Design And Implementation Of Automotive Electronic Water Pump Controller Based On FOC Algorithm

The cooling system is an important part of the automobile engine.The operating state of the cooling system directly affects the service life and fuel economy of the automobile engine.Cooling system components mainly include:thermostat,cooling fan,water pump and so on.The function of water pump is to pressurize the coolant to ensure its circulation in the cooling system.The traditional automotive water pump is driven by the engine belt,and the speed of traditional water pump is directly coupled with the speed of engine,which can not effectively match the heat dissipation requirements.The speed of electronic water pump is dynamically adjusted by the ECU according to the actual working conditions of the engine,which can effectively improve the service life of the engine and reduce the fuel consumption of the engine.Electronic water pump has a good market prospect and it is valued by major domestic and foreign OEMs.Using PMSM(Permanent Magnet Synchronous Motor)and sensorless FOC(Field Oriented Control/Vector Control)algorithm,the thesis designed and implemented an automotive electronic water pump controller.Firstly,based on the PMSM mathematical model,the thesis derived stator voltage equation,flux linkage equation,electromagnetic torque equation,motion equation,and the thesis studied the vector control algorithm(current loop PI control,speed loop PI control,space vector pulse width modulation,etc.).Then,the thesis studied the method of PMSM rot or position acquisition and sensorless control strategy.The thesis adopted step IQ start as the open loop start strategy,and obtained the PMSM rotor position and speed information through the Luenberger observer and the phase locked loop.The thesis designed and implemented the electronic water pump controller based on PMSM and FOC algorithm.The NXP MC9S12ZVML128 chip is used as the master MCU.The system hardwares mainly include power supply circuit,MCU and peripheral circuit,PMSM drive circuit,single resistance current sampling circuit and LIN communication interface circuit.The Code Warrior development environment is used to develop the FOC control algorithm to implement the PMSM vector control function.The main software function modules include single-resistance phase current reconstruction,Clark transform,Park transform,speed loop PI control,current loop PI control,SVPWM,and speed and position estimation.Finally,the thesis tested the designed automotive electronic water pump controller,including controller startup performance test,bus current stability test,speed stability test and controller efficiency test.At the rated speed(6000 rpm),startup time is 899.90 ms,the bus current stability is 1.06%,the speed stability is 0.33%,and the controller efficiency is 94.00%.The test results show that the main performance indicators of the electronic water pump controller meet the design requirements.