| Since the 21 st century,more and more cars have been integrated into people’s lives.With the development of science and technology and the support of policies in various countries,researching advanced automotive energy management technologies and improving the performance of the entire vehicle have become a hot topic at this stage.For vehicles,the engine directly determines the performance of the entire vehicle,and the cooling system plays a crucial role in the performance of the engine.The traditional cooling method is a mechanical drive,which is directly driven by the front-end belt of the engine connected with the crankshaft.There are problems such as poor adaptability of working conditions,and difficult to match with the heat dissipation requirements of the engine.The new cooling methods mainly include hydraulic drive,motor drive and clutch drive,among which motor drive has been gradually applied to rail transit and new energy vehicles with its advantages of high efficiency and long life.Compared with asynchronous motors,the permanent magnet synchronous motor has advantages such as small size,light weight,good speed regulation performance,high power density,etc.it has been applied in the driving of cooling fan of engine cooling system.The main contents of this paper are as follows:Firstly,according to the characteristics of the load,it is determined that the permanent magnet synchronous motor driver uses a three-phase inverter main topology structure,and the space vector pulse width modulation(SVPWM)method is selected for vector control.The MCU is designed with a dedicated motor control chip TMS320F28069 M introduced by TI company.The rotary transformer-to-digital converter AU6802N1 is used to detect the motor shaft position and speed information.The PT1000 is used to sample the temperature of the cooling system.In addition,the temperature control strategy of the cooling system is studied.Considering that the engine cooling system is a multi-variable,non-linear and coupling between variables,it is difficult to establish an accurate mathematical model.The fuzzy control strategy overcomes the non-linear and time-varying problems in most systems,and does not rely on accurate mathematical models.Therefore,fuzzy control will be used to study the temperature control performance of VAV engine cooling system.Secondly,in order to reduce the energy consumption of the whole cooling system as the starting point,the energy consumption of the fan is optimized and designed,Under the premise of ensuring that the engine works at the optimal temperature in real time,the mass flow of the coolant is increased to reduce the power consumption of the fan.The mathematical model of the system is built under Maltab / Simulink for simulation and experiment.When temperature of the coolant at the engine outlet is set to 90℃,and the mass flow of the coolant is 3kg/s,both the non-linear and fuzzy control strategies can control the temperature error within 0.25℃,and the self-adjusting fuzzy control strategy has a poor temperature control effect.However,compared with the non-linear control strategy,the fuzzy control and the self-adjusting fuzzy control strategy can reduce the energy consumption of the cooling fans 24% and 33% respectively.verifying the feasibility of the energy consumption optimization strategy to improve the power utilization efficiency of the cooling system.Finally,according to the theoretical calculation of the design indexes,the scheme of 25 kW PMSM Vector driver and the schematic design of each module are completed,and the experimental results of the simulation and the prototype are tested,analyzed and summarized.It is hoped that the design of the hardware circuit and the research of the control strategy of the motor driver of the vehicle engine cooling system will have certain reference significance and reference value. |
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