Transistor Converter Research Articles

Control Modes of Charger Based on a Half-Bridge Transistor Converter with Dosage Capacitors

Control Modes of Charger Based on a Half-Bridge Transistor Converter with Dosage Capacitors

Выявление перспективных способов преобразования параметров электрической энергии

This paper performs an analysis of the electric power conversion methods, and also examines the development trends of DC-to-DC, AC-to-AC, AC-to-DC and DC-to-AC power converters with the use of the International Patent Classification (2023). A comparison has been made of such different kinds of converters as power converters with intermediate conversion and without intermediate conversion into AC or DC, converters using devices of a transistor and thyristor type, and specific circuit implements corresponding to the IPC classification. Perspective directions of such converters’ development have been revealed. The analysis was carried out on the basis of the US patents databases which were formed by the authors for the IPC groups H02M3, H02M5, H02M7 within 2012 to 2023. The perspective directions were revealed by constructing time series of the US patents for the analyzed power converters and their further comparison by the issued patents number and growth patterns. As a result of research, the advantage of transistor converters circuits has been proved, the perspective development directions of the electric power parameters conversion methods as well as their implementation have been described. There was found a decrease of the issued US invention patents in the considered IPC groups by 40% within 2019 to 2022.

Повышение эффективности электропривода электровоза с управляемым преобразователем возбуждения тяговых двигателей

Purpose: To substantiate the circuit design and algorithms for individual smooth and automatic control of single-phase direct current electric locomotives according to the laws of constant traction force and constant power without breaking the electric locomotive power circuits in order to increase the efficiency of its electric drive with controllable traction motor excitation converters. As a circuit design solution, it is proposed to apply a power electrical circuit with two rectifier-inverter converters for each section of the electric locomotive for bogie-based traction control, as well as individually controlled bridge transistor converters, shunting field windings, for axial traction control within each bogie. Methods: The development of circuit solutions using modern power semiconductor converters; theory of automatic control and design of finite state machines; mathematical modeling of electromagnetic, electromechanical and mechanical processes. Results: The developed control algorithms provide the possibility of obtaining traction characteristics of an electric locomotive that vary according to the laws of constancy of traction force or constancy of power, bringing the traction characteristics of electric locomotives with collector traction motors to the characteristics of electric locomotives with asynchronous traction motors. The calculations performed confirmed the possibility of implementing an algorithm for individual control of traction motor currents and their excitation currents, as well as traction forces, which ensures a smooth increase in the traction force of an electric locomotive.Practical significance: The developed technical solutions applicable in the manufacture of modern and modernization of operated electric locomotives will ensure an increase in the traction properties of singlephase DC electric locomotives and will contribute to an increase in the throughput and carrying capacity of the railway network.

Моделирование режима электрического торможения тепловоза с последовательным возбуждением коллекторных тяговых двигателей при использовании силового полупроводникового преобразователя

Purpose: To consider the structure, advantages and operating principle of a new transistor converter based on isolated gate bipolar transistors (IGBT) for diesel locomotives with commutator traction motors in the electric braking mode, as well as the implementation features of this mode on diesel locomotives. To show the functional structure of the converter automatic control system for the electric braking mode. To plot a potential braking characteristic of a diesel locomotive with a new converter. Methods: Simulation modeling of the electric braking mode using a computational mathematical model of a traction drive in the Matlab Simulink environment. Analysis of the simulation results of the traction drive operation in stationary and dynamic conditions. Comparison of the obtained braking characteristic with the existing one for 2TE25KM diesel locomotive. Results: It is established that the use of the proposed transistor traction converter in the power electrical circuit of a diesel locomotive provides axis-by-axis control of a commutator traction electric drive in the electric braking mode with series excitation of traction motors and allows to significantly increase the electric brake efficiency at low speeds. The proposed solution implements the target braking force of the locomotive in a wide range of speeds, as well as its limitations due to the electromechanical parameters of the diesel locomotive assemblies. Practical significance: It is shown that the proposed solution provides the increase of the electric brake efficiency, life extension of brake shoes and wheels of the rolling stock.

