The purpose of this article is to optimize a VR machine for traction electric drives in agriculture, as well as to identify its advantages and disadvantages, to compare an electric drive based on a test machine with an asynchronous electric drive of the same size. The optimal ratio of the elements of the magnetic system of the electromechanical converter based on the VR machine. It is shown that the overload capacity of an electric drive with a VR machine is about 25%. The specific electromagnetic moment of the studied machine is 30% higher than the corresponding indicator of an asynchronous machine of the same size in the nominal operating mode. The disadvantage of this machine is its low power factor, only 7%. This is due to the small ratio of conductivities along the longitudinal and transverse axes of the machine due to the large number of stator and rotor teeth. The problem is solved by introducing additional DC or AC windings on the stator. It is shown that a change in the air gap significantly affects the specific moment. Only by reducing by 2 times the air gap managed to increase the moment by 48%.

The article provides a comparative analysis of the most common electric drive control systems: scalar control, vector control and direct torque control DTC. The analysis is carried out according to the criteria for the performance of the torque loop, the robustness of the systems, the level of torque ripple and overshoot in the torque loop. Comparison is made by subjectively assigning points for each of the criteria based on a qualitative assessment. The simplified mathematical models are used for analysis, that taking into account the pulsating moment pulsations. In conclusion, it is concluded that it is advisable to use one or another control system for electrical equipment in various fields of agricultural use.

The article describes the experimental studies of traction drive generators. The surveyed traction drive generators are made in accordance with the requirements of current regulatory documents (state standards and industry specifications). The actual life of the traction drive generators and all its main examined units, elements are significantly higher than the average service life. All the equipment under examination, to one degree or another, has signs of a decrease in resource, which is confirmed by deviations of the technical condition identified during the scheduled repairs and during the inspection. In most cases, deviations of the technical condition can be eliminated without consequences (localized) in scheduled repairs. During the examination, special attention was paid to deviations of the technical condition, which affect the service life, reliability, and also the duration of the overhaul period. Assessment of the technical condition of the components of a traction drive generators. Based on the results of the survey, the following conclusions can be drawn on the state of the main basic components of the tour generator, which determine the reliability of its operation.

In the article schemes of power circuits of a feed of synchronous reluctance machines are considered. The features of the choice of the most rational scheme by the criterion of improved weight and size parameters are shown. It is shown that the specific parameters of electric drives have values that exceed similar synchronous electric drives by approximately 20%. Improvement of specific parameters in the agriculture electric drive can be achieved not only due to the complexity of the electric machine construction, but also due to the choice of optimal schemes of power circuits. So, in agriculture electric drives with individual sources with rectangular current form, the values of overloads corresponding to electric drives with complex (compound) rotor design.

The article presents ways to improve reliability of agricultural semiconductor frequency converters. It is shown that an increase in reliability of semiconductor converters can be achieved increasing the power reserve. At the same time, if the economic indicator is chosen as an optimization criterion, the coefficient of failure-free operation reaches no more than 0.8. In the event that resulting coefficient of failure-free operation is allowed according to operating conditions, selected criterion can be successfully applied at design stage of semiconductor converters.