A Position Sensorless Control of PMSM in Full Speed Range Using Improved Current Derivative Method

This article describes position sensorless control for permanent magnet synchronous motors (PMSM) based on improved current derivative method, unlike the traditional current derivative method, this method only needs to sample the motor current at the middle and end moment of each pulse width modulation (PWM) cycle, and does not need to measure the current derivative at each voltage vector interval. It solved the problem that traditional methods require a current derivative sensor or sampling currents at irregular times. Experiments verified its effectiveness and satisfaction, which have achieved accurate estimation of both rotor position and speed in the full speed range of the motor, and when the motor is suddenly loaded or unloaded, it can respond quickly.