Improved adaptive backstepping sliding mode control for a three-phase PWM AC–DC converter

Abstract

The stability problem of a three-phase voltage source PWM AC-DC converter is addressed through an improved adaptive backstepping method, which combines the following contents: input-output linearisation, adaptive backstepping method, error compensation and sliding mode control. The state equation of the three phase system is obtained by the power balance relationship between the input current and the output voltage, and then the coordinate conversion is carried out in order to design the controller. When the input-output linearisation method transfers the system model to a strict-feedback form, an improved adaptive backstepping control approach is given to stabilise the converter. Finally, the simulation results show that the improved method has three benefits: retain a faster stability of rectifier, reduce overshoot of DC voltage and bring about a real-time parameter estimation.