| The miniaturization and high-frequency development of advanced power transmission and transformation equipment has become a trend.Amorphous nanocrystalline and other new soft magnetic materials have become suitable materials for high-frequency transformer cores due to their high initial permeability,high saturation magnetic induction,low high-frequency loss,and low coercivity.Reasonable use of such materials can effectively reduce the volume of the equipment and improve the high-frequency performance of the equipment.Effectively measuring the hysteresis loop and loss of magnetic materials is an important step in the design of high-frequency transformer cores.In response to the need for accurate and flexible excitation voltages in the process of magnetic material measurement,this thesis designs a high-frequency magnetic characteristics measurement platform for soft magnetic materials,and carries out related tests theoretical analysis.The main research contents of this thesis are as follows:(1)Improved the driving mode of the switch tube of the traditional current-fed push-pull resonant inverter circuit,which can more accurately control the frequency of the inverter waveform,and match the frequency of the drive signal by adjusting the parameters of the resonant components,which can achieve 1kHz-20kHz Frequency adjustment of the frequency band.Using PSCAD software,it is proved that the improved circuit can realize the function of effectively outputting the inverter waveform.(2)Based on the improved push-pull resonant inverter circuit,a high-frequency measurement platform for the magnetic characteristics of the magnetic rings is built by using a DC power supply with a push-pull resonant inverter circuit instead of the traditional function signal generator and power amplifier,which has high transmission power,high efficiency,continuously adjustable resonance frequency,etc.The loss measurement of the magnetic rings under different magnetic flux densities was carried out,and the results were compared with the measurement results of the traditional measurement platform.The minimum error was 3.3%,which proved that the measurement results of the platform had high accuracy.(3)The use of adjustable resistors for real-time output voltage adjustment can effectively observe the change trend of the hysteresis loop with the excitation voltage.Use an equivalent inductance core model to replace the magnetic ring which to be tests.Besides,use Matlab/Simulink software to simulate and analyze the output characteristics of the measurement platform,such as the output voltage,output power,waveform distortion rate and other factors which have affected by load parameters and the frequency of the switches.The influence of this factors was studied.The simulation results are compared with the experimental results to verify the validity of the analysis results. |
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