Based on multiple reference frames (MRF), this article investigates high-precision harmonic current extraction for permanent magnet synchronous motor, while taking the disturbance of speed harmonics into account. First, the extraction error in MRF caused by speed harmonics is deduced and analyzed, showing that the error is nonignorable and detrimental. Second, a novel preprocessing of fundamental current reconstruction and elimination in MRF is proposed, which effectively suppresses the extraction error. Third, a variable forgetting factor recursive least squares algorithm is proposed for the fundamental current amplitude identification, which guarantees fast and accurate preprocessing. Furthermore, the above method parallelly resolves the conflict between rapid extracting and low steady-state fluctuation in MRF, which significantly enhances harmonic current extraction performance. The superiority and accuracy of the proposed algorithms are proved by experiments.

The conventional finite-control-set model predictive control (FCS-MPC) approach for controlling three-phase three-level inverters is plagued by significant current ripple. To minimize the root mean square error (RMSE) of the current control, this paper proposes a more straightforward and efficient solution using dual vectors. Firstly, a dual-vectors algebraic preselection method is presented to reduce computational complexity. Secondly, the continuous current reference is adopted for the first time instead of the discretized value to improve the accuracy of the current control error calculation, which leads to a more precise RMSE calculation. Thirdly, the impact of the sequence and duty cycles of the vectors on the RMSE is quantified for the first time, and the optimal solution is proposed to minimize RMSE. Compared to existing dual-vectors optimization algorithms, the proposed algorithm reduces the RMSE and total harmonic distortion of output current by more than 25% and 10%, respectively. Experimental results are presented to validate the advantages of the proposed algorithm.

PWM output delay caused by calculation is widely presented in permanent magnet synchronous motor drive systems, which reduces control performance, accuracy, and stability. This article proposes a novel enhanced SVPWM update strategy, which is easy to implement and achieves completely delay-free output. Compared to traditional methods, this approach is simpler to compute, does not rely on motor parameters, and does not require an increase in sampling frequency. The effectiveness and superiority of the proposed algorithm are verified through comparative experiments.

This article presents an improved control strategy based on the traditional sliding-mode controller (SMC), integrated with a generalized higher-order disturbance observer (DOB), to enhance the speed regulation of permanent magnet synchronous motors (PMSMs) during operation. The proposed method is mitigated and employed to smooth system disturbances by utilizing the disturbance observer (DOB) in conjunction with a low-pass filter (LPF). The low-pass filter is employed to smooth the q-axis current component and reduce speed oscillations. Initially, the paper builds upon the conventional control law and introduces a more optimized approach. The stability of the control strategy is then analyzed using Lyapunov stability theory. Different sliding surfaces are compared to develop the proposed SMC. Finally, the novel control method is introduced by integrating the DOB with the LPF. This approach results in improved speed stability and enhanced adaptability compared to traditional SMC techniques. Simulation and experimental results demonstrate that the proposed control algorithm outperforms traditional methods, particularly in terms of the dynamic response and disturbance rejection.

In this article, a novel deadtime compensation method is proposed for permanent magnet synchronous motor (PMSM) drives. The method aims to insert an adaptive antideadtime into the pulsewidth modulation duty, with the same phase and opposite amplitude as that of the real deadtime. First, the deadtime related harmonics model considering sampling delay in the fifth multiple reference frame (MRF) is derived. Second, the harmonic model based shift MRF strategy is proposed, which optimizes the phase of extracted fifth harmonics. Thirdly, to adjust the amplitude and phase of the antideadtime, a new deadtime compensation frame based on the cross-coupling control algorithm is established. Parameters of controllers are set by bode analysis and zero pole cancellation. Compared with existing approaches, this method has low computational complexity and strong robustness, does not rely on additional hardware, and can eliminate all order of deadtime related harmonics. Experimental results are presented to validate the superiority and effectiveness of the proposed algorithm.

This article introduces a receiver position identification (RPI) method based on sensing intermediate (SI) coils in a 3-D orthogonal wireless power transfer (WPT) system. The proposed method involves the placement of SI coils in the same plane as the transmitting (TX) coils, facilitating precise calculation of the spatial position information of the receiver (RX) coil in 3-D space. The currents of the TX coils and the SI coils are measured, and a genetic algorithm is employed to determine the RX position using the multiaxis rotational mutual inductance ratio calculation model developed in this article. Furthermore, the working modes of the SI coils can be adjusted to achieve power enhancement after completing the position detection process. Experimental results demonstrate that the proposed method achieves an average angular error of only 2.71$^{\circ }$ for RPI. In addition, the utilization of the SI coils leads to a substantial increase in transmission power, accompanied by a modest improvement in transmission efficiency.