Подхват асинхронного двигателя после потери питания транзисторного электропривода

The solution of the problem of connecting an asynchronous machine with a squirrel-cage rotor to a transistor converter after their disconnection in the absence of a rotor speed sensor is considered. This problem may arise in the drives of pumps, fans, in wind power plants and in other systems, if it is necessary to urgently breaking the mechanism or to ensure its uninterrupted operation. In the article, the problem is solved in relation to the ship's electric propulsion system. When the drive power is lost, the propeller and the rotor of the machine are first slowed down relatively quickly to a speed corresponding to the speed of the vessel. Then braking slows down due to the large inertia of the vessel. The significant duration of the process allows the use of an algorithm for determining the rotor speed, based on testing the machine by feeding the stator of an asynchronous motor from an inverter with low voltages with a frequency that varies within the specified limits. Mathematical and computer models of the system are constructed, numerical experiments are performed confirming the effectiveness of the considered solution.

Design and simulation of wind energy conversion system commanded by converter and mechanical brake

This paper concern the design and control of a wind energy conversion system regulating generator phase’s currents, voltages, and batteries charging voltage using barking systems and AC–DC converter. Indeed, the braking system permit the regulation of the generator’s angular speed and electromotives forces magnitude, and the AC–DC converter permit the regulation of the phase’s voltages, currents, and the batteries charging voltage. This method is suitable for permanent magnet axial flux synchronous generators and for Insulated Gate Bipolar Transistor converters (IGBT). In addition, we propose an innovative strategy to push the problem of adding an impedance matching transformer to minimize the over-current effect caused by the sudden variation of the voltage at the generator inductor using the AC–DC converter. It offers the advantage of power chain cost reduction and the improvement of its performances. The overall model of the power chain is implemented under the simulation environment MATLAB-Sumilink for performances analysis of studied structure.

ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ КОНТРОЛЕРА ДЛЯ КЕРУВАННЯ ТЯГОВИМ ЕЛЕКРОДВИГУНОМ НА ПОСТІЙНИХ МАГНІТАХ

The controller of traction electric motors on permanent magnets for vehicles in which the power transistor converter is made on the modified IGBT modules with the improved characteristics is described in this work. The use of these modules, which are widely used today in semiconductor devices of modern dual-use technology, allows to reduce the size and weight of the converter, simplify the cooling system, increase efficiency and reliability of the semiconductor converter and electric drive in general due to harsh operating conditions. Bench tests of the experimental sample of the semiconductor converter and the microprocessor control system in various operating modes, including at the maximum load corresponding to real operating conditions are made and carried out. As a result of tests, it was determined that the technical characteristics of the controller meet the requirements of such devices. The created semiconductor controller on IGBT modified modules can be used to control motors on permanent magnets and motor wheels with a nominal power of 40-50 kW, maximum - 100 kW. References 11, figures 8, tables 4.

Mechanical Power of DC Motors with Polygarmonic Power Supply

The aim of the work is to develop a method for determining the mechanical power of DC mo-tors when they are powered by semiconductor converters, since the harmonic components of the armature current do not create a torque on the shaft. This means that at the nominal electric power of the motor, it is necessary to reduce the mechanical power to ensure the nominal tem-perature regime of the armature winding. The aim is achieved by solving the problem of deter-mining the dependence of the mechanical power of the motor on the armature current pulsations factor, the value of which depends on the control parameter of the thyristor or transistor con-verter, on the inductance of the armature circuit and the load current. As a result, it was pro-posed to express the dependence of the mechanical power in terms of the allowable mechanical load factor, which, in turn, depends on the armature current pulsations factor. The method is as follows: 1) on a computer model determine the armature current pulsations factor; 2) determine the allowable mechanical load factor and the allowable mechanical power. The novelty of the work lies in the fact that the expression for determining the allowable mechanical load of DC motors with polyharmonic power has been further developed, which, unlike the known ones, contains the square of the armature current pulsations factor. An example of the practical use of the proposed method for calculating the allowable mechanical power of DC motor when pow-ered by single-phase thyristor rectifier.

