Research On High-power IGBT Drive Technology For Medium And High Voltage

As a third-generation power semiconductor device,IGBT(insulated gate bipolar transistor)has developed extremely rapidly and is widely used in general-purpose inverters,electric traction,electric vehicles,high-power switching power supplies,photovoltaic inverters,Wind power converters and other fields,and IGBT drive circuits are very important for the reliable operation of IGBTs,directly related to the efficiency,reliability and safety of the system.Although there are many IGBT special drivers at home and abroad,and even some drivers have superior performance,they are quite expensive.Therefore,designing a driver with good performance and low price is of great significance to the power electronics industry.In view of the above problems,the main research contents and research results of this paper are as follows:(1)Firstly introduce the internal structure,switching characteristics,safe working area and IGBT failure mechanism of IGBT.According to the requirements of IGBT for the driver,determine the voltage,isolation mode and protection circuit driving scheme of IGBT gate drive circuit and the overall frame diagram of IGBT driver.(2)The IGBT drive input interface circuit is designed to suppress the glitch signal with a small pulse width in the drive signal.Then,in order to realize the signal isolation function,the principle of magnetic isolation signal transmission is adopted,and the modulation and demodulation circuit with high speed transmission,wide duty cycle and strong anti-interference is designed.The feasibility and effectiveness of the modulation and demodulation circuit are verified by experiments.The drive performance then selects the type of IGBT drive gate circuit.(3)In order to realize timely protection under fault conditions and short delay time under normal conditions,a drive protection circuit is designed.Detailed analysis of overcurrent fault soft shutdown,power supply undervoltage protection,overtemperature protection,and blocking of the driver for 10 ms is only reset when the controller outputs a low level driver.According to the previous design and theoretical analysis,the simulation software is used to verify and analyze the circuit,and the protection circuit can detect the fault in time and perform the shutdown function.(4)Considering the high power isolation voltage level,additional drive power is required,and an isolated power supply with stable output voltage is designed to test the stability of the power supply voltage through experiments.