Two-Stage Sequentially Operated Regenerative Converters with Controlled Flywheeling

Separately excited dc motors fed by sequentially operated multistage converters are commonly used in mainline traction. The drive performance can be greatly improved by operating the fully controlled converters with controlled flywheeling. The analysis and performance of dc drive fed by two-stage sequentially operated fully controlled converters with controlled flywheeling are described. The modes of operation of the converter system are identified, and a method of performance calculation, taking these modes of operation into account, is presented. The nomograms and the analytical method of calculating them are presented for the calculation of optimum value of filter inductance. The performance of the drive with controlled flywheeling is compared with that with normal control. The modes of operation and certain aspects of drive performance are verified experimentally.