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.

Finite control set model predictive control (FCS-MPC) has emerged as a powerful strategy for permanent magnet synchronous motor (PMSM) drives. However, its performance strongly depends on appropriately chosen weighting factors, which directly affect control quality and, in some cases, may even lead to instability. Despite the crucial role of weighting factors, there is no systematic or generally accepted procedure for selecting their values, which limits the robustness and practical applicability of conventional FCS-MPC methods. To overcome this limitation, this paper presents the experimental validation of a sequential direct speed predictive control strategy for PMSM. The individual cost functions are evaluated sequentially, thereby tuning is simplified and weighting factors are reduced. Experimental results show that the original version of sequential direct speed control, as proposed in the literature, exhibits promising dynamic performance but suffers from instability and current ripples under certain conditions. To address these issues, an enhanced version of the sequential direct speed predictive control is proposed in the paper. It effectively suppresses instabilities and enhances the speed dynamic response of the drive. The proposed approach was experimentally validated using the OP 5600 rapid control prototyping platform running RT-LAB software and a 1.1 kW PMSM machine.