摘要:

Diagnostic measurements have been carried out in the 25 kV electrification trackside switching stations on British Railways since 1972, following the discovery of audible discharge in the synthetic resin-bonded paper bushings. Laboratory measurements of discharge magnitude, capacitance, dielectric loss and ultrasonic noise were correlated with physical damage at the bushing foils and criteria for bushing rejection were established. A batch of inferior-quality bushings was identified which were spread between 16 switching stations. Further service experience, including bushing punctures, led to a revision of the rejection criteria and prompted diagnostic testing of 2500 bushings in all 92 switching stations. The results are discussed in terms of the rate of deterioration, critical discharge levels for stability and the merits of various diagnostic techniques.

DOI:10.1049/ip-b.1985.0001

出版商:IEE    

年代:1985

数据来源: IET

摘要:

A new design philosophy is proposed for developing microprocessor-based power-electronic systems; it allows all the design stages from initial conception, analysis, simulation, synthesis, test and implementation, to be performed on the same microprocessor hardware/software configuration. The practical embodiment of this new design philosophy is demonstrated using a 16-bit microprocessor-based development system for the computer-aided design and real-time control of PWM inverter drives.

DOI:10.1049/ip-b.1985.0002

出版商:IEE    

年代:1985

数据来源: IET

摘要:

This paper describes the circuits and algorithms used in a microprocessor-controlled AC/DC thyristor convertor to implement a wide-bandwidth closed-loop current source. The convertor consists of two three-phase bridge circuits for four-quadrant operation, with direct digital control using a M6809 microprocessor. The timing pulse generator is linked to the supply frequency via a phase locked loop, making the system insensitive to supply frequency variation. The use of proportional-plus-integral (PI) control algorithms leads to fast responses to step changes in reference input. Results from constant-gain PI controllers are compared in the paper with theoretical responses based on approximate z-transform analysis to obtain optimum parameters for various modes of operation. In addition, results are presented from a simple variable-gain adaptive controller which adjusts the controller parameters depending on the reference change and operating point.

DOI:10.1049/ip-b.1985.0003

出版商:IEE    

年代:1985

数据来源: IET

摘要:

Although conventional commutator-brush DC servomotors and gearing systems have found wide application in drives for small- and medium-sized industrial robots, they have a number of limitations. The work described has involved the development of a brushless DC motor direct-drive system for a high-positional-accuracy robot, which overcomes these limitations and improves performance. Typical experimental results on a test rig are presented and discussed.

DOI:10.1049/ip-b.1985.0004

出版商:IEE    

年代:1985

数据来源: IET

摘要:

The multiport dual model of a DC machine with gyrators is a compromise. It possesses the same external behaviour as the multiport model and a similar internal configuration as the dual of the multiport model. The results of simulation by the dual model with gyrators are the same as by the multiport model. It is superior to the dual model as no modification in the external circuit is required for the connection of the gyrator model to the simulated external system. Compared with the multiport model, fewer equations need to be solved, and therefore less computer storage and execution time are required using the gyrator model. Hence, the gyrator model is qualified as a substitute for the multiport model.

DOI:10.1049/ip-b.1985.0005

出版商:IEE    

年代:1985

数据来源: IET