The Dynamic Model of Three-phase Inverters with Magnetic Couples

In three-phase inverters, three-pole reactors and transformers are frequently used for consideration of cost and size. However, the magnetic couples between three phases make dynamic analysis of three-phase inverters very difficult. This paper will establish the dynamic model of three-phase inverters with three-pole reactors and three-pole transformers based on instantaneous symmetrical components transformation. This simple and practical model will decouple magnet fluxes between three phases. Analyses of three-phase inverters with magnetic couple based on this model indicates that instantaneous zero sequence voltages output from inverter bridges can greatly influence upon three-phase inverters, esp. in parallel inverter systems. The simulations and experiments validated the above conclusion.