A PWM control method has been developed that provides optimum performance of inverter-fed induction motor drives by minimizing additional losses and torque pulsations. That method has been employed for many years in an inverter-fed induction motor drive series where the frequency converter has a diode rectifier-dc chopper-PWM inverter configuration. PWM is used to obtain high quality output waveforms. A diode rectifier-PWM inverter configuration has also been developed that employs pulsewidth ratio control in the inverter so as to keep the optimum performance of the previous system with the same inverter configuration. A special commutation sequence had to be devised that takes into account the limitations imposed by the inverter commutation circuitry. It is shown in the paper that due to various modes of operation and the internal impedances of the inverter the flux waveforms of the motor become distored, that by generating undesirable harmonics, deteriorates the efficiency of the optimization unless proper measures are taken. The operation of the control system that compensates the effects, distorting the flux waveforms, is described in some detail. Results of laboratory tests of an actual system are also presented. The method of analysis is based on the use of Park vector representation.