Research On The Software Decoupling Of The Force Coupling And The Control System In Active Magnetic Bearing

Active magnetic bearing (AMB) is a new high performance bearing which utilizes the controllable magnetic force to suspend the rotor without friction and lubrication. Compared with other types of bearing, AMB has many special performance: high circumference velocity, no need of lubrication and seal, no noise completely, small heat and low dissipation, good adaptation to the circumstance, automatic equilibrium, controllable precisely rotor position, high reliability. Therefore, the appearance of AMB is named a revolution of bearing technology at home and at abroad. If the AMB technology is applied to support the hard disk, the hard disk will be characterized by high precision, few heat, low dissipation, no noise and high clearness, which cannot be realized through hard disks supported by other bearings.In the design of hard disk, it is inevitable for nonlinear and mechanic-electric coupling to appear. The coupling complicates the control and brings difficulty to structure design. In addition, there are many problems in the high precision control of AMB hard disk. The main task of this paper is: decoupling theory will be applied to force coupling in AMB, the flow chart of decoupling software will be worked out to realize decoupling control. The power amplifier which acts as actuator in the AMB control system will be researched and made.In this paper, the principle of AMB was introduced simply. The control characteristics of axial single freedom AMB were analyzed. The mathematical model of six freedom AMB was made and described as the form of states space. The a order inverse system decoupling theory was introduced and was applied to the decoupling control of AMB, thus six decoupled single freedom linear son system was attained. At the same time, the flow chart of decoupling program was presented. The merits and demerits of two kinds of power amplifier were compared. The development of linear power amplifier was explored. By experiments, the static and dynamic performance of the developed linear power amplifier were given. Four kinds of switching power amplifier were compared, and the MPW power amplifier was adopted. The designed MPW power amplifier schematic circuit was given. Data and waveform indicated static and dynamic performance of the circuit.