Dual frame cascaded controller design for three phase PWM boost rectifier under generalized supply voltage conditions using singular perturbation method

This paper proposes the design of a dual frame cascaded PI controller for the three phase PWM boost rectifier under unbalanced supply voltage conditions by using singular perturbation method. By inducing two-time-scale motions, namely fast motion sub-system and slow motion sub-system, the desired output transient performance can be achieved with stability conditions imposed on the fast and slow modes with a sufficiently large mode separation rate. The proposed controller is also insensitive to the non- linearities of the system and the variations in the plant parameters. Experimental test results obtained on a 1.6 kVA laboratory based PWM rectifier, validate that the controller can guarantee constant DC link voltage and unity power factor operation under the unbalanced supply voltage operating conditions.