Estudo do controle uni-axial do mancal de levitação magnética do tipo atração para potência nula (ZPC, zero power control).

Abstract

The magnetic bearing of this work is based on the 1-DOF (degree of freedom) control uni-axial magnetic circuit with hybrid-type attraction, which was developed in 2000 at the Polytechnic School, University of Sao Paulo by Silva and Horikawa [1][2]. At both ends of the rotor magnets are fixed, and in opposition are the electromagnetic actuators with ferromagnetic cores. The magnets are attracted to the actuators by the forces due to the presence of ferromagnetic cores of the two actuators. Due to competition between the magnetic forces of attraction, the rotor is confined in the central position of the axial stiffness resulting in efforts to radial. And in the axial direction, the rotor position is defined by the active control that produces the effect of magnetic levitation of the rotor. If the rotor magnetic bearing suffer efforts in the axial direction, the control system should apply more electrical current in the actuators to ensure correct positioning of the rotor, this can generate a huge power consumption. This paper studies the principle of magnetic bearing control with zero power to be applied in designing a mixed centrifugal pump, which has its rotor magnetically suspended. It is called the zero power operating condition with minimal energy consumption in the levitation of the rotor. The pump design will be used to aid blood circulation, relieving the load on the pumping of the left ventricle of the heart sick, so the pump design is called a Ventricular Assist Device (VAD). The technical needs of the DAV justify the use of magnetic bearing system and zero power control. To apply the technique of zero power control is essential that the magnetic bearing system is a hybrid. This study was developed from the magnetic bearing system developed by Silva and Horikawa [1] [2] by the similarity of the bearing properties of the DAV requests. The algorithm of zero power control (ZPC-zero power control ) was developed to provide a simple and small code without compromising the robustness of the control that the project requires the VAD. Key word: Zero Power Control. Virtual Zero Power. Ventricular assistance device. Magnetic Bearing. Bearingless. Artificial organ.