Stability analysis of nonlinear voltage inverter-induction motor system

The paper highlights the increased instability of the induction motor due to the nonlinearity introduced by the voltage inverter, nonlinearity produced by the dead time required for switching devices on the same phase. Voltage errors on phase and between phases against the load null are presented, as well as the fact that phase voltage error against load null is in phase with the current. This permits us to consider that the inverter behaves on each phase as an ideal voltage source series connected with a variable resistance, that leads to an increased motor instability degree. The results obtained by computer simulation are presented.