The Design Of High-speed Micro-motor Used In Medical Power Plant Operation

Surgical power plant is an essential medical instrument for neurosurgery, with main features of drilling, milling, grinding, etc. Surgical power plant with good overall performance can assist doctors to complete neurosurgery operation efficiently, safely, quickly and accurately. As the core component of the surgical power plant, high-speed micro-motor need to have the characteristics of high-speed, low temperature rise, being autoclavable repeatedly, etc. Therefore, high technical requirements for design and manufacture are raised. At present, the domestic power plant operation mostly adopted imported high-speed micro-motor, which impacts the development of the domestic surgical power plant.The high-speed micro-motor used in medical surgical power plant was studied in this paper. Magnetic circuit method and finite element method were used to design the electromagnet and structure of the high-speed micro-motor and the auxiliary cooling system based on micro fluidic channels were innovatively proposed. Main work of this paper includes:1) We adopted equivalent magnetic circuit method to design the structure and electromagnet of rotor and stator and designed an auxiliary cooling system for the surgical power plant. The cooling system consisted of micro fluidic cooling channels located in the stator core, external cooling channels and a cooling pump. Using ansoft rmxprt to analyze the high-speed micro-motor model, we obtained the design form and characteristics curve of high-speed micro-motor.2) We analyzed the magnetic field inside the motor applying the finite element method in the no-load and load conditions and obtained radial flux density, flux waveform, counter electromotive force, torque, phase current, core loss and other performance curves. As well as, we analyzed the influences armature reaction had on the inner magnetic field, the flux and counter electromotive force under the load condition. Simulation results indicated that the motor meet the design requirements.3) We conducted the high-speed micro-motor temperature field finite element analysis using ansys workbench platform. Results showed that the highest temperature of the motor is only 85?, and the closer to cooling channels the lower temperature is, which proved that the auxiliary cooling system had a better cooling effect.4) We drew the blueprints of the motor stator, rotor and cap, produced a motor prototype with 24 V voltage and 50000 rpm rotate speed and tested its performance. The testing results showed that its maximum no-load rotate speed was 54545 rpm, with an error of 7% compared to finite element analysis results, which verified the rationality of the design.The high-speed micro-motor with grooves and no position sensor This article proposed in this paper fundamentally achieves the requirements of the motor used in medical surgical power plant, and has engineering significances. The auxiliary cooling system is manifested can help solve the heat problem in long-term load condition through the simulation. Further research needs to be conducted in high-speed motor control system.