Experimental verification of a dual single-input single-output model of a three-phase boost-type PWM rectifier

This paper proposes a simple dual SISO (single-input-single-output) model for a three-phase boost-type PWM rectifier under balanced line voltage conditions. In the proposed model, the q-axis model is a first order linear system determining the power factor regulation, whereas the d-axis model, which is shown to be similar to a traditional DC-DC boost converter, is a second-order non-linear system determining the power delivery. It is much easier to analyze and control a complex three-phase PWM rectifier using the proposed model. In addition, the complex non-minimum phase feature inherent in a AC-to-DC rectifier becomes a simple right half plane (RHP) zero appearing in the small-signal control-to-output transfer function of the proposed d-axis model. The knowledge of RHP zero´s location is vital to the successful design of a stable controller for the rectifier, as the presence of the RHP zero imposes a strict limit on the achievable closed loop performance. The validity of the proposed model is verified through experimental Bode plot results obtained using a hardware prototype