Thyristor Chopper Research Articles

Control of Armature and Field Current of a Chopper-Fed-DC-Drive by a Single Ship Microcomputer

A microprocessor based control scheme for a chopper-fed-d.c.-drive intended for the use in an electric vehicle is described in this paper. The drive consists of a thyristor chopper for the armature current and a transistor chopper for the excitation, which are both controlled by an INTEL 8031 single chip microcomputer. The simultaneous control of two real-time-processes with extremly stringent time requirements is achieved by a special program-structure. All timing is done by using the 8031's two built-in 16-bit-timer/counters, so only a small amount of external hardware is needed.

A Microprocessor Controlled DC Traction Drive for Electric/Hybrid Vehicles

A matter that requires close attention within the context of electric/ hybrid venicles is the necessity for provision of regenerative capability to enable the recovery of vehicle kinetic energy at all speeds. This implies allowing transition from motoring to regenerative modes of operation.With this purpose a two quadrant thyristor chopper has been incorporated into the power circuit of a drive system encompassing a battery/d.c. motor combination together with a flywheel.Attention has been focussed into the establishment of operational strategies with the aim of increased efficiency and prolonged battery life. The control function has been implemented by an M6S02 microprocessor. Taken as a whole, the test results were supportive of the popular pronouncements as to the potential of microprocessors in undertaking electric/hybrid vehicle controls.

Effects of reverse recovery time and stray inductance on reverse bias time of thyristor choppers

This paper derives simple equations to determine the effects of the reverse recovery time and stray inductance on the available reverse bias time of the main thyristor to guarantee the commutation of the main thyristor. These effects are illustrated by an example of a practical chopper circuit.

Thyristor chopper with charging reactor for commutating capacitor

Thyristor chopper with charging reactor for commutating capacitor

A thyristor chopper with minimum limits on voltage control of DC drives

This paper explains the requirements of thyristor chopper circuits to operate without any commutation limits and also explains the commutation processes of a thyristor chopper which satisfies these requirements. The practical design equations for the selection of components arc derived and the complete design of the chopper circuit to moot typical drive specifications is presented.

Commutation losses of thyristor choppers

Thia paper explains the methods for determining the commutation losses of a thyristor chopper circuit, derives analytical expressions for each component of commutation losses and demonstrates the importance of commutation losses on the design of the thyristor chopper to guarantee the minimum reverse bias time of the main thyristor.

Three-Phase Static Power Supplies for Air-Conditioned Electric Coaches using High Power GTO

The electrical design, characteristics, construction, and test results of a 170-kVA static power supply using 2500-V 600-A gate turn-off (GTO) thyristors developed for a wide range of electric railway applications are discussed. This power supply is principally composed of a thyristor chopper at an elementary frequency of 360 Hz and three-phase gate turn-off thyristor inverters in the form of a twelve-phase bridge configuration. It is capable of stabilizing a 60-Hz ac voltage and twelve-phase waveform. The bulk and weight of this power supply are ascribed to the avoidance of an inverter commutating circuit, which contains parasitic thyristors, capacitors, and inductances. The applied strategy is derived from the trend of the state of the art regarding switching cells and commuter trains.

A linear ramp control circuit using two LM 556 dual timers

A simple linear ramp control circuit, suitable for use with force-commutated thyrister circuits is discussed here. The circuit is based on only two IM 558 dual timer iCs, operating from a single 15 V supply. The reset terminals facilitate inhibition of the output of any stage. The use of this circuit in a thyristor chopper operating at 400 Hz 13 described.

Operation of a lead/acid battery with thyristor chopper burden

A battery of twelve 2 V cells was used to supply power to a carbon pile resistor, on steady discharge and on pulse discharge created by a thyristor chopper. For frequencies in the range 25–487.8 Hz, at several mark-space ratios, with fixed low discharge rates, the ampere-hour performance on pulsed-discharge was identical to that on steady discharge.

