Transformer Integrated Filtering Theory And Its Application In Shipboard 12-pulse Rectifier System

With the development of integrated power system and power electronics in shipboard power system,the power quality problem is becoming more and more serious.The main propulsion system and the large amount of nonlinear load produce serious harmonic pollution.The reliability requirements of the ship to the electric equipment are extremely high.At present,the harmonic suppression of the main propulsion system mainly adopts the combination of multiple rectification and passive filtering.This filtering scheme can't deal with the bad effect caused by the harmonics on the transformer itself,the loss and the noise level are higher,and too much space is occupied with this filtering scheme.Aiming at the widely used 12-pulse rectifier system,a new method of transformer integrated filtering and a new wiring scheme for 12-pulse rectification are proposed.Around this scheme,this paper has carried out the research work from the following aspects:Firstly,the present situation and characteristics of shipboard power system are introduced.The sources of harmonics of ship power system are analyzed,and the advantages and disadvantages of various harmonic suppression methods are compared.This paper analyzes the technical scheme of 12-pulse rectifier combined with passive filtering.Compared two kinds of structures of the 12 pulse rectifier transformer structure.The transmission characteristics of the harmonic of the traditional ship 12-pulse rectifier system are analyzed.The wiring scheme and the harmonic suppression principle of the traditional 12-pulse rectifier system harmonic suppression method are analyzed.The harmonic model of 12-pulse rectifier system with traditional filtering method and its equivalent circuit are established.Secondly,the transformer integrated filter theory has been deeply studied.The harmonic shielding mechanism of the integrated induction filter winding is studied,and the harmonic model of the integrated induction filter winding transformer is established,and the realization condition of the filter effect is obtained.The winding arrangement and impedance design method of the integrated induction filter winding rectifier transformer in order to achieve the filter realization condition are introduced.The theory of transformer integrated filter reactor is studied.The non-orthogonal decoupling theory and the structure of the integrated filter reactor winding structure are introduced.The principle and method of power decoupling between the integrated filter reactance winding and other windings of the transformer are analyzed.The method of calculating the inductance value of the integrated filter reactor and the technical advantages are introduced.Thirdly,a new field-coupled simulation method is proposed for modeling and analysis of the new kind of transformer.The flow of the new field-coupled modeling and the calculation method of the inductance matrix and the coupling degree matrix are introduced.An integrated filter rectifier transformer model was established with Ansoft software,and the inductance matrix and coupling matrix were calculated.The inductance matrix obtained by electromagnetic simulation is used as the parameters of the integrated filter rectifier transformer coupled inductance circuit model.The current waveforms before and after the integrated filtering method are obtained,which proves the good filtering effect and the simulation correctness.Finally,a 12-pulse integrated filtering rectifier transformer is designed.The experimental results show that the theory of transformer integrated filtering is correct,and reflect the good filtering effect of integrated filter technology.