Research On Control Algorithm Of The High Power Factor Reversible Rectifier

The wide applications of power electronics equipment have caused ever increasing harmonic pollution. It is important to eliminate the harmonic pollution and improve the power factor. This paper mainly investigated the algorithms of Pulse Width Modulation (PWM) rectifier and aimed at enhancing the efficiency of rectifier energy transform and reducing the harmonic by improving the algorithms. The possibility and necessity of integrating different algorithms were systematically discussed through analyzing the control result of classic algorithms. A method named"double Hysteresis"was proposed, which used the active current value as the reference variable for the combination of different algorithms.This paper analyzed the principle of two algorithms of hysteresis Space Vector Pulse Width Modulation (SVPWM) and sliding mode current control, and simulated the rectifier systems which use two control algorithms in Matlab/simulink. The results of hysteresis SVPWM algorithm were satisfactory with achieving unity power factor. This system was able to switch between rectifier and inverter state and it can be employed to design actual system according to the simulation model. During the simulation of sliding mode current control, the description of sliding mode is successful, but the simulation results still need to be enhanced further.In addition, this paper discussed the issues of rectifier system simulation in Matlab/simulink, such as the establishment of rectifier's mathematics model, and the coordinate transformation in Matlab/simulink. The rectifier mathematical model was established in the 3-phase stationary coordinate (a, b, c) system and 2-phase rotate coordinate(d,q)system. The simulation of hysteresis SVPWM algorithm was conducted based on the 3-phase coordinate system and the simulation of sliding mode current control was done based on the 2-phase coordinate system. Coordinate Transformation Module's function can be converted between the 3-phase stationary coordinate system and the 2-phase rotate coordinate system. Not only can this function meet the needs of the control algorithms, but it also provides a method analyzing 3-phase intersect flow in the coordinate (a, b, c) through the direct flow coordinate (d,q).