摘要:

A novel wind-turbine-driven electric power system for isolated communities is described. The system components consist of an induction generator and a synchronous condenser. The synchronous condenser supplies the magnetisation current to the induction generator. Besides supplying the load power, the induction generator feeds the synchronous condenser with real power to replenish windage, friction andI2Rlosses to sustain it at synchronous speed. The theory of operation is given, and predictions based on it are experimentally verified. The controllers required to maintain regulated voltage and frequency in spite of load and wind velocity changes are investigated. Slip-energy recovery is involved, and preliminary test results are presented.

DOI:10.1049/piee.1979.0012

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The microprocessor is an integrated circuit which functions as the central processor of a digital computer. Since its appearance seven years ago, it has been the subject of considerable development and is now used extensively in electronic systems. The key to its success is its universal applicability, using special-purpose software implemented in general-purpose mass-produced hardware. In control and automation, the microprocessor has been used as a component to replace both hard-wired logic systems and minicomputers. As costs have decreased, it has become the most economic controller for most domestic and industrial applications, providing widespread automation down to very low levels. The implication for the engineer is that software will play an increasing part in electronic-system design, and is therefore to be regarded as an important engineering tool to be fully understood and mastered. The implication for society is that the microprocessor will influence what we make, and how we make it, and is therefore to be incorporated into our products and production processes without delay. A social challenge is to provide the support required for this, to ensure that Britain survives as a high-technology nation, while at the same time maintaining a balance between work and leisure in a society where most routine tasks are automated.

DOI:10.1049/piee.1979.0015

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The single-step optimal control of a variable-reluctance stepper motor is presented. The optimal policy is shown to be bang-bang, with current drive control, for an established nonlinear model with the torque proportional to the square of the current. The analytic result is confirmed by extensive computations of the actual optimal strategy. The formulation used retains the benefits of the open-loop control of the motor. The responses obtained are compared to the step response and are shown to exhibit substantial improvements. The general form of the control equally applies to machines, such as the reluctance motor, with similar models.

DOI:10.1049/piee.1979.0016

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The paper describes the design and testing of a multivariable controller for a turbogenerator which takes account of the practical requirements and difficulties that arise in implementation. The controller is based on a discrete state-space model, using actual values of variables instead of deviations from defined reference levels, and incorporates output integral control on selected states. The controller regulates terminal voltage and speed regardless of changes of operating conditions or system configuration, and can drive to new operating points. It has been extensively tested on a laboratory micromachine system, and shown to give improved performance.

DOI:10.1049/piee.1979.0017

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The program obtains the exact solution for a limit cycle in a single-variable relay control system using A-locus method. The resulting nonlinear equations are solved using Rosenbrock's minimisation technique. An example is given to illustrate the usage and the generality of the program.

DOI:10.1049/piee.1979.0018

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The addition of a cross-product term to the performance criterion in the l.q.p. optimal-control problem modifies the frequency-domain conditions for optimality. The weighting term can be chosen so that the locus of the determinant of the return-difference matrix can enter the unit circle. This improves the performance of the system relative to classical performance criteria and enables a wider range of transient responses to be obtained.

DOI:10.1049/piee.1979.0019

出版商:IEE    

年代:1979

数据来源: IET

摘要:

An algorithm is presented that enables the fitting of complex frequency-response data to a rational transfer function. Parameter estimates are updated, without matrix inversion, as more frequency-response data become available. The method is particularly suitable for online identification.

DOI:10.1049/piee.1979.0020

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The paper proposes a new statistical prediction system of air pollution which is developed by applying the multivariate analyses to the accumulated data. First, the data are classified into some clusters corresponding to the patterns of daily fluctuations and various regression models are prepared. Secondly, based on the above models, the following two-stage predictor is introduced; at the first stage a suitable model for the pattern of the predicted day is selected by the discriminant function with the qualitative and quantitative data, and at the second stage the coefficients of the selected one are determined for the prediction of concentration levels. Finally, results are shown that are obtained by applying this method to the prediction of the SO2concentration levels one and two hours ahead.

DOI:10.1049/piee.1979.0021

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The paper deals briefly with the origins of technical innovation as an essential part of engineering activity and traces its growth and the establishment of the research and development (r. & d.) function in the technically based company. The present-day relationship between innovation and r. & d. in a company is discussed in the particular context of the organisational problems that can arise. The possible use of a ‘new ventures unit’ with direct responsibility for innovation is also considered. Particular attention is given to the differing roles and attitudes of the innovator, the r. & d. manager and of top management. Some of the more significant findings of investigations into innovation are reviewed, and the future environment for innovation and the innovator is considered in terms of the constraints and rewards that may be expected.

DOI:10.1049/piee.1979.0023

出版商:IEE    

年代:1979

数据来源: IET

摘要:

Static-field computations can be simple and fast if the method of images can be used. However, except for some simple geometries such as planes and spheres, one cannot determine the locations and strength of the images. This paper overcomes this difficulty, and makes the desired determinations on a set of simulated images by an optimisation technique. Two examples are included to demonstrate the rapid convergence of this method.

DOI:10.1049/piee.1979.0024

出版商:IEE    

年代:1979

数据来源: IET