An explicit state model of a synchronous machine - transformer - SCR bridge unit

A rigorous mathematical model of a synchronous machine-transformer-thyristor bridge unit is presented in an explicitly expressed state space form with coefficients which are explicit functions of conventional parameters. The use of the model is demonstrated by considering the charging circuit of a high power pulse generating system as the dc network. An illustrative set of simulation results is shown from which relevant information is obtained. Comparison of the simulation results of the full order model and approximate models shows that the system can be accurately represented by a third order reduced model for the short term response and by a second order reduced model for the long term response. The results also show that the harmonics contents of the machine line currents are reduced by using a delta-Y or Y-delta transformed connection. Finally, it is found that the effect of the transformer magnetization current is negligible.