RAPID TRANSIT PROPULSION SYSTEMS

DATA ARE PRESENTED CONCERNING THREE CHOPPER-CONTROLLED DC PROPULSION SYSTEMS FROM A PERFORMANCE EVALUATION OF EACH PROPULSION SYSTEM, AND A DESCRIPTION OF INDUCED RIPPLE CAUSED BY COMBINATIONS OF THE THREE SYSTEMS. PERFORMANCE, INTERFERENCE, AND ENERGY-CONSUMPTION TESTS WERE CONDUCTED ON THE SERIES CHOPPER SYSTEM, THE SHUNT-RESISTANCE CHOPPER SYSTEM, AND THE SEPARATELY EXCITED DC CHOPPER SYSTEM. FAST RESPONSE AND MINIMUM DEAD TIMES ARE PRIME PERFORMANCE OBJECTIVES OF BAY AREA RAPID TRANSIT (BART) FOR ANY PROPULSION SYSTEM TO BE OPERATED UNDER PRECISE AUTOMATIC CONTROL. ALL SYSTEMS TESTED EXHIBITED AN EXCESSIVE VALUE OF DEAD TIME IN ONE OR MORE AREAS WHICH IS INHERENT TO THE BASIC DESIGN. JERK CONTROL WHICH IS IDEALLY A PURE RAMP FUNCTION, PROVED TO BE SLIGHTLY INCONSISTENT ON ALL THREE SYSTEMS. THE SERIES-CHOPPER AND SEPARATELY EXCITED SYSTEMS CLOSELY APPROXIMATED THE DESIRED RAMP FUNCTION, BUT APPEARED TO INCREASE THE JERK VALUE AS TRACTIVE-EFFORT DEMAND WAS INCREASED. THE SHUNT-CHOPPER SYSTEM EXHIBITED EXCESSIVE INSTANTANEOUS JERK VALUES DURING THE BUILD UP OF POWER AND THE BUILD UP OF DYNAMIC BRAKE. ACCELERATION AND BREAKING RATES WERE GENERALLY WITHIN THE ACCEPTABLE LIMITS FOR ALL SYSTEMS. OSCILLOSCOPE MEASUREMENT OF CHOPPER-INDUCED RIPPLE ON THE COLLECTOR POWER SUPPLY RAIL INDICATES THAT TWO OF THE THREE SYSTEMS ARE GENERALLY WITHIN ACCEPTABLE LIMITS. HOWEVER, REFLECTED INTERFERENCE IS DIRECTLY DEPENDENT ON THE AMOUNT OF FILTERING INCLUDED IN THE POWER CIRCUIT AND THE FREQUENCY AT WHICH THE CHOPPER OPERATES. IT IS CONCLUDED THAT THE GENERAL PROBLEM OF RIPPLE AND INTERFERENCE IS CRITICAL TO TROUBLE-FREE OPERATION OF VEHICLE ELECTRONIC SYSTEMS, AUTOMATIC-CONTROL SYSTEMS, AND COMMUNICATIONS SYSTEMS. POWER CONSUMPTION OF EACH SYSTEM UNDER TEST WAS MEASURED OVER THE SAME TEST ROUTE OF PROGRAMMED SPEED LIMITS, ACCELERATION RATES, AND KNOWN DISTANCE. TEST RESULTS INDICATE LOWER VALUE OF ENERGY CONSUMPTION PER CAR MILE THAN HAD BEEN ANTICIPATED. THIS INDICATES THAT HIGH VALUES OF SYSTEM EFFICIENCY WERE PRIME FACTORS IN THE DESIGN OF EACH SYSTEM.

  • Supplemental Notes:
    • Tr 4, Vol 2, 157 PP, 86 FIG, 1 APP
  • Corporate Authors:

    San Francisco Bay Area Rapid Transit District

    P.O. Box 12688
    Oakland, CA  United States  94604-2688
  • Publication Date: 1968-9

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Filing Info

  • Accession Number: 00241147
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 26 1994 12:00AM