| The top drive drilling device is the cutting-edge technology and equipment of today ’s oil drilling.It is one of the three major technical achievements of modern drilling equipment(AC/ DC frequency conversion electric drive system and downhole bit pressurization system).As the key equipment,the top drive motor plays an important role in the efficiency and energy saving of oilfield exploitation.However,the traditional top drive motor is bulky and difficult to install,which can not meet the requirements of low speed and high torque of top drive motor.In this thesis,a new split-tooth permanent magnet vernier motor optimization design is proposed,which can eliminate the variable gear box and realize the direct drive of the top drive unit with low speed and high torque.At the same time,in order to improve the field weakening speed regulation range of this kind of motor,a hybrid excitation scheme is introduced to ensure the efficient operation ability of the top drive motor under different speed regulation conditions.The main research contents are as follows :(1)According to the application background and design requirements of the drilling top drive,the topology of the motor is determined.The advantages and disadvantages of the integer slot winding and the fractional slot winding and the electromagnetic performance of the motor under different pole-slot ratios are compared and analyzed.A 24 / 5 / 19 combination(number of modulation teeth / number of armature winding poles / number of rotor permanent magnet poles)split-tooth permanent magnet vernier motor is proposed,which is characterized by nonuniform distribution of stator modulation teeth.The parametric design and analysis of the stator and rotor of the motor are carried out,and the global optimization of the motor is carried out by genetic algorithm.The designed non-uniform split-tooth permanent magnet vernier motor is compared with the uniform split-tooth permanent magnet vernier motor to verify the multiworking harmonic characteristics of the non-uniform distribution of the modulation teeth.(2)In order to solve the magnetic flux leakage of the split-tooth permanent magnet vernier motor and improve its power density,a split-tooth stator-rotor dual-excitation permanent magnet vernier motor is proposed.The key is to embed auxiliary magnets between the stator modulation teeth.The rotor permanent magnet adopts Halbach array structure,and its key parameters are optimized by orthogonal test method,which effectively improves the torque density and power density of the motor under the same permanent magnet dosage.The electromagnetic performance of the optimized motor and the initial motor is compared and analyzed.The results show that the optimized motor has smaller flux leakage,the torque density is increased by 28.29 %,and the torque ripple is decreased by 7.4 %.At rated operation,the motor efficiency is 90 % and the power factor is 0.85,which meets the working requirements of the drilling top drive motor.(3)In order to improve the flux-weakening ability of split-tooth permanent magnet vernier motor,a split-tooth hybrid excitation permanent magnet vernier motor is proposed by combining split-tooth permanent magnet vernier motor with reluctance motor.The principle of multi-working harmonics of the motor is introduced,and the key size parameters of the stator and rotor of the motor are analyzed and designed.The finite element model is established to analyze the electromagnetic performance of the motor under different excitation currents,and the effectiveness of the magnetic adjustment principle is verified. |
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