Design Method For High-speed Motorized Spindle Motor Based On Analysis Of Harmonics

High-speed machining is a technology, which is representing the development trend of modern manufacturing. It not only has high efficiency, but also can improves the machining precision and surface quality significantly. Therefore, it can realizes high efficiency and precision machining for the difficult-to-machine materials and the parts of parenchyma. High-speed machine is the equipment foundation of high-speed machining. The motorized spindle is the core component of high-speed machine. To a large extent , the performance and technology level of the high-speed machine are depending on the performance of the motorized spindle. Because the motorized spindle is supplied by inverter, the actual performance is changing greatly compared with the performance of the motor supplied by sinusoidal voltage. So it is necessary to research the design method of the high-speed motorized spindle deeply.On the basis of the analysis of SPWM (Sinusoidal Pulse Wiath Modulation) modulation principle, the effect of harmonics on the efficiency , power factor and electromagnetic torque of motorized spingdle is studied deeply. The research shows that the high-order harmonics are an important factor, which makes the steady performance drop, such as the efficiency , power factor and electromagnetic torque. On the basis of the effect of high-order harmonic currents on the motorized spindle, a electromagnetic design procedures is developed for calculating the steady performance. Then, the quantitative analysis of the effect of electromagnetic parameters on the efficiency , power factor and electromagnetic torque is carried out. A practical example shows, when the effect of high-order harmonic currents is considered fully, the design method for hihg-speed motorized spindle is more accurately and more reasonable, compared to the design method for the ordinary motors supplied by sinusoidal voltage.The general electromagnetic design method for high-speed motors is only reflecting steady performance but not refrecting the dynamic performance. According to the deficiencies,a mathematical model is established including a motor , an inverter and loads. On the basis of the model, a simulation procedure for calculating the dynamic performance is developed, which is used to study different design solutions of a motorized spindle paratively, which involve winding pitch, winding type and rotor slot shape. The effect of design parameters on the dynamic performance of the motor is analyzed, especially for the ripple torque causeed by high-order harmonic currents. The research indicates it can suppress the high-order harmonic currents that cause more losses and vibration to improve the dynamic performance and the steady performance such as efficiency, power factor by optimizing electromagnetic design.Finally, the effect of working parameters on the stator current and the spectrum performance of the cureent is researched by the experiments. The results indicate that the output current of inverter is not sinusoidal. Then, a strategy is proposed that it can suppress the high-order harmonic currents to improve the steady performance and dynamic performance by optimizing the working parameters of the inverter.The research has a reference value for the electromagnetic design and the analysis of dynamic performance of induction motoried spindle.