Wind energy generated from the wake of moving cars has a large energy potential that has not yet been utilized. In this study, a vertical axis wind turbine (VAWT) was used to recover energy from the wakes of moving cars. The turbine was designed to be planted by the side of the car lane and driven by the wake produced by the car. Transient computational fluid dynamics (CFD) simulations were performed to evaluate the performance of the VAWT. The influence of two main factors on the performance of the VAWT, the velocity of the car and the gap between the car and the rotor, were studied. The simulations confirmed the feasibility of this plan, and in the tested cases, the VAWT was able to generate a maximum energy output of 100.49 J from the wake of a car. The results also showed that the performance of the VAWT decreased with the velocity of the car, and the increased gap between the car and the VAWT.

A rim driven thruster (RDT) is an integrated deep-sea motor thruster that has been widely studied. In order to improve the performance of RDT, a novel RDT motor with a modular stator is proposed in this paper. The electromagnetic performance of the new RDT motor is analyzed by the finite element method (FEM). The influence of structure parameters on the electromagnetic performance of the new RDT motor are analyzed in detail. It is shown that the effect of additional tooth width and pole arc coefficient on the electromagnetic performance of the stator modular RDT motor is significant. To obtain the optimal design with a maximum average electromagnetic torque and minimum torque fluctuation ratio, a multi-objective optimization design method combining the non-dominated sorting genetic algorithm II (NSGA-II), Kriging method and FEM is presented in this paper. A set of Pareto optimal solutions is obtained, and the optimal design point is selected from the Pareto fronts. Compared with the initial design, the average electromagnetic torque of the optimized model is improved by 16.591% and the fluctuation ratio is reduced to 3.18%.

Permanent magnet couplings (PMCs) are widely used in underwater propulsion because it can solve the deep-sea sealing problem effectively. In this paper, a new type of conical permanent magnet coupling (CPMC) is proposed, which is able to match the tail shape of the underwater vehicle and make full use of the tail space to increase pull-out torque capability. Based on the three-dimensional finite element method (3D-FEM), the electromagnetic characteristics of an initial model for CPMC are analyzed. In order to facilitate the design and optimization of CPMC, an equivalent three-dimensional (3D) analytical method for the pull-out torque calculation is presented, and its accuracy is verified by comparison with the 3D finite element results. Finally, the influence of design parameters such as half-cone angle, pole pair, pole arc coefficient and permanent magnet thickness on maximum pull-out torque and torque density of CPMC is analyzed, and a preliminary optimization model is obtained.

How to reduce the cogging torque of the integrated propeller motor is an important means to improve its noise performance because cogging torque is one of the key factors causing torque ripple. We proposed a method to reduce the cogging torque by optimizing the size of the Halbach array’s auxiliary pole. First, an analytical model for the airgap magnetic field of Halbach array based on different dimensions (including the circumference ratio and the radial thickness) of the auxiliary pole is given. Then the finite element method is used to verify the analytical model. On the basis, we calculated the cogging torque of different size of auxiliary poles as sample data by combining different circumference ratio and radial thickness. Furthermore, using the two-variable single-objective neural network genetic optimization algorithm based on Backpropagation (BP), we obtain the optimal size of the auxiliary pole. Finally, comparing the motor cogging torque and torque ripple before and after optimization indicated that the cogging torque and torque ripple are effectively reduced after optimizing the size of the auxiliary pole.

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.

Integrated motor propulsor (IMP) is an open-type underwater propulsion device, which has no watertight problem and combines the advantages of permanent magnet motor and pod propeller. In this paper, a novel design of IMP named stator modular integrated motor propulsor (SM-IMP) was introduced. The motor part adopts a modular permanent magnet (MPM) motor with additional tooth structure. Both 18-slot/20-pole and 24-slot/20-pole MPM motors were investigated and compared with traditional permanent magnet motor for IMP. The effects of the additional tooth on the back-EMF, air gap flux density and cogging torque of MPM motors were calculated by using the electromagnetic field analysis software. The results show that the SM-IMP proposed in this paper simplifies the machining process and substantially eliminates the cogging torque, which is beneficial to improve the performance of IMP.