Inductance Estimation for Reliable PMSM Sensorless Control
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Summary
Problems
Permanent magnet synchronous motors (PMSMs) used in air conditioning compressors face challenges in accurately estimating inductance during sensorless operation due to parameter errors, which affect control performance and reliability, especially under varying environmental conditions without position sensors.
Innovation solutions
A method and apparatus that inject a random signal into the rotor coordinate system of a PMSM, sense current responses, and detect inductance values based on the magnitudes of these responses, allowing for accurate estimation of inductance without relying on position sensors, by changing inductance values and comparing current responses to identify the actual inductance value.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If sensorless control technique using voltage equation is applied to drive PMSM, then position sensor is eliminated reducing cost and improving reliability, but parameter errors affect position estimation performance and control performance deteriorates
Why choose this principle:
The patent changes the parameter being measured from direct position detection to inductance parameter identification. By injecting random signals and observing current responses at different inductance values, the system identifies the actual inductance parameter that reflects the true magnetic flux position, thereby maintaining measurement precision without requiring additional sensors.
Principle concept:
If designed parameter values are used in sensorless control, then control implementation is simplified, but parameter errors due to environmental variation and manufacturing tolerance reduce control performance
Why choose this principle:
The patent implements a feedback mechanism where the system injects random signals, measures current responses, and iteratively adjusts the inductance parameter until the measured response matches the expected response. This closed-loop parameter identification process continuously updates the inductance value to reflect actual environmental conditions and manufacturing variations, ensuring reliable control performance.
Application Domain
Data Source
AI summary:
A method and apparatus that inject a random signal into the rotor coordinate system of a PMSM, sense current responses, and detect inductance values based on the magnitudes of these responses, allowing for accurate estimation of inductance without relying on position sensors, by changing inductance values and comparing current responses to identify the actual inductance value.
Abstract
A method of estimating inductance of a permanent magnet synchronous motor (PMSM) includes injecting a signal having a frequency differing from an operating frequency of the PMSM into the PMSM during sensorless operation, sensing magnitudes of current responses to the injected signal, and estimating an inductance value at which the magnitude of the sensed current response is minimal to be an actual inductance value of the PMSM, thereby estimating inductance used in the PMSM regardless of position estimation error of the PMSM and thus more accurately and reliably estimating inductance of the PMSM.