CONTROL OF A BRUSHLESS DC MOTOR WITHOUT SENSORS OF POSITION TO BE APPLIED IN ARTIFICIAL CIRCULATION

The motor performance is a very important characteristic to artificial blood circulation devices that use an electrical motor such a responsible component by blood pumping, is the motor performance. The absence of brushes in a Brushless direct current (DC) motor, provides special characteristics in comparison to common motor. Therefore, it is highly recommended for that blood pumping application. However, to operate, that kind of motor it is necessary an electronic controller that needs to know the instantaneous rotor's position. Generally, this information is obtained with a set of "Hall" devices installed on the stator structure. Nevertheless, in some applications, because of the physical space available on assembly, the use of "Hall" sensors is not allowed. Further, the position of sensors makes necessary additional wires between the motor and the controller and, in case of sensor fault, whole system is committed. This work presents a method of BLDC motor drive with no sensor, called " Sensorless ", based on the detection of back electromagnetic force(BEMF). The system was tested, in a first moment, on the electric simulator PSPICE®, and then, through an implemented system in our laboratory. The obtained results were appraised and discussed according to the characteristic of some blood pumps.