High-frequency (HF) signal injection methods are one of the key techniques for accurately estimating the rotor position of permanent magnet synchronous machines (PMSMs). The rotor position is determined by superimposing HF signals onto the fundamental control signals, producing a combined signal that serves as a reference for the PWM modulator. The rotor position is then extracted from the current response caused by the injected signal. This paper introduces a modification to the HF pulse signal injection method for sensorless control. The proposed approach improves control dynamics by reducing the signal injection period from two control periods to just one, and by adding the cogging torque compensation, thereby minimizing current and speed ripple. Experimental results obtained with a 2.5 kW PMSM and RT-LAB software obtained for the 1% of nominal speed validate the effectiveness of the proposed method.

This paper presents the design of Unscented Kalman Filter (UKF) for estimation of state space variables of permanent magnet synchronous machine (PMSM). The UKF is shown together with the field oriented speed control. At first, the position and the speed of PMSM are measured, and UKF is used only for a load torque estimation. It is indicated how differences in sampling time of the speed and the current loop affects overall estimation performance. Subsequently, speed sensorless performance of the UKF with the same parameters is shown for comparison. Designed filter is verified only by Matlab simulation.