摘要:

This report describes an investigation into the feasibility of using computer-modelling techniques for evaluating the transient performance of inverters. A computer-analysis package has been developed which can be used to model and investigate various aspects of the design and performance of power-electronic equipment. The feasibility of using this computer package for evaluating the transient performance of inverters has been demonstrated using a commercial static frequency changer (SFC). It is concluded that the results of this study have confirmed the validity and accuracy of the computer-modelling techniques used, and that these techniques can now be used to predict the performance of future inverter designs.

DOI:10.1049/ip-b.1982.0043

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The paper considers the application of electronic tap changing to solid-state inverters, particularly thyristor inverters. By means of experimental investigation, this method of inverter regulation is shown to offer the advantages of both high efficiency and low waveform distortion. The technique proposed appears to possess considerable potential for exploitation in areas where power control and conditioning are required.

DOI:10.1049/ip-b.1982.0044

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A mathematical model for the type of transformer/rectifier unit used in aircraft power-supply systems is described. The model is suitable for investigating both the effects of variations in the transformer parameters on the unit performance and the interaction of the unit with other items of plant in the supply system. The experimental unit on which the model was validated exhibits a marked imbalance between the two diode bridges fed from the transformer secondary windings, and this is satisfactorily predicted by the model. Introducing even a moderate harmonic content into the supply voltage to the transfer increases considerably the imbalance, which under full-load conditions could result in overloading and possible failure of the diodes of one of the bridges.

DOI:10.1049/ip-b.1982.0045

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A new method for the reliable prediction of the pull-out torque characteristics of hybrid stepping motors is described. An important feature of the approach is the detailed representation of the switching characteristics of the stepping-motor drive circuit. Comparisons between experimental and predicted results are presented in terms of pull-out torque/stepping-frequency curves.

DOI:10.1049/ip-b.1982.0046

出版商:IEE    

年代:1982

数据来源: IET

摘要:

Equations are derived which describe the terminal behaviour of the uncontrolled resistance-inductance fed bridge convertor. Generalisation of these equations to the controlled case is accomplished by a substitution of variables. Boundaries within which the uncontrolled rectifier can operate are specified. Plots of the terminal characteristics for the uncontrolled case visually show the approximation involved when the resistive portion of the commutation impedance is neglected. Simple approximations are provided for the fundamental current component equations which are derived.

DOI:10.1049/ip-b.1982.0047

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A completely digital 3-phase 6-pulse convertor-fed DC-motor drive system is proposed. Simple mathematical relations are derived for the speed and current controllers, assuming them to be two independent 1st-order loops. Simulated results for theoretical controller parameters and experimental results are in close agreement. The tuning procedure is simple and straightforward. The scheme incorporates some novel features in the hardware and software of the system.

DOI:10.1049/ip-b.1982.0048

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The preliminary results for a new, simple and highly reliable technique for semiconductor variable-frequency feeding of 3-phase motors are presented. The method involves the use of two antiparallel winding coils per phase, each in series with a main switching thyristor.

DOI:10.1049/ip-b.1982.0049

出版商:IEE    

年代:1982

数据来源: IET

摘要:

An energisation sequence is proposed which enables satisfactory static torque/angular position characteristics to be obtained with the 4-phase, single-stator, variable-reluctance (VR) stepping motor when operating in the halfstep mode. It is shown to be advantageous to utilise 3-phase excitation, where a substantial increase in holding torque is obtained when the distribution of magnetomotive force (MMF) among the phases is optimally proportioned, subject to the thermal constraint on the stator-winding losses. Experimental results are presented, and a simple analysis of the magnetic arrangement is developed.

DOI:10.1049/ip-b.1982.0051

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The paper proposes a number of protection methods which can be used with power transistors in power-control units. They give satisfactory protection against simultaneous conduction of the two devices in an inverter leg. The techniques, which are independent of the control electronics and base-drive circuits, are simple and reliable to implement. They include an instantaneous and electrically isolated method of fault indication, a fast-acting crowbar circuit and a means of diverting the current away from the power devices in the event of a fault.

DOI:10.1049/ip-b.1982.0052

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The paper presents a rigorous 2-dimensional analysis of a double-sided linear induction motor, with particular reference to the entry-end and the exit-end effects. The analysis takes into account the discontinuity of the stator winding as well as the discontinuity of the stator iron. The field equations, together with the boundary conditions, constitute a mixed boundary value problem, which is solved by the use of Wiener-Hopf technique (WHT). The results clearly bring out the individual effects of (i) the discontinuity in the winding and (ii) the discontinuity in the iron, as well as the 2-dimensional nature of the field quantities. The analysis is illustrated by applying it to the data of two linear induction motors.

DOI:10.1049/ip-b.1982.0053

出版商:IEE    

年代:1982

数据来源: IET