Research On Unbalanced Valve Side Winding Current Issue And Mutual Inductance Of The 12-pulse Common Core Rectifier Transformer

In recent years,with the rapid development of power electronic technology,high power rectifier technology plays a more and more important role in many traditional industries and high-tech fields.It transforms alternating current into direct current using power electronic devices,opening up a new way of energy transformation and utilization.Especially in the electrolysis process,based on the requirement of the efficiency of rectification,current stabilizing precision,reliability and production cost etc,the 12-pulse common core rectifier transformer has been used more and more widely.In practical application we find that because of valve side winding turns ratio mismatch and phase difference and other reasons,the valve side winding current of the 12-pulse common core rectifier transformer is not balanced and will produce a kind of current not flowing through the load,and the mutual inductance between the valve side winding will also have a certain impact in the whole rectifier system.It is an urgent problem to be solved.Based on the above mentioned thing about unbalanced valve side winding current issue and mutual inductance of the 12-pulse common core rectifier transformer,this paper studies the following aspects:Firstly,this paper introduces the research background and significance of the topic,summarizes the research situation and the problems of high power rectifier system,analysis the research situation of unbalanced valve side winding current issue and mutual inductance of the 12-pulse common core rectifier transformer,establishes the research direction of this paper.Secondly,this paper elaborates the topological structure of the high power rectifying system.After the introduction of some traditional rectifier transformer,this paper describes a new rectifier transformer based on the principle of the inductive filtering,and discusses the difference between two kinds of the 12-pulse rectifier transformer.Then this paper equivalently analysizes the circulation of 12 pulse rectifier system and the valve side winding current imbalances of the 12-pulse common core rectifier transformerare.It studies the causes of circulation,the circulation theory based on different methods and the specific measures to limit the circulation.Next,we analyze the mutual inductance of the 12-pulse common core rectifier transformer,study the influence factors of rectifying system for overlapping angle and presents the calculation method of mutual inductance,obtain the inductance matrix of valve side winding by using Ansoft simulation software.Finally,this paper uses Matlab simulation software to build a model of the 12-pulse common core rectifier transformer which simulating the two problems above,draw a conclusion.