This paper proposes a modulation strategy for a 9-level Active Neutral Point Clamped and H-bridge (9L-ANPC-H) converter that features harmonic optimization and low total harmonic distortion (THD), while also incorporating a phase capacitor voltage balancing control. The strategy decomposes the original modulation scheme using a variable threshold calculation method, which equivalently adjusts the voltage contribution of different power stages by varying the threshold values. This enables effective voltage balancing of the three-phase floating capacitors. The algorithm introduces the concept of switching sequence planning and integrates modulation characteristics based on phase arrangement. A hybrid modulation process based on independent modulation, carrier phase shifting and sub modulated signal normalization processing is designed to achieve SPWM-based switching state planning, the output current has lower harmonic components and the overall THD is better than that of the conventional modulation, and the feasibility and validity of the proposed modulation strategy are verified by simulation.

To enhance the fault tolerance of modular multi-unit three-phase PMSMs, this paper investigates the influence of pole-slot combinations and stator slot geometries on inter-phase magnetic coupling. A novel open-slot structure with fault-tolerant teeth (FTT) is proposed to improve magnetic decoupling and unit-level independence.Two configurations— 40p48s and 40p36s—combined with three slot types are analyzed via finite element simulation. Flux distribution and inductance matrices are obtained to quantify magnetic coupling, and a coupling coefficient is defined for comparison.To evaluate short-circuit performance, turn-to-turn faults of varying severity are introduced via an external circuit model. Results show that the 40p36s structure with FTT provides superior decoupling and fault containment, enabling continued operation of healthy units without control intervention.

Conventional motor drive systems have numbers of disturbances and uncertainties in all frequency band, which seriously affect current control performance. To solve this problem, this paper proposes a composite controller based on the combination of modified equivalent-input-disturbance (MEID) and fractional-order phase-adaptive feedforward repetitive control (FPFRC) to suppress various types of disturbances and harmonics. Firstly, a unit proportional internal mode feedforward term is introduced in conventional repetitive controller to essentially improve resonance gain and convergence speed. Secondly, the resonant frequencies are modified in real time according to motor speed by using a phase-adaptive mechanism based on the fractional-order IIR filter. Thirdly, the state estimation accuracy and noise immunity of conventional EID strategy are improved by designing a proportional-integral augmentation observer based on the integral term of measured current as an augmentation variable. Finally, a modified filter with phase lead compensation is proposed to realize phase delay-free estimation of low-frequency disturbances in MEID. Experiments results verify the effectiveness of the proposed method, with suppressed current harmonics and improved output torque performance upon system disturbance.

This paper presents a prototype of magnetostrictive material-based vibration energy harvester, which is used to generate electricity during human walking with high power density. According to Villari effect (inverse-magnetostrictive effect), the harvester consists of a coil-wound magnetostrictive rod. In order to improve the harvesting effect, a magnetostrictive/electromagnetic hybrid configuration with an adjustable air gap is designed. It is followed with detailed analysis of mode effects on ΔB induced by single Δσ and ΔH for optimized design. Then, the magnetic field and leakage of the harvester are analyzed, mechanical parameters of the harvester are optimally determined. Lastly, a prototype of harvester is fabricated and tested. The proposed structure has larger piezomagnetic effect than traditional harvesters, especially under the 5-10MPa compress stress (impact of human walking is set about 5-12.5MPa). Also, it has good harvesting effects in 0.01-0.1s impact vibration time, and can be safely used in up to 20MPa transient impact, which is suitable for future researches of power generating floor systems.