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Interior permanent magnet synchronous motors (IPMSMs) have high power densities and speed control performance, and they are widely used in the industry. The problem of reducing the torque ripple of an IPMSM is one of the hot issues in the field of electrical machine design. In order to determine the optimal combination of the geometric parameters to reduce the torque ripple of an IPMSM, a range analysis was conducted on the data from the orthogonal experiments in this study, dividing the rotor geometric parameters into two categories (important and ordinary) based on their degree of impact on the torque ripples of the IPMSM. Thereafter, an optimization of the ordinary parameters was carried out based on the results of the range analysis, whereas the optimization of the important parameters was carried out through a method that combined a multi-island genetic algorithm (MIGA) and Radial Basis Function (RBF) neural networks. The torque ripple of the IPMSM was effectively reduced without materially affecting the output power. Finally, the results of this optimization process were verified using a finite element simulation. The optimization method used in this study divided the motor geometric parameters into two categories and applied a different method of optimization to each parameter type, so it was able to efficiently optimize multiple geometric parameters for the IPMSM.

Surface-mounted permanent magnet synchronous motors (SMPMSM) with high power density and good speed regulation are widely used in industrial applications. In order to further improve its power density, this paper studied the relationship between the thickness of the stator yoke, the thickness of the rotor yoke, the relative magnet span of the motor and the motor power density using the finite element simulation method. On this basis, a response surface model between the three parameters and the power density of the motor was established. Based on this model and a differential evolution algorithm, the motor was optimized and the power density was improve, finally, the optimization results were verified using the finite element simulation method. In addition, the optimization results showed that, when other structure parameters remain unchanged, there is an optimal combination of parameters that can maximize the motor&rsquo, s power density, including the thickness of the stator yoke, the thickness of the rotor yoke and relative magnet span of the motor.

This paper deals with the problem of controller design based on Box-Jenkins model to achieve both regulating and tracking control. The greatest challenge of this problem lies in embedding the complicated noise term of the Box-Jenkins model into the control law. To solve this problem, this paper establishes a novel control method complemented by the generalized minimum variant control criterion, and introduces an ingenious design of Diophantine equation to deal with the complicated noise term. In addition, this control methodology can be applied to non-minimum-phase system and allows arbitrary pole placement that enables the designer to achieve the desired dynamic response. Also, the corresponding computation algorithm is designed to determine the polynomials in the controller. Finally, an application on gas flow control system is introduced to demonstrate the correctness and effectiveness of this control method.

The wave-shaped metal sealing ring is widely used in the aerospace field, whose failure will directly affect the flight safety and even cause major personal accidents and economic losses. The performance optimization problem of the wave-shaped seal is a multi-objective optimization problem, and the multiple targets are affected by the geometric design factors, and are not completely independent of each other. In this paper, for the sealing problem under the severe conditions of aero-engine, the corrugated metal sealing ring is taken as the research object. The W-shaped metal sealing ring is selected as an example, and the finite element model is established by using ANSYS software. Sealing, stability and resilience are chosen as indicators to evaluate the sealing performance. The multi-objective optimization problem is transformed into a single-objective optimization problem by hierarchical solution method, and the sealing structure is parameterized. The optimization results of the geometric parameters of the sealing ring are highly consistent with the product manual of the sealing ring. The correctness and feasibility of the optimization design method based on the analysis of three aspects of performance and the hierarchical solution for dimension reduction are verified.

The application of high power density motors is increasingly widespread, but the motor power density has been limited by the thermal load and the performance of the electromagnetic material. In order to reduce the thermal load of the motor, the relationship between the size of the motor Hs0 and Bs0 and the core loss of the motor is studied in this paper. It is found that the decrease of Hs0 and the increase of Hs0 can reduce the core loss of the motor. Meanwhile, with the increase of Bs0, the output torque of the motor increases first and then decreases. As the Hs0 increases, the output torque of the motor increases gradually. According to the above conclusions, the size of the notch of a high power density permanent magnet synchronous motor is optimized, and the core loss of the motor is reduced without affecting the output torque of the motor.

As a basic mechanical component, the sealing ring is widely used in industrial, aerospatial, and other fields. In this study, an elastic metal C-shaped sealing ring with a wave structure was taken as an example, and its performance was analyzed theoretically and measured experimentally. First, an experimental study was performed on the C-ring seal. The proposed method for experimental measurement of the contact stress of the C-ring seal involved innovative use of a universal electronic testing machine and pressure sensitive paper, in conjunction with the hue&ndash, saturation&ndash, brightness (HSB) method. Based on the discoloration of the pressure sensitive paper after contact stress, computer software was used for analysis, the discoloration was digitized, and the contact stress was established. Second, a theoretical calculation model of the C-ring seal was established using ANSYS software, and a finite element theoretical calculation of the mechanical properties of the sealing ring was established. Finally, the contact stress results were compared with the model calculation results of the C-ring seal. The error between the two was small (4.8%), which proved the validity of the calculation model and the scientificity of the experimental method.

A two-dimensional axisymmetric finite element model of metal multi-convolution ring was established by using FEM analysis software ANSYS. Influence on mechanical properties and sealing performance in working condition resulted from changes of structure parameters such as the thickness, wave height, crest radius, trough radius were analyzed by orthogonal design, put forward some suggestions for the structural parameters design of metallic multi-convolution ring by taking manufacturing condition and actual demand into consideration.