The Hardware Circuit Design Of 45KW PMSM Drive System Applied To Electric Vehicle

According to statistical analysis,the proportion of China’s automobile fuel consumption will reach 67%by 2020.Therefore,the development of new energy vehicles can greatly reduce China’s dependence on imported oil and avoid large The impact of the scale energy crisis on China is of great significance to the country’s energy security and social stability.One of the key factors in the development of electric vehicles is their internal motor drive system,which is the "brain" in electric vehicles.Its performance,safety reliability and energy efficiency are crucial for the entire vehicle.Therefore,in recent years,domestic manufacturers have launched research and development of electric vehicle motor drive systems.However,the products currently on the market lack a certain degree of maturity,and they perform poorly in power density,reliability under complex conditions,and energy saving,failing to meet the requirements of automotive grades.In response to these problems,this article takes the opportunity of developing a high-power motor drive system for an electric vehicle manufacturer in China by Siemens Electric Vehicle Powertrain System Co.,Ltd.,considering the various factors,the selection of important electrical components in the motor drive system.Optimized with the circuit design to design a product that is truly suitable for automotive applications.First of all,analyze and compare the operating characteristics and advantages and disadvantages of different types of motors,and finally choose the most suitable synchronous permanent magnet motor for automobiles.In the selection of the main system components,the film material capacitor is used as the bus DC capacitor,and a series of structural optimization designs are carried out.The temperature is verified by Icepak thermal simulation,and the capacitor is miniaturized while ensuring its heat dissipation capability.Reliability;cooperated with Infineon of Germany to develop a new generation of Hybrid PACK series automotive grade IGBTs,which will increase the maximum junction temperature to 175 ℃,and use the electric field stop technology(Trench Stop Technology)to reduce the on-state loss,and the bottom of the IGBT is added.The mesh-shaped heat sink reduces thermal resistance and improves heat dissipation.Finally,the power density is increased,and the ability to output 80KW peak power in a high temperature environment is realized.Next,in the gate driving circuit,soft turn-off and two-level turn-on turn-off are designed to weaken the peak voltage,which not only reduces power loss and electromagnetic interference,but also in the case of high current and high voltage.The IGBT is protected from breakdown damage and verified by actual testing.The short circuit desaturation protection circuit,the upper and lower interlock circuit of the same bridge arm and the over temperature protection circuit of the chip are designed to enhance the reliability protection of the IGBT.In the power module switching power supply,the LLC quasi-resonant circuit is designed,and the appropriate resonant inductor Lr and resonant capacitor Cr are strictly selected to make it inductive(ZVS)state,so that the output current of the driving MOSFET of the switching power supply is sine wave,realizing soft The switching characteristics solve the switching loss and switching noise problems in the half-bridge switching power supply.At the same time,the 555 circuit outputs a hundred KHz driving signal,and the high-frequency switching power supply circuit finally realizes miniaturization.Subsequently,the Hall current detection circuit is designed to perform three-phase output current detection,the differential Hall circuit is used to eliminate common mode interference,and the detection accuracy is improved.The U-shaped magnetic sheet is used to shield the external magnetic field coupling well,and the current detection sensitivity is improved.Linearity;an isolation transmission chip with ∑-△mode-to-analog conversion is used in the bus voltage sampling circuit to improve the resolution and anti-interference ability of the entire circuit,and another redundant design ensures reliability.WCA(Worst Case Analysis)is used to verify the worst-case condition of the IGBT temperature sampling circuit by input power and component accuracy and temperature coefficient parameters to ensure high detection accuracy of the IGBT temperature sampling circuit.