Design And Realization Of High-precision Testing System For DC Switching Power Supply

With the increasing application scenarios of switching power supply,the use environment of switching power supply is becoming more and more complex,and the requirement of switching power supply quality are also getting higher and higher.At present,the testing of factory switching power supply usually adopts the testing method of multi-equipment combination,which has low working efficiency and low precision of testing results.According to the testing standard of switching power supply,the high precision and high efficiency testing method of switching power supply is studied in this paper.The main research contents are as follows:Firstly,the index of the switching power supply testing system is analyzed,and the characteristics of the parameters to be measured are determined.In order to improve the testing accuracy,two aspects are studied.One is to analyze and design the signal acquisition circuit and study the influence of circuit noise on the testing accuracy.The other is the study of data processing methods after the completion of signal acquisition.Secondly,the acquisition circuit is designed according to the testing index of the system,the channel conversion circuit based on different gears is designed according to the characteristics of different signals,and the voltage signal is taken as an example to design the post-stage analog signal processing circuit.The divide-voltage attenuation circuit,program-controlled gain circuit,anti-aliasing filter circuit and AD conversion drive circuit are designed for large voltage.The influence of parasitic capacitance on the circuit is analyzed and optimized by Cadence simulation.Thirdly,the corresponding digital signal processing algorithm is designed according to the characteristics of the measured parameters of the power supply.A median average compound filter algorithm is designed to process the slowly varying signals.For transient signals,the methods of cubic spline interpolation and least squares fitting were compared,and the least squares processing algorithm was selected and the appropriate least squares polynomial was selected.An improved VMD-Hilbert algorithm was proposed for the ripple of the parameters to be tested and the simulation was carried out.The optimal K value determination algorithm based on fuzzy entropy was designed for simulation,and the effectiveness of the algorithm was verified.The amplitude-frequency characteristics of the signal components are obtained by the Hilbert transform.It is proved that the improved VMD-Hilbert algorithm has better extraction effect on the ripple components and high testing accuracy.Finally,design and write the software module,detailed design of the software framework,show the final effect of the software.The system verification platform was built,and the testing effect of the switching power supply testing system was verified from the perspective of the characteristics of parameters to be tested,which reached the expected indexes.Meanwhile,the finished prototype of the switching power supply testing system was completed.