Analysis Of Switching Characteristics And Application Research Of GaN Devices

With the development of power electronic devices towards the trend of high efficiency,portability and lightweight,the requirements for power semiconductor devices are increasingly high.However,the semiconductor devices of Si materials have basically developed to their theoretical limits and can no longer meet the needs of further development of power electronics technology.In this context,more and more researchers begin to pay significant attention to the third generation wide bandgap semiconductor devices represented by GaN devices.At present,the production technology of GaN devices has become mature,but there are still some problems to be solved in the application field.In this paper,the problems encountered in the application of GaN devices in the field of switching power supply are analyzed,and the application of GaN devices in the actual switching power supply is studied to meet the requirements of high power density.First of all,the classification of GaN devices,the equivalent model and structure of enhanced GaN HEMT are briefly introduced in this paper.The working principle and switching characteristics of enhanced GaN HEMT are analyzed.The loss analysis and switching characteristics simulation of enhanced GaN HEMT are carried out.Since GaN HEMT has very high switching speed and extremely low on-off resistance,it will lead to GaN HEMT having large dv/dt and di/dt in the switching process,which will cause spikes and oscillations in the waveform of GaN HEMT during the switching process.Secondly,the reasons affecting the switching speed of GaN HEMT are analyzed,and the methods to suppress the peak and oscillation in the waveform of GaN HEMT in the switching process are studied.By designing a reasonable PCB placement,parasitic parameters in PCB board can be reduced so as to effectively suppress the spikes and oscillations in the switching waveform of GaN HEMT.Based on the characteristics of GaN HEMT,it is applied to the robot power supply.The robot has a high degree of internal integration,so it has a very high requirement for the power density of the power supply,and the robot power supply based on GaN HEMT can achieve this goal.The power supply prototype adopts synchronous rectification Buck converter.After each parameter is designed according to the design steps,the hardware circuit of the robot power supply is designed,and the PCB placement of the robot power supply is optimized.A 170 W experimental prototype of robot power supply was designed and manufactured,and its performance and waveform were tested and analyzed.The performance test results of GaN HEMT robot power supply prototype show that its maximum efficiency reaches 95.476%,compared with the power supply prototype made by Si MOSFET with the samevoltage grade,the efficiency is improved by nearly 2%.It proves that GaN HEMT has great application value and development potential in the field of high power density switching power supply.