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The article presents a case-study of mathematical modeling of electromagnetic and electromechanical processes in a downhole vibration exciter EM drive. The authors propose the mathematical model of EM drive on the basis of a double-acting EM machine. This model maintains a wide-range analysis of transient and quasi-stable operating regimes. The algorithm and implementation of the model using the structural modeling methods and means in the Matlab Simulink environment are described. The model verification is carried out by means of comparison of the simulation and physical models of EM drive within the configuration of downhole pulse vibration exciter. The appropriateness of the model is proved. The authors give recommendations on further improvement of the model and its accuracy in calculation of dynamic behavior of drives.

Under consideration is feasibility of voltage stabilization in permanent-magnet synchronous generator with variable frequency in self-contained systems of power supply. The method of stabilization is based on varying speed of rotation of generator shaft. The authors have derived analytical expression for regulating characteristics and determined required ranges for rotational frequency variation at preset parameters of generator and loading. The symmetry conditions are found for a regulating characteristic relative to rotational speed change.

The paper proposes the analysis of three design and control scenarios for the system intendeded to generate the variable-frequency and constant-voltage electric energy on the basis of a synchronous generator and a paralleled semiconductor converter. The research scientists demonstrate the stabilization of the synchronous generator voltage, evaluation of basic electrical parameters, and the relationship between them and operation modes of the system.

The processes in the system composed of a continuous magnet synchronous generator and a three-phase bridge back emf rectifier are under analysis in this article. Such systems are usable in self-contained facilities to charge accumulation cells in mines and open pits. The authors determine possible regimes of the systems under varying rate speeds of synchronous generator shaft and altered commutation delay angles of the controlled rectifier, derive analytical expressions for determining parameters of the analyzed system, and find generated power limit.

It is suggested to replace the double-winding transformer of the excitation system of a synchronous machine with a valve-side winding rated for the total forcing voltage and rated current by a three-winding transformer with two valve-side windings, i.e., working and forcing. In the proposed transformer, each of the windings is connected to its own converter bridge circuit and the voltages are summed up during field forcing, which allows the power of the rectifying transformer to be decreased, the shapes of the current and voltage curves at the converter inlet and outlet to be improved, transformer losses and voltage crests on the rotor, and inverse voltages on the thyristors to be reduced, etc.

In the mining and building industries it is necessary to use powerful electromagnetic percussive machines with impact energies of over i000 J, which have several advantages over similar pneumatic and hydraulic percussive machines. In order to preserve the maximum possible productivity of the machine, it is necessary to choose a control law with optimum rapidity of action for each value of the impact energy. In this article we will consider the design of regulators with optimally rapid action for electromagnetic percussive machines [i] consisting, for example, of a yoke 5 with poles i, 4, 6, 8, idling stroke coil 7 and working stroke coil 3, and armature 2 (Fig. i).