GENERALIZED HYBRID COMPUTER TECHNIQUE FOR SIMULATING INVERTER-FED AC MOTORS DRIVES

In the paper an investigation technique is described useful for studying steady state and dynamic performances of convertor-fed AC drives, by way of hybrid computer and with the opportunity of directly supplying the machine model with the convertor's voltage waveforms. Starting from some general considerations concerning the possibility of describing a quite general supply voltage system by way of an opportune space vector, it is pointed out that the opportune knowledge of such vector in module and position is sufficient to define the input voltages valid for any two-phase equivalent rotating machine model. It is shown that for an inverter-fed machine the module and argument space vector determination and the input model voltages are deducible from the real inverter voltages, for any reference frame, with an opportune hybrid technique. A natural hybrid simulation technique is deducible. Some examples are reported concerning the method application to the case of an inverter-fed variable speed synchronous drive when different modulation techniques are utilized.