Research On Design And Optimization Method Of Three-phase Inverter Bridge Based On IGBT Power Module

With the economic development and social progress,the number of global vehicles has increased steadily.Nevertheless,the heavy use of fuel vehicles has increased energy shortages and environmental pollution.Electric vehicles that use the electric drive system of the motor and motor controller as the power,can convert electrical energy into mechanical energy.Comparing with fuel vehicles,electric vehicles have higher efficiency of energy utilization and no air pollution.Therefore,it is the general trend for electric vehicles to replace fuel vehicles.In recent years,there has been an upsurge to ban the sale of fuel vehicles and to promote electric vehicles in the world.China has also issued a series of policies to encourage the development of electric vehicles.At present,the energy density of electric vehicles is lower than that of fuel vehicles.Battery packs and electric drive systems generally account for more than 40% of the total vehicle quality.In order to realize the lightweight of electric vehicles,the importance of improving their power density is self-evident.The three-phase inverter bridge and its driving system are the core components of the power conversion of the motor controller.The three-phase inverter bridge consists of six power devices,which can be assembled in three forms,such as discrete device,wafer direct packaging and power module.Among them,the power module is widely used because of the advantages of low assembly technology,convenient use,safety and reliability.However,due to the size and shape of the power module has been determined,improving the power density of the core components of power conversion needs to start with optimizing the drive system,improving space utilization and saving heat dissipation space.Therefore,this paper takes the three-phase inverter bridge and its driving system based on power module as the research object,and proposes a design scheme of three-phase inverter bridge and its driving system,which integrates the radiator of power module and the radiator of driving system.Switching loss and conduction loss will occur when power module works,which is the main source of heating.It is necessary to design appropriate radiator for power module.Accurate calculation of module loss is the basis of radiator design.Therefore,based on the parameters from datasheet and operating conditions of the power module,the loss of the power module is calculated in detail,which provides a basis for the selection of devices and subsequent design.Secondly,the optimal design of the auxiliary power supply circuit in the drive system is carried out.Because the auxiliary power supply circuit supplies power for control circuit,driving circuit and so on,it is the main heating source of the system.In order to achieve good heat dissipation and improve the utilization ratio of space and components,this paper presents a separate design idea,so that the heat source in auxiliary power supply circuit can share the space of water-cooled heat sink with power module.At the same time,the parasitic inductance of connection line can be fully utilized.Finally,the power module,drive system and integrated heat dissipation system are redesigned.And the thermal simulation software FLOTHERM is used to simulate and verify,which realizes the shape optimization of heat dissipation plate and further improves the space utilization rate.Finally,the prototype is assembled according to the above design,and the experimental bench is built.The experimental results are consistent with the analysis and design,which verifies the performance of the designed three-phase inverter bridge and its drive system.