| With the continuous improvement of Chinese industrial level,the industrial robotics industry has also seen higher requirements in terms of precision as well as adaptability.In today’s environment where the industrial field is moving to the middle and high-end level,conventional motor design can no longer meet the demand of lean production,expecting the motor to have higher torque overload capacity to meet a wider range of application scenarios and production needs while pursuing smooth operation.In this paper,a robot joint motor with rated power of 1k W and overload capacity of 5 times is required as the design target,and the optimized design method for true fractional slot motor with three-phase unbalance and motor overload capacity is analyzed and verified by finite element modeling,and the temperature field characteristics of the optimized method are analyzed and the rationality of the scheme is verified by temperature field finite element modeling.The smooth running quality of a motor is directly affected by the method of suppressing torque fluctuations and harmonics of the motor,so permanent magnet motors that require torque fluctuations are often designed to suppress them by means of fractional slot.However,for many fractional-slot motors,especially true fractional-slot motors,the problems of large and small phase bands and uneven phase splitting often lead to high second harmonic and subharmonic components.In order to take into account the advantages of low slot torque,in this paper,the winding design method of the true fractional slot motor with 12 poles and 33 slots is firstly analysed,to suppress the high harmonic components caused by the unbalanced three-phase magnetic potential and the large and small phase bands of the winding under this pole-slot combination,a new type of multi-set layer winding is proposed and designed.The design logics and characteristics of this new type of winding are also studied,utilizing inite element modeling,the electromagnetic characteristics of the new winding are analyzed and summarized.Secondly,the preliminary scheme of the motor proposed in this paper is optimized for the design of torque overload capacity at constant speed,and the mathematical model of the ultimate output torque of the table-mounted permanent magnet synchronous motor is analyzed to summarize the design parameters which have a significant influence on the ultimate output torque of the motor.In which the stator split ratio,permanent magnet thickness,air gap length and pole arc coefficient of the preliminary scheme are also optimized,and the variation law of the marginal contribution of the four parameters to the motor overload torque multiplier（SHAP value）is compared and studied.The influence law of the number of pole pairs and short pitch coefficient etc.on the motor overload capacity is studied by comparing the program output results.The effect of the new winding on the overload capacity of the motor and the electromagnetic characteristics of the optimized scheme are analyzed by combining the optimized scheme with the finite element modeling of the new multilayer set winding design.Finally,the new multi-set layer winding is proved to have the ability to reduce the temperature rise of permanent magnets by suppressing eddy current losses utilising the temperature field finite element modeling analysis of the final design.Meanwhile,higher input current is required which leads to the increase of copper loss of the motor.Since the loss distribution of the high overload motor is different from the conventional design,it is necessary to verify whether the motor permanent magnet is demagnetized and conductor temperature exceeds the insulation limit under high overload conditions within the temperature rise. |
PDF Full Text Request