Gulzuhra Turymbetova

This paper addresses the problem of improving the efficiency of the traction electric drive of an agricultural electric vehicle operating under variable load conditions typical of agricultural transportation. The study substantiates the feasibility of employing a low-power (2 kW) induction motor as a cost-effective, technically robust, and reliable solution for mobile power systems. Particular attention is given to the operating characteristics of the traction drive under fluctuating loading conditions, which significantly affect the energy efficiency and overall performance of agricultural electric vehicles. A comprehensive structural and mathematical model of the induction motor was developed based on a proprietary implementation without the use of standard MATLAB R2020b/Simulink library blocks. The model was formulated using the transformation of a three-phase coordinate system into a two-phase stationary α–β reference frame, enabling a more accurate representation of the electromagnetic and electromechanical processes occurring within the machine. The analysis was carried out with consideration of transient processes, dynamic characteristics, and energy performance under realistic conditions regarding the influence of control strategies on the energy consumption of the electric drive system. The results of this can be applied to the design and optimization of electric transportation systems for agricultural applications, as well as to the development of energy-efficient control algorithms for traction electric motors.

The paper presents a comprehensive experimental and modelling study of the effect of a pulsed high- voltage electric field on agricultural crop pests in greenhouse conditions, using strawberries as an example. An experimental setup based on a high-frequency, high-voltage transformer (HVT, 6 kV) enables the formation of a quasi- stationary electric field with adjustable voltage and current parameters. A series of field experiments was conducted at voltages up to 6 kV with a fixed exposure time of 5 minutes, during which a pronounced nonlinear, threshold dependence of pest control efficiency on the level of electrical exposure was observed. To interpret the results, an equivalent RC model of the biological object was combined with numerical modelling of the electric field distribution via the finite element method. The modelling showed that, under the conditions studied, the temperature increase of the biological object does not exceed a fraction of a degree, thereby excluding a thermal mechanism of action. It was established that the observed biological effect is due to electrically induced processes associated with the local electric-field concentration and the polarisation of membrane structures. The results confirm the promise of using pulsed high-voltage electric fields as an environmentally safe alternative to chemical methods of plant protection and create the conditions for optimising the parameters of electrical exposure in greenhouse technologies.

В статье предлагается модель, предназначенная для описания нестационарных термоэлектрических процессов, возникающих в литий-ионном элементе в режимах заряда и разряда. Модель сформулирована в виде нелинейных частично дифференциальных уравнений, отражающих пространственно-временное распределение концентрации ионов лития, электрических потенциалов и температурного поля в электродных материалах и электролите. Особый акцент сделан на учёте взаимно обусловленного характера процессов переноса заряда, массы и тепла, а также нелинейной электрохимической кинетики, реализуемой реализуемой на межфазных границах. Разработанный математический подход позволяет проанализировать взаимное влияние сопряжённых электротермических полей на эффективность протекания электрохимических реакций и формирует теоретическую основу для оптимизации конструкции литий-ионных элементов с целью повышения их энергетической эффективности и термической стабильности.