The Research Of Underactuated Three-Phase Voltage-Source PWM Rectifier

The research of three-phase PWM rectifier has become popular in and outside the country for its excellent performance, such as sine curve of the input current, unity power factor, double-direction transmission, and fast dynamic response, and so on. Also it is use more and more extensively in lots of fields, eg, active filter, unity power quality control, wind-turbine system. Meanwhile the proposition of quite a few new control theories, methods offers orignal ideas for control of the PWM rectifier.The mathematical description and general characteristics of the underactuated systems are studied in the paper, and the demonstration of the three-phase voltage source PWM rectifier as an underactuated system in theory is given out. Also, the partial feedback linearization of the underactuated systems is classified, and the normal forms of underactuated sytems are proposed according to transformation of coordinate.In this paper the EL model of three-phase voltge source PWM rectifier is deduced based on Euler-Lagrange formula, the controllability of the EL system is discussed. Then, the characteristic of underactuate is proposed and the normal form of the EL model of three-phase voltge source PWM rectifier is deduced based on the deep study of the EL model. Also, the passivity of the system is another result which makes possible the passive-based control of the system. Meatime, the discussion of the system as a non-minimum phase system is holded out.There are two kinds of nonlinear control strategies studied in the paper: control law based on normal form and passivity-based control law which is often used for underactuated systems. According to the normal form of three-phase voltage sourve PWM rectifier, the nonlinear control strategy is designed. The two kinds of passivity-based control laws are proposed: ESDI-PBC (Energy Shaping and Damping Injection-Passivity-Based Control), IDA-PBC (Interconnection and Damping Assignment- Passivity-Based Control ) according to the passivity of the three-phase voltage sourve PWM rectifier system. The simulation results show that these two kinds of nonlinerar control laws have excellent responses in power factor and fixed output control and the comprison between the two kinds of control laws is given out.Finally, the basic design for the experimental sample for three-phase voltage sourve PWM rectifier is proposed in this paper.