Design Of Sensorless BLDCM Control System Based On Kinetis

The Burshless DC Motors(BLDCM) have advantages of simple structure, highefficiency and reliable performance. But position sensors limit the uses of BLDCM due totheir high failure rate and difficult maintenance. Therefore, the development of sensorlessBLDCM technology is the research direction of BLDCM control in the future. FreescaleSemiconductor launched Kinetis E series of ARM microcontrollers with a high costperformance, and they are suitable for BLDCM control. This paper designs a controlsystem of BLDCM without position sensors using MKE02Z64VQH2which belongs toKinetis E series as core controller, realizes the operation control of BLDCM successfullyand gets the desired effect at last.Firstly, this paper summaries the research status of BLDCM and its sensorless controltechnologies, and then detailedly discusses the basic structure, operational principle andcontrol method of BLDCM. Secondly, this thesis focuses on the critical technology ofBLDCM’s sensorless control, including zero crossing detection, motor start technologyand single neuron adaptive PID control strategy, and then deeply analyzes the principle ofBEMF zero crossing detection, the way to capture zero crossing signals, and timemanagement during commutations.In the hardware part of this sensorless BLDCM control system, the paper analyzes theoverall hardware structure, MCU peripheral circuit, driver circuit, analog signal detectioncircuit, power circuit. In the part of software design, the paper analyzes the complement ofvarious control sections, including PWM modulation, sampling and computation of currentand voltage signal, software design of zero crossing detection, complement of sensorlesscommutation, motor speed calculation, system fault detection and protection. Finally, thissystem has GUI interface designed on FreeMASTER.Based on the hardware platform, the software of the control system completes the close-loop sensorless control using the BLDCM45ZWN24-40as experimental subject.And the exam results show that the control system has a good speed response and satisfiesthe requirement of the venture. This thesis can also be regarded as a successful referencedesign of Kinetis E series used in home appliance like washing machine and fridge.