Simulation of converter-synchronous machine drives in normal and fault operation

A multiport transient equivalent circuit models of synchronous motors applicable in the simulation of power converter drive systems, are presented. The proposed circuits exhibit networks with the same number of external terminals as the motor and model the machine behaviour directly in terms of the stator and/or rotor and mechanical variables as well. The main advantage of the approach is the ease of describing the system in terms of its topology. Thus, different control strategies for normal and fault operation of any converter-synchronous machine drives can be investigated. To determine the transient stator current, torque and rotor velocity for any desired supply voltage, frequency and load, the global converter-synchronous motor circuit is transformed into a sequence of DC analyses of resistive networks upon replacing each of the energy storage elements (inductances, rotor inertia) by a preselected implicit numerical integration algorithm. The approach is demonstrated using a 3-phase synchronous machine supplied by a voltage source inverter. The simulation results prove that the proposed approach can be recommended for CAD programs