Design Of High-speed Brushless DC Motor Control System Based On F28035

Due to the excellent features of high power density, simple control, high-speed permanentmagnet brushless DC motor has great application in areas such as the aerospace. Thus, the full digitalcontrol platform is adopted to study the following problems related to BLDC motor control.Since the motor cannot start without position sensors at standstill or low speed, an improvedthree-stage start method is proposed. The proposed starting method adopts constant current frequencyacceleration strategy and achieves soft start of motor. Moreover, research of middle and high speedsensorless technology based on coordinate transformation is performed. Three-phase terminal voltageof coordinate transformation algorithm is sampled and passed through a RC filter. The sine wave isconstructed which contains only fundamental wave of back EMF and its zero crossing is exactly thecommutating point. The proposed method can adjust rotating degree of three-phase coordinate so as tocompensate phase delay caused by RC filter in real-time. Sensorless control of full speed range issuccessfully realized.Regulating speed by means of adjusting output voltage of Buck converter is studied. Buckconverter undertakes the task of speed regulation and three-phase inverter is specialized forcommutation of motor. Three-phase interleaved technology of Buck circuits adopting peak currentcontrol is employed to increase the power density of the whole system. A single chip of DSP28035can achieve both analog and digital control of the system in real-time with three analog comparators.In MATLAB/Simulink software environment, the model based on speed closed-loop control andposition sensorless control is established and simulation results testify the correctness of theory above.Finally, implementation scheme on software and hardware of the system and debuggingprocessis introduced. Experimental results verify the validityof the proposed algorithmof system. Thesystem presented a good dynamic and static performance, which lays the foundation for further studyof the high-speed BLDC motor control system.