The IGBT Gate Driving Circuits With Health Condition Monitoring Technique

As core devices of high power electronics equipments,high-voltage high-power insulated gate bipolar transistors（IGBTs）are usually employed in the efficient conversion,transmission and utilization of modern electric energy.The key to the optimal performance of the IGBT and the normal operation of the system is the reasonable match between IGBT modules and gate drivers.As important interfaces between IGBT modules and microcontrollers,the appropriate gate drivers do not only control the reliable operation and reduce switching stress and energy loss,but also ensure that the operation statues are limited to the safe operating area of the IGBT modules.At present,the common commercial technology for IGBT modules is the constant voltage-source gate driver with the constant gate resistors.To improve the reliability of IGBT modules,there are basic fault-detection methods designed in gate drivers with active clamping method or soft turn-off method,including over-voltage,under-voltage and over-current detection.Moreover,a small number of gate drivers implement successfully power supply protection method,active gate driving method or multi-level turn-off method to improve control accuracy and protection performance.Nowadays,gate drivers can only control and protect IGBT modules according to the current operating conditions.Benefiting from the refined and intelligent development of gate driving technology and the development of big data mining technology for driving control loop characteristic parameters,it has become possible to comprehensively obtain and monitor the operation status of IGBT modules through gate drivers.This paper proposes an IGBT gate driving circuit with health condition monitoring technique,in order to monitor the changes of the IGBT module’s operating state parameters during the whole life cycle,and provide guarantee for the IGBT conversion system’s protection and maintenance from the bottom device level.Firstly,the existing operating state parameters’characteristics of IGBT and the gate driver’s basic functional structure are investigated.The paper analyzes the parasitic parameters’effects on saturated on-state voltage drop V_ce（sat）,short-circuit current I_sc,turn-on delay time t_don and gate peak current I_gpeak using the equivalent circuit of high-power IGBT module.And based on the variation range under different aging degrees,the life cycle safe operating area is established.Then,the paper analyzes and compares the state detection methods’principle and realization of IGBT gate drivers.Secondly,the detection,protection and feedback methods for short-circuit faults are discussed.In consideration of IGBT’s short-circuit withstand capability,the paper presents the gate driving circuit that uses the data processing unit to realize the fault detection,record and feedback the cumulative short-circuit-fault times.The method can make the original short-circuit-fault times non-volatile even if the gate driver restarts,so as to ensure the short-circuit status monitoring during the full life cycle of the IGBT module.Then,the paper proposes the condition monitoring and protection circuit based on parallel comparison of quantized voltages.Taking V_ce（sat）and t_don as the detection signals,several specific thresholds are set based on the life cycle safe operating area.The detection signals are quantized by the specific thresholds,and the multiple-comparator circuit is used to monitor the state parameters’changes.The logic output signals are used to judge degradation degree of the IGBT module in real time,so as to realize the prediction of the IGBT modules’operating life cycle.Finally,the overall design scheme of the IGBT gate driving circuit is introduced,which integrates the short-circuit status monitoring and full-life-cycle operating condition.The gate driver has been developed and its welding and debugging work has been completed.And the low-voltage and high-voltage experimental platforms are built to test the performance and switching characteristics of the gate driving circuit.And the experimental results verify the feasibility of the IGBT gate driving circuit with health condition monitoring method in this paper.