential measurement requirements by eliminating the need for sinusoidal voltage sources and winding rearrangement. It uses standard three-phase power supply and existing winding configurations, taking out the complex additional equipment while retaining adequate measurement capability through intelligent signal processing of standard operating conditions.
Solution Approach 2:
The estimation method uses the electrical machine's own operating characteristics and naturally occurring current harmonics under standard VSD control to perform self-diagnosis. The machine's own current measurements during normal operation provide sufficient information for leakage inductance estimation without requiring external test equipment or special test configurations.
2Reliability
If accurate leakage inductance estimation is achieved, then reliability is improved, but loss of time increases due to complex procedures
Solution Approach 1:
The patent performs preliminary analysis of current harmonic characteristics under standard VSD control to identify the specific frequency components containing leakage inductance information. By pre-processing the current measurements to isolate relevant harmonic content and applying dedicated estimation algorithms, the method achieves rapid and reliable leakage inductance determination during commissioning without time-consuming procedural steps.
3Ease of operation
If simple estimation methods are used, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent changes the analysis parameters by examining current measurements in the frequency domain, specifically targeting harmonic frequency components that are directly related to leakage inductance. By transforming the approach from time-domain analysis to frequency-domain harmonic analysis, the method achieves high measurement precision using simple, straightforward measurement and calculation procedures that are easy to implement during commissioning.
Data Source
AI summary
A method for estimating at least one leakage inductance of a 3n-phase electrical machine includes performing a first machine investigation scheme and a second machine investigation scheme, the first scheme including ordering a machine drive stage to control one of the 3-phase windings, obtaining a first set of measured currents from the 3-phase winding and processing the first set of measured currents to obtain primary characteristics of an electrical quantity of the electrical machine, the second scheme including ordering the machine drive stage to control all the 3-phase windings using a VSD control model, the controlling involving only controlling a first fundamental subspace of the VSD control model, obtaining a second set of measured currents from all 3-phase windings and processing the second set of measured currents to obtain a leakage inductance estimate and secondary characteristics of the electrical quantity, for which leakage inductance estimate the primary and secondary characteristics match.