High-power Ipm Key Technology Research Based On Integrated Shunt

Power semiconductor devices are the basis of power equipments and systems,and their safety,stability and reliability have a great influence on the stability of power devices and systems.As a representative of power modules,silicon-based IGBT IPM is recognized by the market for high integration and high power density and is widely used.IPM key technologies,besides chip technology and package manufacturing technology,both drive technology and short-circuit protection technology directly affect the stability and reliability of IPM.Hence,it is of great significance to study the driving protection technology of high power IPM.The structure and driving protection technology of IPM are studied in this paper.The main work and innovative results are as follows:1.To solve the problem of detecting blanking time in the VCE desaturation short-circuit detection method used in high power IPM,this paper proposes a scheme to integrate shunt on the IPM internal Direct Bonded Copper(DBC)to realize fast short-circuit detection without blanking time.The shunt is integrated at the emitter E end of the IGBT chip.By measuring the voltage at both ends of the shunt,the IC can be accurately measured.However,the shunt is integrated inside the IPM module,which brings parasitic parameters and generates heat.To study the power loss of the shunt and the influence on the module operating temperature,firstly,the power consumption of the IPM power unit of the integrated shunt is analyzed and the corresponding power consumption calculation method is given.Then,according to the thermodynamic theory,the Cauer thermal network model is established and the thermal resistance calculation method of the power unit is given.Finally,the finite element method is used to study the layout of the module power unit,and the simulation shows that the heat distribution of the staggered layout is uniform,the thermal coupling between the chips is reduced,and the thermal stress of the module is reduced,thus the feasibility of the scheme is verified.2.Aiming at the difficult problem of optimizing the module driving strategy,this paper proposes a back-propagation neural network optimized by the mind evolutionary algorithm to predict the optimal driving strategy of high power IGBT,which can realize the intelligent optimization of IGBT module driving parameters.A neural network prediction model is established to predict the turn-on and turn-off driving strategies of IGBT active gate driver with variable gate resistance.The weights and biases of neural network are optimized by mind evolutionary algorithm,and the optimal weights and biases are obtained.To verify the effectiveness and generality of the driving strategy prediction method proposed in this paper,the IGBT module of 4500V/900A is taken as an example to verify.Compared with the conventional gate driver,the predicted driving strategy reduces the turn-on energy loss,the turn-on time,the over-current,the comprehensive evaluation method,the turn-on delay time and the trailing voltage duration by 59.31%,46.38%,36.99%,65.65%,1.9,us,2.9?s,respectively.3.Aiming at the compromise of switching loss,voltage and current overshoot in IGBT driver design and the non-uniformity of driving effect evaluation method,this paper presents a method of simultaneous optimization of switching loss and overshoot with switching time as the constraint condition.This optimization method takes the switching time as the constraint condition and makes the switching loss and overshoot smaller without increasing the switching time,thus solving the compromise between switching loss and overshoot.In this paper,a five-coordinate radar image driving effect evaluation method is developed based on five parameters:switching loss,switching overshoot,switching time,switching delay and current voltage change rate.According to the evaluation method,the strategy that the five parameters of driving effect are all superior to conventional gate driver,which is called good driving strategy,thus providing a driving effect evaluation method for the driving strategy prediction model.4.Aiming at the problem of IPM short-circuit protection,the high-power IPM short-circuit protection circuit of internal integrated shunt is designed to realize fast short-circuit detection without blanking time.The trial production of 1700 V/150A IPM samples shows that the effect of integrated shunt method is obviously better than that of VCE desaturation method.The proposed IPM only need 380 ns and 1.4?s to detect short-circuit I and short-circuit II faults,respectively.The short-circuit withstand time of the short-circuit I and short-circuit II are only 2.06?s and 0.62?s,respectively.Furthermore,compared with the VCE desaturation method,the short-circuit energy loss of the short-circuit I and short-circuit II are reduced by 66%and 64.3%,respectively.In conclusion,the driving strategy prediction method proposed in this paper can be used to guide the driving strategy formulation of high power IGBT and IPM module drivers.A short-circuit fault detection method of integrated shunt solves the problem that IPM short-circuit detection has blanking time,and obtains good short-circuit protection effect.