Thyristor Voltage Research Articles

THE EXPERIENCE OF "MATLAB 6.0"® USE IN THE SIMULATION OF THE PULSE-PHASE CONTROL SYSTEM OF THE THYRISTOR VOLTAGE REGULATOR WITH THE ACTIVE-INDUCTIVE LOAD

The paper is dedicated to the realization of the structural model of the pulse-phase control system (PPCS) of the thyristor voltage regulator (TVR) with an active-inductive (RL) load in the medium of "MATLAB 6.0" ® Describing the possibilities of "MATLAB 6.0" ® in the dynamic systems simulation, some problems connected with the use of special instrument means, included in structure of Toolbox Simulink Library, are examined.

A Novel Comprehensive Draw-Out Power Circuit of High Voltage Thyristor

The method of self-energy extracting has been adopted in high voltage thyristor device more and more widely. In consequence of the existing insufficient of high heat loss and large variation range of storage voltage value, this paper designs a novel comprehensive draw-out power circuit which is suitable for almost all kinds of working conditions of thyristor. The circuit includes voltage draw-out power module, current draw-out power module and the coordination control module between them. The principle of each module has been detailed analyzed and the calculation formulas of the corresponding parameters have been concisely given. At last, every conclusion drawn in this paper has been verified in simulation.

Thyristor voltage pulse shapers for controlling high-voltage switching electronic elements

The efficiency of using switching high-voltage electron-beam valves (EBVs) in power-supply systems of electrophysical and other high-power units is shown. The novelty of the scientific and engineering solutions applied to design EBVs with high electric parameters is emphasized. The rationale for using single-operation SCR thyristors for EBV control is provided. The principles of constructing thyristor voltage pulse shapers are analyzed and generalized.

Совершенствование автоматизированных электроприводов агрегатов прокатного производства

Although the majority of domestic metallurgical enterprises purchase and install processing lines from foreign suppliers, development, implementation and promotion of domestic equipment is still an urgent and challenging task. Technological achievements of the joint research teams from Magnitogorsk State Technical University, the South Ural State University and the OJSC “Magnitogorsk Iron and Steel Works” (OJSC “MMK”) are described in the article. One of the priorities in the research work is energy saving both in electric drives and in automation equipment of electric drives. The authors describe the approach and the technical solutions providing reduction of electric power losses due to the reduction of reactive power consumption by thyristor electric drives of rolling mills. Technical efficiency is achieved thanks to the reduction of the thyristor voltage converter storage without any compensating devices. Some algorithms and software providing energy and resource saving due to improvement of the speed and load modes of electric drives in the process of plate production from the difficult-to-form/hard steel grades are given. The structure of the automation system for 5000 plate mill rolling stand is presented. Local systems of the automatic end-point control providing adjusting of certain technological variables are described. Automation of level 2 ensuring the production process control according to the schedule predetermined by the operator is considered. Great attention is paid to the developed resource saving electrical systems of the wide strip hot rolling mill. The authors introduced a complex of scientific developments aimed at improvement of automatic electric drives and process variables control systems. The resource saving is provided by reduction of specific consumption of materials as a result of defective product reduction and the decrease of wastes caused by strip end crops. The authors studied the system of automatic tension control with an extra fast acting channel adjusting the hydraulic screw-down structure of the rolling stand. They intro-duced the method and the algorithm of tension control in the intestand gaps of the hot rolling mill roughing train. All the de-veloped control methods and algorithms have been implemented into the operating rolling mills of the OJSC “MMK”. The main advantages of the developed solutions are high efficiency and relative simplicity of implementation/putting into practice. The introduction of the algorithms will improve the production capabilities of the operating and new rolling machinery, contribute to production efficiency improvement, resource and energy saving and make the final product more competitive in the market.

Исследование сверхмощных дуговых сталеплавильных печей с тиристорным регулятором напряжения в промежуточном контуре печного трансформатора

This article presents the possibility of secondary voltage thyristor control of the furnace transformer EAF-180 JSC “MMK”. The negative influence of dispersion current electric arc by an amount of active power injected into the furnace. Based on the research, the authors propose a new concept of building a combined system of automatic control mode electric arc furnace, providing increase its stability.

