Development Of An Electronic Water Pump Controller For Passenger Cars

In response to with the increasingly severe contradiction between supply and demand of fuel and environmental problems,countries around the world are accelerating the pace of deploying new energy vehicles and promoting vehicle energy-saving technologies.The automobile electric water pump is an important part of the automotive thermal management system.It has outstanding advantages in terms of precise control of the cooling system and reduction of losses.In the case of using a water cooling system,each vehicle needs to be equipped with 2-5 electronic pumps.The assembly of automobile electric water pump has become a mainstream trend.It is estimated that by 2022,the Chinese automobile electric water pump market will exceed 5 billion.RMBThis thesis designed an electronic pump controller based on the MLX81325 main control chip for Shanghai XXX New Energy Automotive Parts Co.,Ltd.Use SVPWM algorithm to control 2-pair PMSM motor-which has 60 W maximum power,DC 12 V rated working voltage,9?16V working voltage range,4800 RPM rated speed,1000?6000RPM speed regulation range.The controller communicate ECU with PWM method,and the accuracy of signal acquisition is 1%.The automobile electric water pump has a protection function,which can effectively achieve dry running,stalling,over temperature,short circuit,open circuit,over voltage,under voltage and reverse connection protection.Fault codes can be uploaded to the ECU via the PWM bus.The EMC performance of the automobile electric water pump meets the SMTC 3 800 006-2017 standard of Shanghai Automotive Industry Corporation.The standard includes items such as Conduction Emission(CE),Radiated Emission(RE),Immunity(RS and CS),Electro-Static Discharge(ESD),transient Emission and other items.Laboratory test results show that the prototype of the automobile electric water pump meets the design indicators and meets the requirements of the project mandate.The test result of the third-party EMC laboratory shows that the standard is in compliance with the requirements of Shanghai Automotive Industry Corporation SMTC 3 800 006-2017,except a small number of individual frequency points in the AM band.It has obtained user's approval.Finally,the AM band spectrum problem is studied in this thesis,The cause of exceeding the standard is the harmonics caused by the periodicity of the PWM control signal.To solve the problem,a pulse density modulation(SDM)algorithm was studied.The SDM algorithm was used to establish a permanent magnet motor control model using simulink.The result of simulation shows that compared with the SVPWM algorithm,the SDM algorithm can effectively improve the harmonic noise in the AM band in the current spectrum.The results of this thesis have important guiding significance for the development of automobile electric water pump controllers.