SIMULATION STUDY OF AN OPTIMAL NUMERICAL CONTROL OF A THREE-PHASE CYCLOCONVERTER.

The paper presents a study of the problem of discretization which is linked with the numerical control voltage of a three-phase cycloconverter controlled by a microprocessor. The study is made to define a compromise between either using large number of steps of the desired control voltage, which lead to increase the memory size of the microprocessor, or using small number of steps, which lead to a high rate of harmonic of the load current. To achieve such study, a digital simulation of the whole system is used. Two types of numerical control-voltage are compared in relation to the harmonic spectrum of the load current. Conclusion is given for the optimum number of steps and the types of the numerical control-voltage.