Research On Parasitic Parameters Of Electromagnetic Compatibility Of Three-level Variable Frequency Speed Regulation System

The three-level variable frequency speed regulation system with IGBT as the core device has been widely used in high-power occasions due to higher withstand voltage characteristics and good operating characteristics.With the development of semiconductor devices and the development of control technology,the EMI problems caused by that the switching frequency continues to increase and the IGBT generates an excessively high voltage change rate and current change rate at the moment of turn-on and turn-off poses a serious threat to itself and surrounding equipmentThe paper first analyzes the generation mechanism and coupling path of conducted EMI,and introduces the separate circulation paths of common mode and differential mode interference in the system respectively.It is pointed out that the electromagnetic interference of the three-level variable frequency speed regulation system is largely determined by the high level of the system Frequency parasitic parameters.The experimental measurement of parasitic parameters requires high equipment and test environment.If the accuracy of parasitic parameters cannot be guaranteed,the accuracy of conducted interference analysis will be difficult to guarantee.Therefore,this paper uses the method of finite element software Q3 D extraction to extract the parasitic parameters of the system.Secondly,the resistance,capacitance,inductance,cable,DC laminated busbars and asynchronous motors and other components and equipment were modeled and analyzed based on the method of extracting parasitic parameters by finite element software.The impedance analyzer performs experimental measurements on the above components and equipment,and compares the measurement results with the results extracted by ANSYS Q3 D.It is concluded that the parasitic parameter software extraction method has more stable and accurate advantages,especially for the installed equipment The measurement is inconvenient and the software extraction method can make up for this deficiency.On the basis of accurately extracting the main parasitic parameters of the system,based on the combination of "field" and "road",the control strategy of "road" and the electromagnetic process of "field" are combined and the combination of Simploler and Maxwell field circuit The simulation analyzes the conducted interference of the three-level variable frequency speed regulation system.At the same time,it introduces the test method of conducted EMI in the high-power three-level frequency conversion speed regulation system,and analyzes the difference between the measurement of conducted interference based on high-voltage probes and the measurement of interference based on LISN and their respective applicable occasions.For the measurement method,the LISN network-based method is used in the field-circuit co-simulation.Finally,the field-path co-simulation results are compared with the actual measurement results based on the high-voltage probe.The simulation prediction of conducted interference has a higher accuracy conclusion.There are 81 figures,4 tables and 90 references in this paper.