Implantable Left Ventricular Assist Pump Control System Development

Heart disease has become a threat to human life, Left ventricular assist device (LVAD) as a primary means of treating heart disease, has been widespread attention to the medical profession at home and abroad.This article discussed the current situation and development trend of the implantable LVAD, briefly introduced the implantable LVAD performance requirements and structural design, Selected Sensorless Brushless DC (BLDC) Motor drive control system as blood pump control methods. Studied the method of rotor position detection and starting control as well as the speed control strategy, designed relevant hardware circuits and control software accord to the Control algorithm. The hardware circuit was included by power supply circuit, driver circuit, protection circuit and Back-EMF zero-crossing detection circuit. Control software was included by the main program design and the design of the subprogram, the main program mainly to initialize the various function modules and realized the motor start-stop control. The subprogram was composed of ADC interrupt subroutines, commutation interrupt routines and the design of PID controller. At the same time the size of the stator coil and the distance between the stator and rotor all have a great impact on back-EMF, After a number of experiments, found the best installation location of the stator coils, thus ensured the accuracy and stability of the control system.In order to solve the problem of temperature rise of the motor, optimized the motor back EMF zero-crossing detection algorithm, commutation algorithm and the motor starting curve, At the same time through the matlab simulation and motor Debugging, at last resolved the problem of motor temperature rise.This paper uses the double closed-loop control, which is the current loop and speed loop. Set up the relevant control model, as the existence of integral saturation phenomenon in the PID control system, we joined the Anti-windup module.Finally, the experimental data and analysis results show that the design of the control system is able to meet the requirement of the left ventricular assist device with high precision control, stability operation, load capability, as well as little heat.