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Abstract In order to control urban dust pollution and to improve the utilization of agricultural and forestry straw solid waste, this paper prepared an environmentally friendly dust suppressant with plant straw using nine different types of waste straw as raw materials with environmentally friendly additives. By the single factor experiment, the composition of each component reagent and the effect of mass concentration on its properties under single factor were determined. Multi-factor interaction tests were designed by response surface method. Three independent variables including wheat straw based superabsorbent polymers (SAP), hydroxyethyl cellulose (HEC10S) and octyl glucopyranoside (APG0810) were selected. Viscosity (Y1), anti-evaporation rate (Y2) and surface tension (Y3) were determined as response values. Meanwhile, the functional relationship between the fitting factors and the response values is established by regression analysis. The results showed that the predicted values are in good agreement with the experimental values. The plant straw-based dust suppressant with 1.93% SAP, 0.10% HEC10S and 0.80% APG0810 exhibited good bonding performance, wettability and anti-evaporation rate.

In recent years, the hairpin winding flat wire motor has received more and more attention because of its high power density and high torque, but the problem of increased AC copper loss caused by the increase of its wire diameter has restricted the use of the motor. Aiming at the problem of large AC copper loss in hairpin winding flat wire motors, this paper introduces the use of formed transposition windings into permanent magnet synchronous motors. Through analysis and comparison, the transposition bar suitable for permanent magnet synchronous motor is determined, and a method of inter-turn transposition that can improve the slot full rate of the motor is proposed. Taking a 223kW permanent magnet synchronous motor as an example, the transient field of the stator bar under 360° transposition was calculated by using the field-circuit combined three-dimensional(3-D) finite element method. By calculating the data, combined with the AC copper loss calculation method of the formed transposition winding given in the article, the distribution of the DC copper loss, eddy current copper loss and circulating copper loss of the motor is obtained. Compared with hairpin windings, the use of formed transposition windings can reduce the AC copper loss of the motor to a certain extent, the feasibility of using the formed transposition winding in the permanent magnet synchronous motor is verified.

Permanent magnet synchronous motors with the formed winding can not only improve the slot fill factor and heat dissipation capacity but also effectively reduce the additional loss in the winding. Formed winding permanent magnet synchronous motors will become the future development tendency. Due to inherent features of the formed winding, the circulating current loss is a non-negligible issue. This paper proposes using the formed winding in permanent magnet synchronous motors and analyzes the circulating current loss in the formed winding. First, the finite element models of integer slot and fractional slot motors are established, and the magnetic field analysis are carried out. Then two commonly used methods of calculating circulating current loss are introduced in detail, and their calculation results are compared. Moreover, the high-precision field-circuit coupled finite element method is used to calculate the circulating current loss of integer and fractional motors. And circulating currents of the hairpin winding and the formed winding are compared. The analysis indicates that the circulating current in the formed winding cannot be ignored. Finally, comprehensive and in-depth research on the influencing factors of circulating current loss in the formed winding has been conducted. The results clarify that the number of parallel strands, the width of the slot opening, and the stator current have a considerable influence on the circulating current loss.