| The treatment of heart failure is a common problem in the world today.The appearance of artificial heart pump provides an effective way for patients.Magnetic levitation technology has been widely used in various fields because of its advantages of non-contact and friction free.Maglev artificial heart pump has developed rapidly.It can solve the problem of hemolysis and thrombosis caused by the mechanical bearing and increase the service life and stability of the heart pump.Drive motor is the power source for artificial heart pump,and its performance directly determines the parameters of the artificial heart pump.Because artificial heart pump is the implantable medical devices,the drive motor must have the advantages of small volume,high efficiency and low power consumption.This subject is based on the research situation at home and abroad.A small size heart pump with permanent magnetic bearing and axial fluid-film bearings is designed.The axial heart pump adopt direct-drive system.A new type of permanent magnet brushless DC motor and its controller were developed for the heart pump.The motor stator is slotless structure,as far as possible to increase the space of impeller.Experiments show that the drive motor can meet the requirements of the performance index of heart pump.First,this paper summarizes the background,status and development trend of the artificial heart pump and its drive system.The advanced heart pump products at home and abroad are introduced is expounded.The characteristic and electromagnetic characteristics of slotless motor are mainly introduced.On this basis,the research method in this paper is put forward.In this paper,the parameters of the motor are designed and optimized from two aspects:the classical magnetic circuit calculation and the finite element simulation.In the magnetic circuit calculation,according to the special structure of the slotless motor,the formula of the traditional magnetic circuit calculation is modified to improve the calculation precision of the magnetic circuit design.By using the method of combining field and circuit,the magnetic field distribution,starting characteristic and loss of the motor are simulated with Ansoft finite element simulation software.The fast of magnetic circuit calculation and the high precision of finite element simulation are combined in this paper.A drive motor is designed and manufactured to meet the requirements of the heart pump.In the drive control part,Control ASIC ML4435 produced by MicroLinear Company is applied.Using sensorless control method reduce the difficulty of control and controller volume.The drive control of the motor and wide-range speed governing realized.At last,the heart pump and controller were developed successfully and its experimental study was carried out.The experimental results show that the system can achieve stable closed-loop operation,it also has the advantages of smooth rotation,low noise,and strong anti-jamming capability.According to the speed curve which is like a straight line,the system can meet the requirements of the performance index of heart pump. |
PDF Full Text Request