U421065.pdf (134.22 MB)
A static scherbius system of induction motor speed control.
thesisposted on 2015-11-19, 08:58 authored by Gordon Arthur Smith
This work describes a control system in which a cycloconverter is connected between the secondary winding of a three-phase induction machine and the a.c. mains supply to give variable speed sub- and super- synchronous operation. The operating requirements for a three-phase cycloconverter operating in the secondary circuit of an induction machine have been determined. These considerations show that the cycloconverter control signal must be synchronised to the induced secondary emf of the machine. A novel generator based upon digital circuitry was developed to produce such a control signal. A theory in which the cycloconverter is represented as a controlled current source in the secondary circuit of the induction machine has been proposed and verified. Computer programs based upon this theory were used to analyse machine performance. A complete three-phase drive system has been designed and successfully operated over a range above and below synchronous speed with both braking and overhauling loads. Experimental observations have shown that smooth control is possible through synchronous speed.
Date of award1975-01-01
Awarding institutionUniversity of Leicester