Computer simulation of a cycloconverter drive and development of a full digital field oriented control

The paper reports the results of a research in the simulation and control fields for the analysis of the operation of cycloconverter drives and the design of a new advanced digital control for such equipments. It describes in detail a simulation tool realised in C language to study power and control problems arising when using a cycloconverter to feed an AC motor. The power section is represented by means of a new model that allows easy adaptation to various circuit structures in steady state, transient and fault conditions. It also allows immediate calculation of electrical parameters sizing and cost of the components. Concerning the control section, the simulator allows the analysis of hardware and software interferences, a discrete time model is used so that the same C language routines are valid and portable on the real system. As a result of this research Ansaldo Industria, in its Milan research centre, is on the way to test the first prototype of a 150 kW drive, based on a full digital controlled six pulse no-circulating current cycloconverter supplying an induction motor with field oriented control