Design And Implementation Of 3kW Output Current Controlled Conversion System

VIENNA topology rectifier is a three-level voltage circuit which features low voltage pressure,low THD,high power factor and simple structure.So it has been widely researched by domestic and foreign scholars.Full-Bridge DC/DC converter with high power output capability can use its own parasitic parameters to operate in soft switching state,which makes it widely applied in high power applications.Design and Implementation of 3kW Output Current Controlled Conversion System is proposed based on laboratory project.Engineering design and optimization of front end VIENNA rectifier and back end Full-Bridge DC/DC converter are detailed disclosed in this paper.First,design and optimization of VIENNA rectifier are presented,the modeling and analysis of the three-phase VIENNA topology rectifier is proposed,then engineering design of the 3kW VIENNA system is detailed disclosed,including the design of energy storage elements,filter section and system control loop.Facing the input current harmonics issue caused by the distortion of the grid voltage,a selective harmonic current optimizing method is applied to eliminate the input current harmonic effectively.The resonance problem of LCL filter is solved by adding a damping section,which is easy for engineering realization.The topology and bipolar PWM control are introduced first in design and optimization of Full-Bridge DC/DC converter,then small signal model is derived.By using interleaving technology,voltage pressure of switching devices,current pressure of diodes and inductor current ripple are diseased,which makes easier hot sink design because power loss is evenly distributed.Engineering design of hardware parameters and system control loop are given in detail and simulation platform is built.Facing the output current distortion caused by slow output capacitor discharge before current reversing,a high frequency shoot through method is applied to discharge quickly and optimize output current.The effectiveness of the applied method and design solution is further verified by a 3kW prototype.