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This paper considers the robust control of an active radial magnetic bearing system, having a homopolar, external rotor topology, which is used to support an annular fiber composite flywheel rim. A first-order dynamical compensator, which uses only position feedback information, is used for control, its design being based on a linearized one-dimens...
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Context 1
... dynamical mathematical model for the AMB shown in Fig. 1, can be established as follows: (1) where mass of the rotor (kg); position displacement of the rotor (m); nominal air gap (m); permeability of free space H/m; total pole-face area of each electromagnet (m ); number of turns on each electromagnet coil; electromagnet coil currents (A); an unknown disturbance (N); some known force acting on the rotor (N). When (1) is linearized at the equilibrium point, ie., and augmented with the control structure shown in Fig. 2, the linearized model is obtained as the following second-order system: Due to inaccuracies in the measurement of some of the phys- ical parameters and changing environmental conditions, the system parameters and are generally uncertain. However, without loss of generality, it can be assumed that their values lie within some known intervals where , and are known scalars ...
Context 2
... the dynamical compensator (5) is applied to the orig- inal nonlinear system (1), with a consideration of current satu- ration as in Fig. 2, the closed-loop system is if if if In order to simulate the system, the parameters and and their upper and lower bounds are determined from (2b), based on the parameter values in Table I. In order that the designed controller can tolerate sufficient parameter uncertainties, large intervals for and were chosen. The values of and , and those of the interval boundaries, and , , for both the vertical and horizontal axes, are given in Table II. Choosing , and , the coeffi- cients of the dynamical compensators are obtained as shown in Table ...
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Citations
... The AC homopolar machine is also well-known as the homopolar synchronous machine and the homopolar inductor alternator [85]. The HMs are able to offer encouraging advantages of robust rotor structure, low idling losses, improved reliability, and thus, they are noticeably attractive for long-term high-speed operation, which is essential for great importance in FESSs [85][86][87][88][89][90][91][92][93][94][95][96]. ...
Energy storage systems (ESSs) play a very important role in recent years. Flywheel is one of the oldest storage energy devices and it has several benefits. Flywheel Energy Storage System (FESS) can be applied from very small micro-satellites to huge power networks. A comprehensive review of FESS for hybrid vehicle, railway, wind power system, hybrid power generation system, power network, marine, space and other applications are presented in this paper. There are three main devices in FESS, including machine, bearing, and Power Electronic Interface (PEI). Furthermore, advantages and disadvantages all of them have been presented. In addition a brief review of new and conventional power electronic converters used in FESS, have been discussed. Finally, practical ways to develop this technology in the future are presented.
... In this work, the Wheatstone Bridge (WB) configuration for the AMBs power coil is considered [5]. A wide range of control techniques have been proposed and investigated with the aim to minimize power dissipation [6], improve dynamic response [7] or increase robustness against unknown parameters or disturbances [8]. ...
... The cost functions in (7) represent the tracking errors for each converter leg, where iDC * , ix * and iy * are the current references for the HB 1, 2 and 3 respectively. It is important to highlight that, since the input and output current of each HB are controlled to minimize the error with respect the same current reference, implementing (7) inherently minimize the cost functions in (8). The cost functions in (8) represents the unbalance on each HB currents. ...
... It is important to highlight that, since the input and output current of each HB are controlled to minimize the error with respect the same current reference, implementing (7) inherently minimize the cost functions in (8). The cost functions in (8) represents the unbalance on each HB currents. It can demonstrated that if the cost functions in (8) are kept equal to zero there is no current circulation through the three HBs (i.e. ...
Active Magnetic Bearing (AMB) technology is becoming attractive for several reasons such as high speed operations, high reliability and vibrations exemption. Moreover, AMB can behave as active vibration dampers and provide a real-time control of the shaft. For all these advantages, AMBs are particularly attractive for high power - high speed applications. These desirable features come at the cost of an increased complexity of the system, which now includes a power electronic converter and a control system dedicated to the AMBs. This paper focus on the overall system design, from the AMB design, to the power electronic converter design and control, for an AMB featuring Wheatstone bridge winding configuration. The magnetic design has been developed analytically and validated by means of Finite Elements simulation, to generate up to 2kN of axial forces. The power conversion system is based on three full bridges, one to magnetize the bearing and two to control the axial forces independently on the x and y axes. In order to achieve high bandwidth current control able to generate the desired orthogonal forces, a predictive control strategy has been proposed, for the several advantages it can provides such as fast dynamic response, no need of modulation, easy inclusion of nonlinearities and constraints of the system, possibility of incorporating nested control loops in only one loop and the flexibility to include other system requirements in the controller. The control system has been validated in Matlab/PLECS simulation, including the effect of parameters mismatches in the coils.
... vacuum and r actively con to these advan strial applicatio nergy storage f ompressors, et considers a bas t on each side o l on which the a second-ord turbances. The l described by modeled dyna [2]. To elim output feedbac rotor position s rix inequalitie mulation and de problems. ...
... the system (28) can be converted into the following equivalent state-space form: [2] ∆ ∆ ∆ 0 1 0 , ...
