A Model-based Rapid Calibration Method of Interior Permanent Magnet Synchronous Motor

Abstract

The current practice of motor calibration is inefficient as it typically involves manual adjustments and repeated calculations based on data collected by high-precision power analyzers, which also places high demands on operator experience and instrument accuracy. In light of these issues, the paper proposes a semi-automatic quick calibration method for parameters of interior permanent magnet synchronous motor (IPMSM). To begin, an initial current look-up table is generated based on the characteristic parameters of the motor and controller, and the dynamometer system is measured to indicate its no-load resistance. Next, the speed of the dynamometer is set to match the motor's rated speed, the parameters of the motor control software are recorded under the set current, including the reference current, set voltage, and bench feedback torque, and computation is conducted using the offline calibration software for IPMSM to generate a calibrated current look-up table of the motor. The control stability and torque accuracy of the motor controller were verified in an experiment using two models of motors. The results show that the calibration efficiency is improved using the proposed quick calibration method by 60% compared to conventional methods. The PI output voltage of the current loop remains within ±20 V at rated speeds, and within -60 ~ 40 V across the full speed range, indicating excellent stability. The torque accuracy can be controlled within ±1%, except for working conditions with low torque, high speed, and current limit circle limitations where the torque control accuracy is within ±3%, meeting the torque accuracy requirements of ±3% for most customers in the industry.

Keywords

• permanent magnet synchronous motor (pmsm)
• motor calibration
• current look-up table
• torque control accuracy