This work focuses on the possibility of using a tuned inductor in electric power systems with adaptive features. The presented idea of inductor operation, using an interaction of the magnetic fluxes, is a new approach to designing such devices. Examples of power adaptive systems are devices for improving the quality of electricity. Therefore, various types of ‘compensators’ of reactive power (or both reactive and distortion power) are used in electrical systems as a preventive measure. The tuned inductor, presented in this work, offers wider possibilities for power compensation in electric systems, compared to the classic solutions of compensators based on fixed inductors. Another possible implementation of such an inductor solution is in static power electronic devices, installed in AC transmission grids to increase power transfer capability, stability, and controllability, through a series and/or shunt compensation. Nevertheless, the use of the proposed device in the aforementioned electric systems is only one example of the possible implementations in the power electronics area. In this work, the following issues are presented: exemplary solutions of compensators with the adaptive features, rules of the tuned inductor operation, test results of the 3D field model of the inductor, and test results of the laboratory model of the electric system with this device.

In the paper, the concept of a permanent magnet synchronous generator (PMSG) with uniquely designed stator windings for wind turbines is presented. Two 3-phase windings in the stator are used, one of which is connected in the star, while the other in the delta configuration. Six-pulse rectifiers, mutually coupled by the pulse transformer, whose primary winding is supplied by the so-called “current modulator”, are placed at the outputs of both windings. The modulator output current should meet all the necessary and strict requirements. Both rectifiers operate on a common DC circuit. These solutions provide the sinusoidal magnetomotive force in the stator of the PMSG and the quasi-sinusoidal (taking into account the non-linearity of the magnetic circuit) magnetic flux. In light of the generator principle, it has been called the “PMSG with modulated the magnetic flux”. The slightly higher complexity in the structure of the generator, as compared to the normal three-phase construction, is compensated by the exceptional simplicity of the power electronics section of the system, which allows high efficiency to be reached. The current modulator (as well as the pulse transformer) is a power electronics converter with a relatively low output power as compared to the overall output power of the system. In comparison to other known solutions, the expected cost of the system should be lower. It is also expected that a high degree of reliability in terms of its operation will be achieved, and consequently, that the the ongoing costs of its maintenance will be reduced. In the paper, concept, theoretical basis of operation, and results of the studies of the simulation models of the generator, including the basic power electronics section, are presented.

The paper is the second part of the work, devoted to a DC power supply with a power factor correction function. The power supply is equipped additionally with a shunt active power filter function, which enables the compensation of reactive and distortion power, generated by loads, connected to the same power grid node. A tunable inductive filter, included at the input of the power electronics current source – the main block of the power supply – allows for an improvement of the quality of the system control, compared to the device with a fixed inductive filter. This improvement was possible by extending the current source “frequency response”, which facilitated increasing the dynamics of current changes at the power supply input. The second part of the work briefly reminds the reader of the principle of operation and the structures of both the power supply control system and its power stage. The main purpose of this paper is to present the selected test results of the laboratory model of the electric system with the power supply.

This work focuses on the use of a one-phase direct current (DC) power supply equipped with a shunt active filter feature, which enabled the possibility of compensation (minimisation) of reactive and distortion power, generated by a group of loads, that was connected to the same power grid node as the power supply. A tuned inductor, which was included at the input of the controlled current source (constituting the main part of the power supply) allowed for an improvement in the quality of the compensation process, compared to a device with a fixed inductive filter This resulted in a visible reduction of the nonlinear distortions of the grid current. The improvement was made possible by extending the frequency response of the current source, which allowed to increase the dynamics of the current changes at the input of the power supply. This solution represents a new approach to such power devices. This work describes the principle of operation of the proposed converter solution and presents selected test results for a laboratory model of an electric system with this device.

This work focuses on the concept of operation and possibility of using a tuned inductor in electrical power systems with adaptive features. The idea presented here for the operation of the inductor is a new approach to the design of such devices. An example of a power adaptive system is a device for improving the quality of electricity. The negative impact of nonlinear loads on the operation of a power grid is a well-documented phenomenon. Hence, various types of “compensators” for reactive power, or for both reactive and distortion power, are used in electrical systems as a preventive measure. The concept of an inductor presented here offers wider possibilities for power compensation in power supply systems, compared to traditional solutions involving compensators based on fixed inductors. The use of the proposed solution in an adaptive compensator is only one example of its possible implementation in the area of power devices. In this work, we discuss the structure of the compensator, the basic aspects of the operation of the inductor, the results of simulation studies and the results of measurements obtained from a prototype.

Calculating the values of the parameters of distorted periodic signals in real-time is important for the control of many processes. In particular, this information is necessary for the proper operation of power electronics devices that cooperate with the power grid. In such cases, it is necessary to determine the phase, frequency, and amplitude of the fundamental component of the voltage in the power grid node. Also, in many cases, the control process needs a signal which is synchronised with the power grid voltage. Both processes should be realised in real-time. A number of solutions to the problem of calculating the values of the voltage parameters have been described in the literature. However, these methods generally introduce significant time delays and have several restrictions regarding the variability in the values of these parameters. They also often require the significant computational power of a unit that performs the task of identification. The algorithm presented in this work is based on the properties of a pair of orthogonal signals, generated by a two-dimensional finite impulse response filter, which has a certain transfer function resulting from the needs of the algorithm, what is the innovation of the algorithm. These signals are then used in the program module, which both, calculates, in the time domain, the instantaneous values of the frequency and the amplitude of the fundamental component of the power grid voltage, and generates a signal, being in-phase with this component. The presented algorithm is fast, accurate, and relatively simple; therefore, it does not require a high computational power processor. This algorithm was experimentally verified by implementation in microcomputer-based units, which were then applied in the control systems of the power electronic devices, as well as in analysers of the energy quality.