Steady-state performance of the DC motor supplied from single-phase rectifier with step-up converter-a unity power factor converter

It is shown that the voltage step-up converters supplying DC motors can be operated at a unity power factor when supplied from single-phase rectifiers. If the duty ratio of the main switching device in the step-up converter is continuously adjusted, it is possible to maintain the line current almost sinusoidal and in phase with the input voltage. This remarkable property can be obtained from a certain minimum critical current up to values in excess of the rated armature current