Design and Control of Multicoil Active Magnetic Bearing System for High-Speed Application

Abstract

In the rotating machinery sector, active magnetic bearing (AMB) has drawn great attention due to its benefits over the conventional bearing system. The high-speed technology is enhanced by AMBs, which also reduce maintenance costs and eliminate friction loss. This paper presents a unique, simpler, efficient design and hardware implementation for high-speed applications using two-coil I-type active magnetic bearings. To maintain the 10 mm air gap between the actuator and the rotor, two categories of controllers have been designed for the proposed system to control the position and another for detecting the coil current through the power amplifier. The AMB system is incorporated into a 3D finite element model for determining magnetic properties. The magnetic analysis is then carried out under various situations, and the attractive force characteristics have been evaluated for this suggested system to check the performance of the multicoil AMB system along with the stability analysis. The system is designed and simulated in MATLAB Simulink and implemented in hardware to validate the different outputs viz. position response and current response. Finally, an AC magnet is designed to rotate the rotor after the levitation, and a higher speed of 19,643 rpm is achieved in comparison to conventional bearings, which can be utilized in different industrial applications.

Fuzzy variable gain robust control of active magnetic bearings rigid rotor system

“…In Equation (10), ΔC ec (t) represents the absolute value of the real-time eccentricity coefficient difference; ΔC eca (t) represents the AMB-a real-time eccentricity coefficient; ΔC ecb (t) represents the AMB-b real-time eccentricity coefficient.…”

“…For the problems caused by the uncertainty of the AMB system, scholars have chosen the control methods based on modern control theory to try to solve them: PID control [10,11], adaptive control [12,13], sliding mode control [14] etc. In addition, a series of robust control have strong ability to deal with system uncertainty due to their own design methods.…”

Power Amplifiers and Their Feedback Mechanisms for AMB—A Comprehensive Review

“…These amplifiers operate as high-voltage switches, utilizing transistors that rapidly switch on and off at high frequencies to convey positive and negative voltage levels. This switching action is guided by the pulse-width modulation (PWM) wave signal originating from the controller [34]. Notably, in recent times, switching power amplifiers have replaced traditional analog power amplifiers due to their enhanced performance [35].…”

“…Eddy current sensors offer a good frequency response, nearlinear characteristics, minimal phase shift, and resistance to external interference over a wide frequency range (up to 2 mm displacement). Other non-contact displacement sensors include capacitive, inductive, magnetic, optical, and laser variants [7,34]. Hall sensors, solid-state devices, produce voltage changes proportional to magnetic field density and measure magnetic flux on pole surfaces in AMB systems.…”

“…A novel technique was implemented in [33], for powering the axial AMB in a bearing less permanent magnet synchronous motor, eliminating the need for a 4quadrant chopper. An AMB system incorporating a lowcost chopper type SPA was utilized in [34] to actuate distinctive two-coil I-type structure that has been specially designed to ensure sufficient attractive force for rotor levitation while maintaining a stable position. To reduce costs, a single-switch power amplifier has been implemented.…”