Reseaerch On Load Adaptability Of Dual Pssive Double-tap Uncontrollable Inter-phase Reactor

As the connector of most industrial electronic equipment and power grid,power frequency rectifiers are widely used in industrial occasions.However,in high power applications,due to the non-linearity of the devices for rectification,the rectifier can inject a large amount of current harmonics into the grid.The conventional multi-pulse rectification technology can suppress the input current harmonics on the AC side to a certain extent,but the ability to suppress the input current harmonics on the AC side is limited,and the load types corresponding to high-power rectifier circuits are diverse.So,there are ripples on the output current,and the ripple containing a certain component will have a certain effect on the input current.This paper studies a dual passive double-tap uncontrollable inter-phase reactor for non-isolated occasions,focusing on the analyze of load adaptability and input current harmonic suppression characteristics of the system.The multi-pulse rectifier based on the dual passive double-tap inter-phase reactor uses an auto-transformer for phase-shifting and a double-bridge parallel structure for rectification.According to the relationship between the input and output currents of the auto-transformer and the switch function of the rectifier bridge,the relationship between the input current on the AC side and the output current of the two rectifier bridges is deduced.The circuit structure of the inter-phase reactor is discussed,and the type of the circuit on the secondary side can be selected depending on the application.The operating modes of the two-tap inter-phase reactor and the output currents of each rectifier bridges in different mode are analyzed.According to the relationship between the input current on the AC side and the current on the rectifier bridge,the harmonic suppression principle of the inter-phase reactor is obtained.Meanwhile,according to the load voltage expression of the inter-phase reactor in each operating mode,the necessary conditions for the operation of the secondary rectifier circuit are derived,and the optimal parameters of the inter-phase reactor with the lowest harmonic content of the AC input current are calculated.The correctness of harmonic suppression principle analysis and parameter optimization design are verified by simulation.Theoretical analysis of the load adaptability of the system to the output current with ripple under several common load types is given.The relationship between the output current ripple coefficient and the input current THD is given,and through theoretical derivation,the expression of the output current ripple coefficient is obtained,which gives the condition that the load parameter of the DC side should be satisfied when the input current THD of the grid side is kept within a certain range.The selection method of LC parameters for filtering are given,and the capacity of each magnetic devices in the rectifier circuit is analyzed.The correctness of the theoretical analysis is verified by simulation under different loads.Meanwhile,the multi-pulse rectification system based on the dual passive double-tap uncontrollable inter-phase reactor is compared with the conventional 12-pulse rectification system,so as to verify that the system studied in this paper has better application value.A multi-pulse rectification simulation platform based on the dual passive double-tap uncontrollable inter-phase reactor is built.The validity of the input current harmonic suppression of the inter-phase reactor and the correctness of the theoretical calculations of the optimal parameters are verified respectively.The load adaptability under different load types is studied,which provides a reference for the practical application of the multi-pulse rectifier system of the dual passive double-tap inter-phase reactor.