Analysis Of Testing Mechanism And Method For Electromagnetic Compatibility Of Power Electronic Devices

With the rapid development of the electronic information industry,power electronic devices with power converters as the core are being widely used in various industrial fields,nearly all electrical energy conversion equipment needs to use power electronic devices.Power semiconductor device as the key part of electrical energy conversion,the voltage and current transients caused by high-speed switching operations bring serious electromagnetic interference problems to power electronic devices.These interferences seriously pollute the surrounding electromagnetic environment and power system through the coupling of conduction and radiation.For increasing the adaptability of power electronic devices in complex electromagnetic environments,reduce the electromagnetic interference between various devices and enable various devices to work normally,the research on the electromagnetic compatibility of power semiconductor devices has become an urgent task.Based on this,this paper focuses on the issues related to the electromagnetic compatibility testing technology of power electronic devices represented by power converters.The main tasks are as follows:(1)On the basis of mastering the basic theory of electromagnetic compatibility,the theory and main test items of electromagnetic interference and electromagnetic immunity are described,then analyzed the propagation paths of differential mode interference and common mode interference coupling.In addition,the dual current probe impedance test method is explained in detail.(2)On the basis of mastering the basic knowledge of conducted interference test,the calculation method of loop impedance and loop current is analyzed,and an alternative conducted emission test method without LISN is proposed.Using a switched-mode power supply(SMPS)as an equipment under test(EUT),combined with its actual working state,the equivalent alternative method of conducted emissions measurement under no-load and on-load conditions is studied.The feasibility and universality of the proposed alternative method are proved by the experimental results.This method can be used to establish a relationship between the laboratory and the application environment,and the equivalent substitution can be achieved.(3)Based on mastering the test principle and test procedure of bulk current injection(BCI),the impact of test position changes on test results in the test of the bulk current injection substitution BCI method with ISO11452-4 was studied.The transfer impedance curves of the current monitoring probes corresponding to different interference injection positions are measured experimentally,and the effect mechanism of the test position of the substitution method at different frequencies on the test results is obtained.The DC-DC converter is used as an equipment under test to evaluate its bulk current injection immunity performance.The experiments show that the change trend of the transfer impedance affected by the injection position is consistent with the results of the DC-DC converter’s immunity performance measured by the substitution method,which proves the universality of this method and prefects the bulk current injection test technology,which has certain practical significance.