Study On Axial Field Modulated Permanent Magnet Motor

In many industry applications, gearboxes, clutch and other mechanical transmission mechanism are used in drive electrical transmission systems. However the presence of the mechanical transmission mechanism reduces the reliability and efficiency of the system. Low speed high torque direct drive system can increase the efficiency in many industry applications, hence is also one of the development directions of the electrical drives t. Field-modulated motor is derived from the concept of magnet gears with the field-modulation principle. It is suitable for low speed and high torque direct drive applications.The principle of field modulation is introduced and is verified with the finite element method. Then, an axial-field-modulated motor is proposed designed and optimized. According to the optimization results, a prototype is fabricated. Finally, a test bench is built, and experiments of no-load, load and stall are carried out. The purpose of principle verification, experimental system fabrication and control strategy study is achieved.In addition, according to the feature of field-modulated motor, a novel rotor position detection method for sensorless control of field-modulation permanent-magnet brushless motor is proposed. Instead of using the traditional position sensor such as encoder and resolver, two special sensor windings are installed in the stator slots. The novel method has been studied in thesis and verified with3-D finite element method. The simulation results show that the method is effective and feasible.