Research On Load Adaptation Range And Expansion Method Of Four Star Rectifier Based On AIPR

The three-phase half bridge parallel rectifier system is widely used in low voltage and high current and high power industries,such as in electrolysis,electroplating and electric heating system and so on.But the strong non-linearity of the rectifying device brings serious harmonic pollution to the power grid.The active harmonic suppression technology based on rectifier DC side can greatly reduce the current harmonics at the grid side,Therefore,this paper is based on active harmonic suppression technology,A four star rectifier based on AIPR(Active Inter-phase Reactor)is studied,The load adaptability and the feasibility method to broaden the load range of adaptation are also studied.This paper starts from the working principle of the four star rectifier,B y analyzing the structure of the magnetic device,the mathematical model of the rectifier system is established,The current and voltage characteristics of the AC a nd DC side of the system are determined;The expressions between the grid side current and the load current and the DC side circulating current are derived;The characteristics and capacity of the auxiliary circuit of the AIPR secondary side analyzed;Finally,the type of circulating current in the DC side and the mechanis m of the circulating current suppression grid current harmonic are obtained when the grid current harmonic is minimum.In order to verify the mechanism of the circulating current suppression ne t current harmonic,A single-phase PWM rectifier circuit is designed and implemented as an active auxiliary circuit to suppress the current harmonics in the grid side.Firstly,the main topological structure and working principle of the auxiliary circuit are given,and the parameters of the main components are designed.Then,the control circuit and drive circuit for extracting the characteristic harmonic energy are designed;Finally,through simulation and construction of 2.5kW output power of the four star rectifier based on AIPR,the effect of current on the harmonic suppression of the grid side is verified.Based on the simulated and physical platform,the adaptability of the two common load(LR and LCR)of the four-star rectifier based on AIPR is studied.This paper analyzes the relationship between the output current ripple,the circulating current and the harmonics of the grid.Then,according to the influence of different load parameters on the load adaptability,the adaptive range of these two kinds of loads is determined;The corresponding simulation and experimental verification are given,which is of great significance to selecting parameters of different load types in practice.By analyzing the load adaptability of rectifier system,it can be concluded tha t the uncontrollable feedback current of PWM rectifier circuit increases the ripple of system output current,While the large inductance load causes the system cost and volume increase,also limits the adaptive range of the load.Therefore,in order to effectively broaden the range of load,the energy required for the system harmonic energy and required for ripple suppression are analyzed,A method of stabilizing the output current ripple of rectifier system is proposed.The structure and working principle of the converter are explained in detail.Finally,the equivalent effect of ripple suppression and large inductance is verified by simulation.