High-power IGBT Module Overvoltage Suppression And Short Circuit Protection Research

Insulated gate bipolar transistors(IGBT)are widely used in various inverter power supply and frequency converter fields,and are the most important achievement in the third wave of power electronics technology revolution.With the continuous expansion of the electric vehicles,new energy photovoltaic power generation,and wind power generation markets,the application market for high-power IGBTs has become brighter,and at the same time,higher working stability of IGBTs under high-voltage,high-current and high-power conditions is proposed Claim.The overvoltage suppression and short-circuit protection circuits of high-power IGBT modules determine to a large extent the overall performance of the power module and the stability of the converter device.In the research of this subject,the author first explained the principle of IGBT,mainly introduced its structure,equivalent circuit,switching process,holding effect and safe working area,and focused on the distribution of parasitic capacitance inside the IGBT,and then analyzed the IGBT drive.The related principles of the circuit and the common methods of fault diagnosis and protection.Aiming at the problem of overvoltage spikes during IGBT turn-off,this paper analyzes the causes of overvoltages from the perspective of internal carriers,and proposes a pulse edge control method to suppress overvoltage spikes.In the declining stage of the collector current of the IGBT turn-off process,the gate voltage is adjusted by switching the switch signal to reduce the current drop speed and reduce the turn-off voltage spike.The feasibility of the method is proved by building a double-pulse test platform,and comparative experiments are carried out to summarize the difference in modulation effect under different frequencies,different duty cycles,different bus voltages and different load currents.This paper compares the gate charge fluctuations in the IGBT normal on state and the hard short-circuit fault HSF,load short-circuit fault FUL and over-current fault OCF state,proposes a new simplified short-circuit protection circuit scheme with gate charge as the core,and introduces in detail Circuit hardware and short circuit detection process.Finally,experiments are carried out for the above three abnormal conditions to confirm the feasibility of this protection scheme.