Microcomputer-based power-semiconductor-circuit waveform analyser

The paper describes a signal-processing system developed for the analysis of power-semiconductor waveforms. The system combines the acqusition versatility of a digital tiansient recorder with the computational capabilities of the microcomputer. Waveforms may be displayed, stored or processed, and various processing options are described in the paper. Problems arising from point-by-point calculations are discussed and examples of waveform analysis using thyristor and transistor chopper circuits are presented.

High-power switching regulator type DC-DC converters controlled by time-sharing high-frequency thyristor choppers with energy-storage and -transfer reactors

This paper is concerned with the latest technologies on high-power switching dc-dc converters controlled by time-sharing high-frequency thyristor chopper with energy -storage and -transfer reactor coupling links, which can operate over an ultrasonic chopping frequency region in the extent of 20KHz or more than 20KHz. The possible circuit configurations of new thyristor type switching step-up and down dc-dc converters relating to magnetic-power semiconductor devices and their unique features are described and discussed from a practical point of view. The general procedures of circuit analysis and performance evaluations to offer the desirable design data are presented, and the steady-state open-loop control characteristics and a closed-loop control policy are elucidated on the basis of the theoretical and experimental results. Thyristor type high-frequency switching step-up dc-dc converter using time-sharing control technique is also originally examined and discussed herein.

Analysis, Design and Performance of a Thyristor Chopper

Analysis, Design and Performance of a Thyristor Chopper

A DC Motor Control System for Electric Vehicle Drive

A control system of a dc separately excited motor for electric vehicle drive is described. The armature of the motor is controlled by a thyristor chopper, whereas the field is regulated by a highfrequency transistor chopper. The control scheme combines the advantages of both series and shunt motors and permits maximum possible acceleration within the transient thermal ratings of the motor. In addition, motor torque becomes smoother under all operating conditions. A complete drive system has been formulated, designed, and analyzed, and performances have been evaluated on a hybrid computer. At present, the breadboard of the drive system is being tested in the laboratory.

A Load Insensitive DC/DC Converter for Supply of Telephone Exchanges

The output waveform in thyristor choppers and inverters with parallel capacitor commutation is load sensitive. This can limit the applicability of such circuits where extreme pulse width variation is needed. A solution of the problem is shown on an example of a d.c. converter for the supply of telephone exchanges.

A new high‐frequency thyristor chopper with improved commutating efficiency

A new high‐frequency thyristor chopper with improved commutating efficiency

転流効率を改善した高周波用サイリスタチョッパ回路

転流効率を改善した高周波用サイリスタチョッパ回路

Discussion on “Thyristor chopper control and the introduction of harmonic current into track circuits” and “Thyristor chopper control and the introduction of harmonic current into track circuits: practical tests”

Discussion on “Thyristor chopper control and the introduction of harmonic current into track circuits” and “Thyristor chopper control and the introduction of harmonic current into track circuits: practical tests”

Optimum Design of Commutation Circuit in a Thyristor Chopper for DC Motor Control

This paper deduces the expressions for the commutating capacitor voltage and current during the commutation period of the main and auxiliary thyristor in a chopper for a dc motor control system. After a successful commutation, a certain amount of energy is ``stored'' in the circuit components, and for best component utilization this stored energy has to be minimized. The procedure of minimum stored energy in the commutation circuit has resulted in the selection of optimum values of commutating capacitors and inductors, and the values so obtained are more precisely defined than those indicated by early workers.

Discussion on “D.C.-to-d.c. thyristor chopper for traction application”

Discussion on “D.C.-to-d.c. thyristor chopper for traction application”

D.C.-to-d.c. thyristor chopper for traction application

The paper discusses design principles together with a novel firing mode which enables the advantages of the resonant power controller to be utilised to produce a fixed-frequency chopper circuit, which has complete control over output power even at low output voltages. The resonant arrangement may be designed such that resonant currents are less than the peak load current to be commutated with a consequent reduction of the rating of the semiconductor and wound commutation components.