Drive Motor Development For Axial-flow Magnetic-levitation Artificial Heart Pump

Maglev artificial heart pump allows the pump rotor rotating without friction and solves the problem of hemolysis and thrombosis since its unique advantages of non-contact bearing. It has been rapid developing. As drive power source, the motor's performance and size is directly related to the pump's performance and size. The continuous development and progress of maglev artificial heart pump requested that its drive motor has high efficiency, small size, light weight and so on. This thesis is based on the current study and use small, simple, integrated, axial flow maglev system structure. The motor body and its controller were developed. By experimental verification, the motor reached basic cardiac pump index requirements.In this thesis, the background, current situation and development trend of the artificial heart and brushless DC motor were reviewed first, and the drive motor's application status of the third generation maglev artificial heart pump was introduced. Permanent magnet brushless DC motor working principle and control technology without position sensor was described, and on this basis we put forward in the program and significance of this paper. This design includes two parts:1. this thesis describes in detail the magnetic circuit system and classical motor design methods and formulas. 2. with the modern field-circuit design method and finite element software ANSOFT, the magnetic field distribution and the circuit characteristics on the designed motor was simulated and calculated. As both the traditional magnetic circuit calculation of a quick and direct magnetic field calculation of high accuracy, the precision of magnetic circuit design and calculation were greatly improved, on this basis will be able to produce the required drive motor. For motor drive control part, MICRO-LINEAR company's single-chip integrated controller ML4425 was selected as the master drive controller chips. Through the closed-loop control principles and methods, the external circuitry of the chip has been optimized designed to realize motor driving and speed adjustment. Finally, the ideal waveform and speed curve was achieved after the motor speed experiments with developed ontology and drive control systems.