Analysis of phase-controlled converters for induction motors

A phase-controlled converter for induction motors is analyzed, using a representation of semiconductor switching devices as two-state resistances. The steady state of symmetrically controlled converters (when the states of the semiconductor switching devices change periodically) is considered, and symmetrical components of the motor phase currents are used. This allows classical equivalent circuits of the induction motor to be used. As a result of the analysis the Fourier spectrum of the motor phase currents and electromagnetic torque is determined. An example that shows the application of the relations presented here is given.