Research Of High-frequency Excitation Sources And Magnetic Loss Measurement

With the development and application of new wide-band semiconductor material technology,power converters rapidly develop toward high-frequency and power density.Therefore,the loss of high-frequency magnetic components becomes a vital issue in the field of high-frequency magnetic technology.The measurement technology for magnetic component loss is the basis for evaluating magnetic element loss because the measurement accuracy affects the analysis,optimization,and modeling of magnetic element loss.In the high-frequency environment,the measurement circuit's distribution parameters,the sampling circuit,and the nonlinearity of the core material profoundly affect the accuracy of the measurement method,which makes the measurement technique of magnetic element loss face serious challenges.Therefore,this paper deeply studies the loss mechanism of magnetic components and the loss characteristics at high-frequency and studies the high-frequency PWM excitation source and highfrequency loss measurement method.The main research contents and achievements of this paper include:Firstly,the excitation waveform of magnetic elements in the power converter is mostly PWM waveform.In order to research the loss of magnetic components under high-frequency PWM excitation source with man-machine is developed.A full-bridge inverter circuit based on TMS320F28335 digital control is designed for the excitation source using Gan switch as power devices.The parasitic parameters in the highfrequency driving process are studied in detail,and the PCB layout is optimized.Lab VIEW software is used to create a human-computer interaction interface.Through the communication between the host computer and DSP,the control of frequency,dead time,and duty cycle parameters can be realized,which can generate PWM excitation waveforms under different operating conditions.Experiments show that the established high-frequency PWM excitation source can generate PWM waveforms with different duty cycles in the frequency range of 50?1000k Hz.Secondly,the main influencing factors of the traditional AC power measurement method in measuring the loss of high-frequency magnetic components are analyzed in depth.This paper proposes a high-frequency inductor winding losses measurement circuit and method that can reduce the measurement impedance angle.The working principle of the measurement circuit is discussed in detail to study how the key factors affect the measurement accuracy during the measurement process.A hollow inductor made from a 3D printed toroidal skeleton was used as the measured inductor under test,and experiments were conducted to measure winding losses at different frequencies.The experimental results show that the proposed method can effectively reduce the measurement impedance angle and realize the accurate measurement of winding loss under high-frequency excitations.Finally,to realize the accurate measurement of core losses in the high-frequency case,the characteristic factors of significant errors caused by phase errors when measuring core loss by the AC power meter method are analyzed and obtained from the perspective of energy.The working principle of the measurement is analyzed in detail,and the measurement circuit is designed.Simulation of the designed core losses measurement circuit using Multisim circuit simulation software.The efficiency of the proposed method is verified,the proposed method realizes that the measurement impedance angle is close to 0°,which overcomes the influence of the larger measurement impedance angle on the measurement error of core loss.