Making electrical driving systems cheaper, lighter, and more reliable is the consistent pursuit of current research and development. Mono-Inverter Multi-Permanent Magnet Synchronous Motor systems tend to share the static converters in electro-mechanical systems by connecting machines in parallel. This type of system has an obvious advantage in overall weight and cost. In this paper, we have proposed a new Maximum Torque Per Ampere (MTPA) control strategy for a MIMPMSM system, which supports three or more machines in parallel and works both in motor mode and brake mode. The calculation of the MTPA point minimizing the overall joule loss of the system is also given. The synchronization condition, stability, and optimal efficiency of the system are strictly proven. This new control structure is simple making current single PMSM systems easy to upgrade to support the MIMPMSM system. The experiment has demonstrated its feasibility, stability, and improvements in efficiency.

Current research and development programs in aviation are promoting new technological advances to make electrical systems cheaper, lighter and more reliable. Mono-Inverter Dual-Permanent Magnet Synchronous Motor (MIDPMSM) systems tend to share the static converters in electro-mechanical systems by connecting motors in parallel. However several studies have shown that the efficiency of this configuration is lower than those with a traditional Mono-Inverter Mono-PMSM configuration, especially when unequal load torques are applied. In this paper, we propose an efficiency-optimized control method for MIDPMSM systems which has been designed using rigorous, mathematical calculations. The determinacy, stability, and optimal efficiency of the system, which are essential in an aviation application, are explained in detail. This new control structure is simple making current single PMSM systems easy to upgrade to support the MIDPMSM system. The experiment has demonstrated not only feasibility but also significant improvements in performance.

Although Unmanned Aerial Vehicles (UAVs)-aided wireless sensor networks (WSNs) have gained many applications, it is not for long that research works have been produced to define effective algorithms and protocols. In this article, we address the UAV-enabled WSN (U-WSN), explore the performance and the capability of the UAV, define the UAV functionalities as a communication node, and describe the architectures and the relevant typical technologies that emerge from this new paradigm. Furthermore, this article also identifies the main factors which influence the U-WSN design and analyzes the open issues and challenges in U-WSN. These insights may serve as motivations and guidelines for future designs of UAV-enabled WSNs.

In this work, we study data collection in multiple unmanned aerial vehicle (UAV)-aided mobile wireless sensor networks (WSNs). The network topology is changing due to the mobility of the UAVs and the sensor nodes, so the design of efficient data collection protocols is a major concern. We address such high dynamic network and propose two mechanisms: prioritized-based contact-duration frame selection mechanism (PCdFS), and prioritized-based multiple contact-duration frame selection mechanisms (PMCdFS) to build collision-free scheduling and balance the nodes between the multi-UAV respectively. Based on the two mechanisms, we proposed a Balance algorithm to conduct the collision-free communication between the mobile nodes and the multi-UAVs. Two key design ideas for a Balance algorithm are: (a) no need of higher priority for those nodes that have lower transmission rate between them and the UAV and (b) improve the communication opportunity for those nodes that have shorter contact duration with the UAVs. We demonstrate the performance of proposed algorithms through extensive simulations, and real experiments. These experiments using 15 mobile nodes at a path with 10 intersections and 1 island, present that network fairness is efficiently enhanced. We also confirm the applicability of proposed algorithms in a challenging and realistic scenario through numerous experiments on a path at Tongji campus in Shanghai, China.

Connecting permanent magnet synchronous machines (PMSMs) in parallel to a two-level three-leg inverter is a simple but effective way to reduce the required components in a multimachine system. The parallel PMSM system is an affine nonlinear system with external disturbances; therefore, designing a robust controller for it is a challenging issue, especially when machine parameters are not the same. In this article, to deal with the nonlinearity of the system, a Takagi–Sugeno (T–S) fuzzy model is constructed for it first. Then, a nonlinear feedforward controller is introduced to increase the speed tracking performance of the system as well as reduce the complexity of the constructed T–S fuzzy model. To cope with the external disturbances, guaranteed cost control (GCC) techniques and the H _∞ stability analysis method are combined to achieve zero-error speed tracking and external load rejection. In this way, the optimization of GCC is derived, and an H _∞ stability criterion is analyzed based on the T–S fuzzy model instead of the original system. Finally, the feasibility and the performance of the proposed method are tested through an experiment. The experiment results also demonstrated that, compared with the traditional strategy, the proposed method can make the parallel PMSM system consisting of different machines free of unstable risk.