High-Power Pulse Semiconductor Laser-Thyristor Emitting at 900-nm Wavelength

High-power pulse semiconductor lasers based on epitaxially integrated thyristor heterostructures were developed. The possibility of generating high-power laser light pulses with duration on the order of 100 ns at control signal amplitude on the order of 40-100 mA at extremely low turn-on thyristor voltage of 10 V was demonstrated. The values reached for the peak pulse optical power and peak pulse current were 28 W and 37 A, respectively.

Thyristor Controlled Voltage Regulator and Thyristor Controlled Phase Angle Regulator for Transient Stability Improvement of AC-HVDC Power System

Thyristor Controlled Voltage Regulator and Thyristor Controlled Phase Angle Regulator for Transient Stability Improvement of AC-HVDC Power System

Study of the three-phase saturated transformer coupling new bridge-type SSFCL

SUMMARY In this paper, the principles of the three-phase saturated transformer coupling new-type solid state fault current limiter (SSFCL) are studied using the equivalent circuit method; in addition, considering the nonlinearity of the iron core material in the saturated transformer, the circuit field-coupled 3-D finite-element analysis is employed to investigate the transient performance of the proposed SSFCL. The analysis and simulation results show that the novel SSFCL has negligible impact on the power system during the normal operating stage, automatic response to the short-circuit fault, and especially low secondary voltage level during the current-limiting stage, which are of great significance to the reduction of the thyristor voltage level, the DC reactance, as well as the volume and cost of the whole SSFCL. The current-limiting effect is also tested in the simulation of a multi-machine power system with the protection of SSFCL. Last, the comparison of the simulation and experimental results proves the feasibility of the proposed SSFCL. Copyright © 2012 John Wiley & Sons, Ltd.

Control of startup of an asynchronous thyristor electric drive taking into account a limited heating and network influence

A startup processes with current limitation in the thyristor voltage converter-asynchronous motor (AM) system is described. The combined influence of supply voltage and motor heating limitations on the startup of an AM is analyzed. Based on results of analysis of these limitations acceptable range of startup parameters for this system is defined. The problems of the influence of the converter on the set of harmonics of the supply voltage are considered in brief.

The formation of a dynamic model of synchronous generator with thyristor voltage regulaton

The article deals with the issue of automatic control of threephase alternating voltage power supply system of the aircraft and the formation of a dynamic model of aircontactless synchronous generator with thyristor voltage regulator

Excitation System with Voltage Regulator for Marine-Use Brushless Synchronous Generators

The brushless constant-voltage synchronous generators are fitted with thyristor voltage regulator excitation system. The excitation current can be regulated automatically in accordance with the variation of load, resulting in constant voltage. This style of excitation has excellent kinetic in the condition of load-variation and short-circuit.

Long wavelength infrared (LWIR) photodetection in a modulation doped thyristor

A modulation doped thyristor concept is described for LWIR photodetection based upon intersubband bound to continuum absorption. The intersubband absorption generates photocurrent from undoped quantum wells to modulation doped layers (MDL). Due to the lower dark current compared to conventional quantum well infrared photodetectors (QWIPs), the thyristor infrared detector operates with little or no cooling and with similar or better performance than QWIPs at low temperatures. The operating characteristics of absorption coefficient, quantum efficiency, responsivity, detectivity, infrared gain, and dark current are determined as a function of thyristor voltage and input power level in the range of 1 μW/cm 2.

Estimate of the influence of smooth-start regimes of asynchronous motors on losses and supply mains

Questions of how the regimes of controlled start of asynchronous motors influence losses in a motor and supply mains are considered. A comparative estimate of these factors are made when using thyristor voltage converter-asynchronous motor (TVC-AM) and frequency converter-asynchronous motor (FC-AM) systems.

