Study On High Frequency Modeling Of Key EMC Devices For High-power Switching Power Supplies

Switching power supplies are moving toward miniaturization and high power density with the rapid advancement of power electronics.The study of the electromagnetic compatibility of switching power supplies cannot be delayed in the face of an increasingly complex electromagnetic environment.Conducted interference acted as an important aspect of electromagnetic compatibility research has received more and more attention.At present,scholars at home and abroad have carried out many researches on the suppression of the conducted disturbance of the switching power supply and the simulation prediction.In this paper,the high-frequency modeling of filter elements and switching elements based on AClink high-power switching power supply are studied.The thesis studies the inductors that are suitable for high-power switching power supply EMI filters.The windings of high-power inductors use multi-wire winding to divide the current and reduce the effects of skin effect and proximity effects because of the high voltage and high current characteristics of high-power power supplies.The calculation method of the inductance and distributed capacitance of the multi-winding induction coil are derived by theoretical analysis and formula deduction on the basis of the single-wire wound inductor coil.In order to avoid core saturation,core saturation and analysis methods are given.The calculation method of leakage inductance of common mode inductance and the estimation method of inductor coil loss are given.Simulations and experimental tests are performed on differential-mode inductor coil samples for EMI filters for 100 kW and 30 kW switching power supplies.Using the method of using a wide copper tape instead of multiple wires and winding around the enameled wire,a three-dimensional modeling and simulation calculation was performed.The inductance and distributed capacitance of the inductor obtained by this method are in good agreement with the measured values,and at the same time,the calculation time and the calculation memory are saved.And use an impedance analyzer to test the electromagnetic parameters.It is concluded that the theoretical calculations,simulation values and test values of the inductance and distributed capacitance of the inductor coil are in good agreement.The maximum error of the theoretical calculation value of the inductor relative to the test value is 6%.The maximum error of the simulation value relative to the test value is 0.2%;The maximum error of the theoretical calculation of the distributed capacitance relative to the test value is 7.3%,and the maximum error of the simulation value relative to the test value.It is 4.7%.The study of IGBT electrical behavior modeling is carried out.An IGBT modeling method suitable for electrical engineers is proposed.This method does not require semiconductor knowledge.Based on the double-pulse experimental test data,the IGBT electrical behavior model is modeled.Compared with the traditional modeling method based on Datasheet manual,this method has higher accuracy and can more accurately reflect the dynamic characteristics of current and voltage at the instant of IGBT turn-on and turn-off,and is suitable for circuit simulation and prediction platform.