Application Research On Three-phase Voltage Source High Power Factor Rectifier

Conventional AC/DC conversion circuits often adopt diode rectifier or thyristor rectifier,this kind of rectifier has the following shortcomings: harmonic components of the input current is high and power factor is low;the DC energy cannot be fed back to the grid.To overcome these shortcomings,PWM rectifier uses full-controlled power switching devices(such as IGBT)to replace the diodes and thyristors.This can not only make the power factor to be adjustable and the currents of grid side to be sinusoidal,but also can achieve dual energy flow.So,the research on high power factor rectifier has important practical significance.This dissertation mainly studies the three-phase voltage-type high power factor rectifier and its control problems.The main work includes the following contents:Firstly,the current research status of PWM rectifier at home and abroad is introduced,summary and analyzing on mathematical model,topologies and the control strategies of the PWM high power-factor rectifiers.Secondly,the working principle of three-phase voltage-source PWM rectifier is analyzed,and the mathematical models of PWM rectifier in three-phase stationary coordinate system and two-phase synchronous rotating coordinate system are established respectively.The control methods of the PWM rectifier are divided into the direct current control and the indirect current control.The analyzing and comparison on the commonly used double closed-loop control strategies of two direct control systems are carried out.The research shows that the steady-state performance of the current control mode in three-phase synchronous rotating coordinate system is better than that in three-phase stationary coordinate system.Thirdly,the system model of three-phase voltage PWM rectifier in synchronous rotating coordinate system is set up in MATLAB / SIMULINK environment,and the simulation research on its the controller is carried out.The simulative results indicate that the designed controller of the three-phase voltage-type PWM rectifier realizes the control targets of sinusoidal current and unity power factor at the grid side,DC voltage output stability,dual energy flow.Finally,based on the simulation experiments above,a three-phase high power factor PWM rectifier control device is designed In the designed system the control core is the DSP processor provided by TI,the system also includes voltage,current acquisition circuit,IGBT drive circuit and etc.The circuits' welding and preliminary debugging on them are conducted,and the results are satisfied.