Nonlinear state feedback control design for three-phase PWM boost rectifiers using extended linearisation

The technique of extended linearisation is proposed to design state feedback controllers for three-phase PWM boost rectifiers to achieve DC-bus voltage tracking and unity power factor. Despite the nonminimum phase feature of the boost rectifier, this approach provides direct DC-bus voltage control capability. A nonlinear state feedback law that smoothly interpolates stabilising gains at operating points with infinitesimally small distances is synthesised. The design process involves messy but routine symbolic computation of linear algebraic equations, and is accomplished with the help of MAPLE computer software. Experimental verification of the proposed control algorithm is conducted on a laboratory prototype. Comparisons with a Lyapunov-based controller and a linear PI-based controller are also provided, which demonstrate the salient performance of the proposed design.