Advanced nonlinear control of three-phasePWM rectifiers

Abstract

A nonlinear control of the three-phase PWM rectifier is proposed in which the input q-axis current and output voltage dynamics are modelled in a single-variable nonlinear system, with the d-axis current dynamics excluded. The nonlinear model is linearised by a feedback linearisation technique, not by small-signal analysis, which makes it easier to design the controllers. Furthermore, with the inner capacitor-current control loop, the direct voltage transient response can be faster. The size reduction of the DC electrolytic capacitor due to the fast voltage control of the proposed scheme is studied. The validity of the scheme has been verified through experiment using a TMS320C31 DSP chip.