Research On Predictive Direct Power Control Of Three-phase Voltage-source PWM Rectifier

Three-phase voltage source PWM rectifier is widely used with the development of powerelectronic technology because its control performance in their ability of two-way energyfollowing and power factor. However，if this kind of PWM rectifier is used without controlsystem，it is a serious problem. So, we must research a new effective control scheme. Directpower control is a completely different control scheme from traditional rectifier controlscheme. It has a lot of advantages such as simple structure and good dynamic performance,but it also has shortcomings such as variable switching frequency. In this paper, we use modelpredictive control to modified direct power control scheme.First, we study the development of three-phase PWM rectifier control theory developmentand research the main problems of direct power control theory inland and abroad. Throughcareful analysis of the rectifier control requirements and the characteristics of modern digitalcontrol platform, we decide to use predictive control scheme to modified the traditional directpower control.Secondly, we study the mathematical model of three-phase PWM rectifier in the staticcoordinates and introduces the principle of direct power control system in detail andcomposition, as well as the function of each part. In traditional direct power control, the SVTis the core of the whole control system, the SVT of direct power control system play animportant role in control performance. But predictive direct power control break the limitationof the switch table by traversing the table to seek the best switch vector, it is better insteady-state,dynamic control effect.Then, we study the direct power control with a fixed switching frequency, and twodifferent methods are researched. One is a kind of scheme combined with SVPWM and directpower control, we use SVPWM modulation technology realizing the fixed switchingfrequency. The other one is similar to the SVPWM technology, but we use the power insteadof the average voltage vector, this is more suitable for direct power control.Finally, we mainly research the models used in this paper. We also use the model to designthe DSP software and use PIL tools to verify the codes.