http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
H∞ Suboptimal Tracking Controller Design for a Class of Nonlinear Systems
Yazdan Batmani 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5
In this paper, a new technique is proposed to solve the H∞ tracking problem for a broad class of nonlinearsystems. Towards this end, based on a discounted cost function, a nonlinear two-player zero-sum differential(NTPZSD) game is defined. Then, the problem is converted to another NTPZSD game without any discount factorin its corresponding cost function. A state-dependent Riccati equation (SDRE) technique is applied to the latterNTPZSD game in order to find its approximate solution which leads to obtain a feedback-feedforward controllaw for the original game. It is proved that the tracking error between the system state and its desired trajectoryconverges asymptotically to zero under mild conditions on the discount factor. The proposed H∞ tracking controlleris applied to two nonlinear systems (the Vander Pol’s oscillator and the insulin-glucose regulatory system of type Idiabetic patients). Simulation results demonstrate that the proposed H∞ tracking controller is so effective to solvethe problem of tracking time-varying desired trajectories in nonlinear dynamical systems.
Yazdan Shirvany,Oskar Talcoth,Mikael Persson,Tonny Rubæk,Fredrik Edelvik,Stefan Jakobsson 대한의용생체공학회 2013 Biomedical Engineering Letters (BMEL) Vol.3 No.1
Purpose The aim of this paper is to evaluate the performance of an EEG source localization method that combines a finite element method (FEM) and the reciprocity theorem. Methods The reciprocity method is applied to solve the forward problem in a four-layer spherical head model for a large number of test dipoles. To benchmark the proposed method, the results are compared with an analytical solution and two state-of-the-art methods from the literature. Moreover,the dipole localization error resulting from utilizing the method in the inverse procedure for a realistic head model is investigated with respect to EEG signal noise and electrode misplacement. Results The results show approximately 3% relative error between numerically calculated potentials done by the reciprocity theorem and the analytical solutions. When adding EEG noise with SNR between 5 and 10, the mean localization error is approximately 4.3 mm. For the case with 10 mm electrode misplacement the localization error is 4.8mm. The reciprocity EEG source localization speeds up the solution of the inverse problem with more than three orders of magnitude compared to the state-of-the-art methods. Conclusions The reciprocity method has high accuracy for modeling the dipole in EEG source localization, is robust with respect to noise, and faster than alternative methods.
Yazdan, Tanveer,Kwon, Byung-il Institution of Electrical Engineers 2018 IET electric power applications Vol.12 No.7
<P>This study proposes a two-phase single-air-gap axial flux permanent magnet (AFPM) motor that offers a trapezoidal back-electromotive force (EMF) waveform to improve the performance of the only-pull drive technique compared with the radial flux PM (RFPM) motor. The only-pull drive technique provides the benefit of allowing the use of thin magnets in the motor without suffering from irreversible demagnetisation. In the proposed motor, the design geometry is primarily considered to achieve the desired trapezoidal shape of back-EMF. The effects of the geometry are explained with the help of air-gap flux density, flux linkage, and the leakage flux. Both the radial flux and the proposed motor adopt the same design concept and hold equal electromagnetic loadings. The profile of back-EMF and the electromagnetic torque driven by the only-pull drive technique are compared with that of RFPM motor with non-trapezoidal back-EMF. Furthermore, the split configuration is proposed for the AFPM motor to reduce torque ripples. The demagnetisation analysis is performed to confirm the operating point of the magnets in a split-AFPM motor. The results reveal that the AF motor is a good candidate for the only-pull drive technique.</P>
A Novel Technique for Two-Phase BLDC Motor to Avoid Demagnetization
Yazdan, Tanveer,Zhao, Wenliang,Lipo, Thomas A.,Kwon, Byung-Il IEEE 2016 IEEE transactions on magnetics Vol.52 No.7
<P>Conventional permanent magnet (PM) motors operate in both magnetizing (pull) process and reversible demagnetizing (push) process on the recoil line of magnets. Therefore, thin-surface PMs may easily undergo a risk of demagnetization at the push process under certain fault conditions, which lead to deterioration of motor performance. Thus, thick magnets, whereas contributing the significantly high cost, are usually used to minimize this risk in the PM motors. In this paper, a novel operation technique, that involves only the pull process, has been proposed for a unique design of two-phase brushless DC motor to avoid the irreversible demagnetization of the magnets. The motor, operated only in the pull process, is kept away from the push process of the operation. Therefore, the motor sustains its initial magnetic operating point above the knee point during the normal operation as well as under the short circuit fault conditions. Finite-element analysis is performed to validate the concept of the proposed technique.</P>
Dual three Phase Operation of Dual Airgap Permanent Magnet Vernier Machine Having a Yokeless Rotor
Siddiqi Mudassir Raza,Yazdan Tanveer,Humza Muhammad,Ahmad Ikhlaq,Hur Jin 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4
In order to increase the speed range of permanent magnet machines in constant power regions, diff erent techniques including multi-phase confi gurations are usually adopted. This paper presents the dual three-phase operation of a novel dual-airgap permanent magnet vernier machine having a yokeless rotor. The presented machine comprises two stators, each having a three-phase winding, and a sandwiched single yokeless rotor. The outer and inner stator windings are treated as two diff erent sets of three-phase windings to accomplish the dual three-phase operation. To achieve this, three-phase currents are supplied to these winding sets by considering two cases: (i) out-of-phase currents having the same magnitude and (ii) in-phase currents with varying magnitudes. This dual three-phase operation provides better effi ciency in the in-phase operation. The presented yokeless model has a very high mutual inductance which improves the fl ux linkage between two stators. Moreover, the harmonic analysis and open circuit fault analysis are presented to confi rm the validity of the presented dual three-phase operation compared to the three-phase operation. 2D-FEM analysis is used to investigate the performance of the presented machine for dual three-phase operation.