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Wireless motors employ wireless power transfer (WPT) technology to convert electrical power into mechanical power remotely, eliminating the need for physical wires or cables. However, traditional wireless motors, especially wireless ac motors, still suffer from complicated and bulky motor-side circuits, intricate current commutation, and inefficient control processes. To improve the wireless ac motor, this article proposes a novel permanent magnetic ac (PMAC) motor system with minimized motor-side components. Initially, three independent WPT channels were established to enable simultaneous transmission of control data and power to the motor side, facilitating complete control from the primary side. Furthermore, the secondary-side power switches automatically toggle, functioning at a low motor electric frequency, obviating the requirement for supplementary control circuits and auxiliary power sources. In addition, current vector control with adjustable amplitude is introduced to generate rotating stator magnetic fields, enabling closed-loop motor speed control. Finally, an 800 r/min, 1.8 N·m wireless PMAC wireless motor prototype with 84.3% efficiency is constructed to validate the effectiveness of the proposed system.

In order to improve the linear modulation region in the control, the series-end winding (SW) is applied in the drive of five-phase permanent magnet synchronous motors. However, this drive topology will lead to a zero-sequence loop, so the zero-sequence back electromotive force will produce a zero-sequence current (ZSC). This letter proposes a decoupled modulation strategy for harmonic current suppression, including the ZSC. At first, all the space voltage vectors in the several subspaces have to be obtained. Virtual voltage vectors, which only contain the α–β or x–y components, are calculated and applied in the space vector modulation strategy. In this way, the current in different subspaces can be controlled separately. Then, the modulation in the zero-sequence subspace is decoupled from the α–β and x–y subspaces through the duty cycle compensation. The reference zero-sequence voltage (ZSV) is obtained by adjusting the duty cycle of each drive leg. The ZSC is suppressed after the ZSV is injected. In the experimental validation, the harmonic current in the x–y subspace and ZSC are reduced greatly to 61% and 59%, respectively.

The five-leg inverter has been investigated widely as a low-cost solution for dual permanent magnet synchronous motors (PMSMs) drives. It installs a common leg between dual PMSMs and can be considered a fault-tolerant approach in the event of an open-circuit fault occurring within an inverter leg. For this topology, the overcurrent of the shared leg should be handled carefully since the confluence of phase current naturally amplifies the current peak. In this article, an enhanced model predictive control (MPC) scheme is presented to realize cooperative dual-PMSMs control, effective overcurrent elimination, lower computational burden, and fast transient response simultaneously. The primary-secondary structure and deadbeat control-based duty cycle partitioning scheme are adopted to eliminate the switching state conflict on the common leg and realize independent current controller construction. In addition, the relations of current phases of dual PMSMs are deduced, designed, and utilized to modify the reference current of the secondary motor. As a result, the overcurrent component is contained in the cost function directly. Finally, the experimental tests of a dual-PMSM system are executed, and the results substantiate the effectiveness and superiority of the proposed algorithm.

Series elastic actuators (SEAs) have been popularly studied as an alternative to rigid actuators due to their high compliance, reliable back-drivability, and necessary transparency. Owing to these advantages, SEAs are employed to achieve safe and efficient human-robot physical interaction, such as wearable robotics and prosthetics. However, because its inherent transmission ratio (TR) cannot be changed, the energy consumed by SEAs tends to be large to realize high torque output. Therefore, it is not easy to achieve force capability while maintaining a limited size. To overcome this deficiency, in this study, we developed a novel SEA with variable torque-speed characteristics (VTSEA) based on reconfigurable epicyclic-driven actuation (REDA) to significantly save electrical energy and optimize the mechanical clutch of VTSEA to obtain a compact size and a large holding force. The experimental results show that the energy consumed by the proposed VTSEA is significantly reduced by over 40% compared with that of the conventional SEA.

Heterosis had been increasingly applied in crop production for nearly a century, but the molecular basis of it was poorly understood especially in foxtail millet (Setaria italica). Zhangzagu10 which derived from two-line hybrid breeding system has the characters of ultra-high yield, good stability and extensive disease and lodging resistance. To gain a better understanding of the molecular basis of S.italicaheterosis, the isobaric tags for relative and absolute quantification based quantitative proteomic analyses was performed between S.italicahybrid Zhangzagu10 and it parents (male parent Zhangzagu10fu and female parent A2). A total of 4015 proteins were detected, among which 610/276 differentially expressed proteins (DEPs) between Zhangzagu10 and the female/male parent, respectively. The cluster analysis showed that the DEPs expression profiles of Zhangzagu10 were closer to those of the male parent. GO functional classification divided the DEPs into three functional categories (Cellular component, Biological process and Molecular function) and 26 subfamilies, among which three subfamilies had 100% difference between Zhangzagu10 and its parents. KEGG metabolic pathway exhibited significant enrichment of DEPs in Metabolic pathways, Carbon fixation in photosynthetic organisms and Photosynthesis. qRT-PCR verification confirmed the differential expression data and revealed that the expression level of 3 selected genes (such as peroxidase 5-like,G-type lectin S-receptor-like serine/threonine-protein kinase SD2-5,two-on-two hemoglobin-3, etc.) was higher in Zhangzagu10 than that in its male parent. The expression level of 7 selected genes (such as peroxidase 64-like, cysteine-rich receptor-like protein kinase 45, indole-3-acetaldehyde oxidase, etc.) was higher in Zhangzagu10 than that in its male parent, but significantly lower than that in A2. Thus, A2 can potentially optimise the agricultural qualities of Zhangzagu10. Taken together, we hope that this study provides valuable information for the further utilisation and study on the molecular mechanisms of heterosis in hybrid millet.

A multimotor system supplied from the reduced-switch-count voltage source inverter (VSI) is considered in this article. First, an improved multiple vectors model predictive control (MV-MPC) scheme is proposed for driving n three-phase permanent magnet synchronous motors (PMSMs) by (2n + 1)-leg VSI. To realize independent control of multimotor, a control period is partitioned into multi-interval, one per motor. In the proposed MV-MPC scheme, the quasi-optimal voltage vectors (VVs) are selected to replace zero VVs under the restriction of identical common leg switching states. Thus, a whole control period can be fully utilized to generate multiple active VVs for a motor. Moreover, the overcurrent in the common leg is discussed and addressed. Take the five-leg VSI as an example, the expression of overcurrent in the common leg is first derived. Next, a general overcurrent elimination method based on current phase regulation is designed for the multimotor system operating at an identical speed. Finally, the proposed MV-MPC scheme combined with the overcurrent elimination strategy is experimentally carried out. The test results indicate that the MV-MPC method can effectively reduce current ripple and achieve a faster dynamic response. The overcurrent elimination method can minimize the overcurrent regardless of the load conditions of the motors.