Варианты систем электродвижения ледоколов мощностью 60 и 120 МВт

Variants of electric propulsion systems for powerful icebreakers with the use of transistor frequency converters or thyristor frequency converters with direct coupling (DFC) are considered. Rowing motors synchronous or asynchronous. With transistor converters, the semiconductor element base is mainly imported, with thyristor FCs, it is mainly domestic. But DFCs work with reactive power consumption, and its generation requires the use of additional devices, such as passive filters or STATCOMs. When the propellers of icebreakers are reversed, the energy of the propellers is recuperated. In electric propulsion system with transistorized FСs, resistors and choppers are used to absorb the regenerated energy. In electric propulsion system with DFC, it is possible to recuperate energy into the mains, and this allows you to reduce the power of the resistors. Resistors are included in STATCOMs, expanding their functions (reactive power generation, voltage filtering, energy absorption).

Study of the suitable value of dead-time between control signals of transistors for a series-resonant inverter with phase-shift control in induction heating systems

Induction heating provides contactless, energy-efficient, accurate, and fast heating of electrically conductive materials. Due to its advantages, IH is increasingly used in different fields such as industry, medicine, and the household sector. High-frequency transistor converters for the induction heating system are often based on series-resonant inverters. This paper analyzes a phase-shift-controlled voltage-source series-resonant inverter for induction heating systems. Mathematical analysis was performed in order to obtain the expressions that describe the output current of the phase-shift-controlled series-resonant inverter in the steady-state mode. Based on the analysis and the obtained expressions of the output current, analytical expressions of the dead-time between the transistors’ control signals of the SRI are obtained. The analytical expressions for determining the value of the dead-time are obtained for two cases:
 1) zero value of the phase-shift;
 2) the phase shift is greater than zero.
 To verify the obtained analytical expressions of the output current, validation was performed in the MATLAB/Simulink environment by comparing the peak current values.
 The verification showed the high accuracy of the obtained expressions, the deviation between the calculated and simulated values of the peak current is less than 0.1 %. The made simplifications of the dead-time expressions also were verified by calculation, the deviation between the calculated values of the drain-to-source voltage at the end of the commutation and the expected value is no more than 3.6 %. The SRI prototype has been designed and implemented in order to validate the analytical and simulation results

The Dependence of Short-Circuit Current in a Transistor Inverter on the Parameters of an Electric Circuit

In the course of the operation of power transistor converters of electric energy, various emergency situations are possible, e.g., a short circuit in the load circuit. The rate of increase in the short-circuit current and its amplitude are affected by the parameters of electric circuit (inductance, power supply voltage of the inverter, control voltage across the gate), as well as by the properties of transistors. A method for preliminary estimation of the short-circuit current and rate of its increase at the stage of designing a converter has been suggested in the paper. This method is based on the theory of planning a multifactor experiment. Calculations of the aforementioned parameters for an inverter with the given technical characteristics have been carried out. A comparison of the results of calculation and physical layout has shown that the suggested approach can be used in the design of any electric energy converters in power semiconductor devices.

The fuzzy logic controllers synthesis method in the vector control system of the wind turbine doubly-fed induction generator

The article is devoted to the improvement of control systems for wind turbines by developing fuzzy controllers with higher transient characteristics and low computational costs of identification in comparison with the applied PI controllers. Based on the self-organization method, a fuzzy speed controller of the doubly-fed induction generator (DFIG) of a wind turbine was synthesized, which uses a zero-order Sugeno fuzzy inference system and is made in the form of a block-oriented Wiener model. This regulator is an element of the vector control system of the transistor converter on the rotor side. The results of simulation modeling of the fuzzy controller showed that it provides a lower transition time compared to the PI controller, by 53.59% during acceleration and by 79.76% during braking, and 23.81% less error speed deviations from the reference signal. Such indicators can minimize losses while maintaining the maximum output power point of the power plant. The implementation of the developed system on wind turbines contributes to increasing the efficiency of wind farms, reducing the cost of electricity production, reducing the payback period of equipment, and the sustainable development of alternative energy in general.

