Study On New Winding Structure Of Permanent Magnet Motor For Automobile Application

Permanent magnet direct current(PMDC)motor uses permanent magnet material as the magnetic field excitation of the motor.Compared with electrical excitation motor,there exists better process because there is no field winding and tolerance of the air gap is less sensitive to performance.Replacing windings with permanent magnets also improves the efficiency of the motor.Above all,PMDC motor has better mechanical properties and speed adjustment performance.Because of these advantages,PMDC motor is widely used in automotive industry.The number of PMDC motor in a car has become an indicator of the advanced nature of the car as an ordinary car has at least 30 sets of PMDC motor.The development of both automobile industry and PMDC motors is inseparable.According to both the layout characteristics and the future development trend of the car,PMDC motor used in automobiles is required to be more compact design,higher efficiency,better manufacturability,and lower cost.In this paper,a new winding structure can be applied to PMDC motors of automobiles by analyzing the overlap and saving quantity of the end windings compared to the traditional one.The proposed structure is similar as the concentrated winding structure used in AC machines.The coils are directly wound on single tooth.By using this new winding,improve the comprehensive advantages of motor in volume,efficiency,manufacturability,and the cost.By the study on the new winding structure,author found that not all the PMDM motor based on the new winding structure has the above advantages.Therefore,this paper summarizes the key points which need to be particularly paid attention to the design.Furthermore the new winding structure is illustrated with some practical applications,such as 6 slots,4 poles,12 segments of the commutator and 4 brushes PMDC motor in order to validate the new winding theory.In order to show the application prospects of the new winding structure used in Automobiles,a 10 slots,6 poles,20 segments of the commutator and 2 brushes PMDC motor was designed and used in the engine cooling fan motor.The benchmark motor is used in the cooling fan system of VW and DPCA which are famous in the automobiles.The experiment proved that the copper volume is reduced 46%,the efficiency is raised 2.5%,the housing diameter is reduced from 111 mm to 72.67 mm,the thickness of the rotor lamination core is reduced from 17.5mm to 13.5mm compared to the benchmark motor.Therefore,the results have shown that the designed PMDC motor is more compact design,higher efficiency,and lower costs.In the process of the study on the new winding structure of PMDC motor,the author applied the numerical calculation method based on EXCEL(EXCEL MATHCAD)to design the structure of the new motor,including calculations of the loss,the heat,the volume of copper winding and iron core,and the mechanical characteristics.The experimental results show that this method can meet the requirements of engineering design,and can effectively reduce the pre-development period of permanent magnet motor and improve the successful opportunities of the automobile system.Finally,this paper presents the new winding technology and EXCEL MATHCAD numerical calculation method,which can help the domestic automobile motor enterprises promote their core competitiveness and provide a new solution for developing PMDC motors.