... where , , and are four scalar controller coefficients, to be designed, and the term is introduced to compensate for the effect of the force , the coefficient being given by [2]: ...
This paper presents a new design procedure for a robust stability, robust H<sub>infin</sub> control and robust H<sub>2</sub> control via dynamic output feedback for a class of uncertain linear systems. the uncertainties are norm bounded type. the state space matrices of the controllers are the solutions of some linear matrix inequalities problems. finally, these procedures are applied to an active radial magnetic bearing system to support a high-speed energy storage flywheel.
Finding efficient and satisfactory energy storage systems (ESSs) is one of the main concerns in the industry. Flywheel energy storage system (FESS) is one of the most satisfactory energy storage which has lots of advantages such as high efficiency, long lifetime, scalability, high power density, fast dynamic, deep charging, and discharging capability. The above features are necessary for electric vehicles (EVs), railways, renewable energy systems, and microgrids. Also, electrical machines, power electronics converters, and control systems are the cores of energy transfer in FESS. Therefore, they have a critical role in determining efficiency, power rating, power factor, cost, angular velocity, and volume of FESS. So, in this study, the FESS configuration, including the flywheel (rotor), electrical machine, power electronics converter, control system, and bearing are reviewed, individually and comprehensively. Additionally, the mentioned components have been categorized to be a guide for future research. The investigated electrical machines are compared by Finite Element Analysis (FEA). Subsequently, our laboratory’s measurement results are reviewed experimentally showing the progress in the field of FESS, such as designing robust control algorithms and an Interior Permanent Magnet-Synchronous Reluctance Machine (IPM-SynRM) to use in FESS.
A rotor system supported by active magnetic bearings (AMBs) is actually a second-order dynamical system, whose dynamical characteristics should be considered in the design process of the controller. The relationships between the dynamical parameters and the control parameters can be established by the eigenstructure assignment. Output feedback dynamical compensators (OFDCs) are proposed based on the eigenstructure assignment for an AMBs-rigid rotor system in this paper. First, the model of the four-degree-of-freedom (4-DOF) AMBs-rigid rotor system was established, and it was decoupled into two single-degree-of-freedom (S-DOF) translational sub-systems and two S-DOF rotational sub- systems through the modal decoupling method. Aiming to the control of the four S-DOF systems, the relationships among the parameters of the OFDCs, the eigenvalues, and the eigenvectors were derived based on the eigenstructure assignment. Then, a multi-objective optimization problem was constructed in which the system stability, the robustness to the bias current perturbation, and the maximum amplitudes of the unbalance displacement and control current were considered. Several Pareto solutions were obtained through NSGA-II, and different solutions were selected to compare the performance of the corresponding systems. The simulation and experimental results verify the effectiveness of the proposed OFDCs and the rationality of the proposed design process.
The active magnetic bearing system is a complex nonlinear system and the system parameters often change with time. In this paper, the adaptive control and sliding mode control are combined to establish an adaptive sliding mode controller (ASMC) which is applied to a single degree of freedom magnetic bearing controlling system. With the system parameters changing the real-time control system can change the corresponding control parameters to make the system performance always maintain the optimal or nearly optimal. The simulation model of the single degree of freedom magnetic bearing based on ASMC and an experimental platform using PC as upper computer and TMS320F2812 as hypogyny are established. The simulation and experimental results show that the ASMS not only weaken the inherent chattering in the sliding mode control, but also has better robustness and rapidity. It can meet the real-time control requirements of the magnetic bearing system.
Aimed at the magnetic bearing reaction flywheel rotor system, a novel model was proposed to describe the dynamic reaction of hybrid magnetic bearing (HMB). Based on Lagrange principle, the unbalance mass moments distributed in two planes were equivalent to the positions of two radial HMBs. Incorporated with the effect of centrifugal force caused by its principal axis of inertia, the dynamic reaction of HMB was obtained. Simulation result show that the rotation amplitude of rotor was significantly dependent on the phase difference, angular velocity and unbalance mass moment. When the values of two unbalance mass moments were equal, for the phase difference of 0, the amplitude was high, near 30μm. However, with an increase in the phase difference to π, the amplitude of rotor diminished down to 10μm. In addition, the vibration amplitude of rotor was 5μm at speed of 1000r/min, which was lower than one at speed of 5000r/min. Tests had a good agreement with the numerical simulations, which shows how to improve the precision and stability of system, by decreasing the vibration amplitude of flywheel rotor.
The axial force mathematical model of magnetic suspending switched reluctance motor (SRM) is analyzed. At aim of the serious nonlinear characteristic of suspending force, the double closed loops-based axial suspending force controller is designed. The sliding model variable-structure control based on discrete-time reaching law is applied to fulfill an accurate displacement tracking control. The inner current closed-loop forces the actual winding current following the desired current. Simulations are carried out, and the results show that the rotor displacement can quickly follow the given displacement, which verifies the proposed method. Moreover, the control system presents stable performance, due to its avoiding partial linearization.