Two-Channel Capacitive Ignition System with a Transistor Converter for Ground-Based Gas-Turbine Engines

A prototype of a two-channel capacitive ignition system for ground-based gas-turbine engines is developed. This system is based on a single-stage flyback transistor converter with a field-effect transistor controlled by an integrated timer. The timer operates in square-wave generator mode, with additional low-voltage voltage stabilization.

A Transformerless 6.6-kV STATCOM Based on a Hybrid Cascade Multilevel Converter Using SiC Devices

We have developed a full-scale prototype of transformerless static synchronous compensator (STATCOM), rated at 6.6 kV and 100 kVA, based on a hybrid cascade multilevel converter using SiC devices. The topology employs multivoltage converter cells, Si and SiC semiconductor devices, and hybrid modulations in the converters. One phase of the STATCOM has two Si insulated-gate bipolar transistor converter cells and two SiC-JFET converter cells connected in series. The SiC cells are operated with high-frequency pulse width modulation. The Si cells carry higher dc voltage, resulting in smaller converter volume by reducing the number of cascaded cells. To minimize the loss, the Si cells are operated with one-pulse. The balance control of dc voltage of the hybrid cells is also discussed. We tested the developed STATCOM in a full-scale 6.6-kV distribution grid. The experimental results show a stable rated operation and fault-ride-through performances. Moreover, we analyzed its loss and volume and discussed them based on the developed STATCOM. The estimated loss was approximately 0.3% at rated power, which is comparable to an all-SiC configuration. It also has an advantage in its small volume compared with other configurations. These analyses revealed that the hybrid configuration is a suitable topology for low-loss and small-size distribution STATCOM.

Modelling and control of permanent magnet synchronous generator based on three level NPC using fuzzy PI

Recently, the permanent magnet synchronous generator (PMSG) has been gained attention by wind turbine (WT) manufactures due to advance of control system and power electronics. The permanent magnet synchronous generator based on three level neutral point control (NPC) system using fuzzy logic control proportional integral (FLC PI) is proposed in this study. The NPC systems of DC link are implemented more easily than two level systems. The NPC systems provide better harmonic reduction than conventional two level voltage source converters. The control strategies of the NPC systems reduce semiconductor losses. The proposed system can be implemented to the multi-level converters above three-level. The proposed system is developed using the steady state technique. The performance of the PMSG system under variation operation condition is investigated in this study and the performances of the PMSG based on three level NPC using FLC PI are analyzed. The validity of the proposed system is implemented and verified in the MATLAB/Simulink using three-level insulated gate bipolar transistor (IGBT) converter.

A Combined Frequency Converter for Soft Acceleration of Induction Electric Drives with Heavy Starting Conditions

The usability of a thyristor frequency converter with a supplementary controlled series compensator for soft starting of induction motors with high torque of inertia of actuating mechanisms is considered as an alternative to transistor converters. It is shown that the supplemental device, in the form of a transistor–capacitor convertor, can be considered as an adjustable capacitor, the equivalent capacitance of which can be varied from very large values (to a maximum of infinitely large) to some fixed minimum value. The voltage of an adjustable series capacitor provides the desired switching conditions of thyristor inverter, and the capacitive reactance ensures the compensation of reactive power consumed by the induction motor and thyristor inverter, reducing the current load of the motor and converter. The addition of a thyristor current converter with a controlled series compensator of reactive power in the form of a transistor–capacitor unit makes it possible to carry out a soft start of induction motors similar to the starting modes of synchronous machines. Simulation results confirming the achievement of the desired effect are presented. It is shown that the supplemental device in the form of transistor–capacitor converter is a robust system well adaptable to various conditions of electric-drive operation. The functional equivalence of a transistor frequency converter and thyristor frequency converter with a supplemental transistor–capacitor unit with a substantially lower cost of the latter makes possible a new mechanism for soft starting of powerful electric drives with induction motors under conditions of high torques of inertia of actuating mechanisms.