Fabrication of high voltage thyristor based on silicon organic compounds and metal oxides type isolation protective material

In this paper, we present some experimental results of the KP 500 thyristor which are fabricated by using silicon organic compounds and metal oxides type isolation material. Investigation on the principles of quality control of the semiconductor devices is also reported. The technique was based on coating the device surfaces with the mixture of high purity silicon organic compounds and metal oxides at a proper mixing ratio to protect the semiconductor p-n junction surface aswell as to control the characteristic properties. At room temperature, the resistivity of the solid isolation protective material ρ>7.5×1015Ω·cm, its dielectric constant is equal to 4.7, and the breakdown voltage V>16kV/mm. We demonstrated the advantages of using this material on KP500 thyristor by significantly improving its surface properties, reducing the leakage current and increasing its voltage breakdown level.

Asynchronous sensorless thyristor electric drive

A speed regulated electric drive for a thyristor voltage converter-induction motor system is presented. The frequency of rotor rotation is determined on the basis of the EMF and the stator voltage

Analysis of start-up regimes of an induction motor controlled by a thyristor regulator

The start-up regimes of an induction motor controlled by a thyristor voltage regulator are considered. The cases of the fixed stator voltage and different types of loads are analyzed.

The use of commercial thyristors in repetitive high voltage switching devices for plasma sources

This paper presents a commercial high voltage thyristor used as a switch allowing a tank capacitor to discharge in a load. In classical high power pulse technology applications the output voltage pulse has to be characterized mainly by its crest value, its rise-time, the period the thyristor is held in the on-state and the fall-time. These parameters are studied as a function of the power circuit and of the trigger circuit. The thyristor presents two behaviours: the main is either higher or lower than the latching current. The low current behaviour is extensively investigated as it allows repetitive operation of the device. Two pulse power applications triggering electrical discharges are presented. Each one necessitates a specific pulsed power supply using series thyristor stacks or Marx structures. The first pulsed source delivers negative pulses with a crest voltage V oM = -35 kV, a turn on capability of T r = 90 ns and a repetition rate F = 900 Hz. The second is built using Marx structure and is characterized by V oM = 60 kV, T,. = 250 ns, F = 900 Hz.

Thyristor-Based HVDC With Forced Commutation

This paper presents a novel converter configuration, based solely on conventional thyristors and aimed for the use with high voltage dc (HVDC) transmission. The converter utilizes resonant turn off and forced commutation with auxiliary thyristors to aid commutation in the converter switches. The PSCAD/EMTDC simulation confirms that the HVDC inverter is capable of operating with a wide range of firing angles, including operation with reactive power export. Further simulation proves that the system is immune to commutation failure even in the case of most severe close single-phase faults. The harmonic generation is comparable to the conventional converter and also the thyristor voltage stress is not significantly increased. The auxiliary thyristors do increase costs, but this is offset by the elimination of reactive power support and the improvements in performance

Novel Controllers for the 48-Pulse VSC STATCOM and SSSC for Voltage Regulation and Reactive Power Compensation

The paper investigates the dynamic operation of novel control scheme for both Static Synchronous Compensator (STATCOM) and Static Synchronous Series Compensator (SSSC) based on a new full model comprising a 48-pulse Gate Turn-Off thyristor voltage source converter for combined reactive power compensation and voltage stabilization of the electric grid network. The complete digital simulation of the STATCOM and SSSC within the power system is performed in the MATLAB/Simulink environment using the Power System Blockset (PSB). The STATCOM scheme and the electric grid network are modeled by specific electric blocks from the power system blockset, while the control system is modeled using Simulink. Two novel controllers for the STATCOM and SSSC are presented in this paper based on a decoupled current control strategy. The performance of both STATCOM and SSSC schemes connected to the 230-kV grid are evaluated. The proposed novel control schemes for the STATCOM and SSSC are fully validated by digital simulation.

A 3.5 kV Thyristor in 4H-SiC with a JTE Periphery

Overcoming the physical limits of silicon, silicon carbide shows a high potential for making high voltage thyristors. After a simulation based optimization of the main thyristor parameters, including JTE protection and a SiO2 layer passivation, 4H-SiC GTO thyristors were realized and characterized. Designed for a theoretical blocking capability of nearly 6 kV, the electrical characterization of all device structures revealed a maximum blocking voltage of 3.5 kV. Comparing simulation and measurement suggests that a negative oxide charge density of ~ 2×1012 cm-2 causes the decrease in electrical strength.