SYNCHRONOUS MOTOR OPERATION ANALYSIS UNDER SHOCK LOADING

At present, in order to re-equip the domestic industry there is a need to carry out automation of production on the basis of wide introduction of modern AC electric drive. Along with asynchronous electric motors, which traditionally form the basis of this electric drive, synchronous motors are increasingly being used in it. The issues that require development include those related to the evaluation of the behavior of synchronous motors (SM) in transient operating modes. Frequent starts, speed control, load fluctuations on the shaft are normal conditions of operation of synchronous motors. These questions represent a difficult problem even for three-phase synchronous machines, with which the development of the classical theory began. The complexity of the problem increases when the operation of synchronous machines from a single-phase network is studied. Until very recently, most of the studies of transients in synchronous motors operating from a single-phase network were carried out either using simplified methods of analysis (e.g., the method of symmetrical components) or experimentally on mock-up samples. Incompleteness of research on the theory of stability and transients of synchronous motors was one of the obstacles that hindered the expansion of their production for automation and robotization of technological processes in industry. Therefore, it is expedient to develop methods for analyzing the stability of synchronous motors operating from both three-phase and single-phase networks, to study transients in asynchronous and quasi-synchronous modes of operation. On this basis, to create methods, perform calculations and analyze the influence of parameters on the operation of the studied SM. When performing the work should be used methods of mathematical modeling of electromechanical objects; methods of numerical integration of nonlinear systems of differential equations; methods of assessing the stability of objects; analytical and experimental studies. The main challenges in doing so are summarized as follows: 1. Creation of mathematical models of the main types of three-phase synchronous machines, allowing to determine the boundaries of the areas of stable operation in the parameter planes of the considered machines. 2. On the basis of numerical integration of systems of nonlinear differential equations to establish the character of the behavior of the studied synchronous machines near the boundary of stable operation. To show a smooth deterioration of damping properties as the operating point describing the behavior of synchronous motors in the parameter plane approaches the stability boundary. 3. To clarify and formulate the concept of the boundary of stable operation (self-oscillation) of a synchronous machine, to consider the properties possessed by a synchronous machine that is directly on the boundary of stable operation. 4. Determine the conditions of the most favorable start-up under load of synchronous motors with electromagnetic excitation. 5. To develop a universal method that allows to calculate the static mechanical characteristics of three-phase and single-phase synchronous motors in the asynchronous start mode. 6. To create a method of calculation of angular characteristics of single-phase synchronous motors, allowing to consider asynchronous and steady-state modes of their operation from the general positions of the theory of synchronous machine. Keywords: synchronous motor, transient modes, angle fluctuations, excitation control, load shedding, infinite power, load graph, resonance phenomena.