Вдосконалена методика оцінки втрат в імпульсних перетворювачах установок контактного мікрозварювання

The paper represents resistance welding characteristics and construction features of power supplies for resistance welding. The authors give an overview of circuit topologies of converters for resistance welding and distinguish the most promising one — the transistor buck converter with a synchronous transistor. It is shown that in order to ensure acceptable energy efficiency of power supply for resistance welding machines, while maintaining sufficient accuracy of current regulation in a welding contact, special modes of pulse transistor converters are used. The analysis of resistance welding features — high currents, low voltages — makes it possible to presume that the evaluation of the power losses in semiconductor elements only is insufficient and needs to be complemented by taking into account the losses on the inductive element of the converter circuit. In this work, the authors propose the method of estimating the power losses in the pulse buck converter of the power supply of resistance welding machine, which allows for more accurate calculations at the design stage due to consideration of the power losses on the inductive element of the circuit. The methodology is to calculate the total power losses as the sum of power losses on all individual elements of the circuit. Power losses on inductance is calculated using the Steinmetz equation. The calculations carried out with this technique proved the advisability of taking into account the power losses on the inductive element, especially in the region of high frequencies. The obtained diagrams demonstrated the dependency of the power losses in the converter on the frequency at different values of current and voltage.

Principles for construction the compensators of reactive power with voltage stabilization for transformer substations

Based on the booster transformer and the transistor converter with a DC link, a system is proposed for fast and accurate unloading the electric network from reactive power with simultaneous stabilization of voltage among consumers. The system contains a discrete stage of reactive power compensation and adjustable part. The adjustable part includes series and parallel reactive power compensators. The series compensator consists of a booster transformer, a voltage inverter and is designed to be switched on to the high voltage of the transformer substations. The parallel compensator consists of a rectifier with an input choke and is connected to the low voltage of the substation. The rectifier and inverter are connected by a DC link with an LC filter. The rectifier regulates the output voltage and the phase of the sinusoidal input current. The inverter regulates the magnitude and phase of the voltage on the control winding of the booster transformer. The rectifier and inverter control systems are synchronized with the network and with pulse width modulation.

Soft‐switching operation of the dual‐interleaved boost converter over all duty ratios

To extend the operating range of the snubber assisted zero-voltage and zero-current transition dual-interleaved boost converter beyond its inherent soft-switching limit of D = 0.5, a resonant pulse transformer is proposed instead of the resonant inductor. The 1 : 2 turns ratio of the transformer ensures full discharge of the snubber capacitor at all duty ratio values to facilitate zero-voltage zero-current switching at turn on of the main switching devices. The effectiveness of the topology has been confirmed by SPICE simulation and demonstrated by a 20 kW SiC metal–oxide–semiconductor field-effect transistor converter. The prototype operated at 20 kW, 112 kHz, 320–600 V achieving 98.7% efficiency and achieved 98.2% efficiency at 6 kW. Taking the additional losses in the auxiliary circuit into account, the switching losses at 20 kW are reduced by 74% compared with hard-switching operation, representing a 54% reduction in overall losses.

Power Smoothening of Grid Connected Direct- Driven Permanent Magnet Synchronous Generator (PMSG) Wind Turbines

Objectives: The main objective of this paper is smoothening of the power fluctuation of a variable speed PMSG wind generator with the help of Energy Capacitor System (ECS). ECS consists of a voltage source inverter, dc-dc converter and an ultra-capacitor bank including their control strategies. Methods/Analysis: In this paper two back-to-back voltage source Insulated Gate Biopolar Transistor (IGBT) converters controlled through highly efficient variable frequency drive control method is considered. By using this method, efficiency of wind farm can be improved and voltage regulation for interconnecting the wind farm with grid can be achieved. Findings: Recent application of power electronic devices and scaling up of MegaWatt (MW) wind turbines, Low-speed high torque Permanent Magnet Synchronous Generator (PMSG) has become the ultimate choice for wind power extraction. At present, a commercial PMSG based wind generator primarily makes use of a rectifier followed by an IGBT converter. Novelty /Improvement: The real power reference for ECS is generated accurately. Simulation is carried out through MATLAB/SIMULINK.