Position Estimation System for PMSM Position Sensorless Control in Inverter Overmodulation Drive

Abstract

This study investigates compensation methods for harmonic components to realize PMSM position sensorless control in inverter overmodulation drive. While applying PMSMs as traction motor motors in an EV or HEV, operating PMSM in inverter overmodulation drive is an effective method to widen high-speed drive region of PMSM and achieve fast torque response when voltage saturates because it enable to utilize 27% higher fundamental voltage as compared to linear drive. In addition, position sensorless control is regarded as an important technique for adding a fail-safe function and downsizing of the drive system. However, the harmonic components which are inevitably generated in inverter overmodulation drive have negative effects on closed current control and position estimation systems.

The key to realize position sensorless control in inverter overmodulation drive is an appropriate compensation for the harmonic components in the input voltage and input current of a the position estimator. There are several methods to achieve this, and differences in position estimation performance possibly exist among these methods.

In this study, the compensation methods for harmonic components in overmodulation drive are compared, and a suitable compensation method for sensorless control is investigated through an experiment.