Development And Test Of Hardware System For Bearingless Motor Based On Dual DSPs

Bearingless asynchronous motor is a new type of motor, which combines the function ofdriving and self-levitation. It can be used in the field of aerospace, life science, new energyand high-speed spindle, due to the characteristic of working without friction, abrasion andlubrication. In this thesis, the hardware systems based on DSP for a5-DOF bearingless motoris built, and following aspects are mainly researched.The principle of bearingless motor is introduced, and the model of levitation force isgiven. Aiming at the relationship of levitation force and air-gap flux linkage of torquewindings, the principle of levitation control for bearingless motor is analyzed usingMatlab/Simulink. In the control system of torque windings, vector control and direct torquecontrol (DTC) are respectively adopted, and the air-gap flux linkage is obtained by detectingstator current and voltage. Then the levitation of rotor is realized by controlling the current oflevitation winding. On the basis of theoretical analysis, the control platform for a5-DOFbearingless motor is built. It can be got from analysis that the control of5-DOF motor can notbe achieved completely by single DSP. So two kind of control system based on DSP can beused, one is the system based on DSP and vector inverter, and the other one is the systembased on dual DSPs.For the system based on DSP and vector inverter, DSP play the role of control core, andthe inverter works as the driving unit for torque winding. The communication between DSPand inverter is achieved through CAN bus, and the air-gap flux linkage of torque windings isindirectly obtained by stator flux orientation in DSP.For the system based on Dual DSPs, the torque windings and levitation windings arecontrolled by Dual DSPs Independently. In the DSP for torque winding, DTC control methodis used, and the stator flux linkage of the two motors is calculated. After that, the air-gap fluxlinkage can be obtained using the datas of stator flux linkage, and will be transmitted to theDSP for levitation windings. Therefore, the two DSPs should collaborate to ensure the stablelevitation and speed control. The development board of dual DSPs is designed, andhigh-speed transportation of data between the dual DSPs is achieved by dual-port RAM.Besides, in order to realize the synchronous debugging of dual DSPs, the JTAG interface ofemulator is extended. Finally, the hardware system of dual DSPs is tested using the fluxlinkage datas, after the realization of the cooperative working of four groups of motors drovedby dual DSPs.