The switching-table-based direct torque control (ST-DTC) has the merits of simple structure, easy implementation, and fast response, but suffers from large torque ripples. Previous literature, i.e., the classical DTC, can achieve torque ripple reduction in the high-speed region but has a limited capability for torque ripple reduction in the low-speed region. In this paper, the issue of torque ripple reduction in the full-speed region, i.e., both the low-speed and high-speed regions, is addressed. The effects of each group in all possible six groups of virtual voltage vectors (VVs) on torque variation are firstly investigated. Then, a multiple VV DTC based on only three groups of VVs is proposed and the corresponding optimal selections of three VV groups and level of torque regulator are presented. The proposed DTC not only can effectively reduce torque ripples in the full speed region, but also is simple and easy to implement. The superiority of the proposed DTC with optimal selections of VVs and level of torque regulator are verified by experimental results.

Shunt active power filters(SAPF) are employed to improve power quality by injecting compensating harmonic current. The modular SAPF offers many new capabilities that are otherwise unavailable by the conventional SAPF, such as high crest factor compensating current and fast dynamic response. However, there are still challenges that are needed to be addressed, such as resonance and stability issues associated with the modular SAPF. To investigate these issues, this work first presents a mathematical model for conventional modular SAPF system. Based on the mathematical analysis, a new hybrid three-level modular SAPF is presented that is composed of two types of modules, each with different current carrying capacities, LCL filter parameters, and switching frequencies. The proposed hybrid system provides a wider current tracking bandwidth and fast dynamic response as compared to the present modular SAPF. A novel self-adaptive, active damping strategy is proposed that effectively suppresses resonance and coupling between modules. Mathematical analysis and experimental results have been used to verify the proposed system.

This paper studies the acoustic noise of induction motor with low switching frequency model predictive control and compares its noise performance with the traditional pulse width modulation with proportional-integral controllers. First, the relationship among the air-gap magnetic field, the electromagnetic force, and the acoustic noise is modeled to describe the influence of control algorithm on the noise characteristics of motors. As the counterpart with the traditional pulse width modulation control, a finite control set model predictive control strategy with low switching frequency is proposed. The steady-state performance and switching frequency constraint ability of the proposed model predictive control strategy are verified on the experimental platform. Second, the noise spectrums of these two control strategies are sampled and compared in different operating conditions, and the influence of the weighting factor on the noise spectrum is also discussed. It is proved by the experimental results that model predictive control has better noise performance than the traditional sinusoidal pulse width modulation under the same switching frequency and the total harmonic distortion of stator current.

In this study, we propose an active junction temperature control method specifically tailored for traction inverters based on active neutral point-clamped (ANPC) three-level topology. This approach not only enables real-time junction temperature equalization across switching devices, but also minimizes switching losses while preserving synchronous modulation. The methodology begins with a detailed formulation of the loss quantification model for ANPC inverters, establishing the relationship between predicted losses and switching vectors. Building on this foundation, we develop a loss equalization modulation control strategy featuring closed-loop loss control. The effectiveness and practicality of the proposed control method are rigorously validated using simulations and low-power experimental testing, demonstrating its potential to enhance both the reliability and efficiency of traction inverters.

This study introduces an enhanced finite-control-set model predictive control (FCS-MPC) strategy for a three-level Si/SiC hybrid active neutral-point-clamped (3L-HANPC) converter, designed to optimize control performance across multiple objectives. Unlike conventional MPC schemes, the proposed approach fully exploits available control degrees of freedom, offering significant improvements in both efficiency and computational simplicity. By reformulating current constraints into voltage constraints, the method reduces computational demands, specifically by minimizing division operations. Furthermore, tailored voltage vector sequences are selected to satisfy the switching frequency requirements of both low-frequency cells (LFC) and high-frequency cells (HFC), enabling fixed switching frequencies and mitigating neutral-point voltage fluctuations. This optimized control framework also promotes a more uniform loss distribution and enhanced thermal management, critical for high-power drive applications. Experimental validation using a 4-SiC HANPC inverter platform demonstrates the superior steady-state and dynamic performance of the proposed FCS-MPC, while significantly reducing the computational burden on the digital signal processor (DSP), underscoring its practical feasibility for real-world applications.