A Controller Design for an Axial Flow Blood Pump Based on Back-EMF without Delay

The article mainly focused on the design of the control system based on C8051F330 to control the speed of an axial flow blood pump. On one hand the terminal voltage comparison was used to recognize the rotor position; on the other hand in order to capture the edge of position signal, the external interrupt0 of the MCU was used that can reduce the interference that came from the axial flow blood pump. The results of the experiment showed that the phase differences of the position signals were 60 electrical degrees, which coincide with the classical theory, Back-EMF crossing-zero sensing method. And the periodic time of the position signal was about 6.7ms, the corresponding speed was 8,955RPM that nearly equal to the reference speed 9,000RPM. Therefore the result demonstrated that by utilizing this control system the blood pump could be driven steplessly without bounce or losing step. The control system had the following advantages: small volume, simple structure, high reliability, favorable speed performance, and low power consumption. Hence, this control system was qualified for the axial flow blood pump.